Do not use index if no limit or limit + offset > expected tuples unless enable_seqscan = off

2026-07-22 20:15:46 +08:00 · 2024-01-20 17:16:42 -08:00
33 changed files with 943 additions and 1470 deletions
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,6 +20,8 @@ jobs:
            os: ubuntu-20.04
          - postgres: 12
            os: ubuntu-20.04
+          - postgres: 11
+            os: ubuntu-20.04
    steps:
      - uses: actions/checkout@v4
      - uses: ankane/setup-postgres@v1
@@ -57,10 +59,10 @@ jobs:
      - run: |
          brew install cpanm
          cpanm --notest IPC::Run
-          wget -q https://github.com/postgres/postgres/archive/refs/tags/REL_14_10.tar.gz
-          tar xf REL_14_10.tar.gz
-      - run: make prove_installcheck PROVE_FLAGS="-I ./postgres-REL_14_10/src/test/perl" PERL5LIB="/Users/runner/perl5/lib/perl5"
-      - run: make clean && /usr/local/opt/llvm@15/bin/scan-build --status-bugs make PG_CFLAGS="-DUSE_ASSERT_CHECKING"
+          wget -q https://github.com/postgres/postgres/archive/refs/tags/REL_14_5.tar.gz
+          tar xf REL_14_5.tar.gz
+      - run: make prove_installcheck PROVE_FLAGS="-I ./postgres-REL_14_5/src/test/perl" PERL5LIB="/Users/runner/perl5/lib/perl5"
+      - run: make clean && /usr/local/opt/llvm@15/bin/scan-build --status-bugs make
  windows:
    runs-on: windows-latest
    if: ${{ !startsWith(github.ref_name, 'mac') }}
@@ -81,10 +83,10 @@ jobs:
    if: ${{ !startsWith(github.ref_name, 'mac') && !startsWith(github.ref_name, 'windows') }}
    runs-on: ubuntu-latest
    container:
-      image: debian:12
+      image: debian:11
      options: --platform linux/386
    steps:
-      - run: apt-get update && apt-get install -y build-essential git libipc-run-perl postgresql-15 postgresql-server-dev-15 sudo
+      - run: apt-get update && apt-get install -y build-essential git libipc-run-perl postgresql-13 postgresql-server-dev-13 sudo
      - run: service postgresql start
      - run: |
          git clone https://github.com/${{ github.repository }}.git pgvector
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,22 +1,11 @@
-## 0.6.1 (unreleased)
+## 0.5.2 (unreleased)

- Fixed error with `ANALYZE` and vectors with different dimensions
-
-## 0.6.0 (2024-01-29)
-
-If upgrading with Postgres 12 or Docker, see [these notes](https://github.com/pgvector/pgvector#060).
-
- Added support for parallel index builds for HNSW
- Added validation for GUC parameters
- Changed storage for vector from `extended` to `external`
 - Improved performance of HNSW
+- Added support for on-disk parallel index builds for HNSW
 - Reduced memory usage for HNSW index builds
 - Reduced WAL generation for HNSW index builds
 - Fixed error with logical replication
- Fixed `invalid memory alloc request size` error with HNSW index builds
- Moved Docker image to `pgvector` org
- Added Docker tags for each supported version of Postgres
- Dropped support for Postgres 11
+- Fixed `invalid memory alloc request size` error with HNSW index build

 ## 0.5.1 (2023-10-10)

@@ -64,7 +53,7 @@ If upgrading with Postgres 12 or Docker, see [these notes](https://github.com/pg

 ## 0.4.0 (2023-01-11)

-If upgrading with Postgres < 13, see [this note](https://github.com/pgvector/pgvector/blob/v0.4.0/README.md#040).
+If upgrading with Postgres < 13, see [this note](https://github.com/pgvector/pgvector#040).

 - Changed text representation for vector elements to match `real`
 - Changed storage for vector from `plain` to `extended`
@@ -81,7 +70,7 @@ If upgrading with Postgres < 13, see [this note](https://github.com/pgvector/pgv

 ## 0.3.1 (2022-11-02)

-If upgrading from 0.2.7 or 0.3.0, [recreate](https://github.com/pgvector/pgvector/blob/v0.3.1/README.md#031) all `ivfflat` indexes after upgrading to ensure all data is indexed.
+If upgrading from 0.2.7 or 0.3.0, [recreate](https://github.com/pgvector/pgvector#031) all `ivfflat` indexes after upgrading to ensure all data is indexed.

 - Fixed issue with inserts silently corrupting `ivfflat` indexes (introduced in 0.2.7)
 - Fixed segmentation fault with index creation when lists > 6500
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-ARG PG_MAJOR=16
+ARG PG_MAJOR=15
 FROM postgres:$PG_MAJOR
 ARG PG_MAJOR

--- a/META.json
+++ b/META.json
@@ -2,7 +2,7 @@
 	"name": "vector",
 	"abstract": "Open-source vector similarity search for Postgres",
 	"description": "Supports L2 distance, inner product, and cosine distance",
-	"version": "0.6.0",
+	"version": "0.5.1",
 	"maintainer": [
 		"Andrew Kane <andrew@ankane.org>"
 	],
@@ -12,7 +12,7 @@
 	"prereqs": {
 		"runtime": {
 			"requires": {
-				"PostgreSQL": "12.0.0"
+				"PostgreSQL": "11.0.0"
 			}
 		}
 	},
@@ -20,7 +20,7 @@
 		"vector": {
 			"file": "sql/vector.sql",
 			"docfile": "README.md",
-			"version": "0.6.0",
+			"version": "0.5.1",
 			"abstract": "Open-source vector similarity search for Postgres"
 		}
 	},
--- a/12
+++ b/12
@@ -1,5 +1,5 @@
 EXTENSION = vector
-EXTVERSION = 0.6.0
+EXTVERSION = 0.5.1

 MODULE_big = vector
 DATA = $(wildcard sql/*--*.sql)
@@ -65,17 +65,13 @@ dist:
 	mkdir -p dist
 	git archive --format zip --prefix=$(EXTENSION)-$(EXTVERSION)/ --output dist/$(EXTENSION)-$(EXTVERSION).zip master

-# for Docker
-PG_MAJOR ?= 16
-
 .PHONY: docker

 docker:
-	docker build --pull --no-cache --build-arg PG_MAJOR=$(PG_MAJOR) -t pgvector/pgvector:pg$(PG_MAJOR) .
-	docker build --build-arg PG_MAJOR=$(PG_MAJOR) -t pgvector/pgvector:$(EXTVERSION)-pg$(PG_MAJOR) .
+	docker build --pull --no-cache --platform linux/amd64 -t ankane/pgvector:latest .

 .PHONY: docker-release

 docker-release:
-	docker buildx build --push --pull --no-cache --platform linux/amd64,linux/arm64 --build-arg PG_MAJOR=$(PG_MAJOR) -t pgvector/pgvector:pg$(PG_MAJOR) .
-	docker buildx build --push --platform linux/amd64,linux/arm64 --build-arg PG_MAJOR=$(PG_MAJOR) -t pgvector/pgvector:$(EXTVERSION)-pg$(PG_MAJOR) .
+	docker buildx build --push --pull --no-cache --platform linux/amd64,linux/arm64 -t ankane/pgvector:latest .
+	docker buildx build --push --platform linux/amd64,linux/arm64 -t ankane/pgvector:v$(EXTVERSION) .
--- a/Makefile.win
+++ b/Makefile.win
@@ -1,5 +1,5 @@
 EXTENSION = vector
-EXTVERSION = 0.6.0
+EXTVERSION = 0.5.1

 OBJS = src\hnsw.obj src\hnswbuild.obj src\hnswinsert.obj src\hnswscan.obj src\hnswutils.obj src\hnswvacuum.obj src\ivfbuild.obj src\ivfflat.obj src\ivfinsert.obj src\ivfkmeans.obj src\ivfscan.obj src\ivfutils.obj src\ivfvacuum.obj src\vector.obj
 HEADERS = src\vector.h
--- a/README.md
+++ b/README.md
@@ -14,13 +14,11 @@ Plus [ACID](https://en.wikipedia.org/wiki/ACID) compliance, point-in-time recove

 ## Installation

-### Linux and Mac
-
-Compile and install the extension (supports Postgres 12+)
+Compile and install the extension (supports Postgres 11+)

 ```sh
 cd /tmp
-git clone --branch v0.6.0 https://github.com/pgvector/pgvector.git
+git clone --branch v0.5.1 https://github.com/pgvector/pgvector.git
 cd pgvector
 make
 make install # may need sudo
@@ -30,28 +28,6 @@ See the [installation notes](#installation-notes) if you run into issues

 You can also install it with [Docker](#docker), [Homebrew](#homebrew), [PGXN](#pgxn), [APT](#apt), [Yum](#yum), or [conda-forge](#conda-forge), and it comes preinstalled with [Postgres.app](#postgresapp) and many [hosted providers](#hosted-postgres). There are also instructions for [GitHub Actions](https://github.com/pgvector/setup-pgvector).

-### Windows
-
-Ensure [C++ support in Visual Studio](https://learn.microsoft.com/en-us/cpp/build/building-on-the-command-line?view=msvc-170#download-and-install-the-tools) is installed, and run:
-
-```cmd
-call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
-```
-
-Note: The exact path will vary depending on your Visual Studio version and edition
-
-Then use `nmake` to build:
-
-```cmd
-set "PGROOT=C:\Program Files\PostgreSQL\16"
-git clone --branch v0.6.0 https://github.com/pgvector/pgvector.git
-cd pgvector
-nmake /F Makefile.win
-nmake /F Makefile.win install
-```
-
-You can also install it with [Docker](#docker) or [conda-forge](#conda-forge).
-
 ## Getting Started

 Enable the extension (do this once in each database where you want to use it)
@@ -264,14 +240,6 @@ HINT:  Increase maintenance_work_mem to speed up builds.

 Note: Do not set `maintenance_work_mem` so high that it exhausts the memory on the server

-Starting with 0.6.0, you can also speed up index creation by increasing the number of parallel workers (2 by default)
-
-```sql
-SET max_parallel_maintenance_workers = 7; -- plus leader
-```
-
-For a large number of workers, you may also need to increase `max_parallel_workers` (8 by default)
-
 ### Indexing Progress

 Check [indexing progress](https://www.postgresql.org/docs/current/progress-reporting.html#CREATE-INDEX-PROGRESS-REPORTING) with Postgres 12+
@@ -430,15 +398,6 @@ To speed up queries with an IVFFlat index, increase the number of inverted lists
 CREATE INDEX ON items USING ivfflat (embedding vector_l2_ops) WITH (lists = 1000);
 ```

-## Vacuuming
-
-Vacuuming can take a while for HNSW indexes. Speed it up by reindexing first.
-
-```sql
-REINDEX INDEX CONCURRENTLY index_name;
-VACUUM table_name;
-```
-
 ## Languages

 Use pgvector from any language with a Postgres client. You can even generate and store vectors in one language and query them in another.
@@ -656,24 +615,44 @@ Note: Replace `16` with your Postgres server version

 If compilation fails and the output includes `warning: no such sysroot directory` on Mac, reinstall Xcode Command Line Tools.

+### Windows
+
+Support for Windows is currently experimental. Ensure [C++ support in Visual Studio](https://learn.microsoft.com/en-us/cpp/build/building-on-the-command-line?view=msvc-170#download-and-install-the-tools) is installed, and run:
+
+```cmd
+call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
+```
+
+Note: The exact path will vary depending on your Visual Studio version and edition
+
+Then use `nmake` to build:
+
+```cmd
+set "PGROOT=C:\Program Files\PostgreSQL\16"
+git clone --branch v0.5.1 https://github.com/pgvector/pgvector.git
+cd pgvector
+nmake /F Makefile.win
+nmake /F Makefile.win install
+```
+
 ## Additional Installation Methods

 ### Docker

-Get the [Docker image](https://hub.docker.com/r/pgvector/pgvector) with:
+Get the [Docker image](https://hub.docker.com/r/ankane/pgvector) with:

 ```sh
-docker pull pgvector/pgvector:pg16
+docker pull ankane/pgvector
 ```

-This adds pgvector to the [Postgres image](https://hub.docker.com/_/postgres) (replace `16` with your Postgres server version, and run it the same way).
+This adds pgvector to the [Postgres image](https://hub.docker.com/_/postgres) (run it the same way).

 You can also build the image manually:

 ```sh
-git clone --branch v0.6.0 https://github.com/pgvector/pgvector.git
+git clone --branch v0.5.1 https://github.com/pgvector/pgvector.git
 cd pgvector
-docker build --build-arg PG_MAJOR=16 -t myuser/pgvector .
+docker build --build-arg PG_MAJOR=15 -t myuser/pgvector .
 ```

 ### Homebrew
@@ -750,32 +729,28 @@ SELECT extversion FROM pg_extension WHERE extname = 'vector';

 ## Upgrade Notes

-### 0.6.0
+### 0.4.0

-#### Postgres 12
-
-If upgrading with Postgres 12, remove this line from `sql/vector--0.5.1--0.6.0.sql`:
+If upgrading with Postgres < 13, remove this line from `sql/vector--0.3.2--0.4.0.sql`:

 ```sql
-ALTER TYPE vector SET (STORAGE = external);
+ALTER TYPE vector SET (STORAGE = extended);
 ```

 Then run `make install` and `ALTER EXTENSION vector UPDATE;`.

-#### Docker
+### 0.3.1

-The Docker image is now published in the `pgvector` org, and there are tags for each supported version of Postgres (rather than a `latest` tag).
+If upgrading from 0.2.7 or 0.3.0, recreate all `ivfflat` indexes after upgrading to ensure all data is indexed.

-```sh
-docker pull pgvector/pgvector:pg16
-# or
-docker pull pgvector/pgvector:0.6.0-pg16
-```
+```sql
+-- Postgres 12+
+REINDEX INDEX CONCURRENTLY index_name;

-Also, if you’ve increased `maintenance_work_mem`, make sure `--shm-size` is at least that size to avoid an error with parallel HNSW index builds.
-
-```sh
-docker run --shm-size=1g ...
+-- Postgres < 12
+CREATE INDEX CONCURRENTLY temp_name ON table USING ivfflat (column opclass);
+DROP INDEX CONCURRENTLY index_name;
+ALTER INDEX temp_name RENAME TO index_name;
 ```

 ## Thanks
@@ -822,7 +797,7 @@ To run single tests:

 ```sh
 make installcheck REGRESS=functions                    # regression test
-make prove_installcheck PROVE_TESTS=test/t/001_ivfflat_wal.pl  # TAP test
+make prove_installcheck PROVE_TESTS=test/t/001_wal.pl  # TAP test
 ```

 To enable benchmarking:
--- a/sql/vector--0.5.1--0.6.0.sql
+++ b/sql/vector--0.5.1--0.6.0.sql
@@ -1,5 +0,0 @@
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
-\echo Use "ALTER EXTENSION vector UPDATE TO '0.6.0'" to load this file. \quit
-
-- remove this single line for Postgres < 13
-ALTER TYPE vector SET (STORAGE = external);
--- a/sql/vector.sql
+++ b/sql/vector.sql
@@ -26,7 +26,7 @@ CREATE TYPE vector (
 	TYPMOD_IN = vector_typmod_in,
 	RECEIVE   = vector_recv,
 	SEND      = vector_send,
-	STORAGE   = external
+	STORAGE   = extended
 );

 -- functions
--- a/src/hnsw.c
+++ b/src/hnsw.c
@@ -4,57 +4,25 @@
 #include <math.h>

 #include "access/amapi.h"
-#include "access/reloptions.h"
-#include "commands/progress.h"
 #include "commands/vacuum.h"
 #include "hnsw.h"
 #include "utils/guc.h"
 #include "utils/selfuncs.h"

-#if PG_VERSION_NUM < 150000
-#define MarkGUCPrefixReserved(x) EmitWarningsOnPlaceholders(x)
+#if PG_VERSION_NUM >= 120000
+#include "commands/progress.h"
 #endif

 int			hnsw_ef_search;
-int			hnsw_lock_tranche_id;
+bool		hnsw_enable_parallel_build;
 static relopt_kind hnsw_relopt_kind;

-/*
- * Assign a tranche ID for our LWLocks. This only needs to be done by one
- * backend, as the tranche ID is remembered in shared memory.
- *
- * This shared memory area is very small, so we just allocate it from the
- * "slop" that PostgreSQL reserves for small allocations like this. If
- * this grows bigger, we should use a shmem_request_hook and
- * RequestAddinShmemSpace() to pre-reserve space for this.
- */
-static void
-HnswInitLockTranche(void)
-{
-	int		   *tranche_ids;
-	bool		found;
-
-	LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
-	tranche_ids = ShmemInitStruct("hnsw LWLock ids",
-								  sizeof(int) * 1,
-								  &found);
-	if (!found)
-		tranche_ids[0] = LWLockNewTrancheId();
-	hnsw_lock_tranche_id = tranche_ids[0];
-	LWLockRelease(AddinShmemInitLock);
-
-	/* Per-backend registration of the tranche ID */
-	LWLockRegisterTranche(hnsw_lock_tranche_id, "HnswBuild");
-}
-
 /*
 * Initialize index options and variables
 */
 void
 HnswInit(void)
 {
-	HnswInitLockTranche();
-
 	hnsw_relopt_kind = add_reloption_kind();
 	add_int_reloption(hnsw_relopt_kind, "m", "Max number of connections",
 					  HNSW_DEFAULT_M, HNSW_MIN_M, HNSW_MAX_M
@@ -73,12 +41,16 @@ HnswInit(void)
 							"Valid range is 1..1000.", &hnsw_ef_search,
 							HNSW_DEFAULT_EF_SEARCH, HNSW_MIN_EF_SEARCH, HNSW_MAX_EF_SEARCH, PGC_USERSET, 0, NULL, NULL, NULL);

-	MarkGUCPrefixReserved("hnsw");
+	/* Behind a variable for now since can be slower than building in memory */
+	DefineCustomBoolVariable("hnsw.enable_parallel_build", "Enables or disables building indexes in parallel",
+							 NULL, &hnsw_enable_parallel_build,
+							 false, PGC_USERSET, 0, NULL, NULL, NULL);
 }

 /*
 * Get the name of index build phase
 */
+#if PG_VERSION_NUM >= 120000
 static char *
 hnswbuildphasename(int64 phasenum)
 {
@@ -92,6 +64,7 @@ hnswbuildphasename(int64 phasenum)
 			return NULL;
 	}
 }
+#endif

 /*
 * Estimate the cost of an index scan
@@ -106,6 +79,9 @@ hnswcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	int			m;
 	int			entryLevel;
 	Relation	index;
+#if PG_VERSION_NUM < 120000
+	List	   *qinfos;
+#endif

 	/* Never use index without order */
 	if (path->indexorderbys == NULL)
@@ -118,6 +94,20 @@ hnswcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		return;
 	}

+	/*
+	 * Do not use index if no limit or limit + offset > ef_search unless
+	 * enable_seqscan = off
+	 */
+	if (root->limit_tuples < 0 || root->limit_tuples > hnsw_ef_search)
+	{
+		*indexStartupCost = 1.0e10 - 1;
+		*indexTotalCost = 1.0e10 - 1;
+		*indexSelectivity = 0;
+		*indexCorrelation = 0;
+		*indexPages = 0;
+		return;
+	}
+
 	MemSet(&costs, 0, sizeof(costs));

 	index = index_open(path->indexinfo->indexoid, NoLock);
@@ -131,7 +121,12 @@ hnswcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	/* Account for number of tuples (or entry level), m, and ef_search */
 	costs.numIndexTuples = (entryLevel + 2) * m;

+#if PG_VERSION_NUM >= 120000
 	genericcostestimate(root, path, loop_count, &costs);
+#else
+	qinfos = deconstruct_indexquals(path);
+	genericcostestimate(root, path, loop_count, qinfos, &costs);
+#endif

 	/* Use total cost since most work happens before first tuple is returned */
 	*indexStartupCost = costs.indexTotalCost;
@@ -225,7 +220,9 @@ hnswhandler(PG_FUNCTION_ARGS)
 	amroutine->amcostestimate = hnswcostestimate;
 	amroutine->amoptions = hnswoptions;
 	amroutine->amproperty = NULL;	/* TODO AMPROP_DISTANCE_ORDERABLE */
+#if PG_VERSION_NUM >= 120000
 	amroutine->ambuildphasename = hnswbuildphasename;
+#endif
 	amroutine->amvalidate = hnswvalidate;
 #if PG_VERSION_NUM >= 140000
 	amroutine->amadjustmembers = NULL;
--- a/src/hnsw.h
+++ b/src/hnsw.h
@@ -3,17 +3,21 @@

 #include "postgres.h"

-#include "access/genam.h"
+#include "access/generic_xlog.h"
 #include "access/parallel.h"
-#include "lib/pairingheap.h"
+#include "access/reloptions.h"
+#include "lib/ilist.h"
 #include "nodes/execnodes.h"
 #include "port.h"				/* for random() */
-#include "utils/relptr.h"
 #include "utils/sampling.h"
 #include "vector.h"

+#if PG_VERSION_NUM < 110000
+#error "Requires PostgreSQL 11+"
+#endif
+
 #if PG_VERSION_NUM < 120000
-#error "Requires PostgreSQL 12+"
+#include "access/relscan.h"
 #endif

 #define HNSW_MAX_DIM 2000
@@ -60,13 +64,10 @@
 #define PROGRESS_HNSW_PHASE_LOAD		2

 #define HNSW_MAX_SIZE (BLCKSZ - MAXALIGN(SizeOfPageHeaderData) - MAXALIGN(sizeof(HnswPageOpaqueData)) - sizeof(ItemIdData))
-#define HNSW_TUPLE_ALLOC_SIZE BLCKSZ

 #define HNSW_ELEMENT_TUPLE_SIZE(size)	MAXALIGN(offsetof(HnswElementTupleData, data) + (size))
 #define HNSW_NEIGHBOR_TUPLE_SIZE(level, m)	MAXALIGN(offsetof(HnswNeighborTupleData, indextids) + ((level) + 2) * (m) * sizeof(ItemPointerData))

-#define HNSW_NEIGHBOR_ARRAY_SIZE(lm)	(offsetof(HnswNeighborArray, items) + sizeof(HnswCandidate) * (lm))
-
 #define HnswPageGetOpaque(page)	((HnswPageOpaque) PageGetSpecialPointer(page))
 #define HnswPageGetMeta(page)	((HnswMetaPageData *) PageGetContents(page))

@@ -95,62 +96,33 @@
 /* Ensure fits on page and in uint8 */
 #define HnswGetMaxLevel(m) Min(((BLCKSZ - MAXALIGN(SizeOfPageHeaderData) - MAXALIGN(sizeof(HnswPageOpaqueData)) - offsetof(HnswNeighborTupleData, indextids) - sizeof(ItemIdData)) / (sizeof(ItemPointerData)) / (m)) - 2, 255)

-#define HnswGetValue(base, element) PointerGetDatum(HnswPtrAccess(base, (element)->value))
-
-#if PG_VERSION_NUM < 140005
-#define relptr_offset(rp) ((rp).relptr_off - 1)
-#endif
-
-/* Pointer macros */
-#define HnswPtrAccess(base, hp) ((base) == NULL ? (hp).ptr : relptr_access(base, (hp).relptr))
-#define HnswPtrStore(base, hp, value) ((base) == NULL ? (void) ((hp).ptr = (value)) : (void) relptr_store(base, (hp).relptr, value))
-#define HnswPtrIsNull(base, hp) ((base) == NULL ? (hp).ptr == NULL : relptr_is_null((hp).relptr))
-#define HnswPtrEqual(base, hp1, hp2) ((base) == NULL ? (hp1).ptr == (hp2).ptr : relptr_offset((hp1).relptr) == relptr_offset((hp2).relptr))
-
-/* For code paths dedicated to each type */
-#define HnswPtrPointer(hp) (hp).ptr
-#define HnswPtrOffset(hp) relptr_offset((hp).relptr)
+#define HnswGetNeighbors(element, lc) (AssertMacro((element)->level >= (lc)), &(element)->neighbors[lc])

 /* Variables */
 extern int	hnsw_ef_search;
-extern int	hnsw_lock_tranche_id;
-
-typedef struct HnswElementData HnswElementData;
-typedef struct HnswNeighborArray HnswNeighborArray;
-
-#define HnswPtrDeclare(type, relptrtype, ptrtype) \
-	relptr_declare(type, relptrtype); \
-	typedef union { type *ptr; relptrtype relptr; } ptrtype;
-
-/* Pointers that can be absolute or relative */
-/* Use char for DatumPtr so works with Pointer */
-HnswPtrDeclare(HnswElementData, HnswElementRelptr, HnswElementPtr);
-HnswPtrDeclare(HnswNeighborArray, HnswNeighborArrayRelptr, HnswNeighborArrayPtr);
-HnswPtrDeclare(HnswNeighborArrayPtr, HnswNeighborsRelptr, HnswNeighborsPtr);
-HnswPtrDeclare(char, DatumRelptr, DatumPtr);
+extern bool hnsw_enable_parallel_build;

 typedef struct HnswElementData
 {
-	HnswElementPtr next;
+	slist_node	next;
 	ItemPointerData heaptids[HNSW_HEAPTIDS];
 	uint8		heaptidsLength;
 	uint8		level;
 	uint8		deleted;
 	uint32		hash;
-	HnswNeighborsPtr neighbors;
+	struct HnswNeighborArray *neighbors;
 	BlockNumber blkno;
 	OffsetNumber offno;
 	OffsetNumber neighborOffno;
 	BlockNumber neighborPage;
-	DatumPtr	value;
-	LWLock		lock;
+	Datum		value;
 }			HnswElementData;

 typedef HnswElementData * HnswElement;

 typedef struct HnswCandidate
 {
-	HnswElementPtr element;
+	HnswElement element;
 	float		distance;
 	bool		closer;
 }			HnswCandidate;
@@ -159,7 +131,7 @@ typedef struct HnswNeighborArray
 {
 	int			length;
 	bool		closerSet;
-	HnswCandidate items[FLEXIBLE_ARRAY_MEMBER];
+	HnswCandidate *items;
 }			HnswNeighborArray;

 typedef struct HnswPairingHeapNode
@@ -178,31 +150,27 @@ typedef struct HnswOptions

 typedef struct HnswGraph
 {
-	/* Graph state */
-	slock_t		lock;
-	HnswElementPtr head;
-	double		indtuples;
-
-	/* Entry state */
-	LWLock		entryLock;
-	HnswElementPtr entryPoint;
-
-	/* Allocations state */
-	LWLock		allocatorLock;
+	slist_head	elements;
+	HnswElement entryPoint;
 	long		memoryUsed;
 	long		memoryTotal;
-
-	/* Flushed state */
-	LWLock		flushLock;
 	bool		flushed;
+	double		indtuples;
 }			HnswGraph;

+typedef struct HnswSpool
+{
+	Relation	heap;
+	Relation	index;
+}			HnswSpool;
+
 typedef struct HnswShared
 {
 	/* Immutable state */
 	Oid			heaprelid;
 	Oid			indexrelid;
 	bool		isconcurrent;
+	int			scantuplesortstates;

 	/* Worker progress */
 	ConditionVariable workersdonecv;
@@ -214,10 +182,16 @@ typedef struct HnswShared
 	int			nparticipantsdone;
 	double		reltuples;
 	HnswGraph	graphData;
+
+#if PG_VERSION_NUM < 120000
+	ParallelHeapScanDescData heapdesc;	/* must come last */
+#endif
 }			HnswShared;

+#if PG_VERSION_NUM >= 120000
 #define ParallelTableScanFromHnswShared(shared) \
 	(ParallelTableScanDesc) ((char *) (shared) + BUFFERALIGN(sizeof(HnswShared)))
+#endif

 typedef struct HnswLeader
 {
@@ -225,15 +199,8 @@ typedef struct HnswLeader
 	int			nparticipanttuplesorts;
 	HnswShared *hnswshared;
 	Snapshot	snapshot;
-	char	   *hnswarea;
 }			HnswLeader;

-typedef struct HnswAllocator
-{
-	void	   *(*alloc) (Size size, void *state);
-	void	   *state;
-}			HnswAllocator;
-
 typedef struct HnswBuildState
 {
 	/* Info */
@@ -266,12 +233,10 @@ typedef struct HnswBuildState
 	/* Memory */
 	MemoryContext graphCtx;
 	MemoryContext tmpCtx;
-	HnswAllocator allocator;

 	/* Parallel builds */
 	HnswLeader *hnswleader;
 	HnswShared *hnswshared;
-	char	   *hnswarea;
 }			HnswBuildState;

 typedef struct HnswMetaPageData
@@ -370,24 +335,23 @@ bool		HnswNormValue(FmgrInfo *procinfo, Oid collation, Datum *value, Vector * re
 Buffer		HnswNewBuffer(Relation index, ForkNumber forkNum);
 void		HnswInitPage(Buffer buf, Page page);
 void		HnswInit(void);
-List	   *HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement);
+List	   *HnswSearchLayer(Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement);
 HnswElement HnswGetEntryPoint(Relation index);
 void		HnswGetMetaPageInfo(Relation index, int *m, HnswElement * entryPoint);
-void	   *HnswAlloc(HnswAllocator * allocator, Size size);
-HnswElement HnswInitElement(char *base, ItemPointer tid, int m, double ml, int maxLevel, HnswAllocator * alloc);
+HnswElement HnswInitElement(ItemPointer tid, int m, double ml, int maxLevel);
 HnswElement HnswInitElementFromBlock(BlockNumber blkno, OffsetNumber offno);
-void		HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint, Relation index, FmgrInfo *procinfo, Oid collation, int m, int efConstruction, bool existing);
-HnswCandidate *HnswEntryCandidate(char *base, HnswElement em, Datum q, Relation rel, FmgrInfo *procinfo, Oid collation, bool loadVec);
+void		HnswInsertElement(HnswElement element, HnswElement entryPoint, Relation index, FmgrInfo *procinfo, Oid collation, int m, int efConstruction, bool existing);
+HnswCandidate *HnswEntryCandidate(HnswElement em, Datum q, Relation rel, FmgrInfo *procinfo, Oid collation, bool loadVec);
 void		HnswUpdateMetaPage(Relation index, int updateEntry, HnswElement entryPoint, BlockNumber insertPage, ForkNumber forkNum, bool building);
-void		HnswSetNeighborTuple(char *base, HnswNeighborTuple ntup, HnswElement e, int m);
+void		HnswSetNeighborTuple(HnswNeighborTuple ntup, HnswElement e, int m);
 void		HnswAddHeapTid(HnswElement element, ItemPointer heaptid);
-void		HnswInitNeighbors(char *base, HnswElement element, int m, HnswAllocator * alloc);
-bool		HnswInsertTupleOnDisk(Relation index, Datum value, Datum *values, bool *isnull, ItemPointer heap_tid, bool building);
-void		HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting, bool building);
+void		HnswInitNeighbors(HnswElement element, int m);
+bool		HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid, Relation heapRel, bool building);
+void		HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting, bool building);
 void		HnswLoadElementFromTuple(HnswElement element, HnswElementTuple etup, bool loadHeaptids, bool loadVec);
 void		HnswLoadElement(HnswElement element, float *distance, Datum *q, Relation index, FmgrInfo *procinfo, Oid collation, bool loadVec);
-void		HnswSetElementTuple(char *base, HnswElementTuple etup, HnswElement element);
-void		HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm, int lc, int *updateIdx, Relation index, FmgrInfo *procinfo, Oid collation);
+void		HnswSetElementTuple(HnswElementTuple etup, HnswElement element);
+void		HnswUpdateConnection(HnswElement element, HnswCandidate * hc, int m, int lc, int *updateIdx, Relation index, FmgrInfo *procinfo, Oid collation);
 void		HnswLoadNeighbors(HnswElement element, Relation index, int m);
 PGDLLEXPORT void HnswParallelBuildMain(dsm_segment *seg, shm_toc *toc);

@@ -407,16 +371,6 @@ void		hnswrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys,
 bool		hnswgettuple(IndexScanDesc scan, ScanDirection dir);
 void		hnswendscan(IndexScanDesc scan);

-static inline HnswNeighborArray *
-HnswGetNeighbors(char *base, HnswElement element, int lc)
-{
-	HnswNeighborArrayPtr *neighborList = HnswPtrAccess(base, element->neighbors);
-
-	Assert(element->level >= lc);
-
-	return HnswPtrAccess(base, neighborList[lc]);
-}
-
 /* Hash tables */
 typedef struct TidHashEntry
 {
@@ -444,17 +398,4 @@ typedef struct PointerHashEntry
 #define SH_DECLARE
 #include "lib/simplehash.h"

-typedef struct OffsetHashEntry
-{
-	Size		offset;
-	char		status;
-}			OffsetHashEntry;
-
-#define SH_PREFIX offsethash
-#define SH_ELEMENT_TYPE OffsetHashEntry
-#define SH_KEY_TYPE Size
-#define SH_SCOPE extern
-#define SH_DECLARE
-#include "lib/simplehash.h"
-
 #endif
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
--- a/src/hnswinsert.c
+++ b/src/hnswinsert.c
@@ -2,7 +2,6 @@

 #include <math.h>

-#include "access/generic_xlog.h"
 #include "hnsw.h"
 #include "storage/bufmgr.h"
 #include "storage/lmgr.h"
@@ -117,7 +116,7 @@ HnswInsertAppendPage(Relation index, Buffer *nbuf, Page *npage, GenericXLogState
 * Add to element and neighbor pages
 */
 static void
-AddElementOnDisk(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *updatedInsertPage, bool building)
+WriteNewElementPages(Relation index, HnswElement e, int m, BlockNumber insertPage, BlockNumber *updatedInsertPage, bool building)
 {
 	Buffer		buf;
 	Page		page;
@@ -135,10 +134,9 @@ AddElementOnDisk(Relation index, HnswElement e, int m, BlockNumber insertPage, B
 	OffsetNumber freeOffno = InvalidOffsetNumber;
 	OffsetNumber freeNeighborOffno = InvalidOffsetNumber;
 	BlockNumber newInsertPage = InvalidBlockNumber;
-	char	   *base = NULL;

 	/* Calculate sizes */
-	etupSize = HNSW_ELEMENT_TUPLE_SIZE(VARSIZE_ANY(HnswPtrAccess(base, e->value)));
+	etupSize = HNSW_ELEMENT_TUPLE_SIZE(VARSIZE_ANY(DatumGetPointer(e->value)));
 	ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(e->level, m);
 	combinedSize = etupSize + ntupSize + sizeof(ItemIdData);
 	maxSize = HNSW_MAX_SIZE;
@@ -146,11 +144,11 @@ AddElementOnDisk(Relation index, HnswElement e, int m, BlockNumber insertPage, B

 	/* Prepare element tuple */
 	etup = palloc0(etupSize);
-	HnswSetElementTuple(base, etup, e);
+	HnswSetElementTuple(etup, e);

 	/* Prepare neighbor tuple */
 	ntup = palloc0(ntupSize);
-	HnswSetNeighborTuple(base, ntup, e, m);
+	HnswSetNeighborTuple(ntup, e, m);

 	/* Find a page (or two if needed) to insert the tuples */
 	for (;;)
@@ -340,14 +338,12 @@ ConnectionExists(HnswElement e, HnswNeighborTuple ntup, int startIdx, int lm)
 * Update neighbors
 */
 void
-HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting, bool building)
+HnswUpdateNeighborPages(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement e, int m, bool checkExisting, bool building)
 {
-	char	   *base = NULL;
-
 	for (int lc = e->level; lc >= 0; lc--)
 	{
 		int			lm = HnswGetLayerM(m, lc);
-		HnswNeighborArray *neighbors = HnswGetNeighbors(base, e, lc);
+		HnswNeighborArray *neighbors = HnswGetNeighbors(e, lc);

 		for (int i = 0; i < neighbors->length; i++)
 		{
@@ -355,15 +351,16 @@ HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, Hns
 			Buffer		buf;
 			Page		page;
 			GenericXLogState *state;
+			ItemId		itemid;
 			HnswNeighborTuple ntup;
+			Size		ntupSize;
 			int			idx = -1;
 			int			startIdx;
-			HnswElement neighborElement = HnswPtrAccess(base, hc->element);
-			OffsetNumber offno = neighborElement->neighborOffno;
+			OffsetNumber offno = hc->element->neighborOffno;

 			/* Get latest neighbors since they may have changed */
 			/* Do not lock yet since selecting neighbors can take time */
-			HnswLoadNeighbors(neighborElement, index, m);
+			HnswLoadNeighbors(hc->element, index, m);

 			/*
 			 * Could improve performance for vacuuming by checking neighbors
@@ -373,14 +370,14 @@ HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, Hns
 			 */

 			/* Select neighbors */
-			HnswUpdateConnection(NULL, e, hc, lm, lc, &idx, index, procinfo, collation);
+			HnswUpdateConnection(e, hc, lm, lc, &idx, index, procinfo, collation);

 			/* New element was not selected as a neighbor */
 			if (idx == -1)
 				continue;

 			/* Register page */
-			buf = ReadBuffer(index, neighborElement->neighborPage);
+			buf = ReadBuffer(index, hc->element->neighborPage);
 			LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
 			if (building)
 			{
@@ -394,10 +391,12 @@ HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, Hns
 			}

 			/* Get tuple */
-			ntup = (HnswNeighborTuple) PageGetItem(page, PageGetItemId(page, offno));
+			itemid = PageGetItemId(page, offno);
+			ntup = (HnswNeighborTuple) PageGetItem(page, itemid);
+			ntupSize = ItemIdGetLength(itemid);

 			/* Calculate index for update */
-			startIdx = (neighborElement->level - lc) * m;
+			startIdx = (hc->element->level - lc) * m;

 			/* Check for existing connection */
 			if (checkExisting && ConnectionExists(e, ntup, startIdx, lm))
@@ -423,9 +422,13 @@ HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, Hns
 			{
 				ItemPointer indextid = &ntup->indextids[idx];

-				/* Update neighbor on the buffer */
+				/* Update neighbor */
 				ItemPointerSet(indextid, e->blkno, e->offno);

+				/* Overwrite tuple */
+				if (!PageIndexTupleOverwrite(page, offno, (Item) ntup, ntupSize))
+					elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
+
 				/* Commit */
 				if (building)
 					MarkBufferDirty(buf);
@@ -444,12 +447,14 @@ HnswUpdateNeighborsOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, Hns
 * Add a heap TID to an existing element
 */
 static bool
-AddDuplicateOnDisk(Relation index, HnswElement element, HnswElement dup, bool building)
+HnswAddDuplicate(Relation index, HnswElement element, HnswElement dup, bool building)
 {
 	Buffer		buf;
 	Page		page;
 	GenericXLogState *state;
+	ItemId		itemid;
 	HnswElementTuple etup;
+	Size		etupSize;
 	int			i;

 	/* Read page */
@@ -467,7 +472,9 @@ AddDuplicateOnDisk(Relation index, HnswElement element, HnswElement dup, bool bu
 	}

 	/* Find space */
-	etup = (HnswElementTuple) PageGetItem(page, PageGetItemId(page, dup->offno));
+	itemid = PageGetItemId(page, dup->offno);
+	etup = (HnswElementTuple) PageGetItem(page, itemid);
+	etupSize = ItemIdGetLength(itemid);
 	for (i = 0; i < HNSW_HEAPTIDS; i++)
 	{
 		if (!ItemPointerIsValid(&etup->heaptids[i]))
@@ -483,9 +490,13 @@ AddDuplicateOnDisk(Relation index, HnswElement element, HnswElement dup, bool bu
 		return false;
 	}

-	/* Add heap TID, modifying the tuple on the page directly */
+	/* Add heap TID */
 	etup->heaptids[i] = element->heaptids[0];

+	/* Overwrite tuple */
+	if (!PageIndexTupleOverwrite(page, dup->offno, (Item) etup, etupSize))
+		elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
+
 	/* Commit */
 	if (building)
 		MarkBufferDirty(buf);
@@ -500,23 +511,19 @@ AddDuplicateOnDisk(Relation index, HnswElement element, HnswElement dup, bool bu
 * Find duplicate element
 */
 static bool
-FindDuplicateOnDisk(Relation index, HnswElement element, bool building)
+HnswFindDuplicate(Relation index, HnswElement element, bool building)
 {
-	char	   *base = NULL;
-	HnswNeighborArray *neighbors = HnswGetNeighbors(base, element, 0);
-	Datum		value = HnswGetValue(base, element);
+	HnswNeighborArray *neighbors = HnswGetNeighbors(element, 0);

 	for (int i = 0; i < neighbors->length; i++)
 	{
 		HnswCandidate *neighbor = &neighbors->items[i];
-		HnswElement neighborElement = HnswPtrAccess(base, neighbor->element);
-		Datum		neighborValue = HnswGetValue(base, neighborElement);

 		/* Exit early since ordered by distance */
-		if (!datumIsEqual(value, neighborValue, false, -1))
+		if (!datumIsEqual(element->value, neighbor->element->value, false, -1))
 			return false;

-		if (AddDuplicateOnDisk(index, element, neighborElement, building))
+		if (HnswAddDuplicate(index, element, neighbor->element, building))
 			return true;
 	}

@@ -524,26 +531,26 @@ FindDuplicateOnDisk(Relation index, HnswElement element, bool building)
 }

 /*
- * Update graph on disk
+ * Write changes to disk
 */
 static void
-UpdateGraphOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement element, int m, int efConstruction, HnswElement entryPoint, bool building)
+WriteElement(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement element, int m, int efConstruction, HnswElement entryPoint, bool building)
 {
 	BlockNumber newInsertPage = InvalidBlockNumber;

 	/* Look for duplicate */
-	if (FindDuplicateOnDisk(index, element, building))
+	if (HnswFindDuplicate(index, element, building))
 		return;

-	/* Add element */
-	AddElementOnDisk(index, element, m, GetInsertPage(index), &newInsertPage, building);
+	/* Write element and neighbor tuples */
+	WriteNewElementPages(index, element, m, GetInsertPage(index), &newInsertPage, building);

 	/* Update insert page if needed */
 	if (BlockNumberIsValid(newInsertPage))
 		HnswUpdateMetaPage(index, 0, NULL, newInsertPage, MAIN_FORKNUM, building);

 	/* Update neighbors */
-	HnswUpdateNeighborsOnDisk(index, procinfo, collation, element, m, false, building);
+	HnswUpdateNeighborPages(index, procinfo, collation, element, m, false, building);

 	/* Update entry point if needed */
 	if (entryPoint == NULL || element->level > entryPoint->level)
@@ -554,8 +561,10 @@ UpdateGraphOnDisk(Relation index, FmgrInfo *procinfo, Oid collation, HnswElement
 * Insert a tuple into the index
 */
 bool
-HnswInsertTupleOnDisk(Relation index, Datum value, Datum *values, bool *isnull, ItemPointer heap_tid, bool building)
+HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid, Relation heapRel, bool building)
 {
+	Datum		value;
+	FmgrInfo   *normprocinfo;
 	HnswElement entryPoint;
 	HnswElement element;
 	int			m;
@@ -563,7 +572,17 @@ HnswInsertTupleOnDisk(Relation index, Datum value, Datum *values, bool *isnull,
 	FmgrInfo   *procinfo = index_getprocinfo(index, 1, HNSW_DISTANCE_PROC);
 	Oid			collation = index->rd_indcollation[0];
 	LOCKMODE	lockmode = ShareLock;
-	char	   *base = NULL;
+
+	/* Detoast once for all calls */
+	value = PointerGetDatum(PG_DETOAST_DATUM(values[0]));
+
+	/* Normalize if needed */
+	normprocinfo = HnswOptionalProcInfo(index, HNSW_NORM_PROC);
+	if (normprocinfo != NULL)
+	{
+		if (!HnswNormValue(normprocinfo, collation, &value, NULL))
+			return false;
+	}

 	/*
 	 * Get a shared lock. This allows vacuum to ensure no in-flight inserts
@@ -576,8 +595,8 @@ HnswInsertTupleOnDisk(Relation index, Datum value, Datum *values, bool *isnull,
 	HnswGetMetaPageInfo(index, &m, &entryPoint);

 	/* Create an element */
-	element = HnswInitElement(base, heap_tid, m, HnswGetMl(m), HnswGetMaxLevel(m), NULL);
-	HnswPtrStore(base, element->value, DatumGetPointer(value));
+	element = HnswInitElement(heap_tid, m, HnswGetMl(m), HnswGetMaxLevel(m));
+	element->value = value;

 	/* Prevent concurrent inserts when likely updating entry point */
 	if (entryPoint == NULL || element->level > entryPoint->level)
@@ -593,11 +612,11 @@ HnswInsertTupleOnDisk(Relation index, Datum value, Datum *values, bool *isnull,
 		entryPoint = HnswGetEntryPoint(index);
 	}

-	/* Find neighbors for element */
-	HnswFindElementNeighbors(base, element, entryPoint, index, procinfo, collation, m, efConstruction, false);
+	/* Insert element in graph */
+	HnswInsertElement(element, entryPoint, index, procinfo, collation, m, efConstruction, false);

-	/* Update graph on disk */
-	UpdateGraphOnDisk(index, procinfo, collation, element, m, efConstruction, entryPoint, building);
+	/* Write to disk */
+	WriteElement(index, procinfo, collation, element, m, efConstruction, entryPoint, building);

 	/* Release lock */
 	UnlockPage(index, HNSW_UPDATE_LOCK, lockmode);
@@ -605,30 +624,6 @@ HnswInsertTupleOnDisk(Relation index, Datum value, Datum *values, bool *isnull,
 	return true;
 }

-/*
- * Insert a tuple into the index
- */
-static void
-HnswInsertTuple(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid)
-{
-	Datum		value;
-	FmgrInfo   *normprocinfo;
-	Oid			collation = index->rd_indcollation[0];
-
-	/* Detoast once for all calls */
-	value = PointerGetDatum(PG_DETOAST_DATUM(values[0]));
-
-	/* Normalize if needed */
-	normprocinfo = HnswOptionalProcInfo(index, HNSW_NORM_PROC);
-	if (normprocinfo != NULL)
-	{
-		if (!HnswNormValue(normprocinfo, collation, &value, NULL))
-			return;
-	}
-
-	HnswInsertTupleOnDisk(index, value, values, isnull, heap_tid, false);
-}
-
 /*
 * Insert a tuple into the index
 */
@@ -655,7 +650,7 @@ hnswinsert(Relation index, Datum *values, bool *isnull, ItemPointer heap_tid,
 	oldCtx = MemoryContextSwitchTo(insertCtx);

 	/* Insert tuple */
-	HnswInsertTuple(index, values, isnull, heap_tid);
+	HnswInsertTuple(index, values, isnull, heap_tid, heap, false);

 	/* Delete memory context */
 	MemoryContextSwitchTo(oldCtx);
--- a/src/hnswscan.c
+++ b/src/hnswscan.c
@@ -21,7 +21,6 @@ GetScanItems(IndexScanDesc scan, Datum q)
 	List	   *w;
 	int			m;
 	HnswElement entryPoint;
-	char	   *base = NULL;

 	/* Get m and entry point */
 	HnswGetMetaPageInfo(index, &m, &entryPoint);
@@ -29,15 +28,15 @@ GetScanItems(IndexScanDesc scan, Datum q)
 	if (entryPoint == NULL)
 		return NIL;

-	ep = list_make1(HnswEntryCandidate(base, entryPoint, q, index, procinfo, collation, false));
+	ep = list_make1(HnswEntryCandidate(entryPoint, q, index, procinfo, collation, false));

 	for (int lc = entryPoint->level; lc >= 1; lc--)
 	{
-		w = HnswSearchLayer(base, q, ep, 1, lc, index, procinfo, collation, m, false, NULL);
+		w = HnswSearchLayer(q, ep, 1, lc, index, procinfo, collation, m, false, NULL);
 		ep = w;
 	}

-	return HnswSearchLayer(base, q, ep, hnsw_ef_search, 0, index, procinfo, collation, m, false, NULL);
+	return HnswSearchLayer(q, ep, hnsw_ef_search, 0, index, procinfo, collation, m, false, NULL);
 }

 /*
@@ -185,24 +184,26 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)

 	while (list_length(so->w) > 0)
 	{
-		char	   *base = NULL;
 		HnswCandidate *hc = llast(so->w);
-		HnswElement element = HnswPtrAccess(base, hc->element);
 		ItemPointer heaptid;

 		/* Move to next element if no valid heap TIDs */
-		if (element->heaptidsLength == 0)
+		if (hc->element->heaptidsLength == 0)
 		{
 			so->w = list_delete_last(so->w);
 			continue;
 		}

-		heaptid = &element->heaptids[--element->heaptidsLength];
+		heaptid = &hc->element->heaptids[--hc->element->heaptidsLength];

 		MemoryContextSwitchTo(oldCtx);

+#if PG_VERSION_NUM >= 120000
 		scan->xs_heaptid = *heaptid;
-		scan->xs_recheck = false;
+#else
+		scan->xs_ctup.t_self = *heaptid;
+#endif
+
 		scan->xs_recheckorderby = false;
 		return true;
 	}
--- a/src/hnswutils.c
+++ b/src/hnswutils.c
@@ -2,13 +2,9 @@

 #include <math.h>

-#include "access/generic_xlog.h"
 #include "hnsw.h"
-#include "lib/pairingheap.h"
 #include "storage/bufmgr.h"
 #include "utils/datum.h"
-#include "utils/memdebug.h"
-#include "utils/rel.h"
 #include "vector.h"

 #if PG_VERSION_NUM >= 130000
@@ -60,6 +56,13 @@ hash_tid(ItemPointerData tid)
 #define SH_DEFINE
 #include "lib/simplehash.h"

+/* Needed to include simplehash.h twice */
+#if PG_VERSION_NUM < 120000
+#undef SH_EQUAL
+#define sh_log2 pointerhash_sh_log2
+#define sh_pow2 pointerhash_sh_pow2
+#endif
+
 /* Pointer hash table */
 static uint32
 hash_pointer(uintptr_t ptr)
@@ -81,31 +84,9 @@ hash_pointer(uintptr_t ptr)
 #define SH_DEFINE
 #include "lib/simplehash.h"

-/* Offset hash table */
-static uint32
-hash_offset(Size offset)
-{
-#if SIZEOF_SIZE_T == 8
-	return murmurhash64((uint64) offset);
-#else
-	return murmurhash32((uint32) offset);
-#endif
-}
-
-#define SH_PREFIX		offsethash
-#define SH_ELEMENT_TYPE	OffsetHashEntry
-#define SH_KEY_TYPE		Size
-#define	SH_KEY			offset
-#define SH_HASH_KEY(tb, key)	hash_offset(key)
-#define SH_EQUAL(tb, a, b)		(a == b)
-#define	SH_SCOPE		extern
-#define SH_DEFINE
-#include "lib/simplehash.h"
-
 typedef union
 {
 	pointerhash_hash *pointers;
-	offsethash_hash *offsets;
 	tidhash_hash *tids;
 }			visited_hash;

@@ -203,53 +184,35 @@ HnswInitPage(Buffer buf, Page page)
 	HnswPageGetOpaque(page)->page_id = HNSW_PAGE_ID;
 }

-/*
- * Allocate a neighbor array
- */
-static HnswNeighborArray *
-HnswInitNeighborArray(int lm, HnswAllocator * allocator)
-{
-	HnswNeighborArray *a = HnswAlloc(allocator, HNSW_NEIGHBOR_ARRAY_SIZE(lm));
-
-	a->length = 0;
-	a->closerSet = false;
-	return a;
-}
-
 /*
 * Allocate neighbors
 */
 void
-HnswInitNeighbors(char *base, HnswElement element, int m, HnswAllocator * allocator)
+HnswInitNeighbors(HnswElement element, int m)
 {
 	int			level = element->level;
-	HnswNeighborArrayPtr *neighborList = (HnswNeighborArrayPtr *) HnswAlloc(allocator, sizeof(HnswNeighborArrayPtr) * (level + 1));

-	HnswPtrStore(base, element->neighbors, neighborList);
+	element->neighbors = palloc(sizeof(HnswNeighborArray) * (level + 1));

 	for (int lc = 0; lc <= level; lc++)
-		HnswPtrStore(base, neighborList[lc], HnswInitNeighborArray(HnswGetLayerM(m, lc), allocator));
-}
-
-/*
- * Allocate memory from the allocator
- */
-void *
-HnswAlloc(HnswAllocator * allocator, Size size)
 	{
-	if (allocator)
-		return (*(allocator)->alloc) (size, (allocator)->state);
+		HnswNeighborArray *a;
+		int			lm = HnswGetLayerM(m, lc);

-	return palloc(size);
+		a = &element->neighbors[lc];
+		a->length = 0;
+		a->items = palloc(sizeof(HnswCandidate) * lm);
+		a->closerSet = false;
+	}
 }

 /*
 * Allocate an element
 */
 HnswElement
-HnswInitElement(char *base, ItemPointer heaptid, int m, double ml, int maxLevel, HnswAllocator * allocator)
+HnswInitElement(ItemPointer heaptid, int m, double ml, int maxLevel)
 {
-	HnswElement element = HnswAlloc(allocator, sizeof(HnswElementData));
+	HnswElement element = palloc(sizeof(HnswElementData));

 	int			level = (int) (-log(RandomDouble()) * ml);

@@ -263,9 +226,9 @@ HnswInitElement(char *base, ItemPointer heaptid, int m, double ml, int maxLevel,
 	element->level = level;
 	element->deleted = 0;

-	HnswInitNeighbors(base, element, m, allocator);
+	HnswInitNeighbors(element, m);

-	HnswPtrStore(base, element->value, (Pointer) NULL);
+	element->value = PointerGetDatum(NULL);

 	return element;
 }
@@ -286,12 +249,11 @@ HnswElement
 HnswInitElementFromBlock(BlockNumber blkno, OffsetNumber offno)
 {
 	HnswElement element = palloc(sizeof(HnswElementData));
-	char	   *base = NULL;

 	element->blkno = blkno;
 	element->offno = offno;
-	HnswPtrStore(base, element->neighbors, (HnswNeighborArrayPtr *) NULL);
-	HnswPtrStore(base, element->value, (Pointer) NULL);
+	element->neighbors = NULL;
+	element->value = PointerGetDatum(NULL);
 	return element;
 }

@@ -316,10 +278,7 @@ HnswGetMetaPageInfo(Relation index, int *m, HnswElement * entryPoint)
 	if (entryPoint != NULL)
 	{
 		if (BlockNumberIsValid(metap->entryBlkno))
-		{
 			*entryPoint = HnswInitElementFromBlock(metap->entryBlkno, metap->entryOffno);
-			(*entryPoint)->level = metap->entryLevel;
-		}
 		else
 			*entryPoint = NULL;
 	}
@@ -404,10 +363,8 @@ HnswUpdateMetaPage(Relation index, int updateEntry, HnswElement entryPoint, Bloc
 * Set element tuple, except for neighbor info
 */
 void
-HnswSetElementTuple(char *base, HnswElementTuple etup, HnswElement element)
+HnswSetElementTuple(HnswElementTuple etup, HnswElement element)
 {
-	Pointer		valuePtr = HnswPtrAccess(base, element->value);
-
 	etup->type = HNSW_ELEMENT_TUPLE_TYPE;
 	etup->level = element->level;
 	etup->deleted = 0;
@@ -418,14 +375,14 @@ HnswSetElementTuple(char *base, HnswElementTuple etup, HnswElement element)
 		else
 			ItemPointerSetInvalid(&etup->heaptids[i]);
 	}
-	memcpy(&etup->data, valuePtr, VARSIZE_ANY(valuePtr));
+	memcpy(&etup->data, DatumGetPointer(element->value), VARSIZE_ANY(DatumGetPointer(element->value)));
 }

 /*
 * Set neighbor tuple
 */
 void
-HnswSetNeighborTuple(char *base, HnswNeighborTuple ntup, HnswElement e, int m)
+HnswSetNeighborTuple(HnswNeighborTuple ntup, HnswElement e, int m)
 {
 	int			idx = 0;

@@ -433,7 +390,7 @@ HnswSetNeighborTuple(char *base, HnswNeighborTuple ntup, HnswElement e, int m)

 	for (int lc = e->level; lc >= 0; lc--)
 	{
-		HnswNeighborArray *neighbors = HnswGetNeighbors(base, e, lc);
+		HnswNeighborArray *neighbors = HnswGetNeighbors(e, lc);
 		int			lm = HnswGetLayerM(m, lc);

 		for (int i = 0; i < lm; i++)
@@ -443,9 +400,8 @@ HnswSetNeighborTuple(char *base, HnswNeighborTuple ntup, HnswElement e, int m)
 			if (i < neighbors->length)
 			{
 				HnswCandidate *hc = &neighbors->items[i];
-				HnswElement hce = HnswPtrAccess(base, hc->element);

-				ItemPointerSet(indextid, hce->blkno, hce->offno);
+				ItemPointerSet(indextid, hc->element->blkno, hc->element->offno);
 			}
 			else
 				ItemPointerSetInvalid(indextid);
@@ -461,14 +417,12 @@ HnswSetNeighborTuple(char *base, HnswNeighborTuple ntup, HnswElement e, int m)
 static void
 LoadNeighborsFromPage(HnswElement element, Relation index, Page page, int m)
 {
-	char	   *base = NULL;
-
 	HnswNeighborTuple ntup = (HnswNeighborTuple) PageGetItem(page, PageGetItemId(page, element->neighborOffno));
 	int			neighborCount = (element->level + 2) * m;

 	Assert(HnswIsNeighborTuple(ntup));

-	HnswInitNeighbors(base, element, m, NULL);
+	HnswInitNeighbors(element, m);

 	/* Ensure expected neighbors */
 	if (ntup->count != neighborCount)
@@ -494,9 +448,9 @@ LoadNeighborsFromPage(HnswElement element, Relation index, Page page, int m)
 		if (level < 0)
 			level = 0;

-		neighbors = HnswGetNeighbors(base, element, level);
+		neighbors = HnswGetNeighbors(element, level);
 		hc = &neighbors->items[neighbors->length++];
-		HnswPtrStore(base, hc->element, e);
+		hc->element = e;
 	}
 }

@@ -543,12 +497,7 @@ HnswLoadElementFromTuple(HnswElement element, HnswElementTuple etup, bool loadHe
 	}

 	if (loadVec)
-	{
-		char	   *base = NULL;
-		Datum		value = datumCopy(PointerGetDatum(&etup->data), false, -1);
-
-		HnswPtrStore(base, element->value, DatumGetPointer(value));
-	}
+		element->value = datumCopy(PointerGetDatum(&etup->data), false, -1);
 }

 /*
@@ -584,27 +533,24 @@ HnswLoadElement(HnswElement element, float *distance, Datum *q, Relation index,
 * Get the distance for a candidate
 */
 static float
-GetCandidateDistance(char *base, HnswCandidate * hc, Datum q, FmgrInfo *procinfo, Oid collation)
+GetCandidateDistance(HnswCandidate * hc, Datum q, FmgrInfo *procinfo, Oid collation)
 {
-	HnswElement hce = HnswPtrAccess(base, hc->element);
-	Datum		value = HnswGetValue(base, hce);
-
-	return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, q, value));
+	return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, q, hc->element->value));
 }

 /*
 * Create a candidate for the entry point
 */
 HnswCandidate *
-HnswEntryCandidate(char *base, HnswElement entryPoint, Datum q, Relation index, FmgrInfo *procinfo, Oid collation, bool loadVec)
+HnswEntryCandidate(HnswElement entryPoint, Datum q, Relation index, FmgrInfo *procinfo, Oid collation, bool loadVec)
 {
 	HnswCandidate *hc = palloc(sizeof(HnswCandidate));

-	HnswPtrStore(base, hc->element, entryPoint);
+	hc->element = entryPoint;
 	if (index == NULL)
-		hc->distance = GetCandidateDistance(base, hc, q, procinfo, collation);
+		hc->distance = GetCandidateDistance(hc, q, procinfo, collation);
 	else
-		HnswLoadElement(entryPoint, &hc->distance, &q, index, procinfo, collation, loadVec);
+		HnswLoadElement(hc->element, &hc->distance, &q, index, procinfo, collation, loadVec);
 	return hc;
 }

@@ -650,79 +596,34 @@ CreatePairingHeapNode(HnswCandidate * c)
 	return node;
 }

-/*
- * Init visited
- */
-static inline void
-InitVisited(char *base, visited_hash * v, Relation index, int ef, int m)
-{
-	if (index != NULL)
-		v->tids = tidhash_create(CurrentMemoryContext, ef * m * 2, NULL);
-	else if (base != NULL)
-		v->offsets = offsethash_create(CurrentMemoryContext, ef * m * 2, NULL);
-	else
-		v->pointers = pointerhash_create(CurrentMemoryContext, ef * m * 2, NULL);
-}
-
 /*
 * Add to visited
 */
 static inline void
-AddToVisited(char *base, visited_hash * v, HnswCandidate * hc, Relation index, bool *found)
+AddToVisited(visited_hash v, HnswCandidate * hc, Relation index, bool *found)
 {
-	if (index != NULL)
-	{
-		HnswElement element = HnswPtrAccess(base, hc->element);
-		ItemPointerData indextid;
-
-		ItemPointerSet(&indextid, element->blkno, element->offno);
-		tidhash_insert(v->tids, indextid, found);
-	}
-	else if (base != NULL)
+	if (index == NULL)
 	{
 #if PG_VERSION_NUM >= 130000
-		HnswElement element = HnswPtrAccess(base, hc->element);
-
-		offsethash_insert_hash(v->offsets, HnswPtrOffset(hc->element), element->hash, found);
+		pointerhash_insert_hash(v.pointers, (uintptr_t) hc->element, hc->element->hash, found);
 #else
-		offsethash_insert(v->offsets, HnswPtrOffset(hc->element), found);
+		pointerhash_insert(v.pointers, (uintptr_t) hc->element, found);
 #endif
 	}
 	else
 	{
-#if PG_VERSION_NUM >= 130000
-		HnswElement element = HnswPtrAccess(base, hc->element);
+		ItemPointerData indextid;

-		pointerhash_insert_hash(v->pointers, (uintptr_t) HnswPtrPointer(hc->element), element->hash, found);
-#else
-		pointerhash_insert(v->pointers, (uintptr_t) HnswPtrPointer(hc->element), found);
-#endif
+		ItemPointerSet(&indextid, hc->element->blkno, hc->element->offno);
+		tidhash_insert(v.tids, indextid, found);
 	}
 }

-/*
- * Count element towards ef
- */
-static inline bool
-CountElement(char *base, HnswElement skipElement, HnswCandidate * hc)
-{
-	HnswElement e;
-
-	if (skipElement == NULL)
-		return true;
-
-	/* Ensure does not access heaptidsLength during in-memory build */
-	pg_memory_barrier();
-
-	e = HnswPtrAccess(base, hc->element);
-	return e->heaptidsLength != 0;
-}
-
 /*
 * Algorithm 2 from paper
 */
 List *
-HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement)
+HnswSearchLayer(Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement)
 {
 	List	   *w = NIL;
 	pairingheap *C = pairingheap_allocate(CompareNearestCandidates, NULL);
@@ -730,17 +631,12 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 	int			wlen = 0;
 	visited_hash v;
 	ListCell   *lc2;
-	HnswNeighborArray *neighborhoodData = NULL;
-	Size		neighborhoodSize;

-	InitVisited(base, &v, index, ef, m);
-
-	/* Create local memory for neighborhood if needed */
+	/* Create hash table */
 	if (index == NULL)
-	{
-		neighborhoodSize = HNSW_NEIGHBOR_ARRAY_SIZE(HnswGetLayerM(m, lc));
-		neighborhoodData = palloc(neighborhoodSize);
-	}
+		v.pointers = pointerhash_create(CurrentMemoryContext, ef * m * 2, NULL);
+	else
+		v.tids = tidhash_create(CurrentMemoryContext, ef * m * 2, NULL);

 	/* Add entry points to v, C, and W */
 	foreach(lc2, ep)
@@ -748,7 +644,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 		HnswCandidate *hc = (HnswCandidate *) lfirst(lc2);
 		bool		found;

-		AddToVisited(base, &v, hc, index, &found);
+		AddToVisited(v, hc, index, &found);

 		pairingheap_add(C, &(CreatePairingHeapNode(hc)->ph_node));
 		pairingheap_add(W, &(CreatePairingHeapNode(hc)->ph_node));
@@ -758,7 +654,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 		 * would be ideal to do this for inserts as well, but this could
 		 * affect insert performance.
 		 */
-		if (CountElement(base, skipElement, hc))
+		if (skipElement == NULL || hc->element->heaptidsLength != 0)
 			wlen++;
 	}

@@ -767,51 +663,38 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 		HnswNeighborArray *neighborhood;
 		HnswCandidate *c = ((HnswPairingHeapNode *) pairingheap_remove_first(C))->inner;
 		HnswCandidate *f = ((HnswPairingHeapNode *) pairingheap_first(W))->inner;
-		HnswElement cElement;

 		if (c->distance > f->distance)
 			break;

-		cElement = HnswPtrAccess(base, c->element);
-
-		if (HnswPtrIsNull(base, cElement->neighbors))
-			HnswLoadNeighbors(cElement, index, m);
+		if (c->element->neighbors == NULL)
+			HnswLoadNeighbors(c->element, index, m);

 		/* Get the neighborhood at layer lc */
-		neighborhood = HnswGetNeighbors(base, cElement, lc);
-
-		/* Copy neighborhood to local memory if needed */
-		if (index == NULL)
-		{
-			LWLockAcquire(&cElement->lock, LW_SHARED);
-			memcpy(neighborhoodData, neighborhood, neighborhoodSize);
-			LWLockRelease(&cElement->lock);
-			neighborhood = neighborhoodData;
-		}
+		neighborhood = HnswGetNeighbors(c->element, lc);

 		for (int i = 0; i < neighborhood->length; i++)
 		{
 			HnswCandidate *e = &neighborhood->items[i];
 			bool		visited;

-			AddToVisited(base, &v, e, index, &visited);
+			AddToVisited(v, e, index, &visited);

 			if (!visited)
 			{
 				float		eDistance;
-				HnswElement eElement = HnswPtrAccess(base, e->element);

 				f = ((HnswPairingHeapNode *) pairingheap_first(W))->inner;

 				if (index == NULL)
-					eDistance = GetCandidateDistance(base, e, q, procinfo, collation);
+					eDistance = GetCandidateDistance(e, q, procinfo, collation);
 				else
-					HnswLoadElement(eElement, &eDistance, &q, index, procinfo, collation, inserting);
+					HnswLoadElement(e->element, &eDistance, &q, index, procinfo, collation, inserting);

-				Assert(!eElement->deleted);
+				Assert(!e->element->deleted);

 				/* Make robust to issues */
-				if (eElement->level < lc)
+				if (e->element->level < lc)
 					continue;

 				if (eDistance < f->distance || wlen < ef)
@@ -819,7 +702,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 					/* Copy e */
 					HnswCandidate *ec = palloc(sizeof(HnswCandidate));

-					HnswPtrStore(base, ec->element, eElement);
+					ec->element = e->element;
 					ec->distance = eDistance;

 					pairingheap_add(C, &(CreatePairingHeapNode(ec)->ph_node));
@@ -830,7 +713,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 					 * vacuuming. It would be ideal to do this for inserts as
 					 * well, but this could affect insert performance.
 					 */
-					if (CountElement(base, skipElement, e))
+					if (skipElement == NULL || e->element->heaptidsLength != 0)
 					{
 						wlen++;

@@ -855,7 +738,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
 }

 /*
- * Compare candidate distances with pointer tie-breaker
+ * Compare candidate distances
 */
 static int
 #if PG_VERSION_NUM >= 130000
@@ -873,38 +756,10 @@ CompareCandidateDistances(const void *a, const void *b)
 	if (hca->distance > hcb->distance)
 		return -1;

-	if (HnswPtrPointer(hca->element) < HnswPtrPointer(hcb->element))
+	if (hca->element < hcb->element)
 		return 1;

-	if (HnswPtrPointer(hca->element) > HnswPtrPointer(hcb->element))
-		return -1;
-
-	return 0;
-}
-
-/*
- * Compare candidate distances with offset tie-breaker
- */
-static int
-#if PG_VERSION_NUM >= 130000
-CompareCandidateDistancesOffset(const ListCell *a, const ListCell *b)
-#else
-CompareCandidateDistancesOffset(const void *a, const void *b)
-#endif
-{
-	HnswCandidate *hca = lfirst((ListCell *) a);
-	HnswCandidate *hcb = lfirst((ListCell *) b);
-
-	if (hca->distance < hcb->distance)
-		return 1;
-
-	if (hca->distance > hcb->distance)
-		return -1;
-
-	if (HnswPtrOffset(hca->element) < HnswPtrOffset(hcb->element))
-		return 1;
-
-	if (HnswPtrOffset(hca->element) > HnswPtrOffset(hcb->element))
+	if (hca->element > hcb->element)
 		return -1;

 	return 0;
@@ -914,28 +769,46 @@ CompareCandidateDistancesOffset(const void *a, const void *b)
 * Calculate the distance between elements
 */
 static float
-HnswGetDistance(char *base, HnswElement a, HnswElement b, FmgrInfo *procinfo, Oid collation)
+HnswGetDistance(HnswElement a, HnswElement b, int lc, FmgrInfo *procinfo, Oid collation)
 {
-	Datum		aValue = HnswGetValue(base, a);
-	Datum		bValue = HnswGetValue(base, b);
+	/* Look for cached distance */
+	if (a->neighbors != NULL)
+	{
+		HnswNeighborArray *neighbors = HnswGetNeighbors(a, lc);

-	return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, aValue, bValue));
+		for (int i = 0; i < neighbors->length; i++)
+		{
+			if (neighbors->items[i].element == b)
+				return neighbors->items[i].distance;
+		}
+	}
+
+	if (b->neighbors != NULL)
+	{
+		HnswNeighborArray *neighbors = HnswGetNeighbors(b, lc);
+
+		for (int i = 0; i < neighbors->length; i++)
+		{
+			if (neighbors->items[i].element == a)
+				return neighbors->items[i].distance;
+		}
+	}
+
+	return DatumGetFloat8(FunctionCall2Coll(procinfo, collation, a->value, b->value));
 }

 /*
 * Check if an element is closer to q than any element from R
 */
 static bool
-CheckElementCloser(char *base, HnswCandidate * e, List *r, FmgrInfo *procinfo, Oid collation)
+CheckElementCloser(HnswCandidate * e, List *r, int lc, FmgrInfo *procinfo, Oid collation)
 {
-	HnswElement eElement = HnswPtrAccess(base, e->element);
 	ListCell   *lc2;

 	foreach(lc2, r)
 	{
 		HnswCandidate *ri = lfirst(lc2);
-		HnswElement riElement = HnswPtrAccess(base, ri->element);
-		float		distance = HnswGetDistance(base, eElement, riElement, procinfo, collation);
+		float		distance = HnswGetDistance(e->element, ri->element, lc, procinfo, collation);

 		if (distance <= e->distance)
 			return false;
@@ -948,31 +821,26 @@ CheckElementCloser(char *base, HnswCandidate * e, List *r, FmgrInfo *procinfo, O
 * Algorithm 4 from paper
 */
 static List *
-SelectNeighbors(char *base, List *c, int lm, int lc, FmgrInfo *procinfo, Oid collation, HnswElement e2, HnswCandidate * newCandidate, HnswCandidate * *pruned, bool sortCandidates)
+SelectNeighbors(List *c, int m, int lc, FmgrInfo *procinfo, Oid collation, HnswElement e2, HnswCandidate * newCandidate, HnswCandidate * *pruned, bool sortCandidates)
 {
 	List	   *r = NIL;
 	List	   *w = list_copy(c);
 	pairingheap *wd;
-	HnswNeighborArray *neighbors = HnswGetNeighbors(base, e2, lc);
+	HnswNeighborArray *neighbors = HnswGetNeighbors(e2, lc);
 	bool		mustCalculate = !neighbors->closerSet;
 	List	   *added = NIL;
 	bool		removedAny = false;

-	if (list_length(w) <= lm)
+	if (list_length(w) <= m)
 		return w;

 	wd = pairingheap_allocate(CompareNearestCandidates, NULL);

 	/* Ensure order of candidates is deterministic for closer caching */
 	if (sortCandidates)
-	{
-		if (base == NULL)
 		list_sort(w, CompareCandidateDistances);
-		else
-			list_sort(w, CompareCandidateDistancesOffset);
-	}

-	while (list_length(w) > 0 && list_length(r) < lm)
+	while (list_length(w) > 0 && list_length(r) < m)
 	{
 		/* Assumes w is already ordered desc */
 		HnswCandidate *e = llast(w);
@@ -981,20 +849,16 @@ SelectNeighbors(char *base, List *c, int lm, int lc, FmgrInfo *procinfo, Oid col

 		/* Use previous state of r and wd to skip work when possible */
 		if (mustCalculate)
-			e->closer = CheckElementCloser(base, e, r, procinfo, collation);
+			e->closer = CheckElementCloser(e, r, lc, procinfo, collation);
 		else if (list_length(added) > 0)
 		{
-			/* Keep Valgrind happy for in-memory, parallel builds */
-			if (base != NULL)
-				VALGRIND_MAKE_MEM_DEFINED(&e->closer, 1);
-
 			/*
 			 * If the current candidate was closer, we only need to compare it
 			 * with the other candidates that we have added.
 			 */
 			if (e->closer)
 			{
-				e->closer = CheckElementCloser(base, e, added, procinfo, collation);
+				e->closer = CheckElementCloser(e, added, lc, procinfo, collation);

 				if (!e->closer)
 					removedAny = true;
@@ -1007,7 +871,7 @@ SelectNeighbors(char *base, List *c, int lm, int lc, FmgrInfo *procinfo, Oid col
 				 */
 				if (removedAny)
 				{
-					e->closer = CheckElementCloser(base, e, r, procinfo, collation);
+					e->closer = CheckElementCloser(e, r, lc, procinfo, collation);
 					if (e->closer)
 						added = lappend(added, e);
 				}
@@ -1015,15 +879,11 @@ SelectNeighbors(char *base, List *c, int lm, int lc, FmgrInfo *procinfo, Oid col
 		}
 		else if (e == newCandidate)
 		{
-			e->closer = CheckElementCloser(base, e, r, procinfo, collation);
+			e->closer = CheckElementCloser(e, r, lc, procinfo, collation);
 			if (e->closer)
 				added = lappend(added, e);
 		}

-		/* Keep Valgrind happy for in-memory, parallel builds */
-		if (base != NULL)
-			VALGRIND_MAKE_MEM_DEFINED(&e->closer, 1);
-
 		if (e->closer)
 			r = lappend(r, e);
 		else
@@ -1034,7 +894,7 @@ SelectNeighbors(char *base, List *c, int lm, int lc, FmgrInfo *procinfo, Oid col
 	neighbors->closerSet = sortCandidates;

 	/* Keep pruned connections */
-	while (!pairingheap_is_empty(wd) && list_length(r) < lm)
+	while (!pairingheap_is_empty(wd) && list_length(r) < m)
 		r = lappend(r, ((HnswPairingHeapNode *) pairingheap_remove_first(wd))->inner);

 	/* Return pruned for update connections */
@@ -1053,10 +913,10 @@ SelectNeighbors(char *base, List *c, int lm, int lc, FmgrInfo *procinfo, Oid col
 * Add connections
 */
 static void
-AddConnections(char *base, HnswElement element, List *neighbors, int lc)
+AddConnections(HnswElement element, List *neighbors, int m, int lc)
 {
 	ListCell   *lc2;
-	HnswNeighborArray *a = HnswGetNeighbors(base, element, lc);
+	HnswNeighborArray *a = HnswGetNeighbors(element, lc);

 	foreach(lc2, neighbors)
 		a->items[a->length++] = *((HnswCandidate *) lfirst(lc2));
@@ -1066,16 +926,16 @@ AddConnections(char *base, HnswElement element, List *neighbors, int lc)
 * Update connections
 */
 void
-HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm, int lc, int *updateIdx, Relation index, FmgrInfo *procinfo, Oid collation)
+HnswUpdateConnection(HnswElement element, HnswCandidate * hc, int m, int lc, int *updateIdx, Relation index, FmgrInfo *procinfo, Oid collation)
 {
-	HnswElement hce = HnswPtrAccess(base, hc->element);
-	HnswNeighborArray *currentNeighbors = HnswGetNeighbors(base, hce, lc);
+	HnswNeighborArray *currentNeighbors = HnswGetNeighbors(hc->element, lc);
+
 	HnswCandidate hc2;

-	HnswPtrStore(base, hc2.element, element);
+	hc2.element = element;
 	hc2.distance = hc->distance;

-	if (currentNeighbors->length < lm)
+	if (currentNeighbors->length < m)
 	{
 		currentNeighbors->items[currentNeighbors->length++] = hc2;

@@ -1091,20 +951,19 @@ HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm
 		/* Load elements on insert */
 		if (index != NULL)
 		{
-			Datum		q = HnswGetValue(base, hce);
+			Datum		q = hc->element->value;

 			for (int i = 0; i < currentNeighbors->length; i++)
 			{
 				HnswCandidate *hc3 = &currentNeighbors->items[i];
-				HnswElement hc3Element = HnswPtrAccess(base, hc3->element);

-				if (HnswPtrIsNull(base, hc3Element->value))
-					HnswLoadElement(hc3Element, &hc3->distance, &q, index, procinfo, collation, true);
+				if (DatumGetPointer(hc3->element->value) == NULL)
+					HnswLoadElement(hc3->element, &hc3->distance, &q, index, procinfo, collation, true);
 				else
-					hc3->distance = GetCandidateDistance(base, hc3, q, procinfo, collation);
+					hc3->distance = GetCandidateDistance(hc3, q, procinfo, collation);

 				/* Prune element if being deleted */
-				if (hc3Element->heaptidsLength == 0)
+				if (hc3->element->heaptidsLength == 0)
 				{
 					pruned = &currentNeighbors->items[i];
 					break;
@@ -1121,7 +980,7 @@ HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm
 				c = lappend(c, &currentNeighbors->items[i]);
 			c = lappend(c, &hc2);

-			SelectNeighbors(base, c, lm, lc, procinfo, collation, hce, &hc2, &pruned, true);
+			SelectNeighbors(c, m, lc, procinfo, collation, hc->element, &hc2, &pruned, true);

 			/* Should not happen */
 			if (pruned == NULL)
@@ -1131,7 +990,7 @@ HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm
 		/* Find and replace the pruned element */
 		for (int i = 0; i < currentNeighbors->length; i++)
 		{
-			if (HnswPtrEqual(base, currentNeighbors->items[i].element, pruned->element))
+			if (currentNeighbors->items[i].element == pruned->element)
 			{
 				currentNeighbors->items[i] = hc2;

@@ -1149,65 +1008,43 @@ HnswUpdateConnection(char *base, HnswElement element, HnswCandidate * hc, int lm
 * Remove elements being deleted or skipped
 */
 static List *
-RemoveElements(char *base, List *w, HnswElement skipElement)
+RemoveElements(List *w, HnswElement skipElement)
 {
 	ListCell   *lc2;
 	List	   *w2 = NIL;

-	/* Ensure does not access heaptidsLength during in-memory build */
-	pg_memory_barrier();
-
 	foreach(lc2, w)
 	{
 		HnswCandidate *hc = (HnswCandidate *) lfirst(lc2);
-		HnswElement hce = HnswPtrAccess(base, hc->element);

 		/* Skip self for vacuuming update */
-		if (skipElement != NULL && hce->blkno == skipElement->blkno && hce->offno == skipElement->offno)
+		if (skipElement != NULL && hc->element->blkno == skipElement->blkno && hc->element->offno == skipElement->offno)
 			continue;

-		if (hce->heaptidsLength != 0)
+		if (hc->element->heaptidsLength != 0)
 			w2 = lappend(w2, hc);
 	}

 	return w2;
 }

-#if PG_VERSION_NUM >= 130000
-/*
- * Precompute hash
- */
-static void
-PrecomputeHash(char *base, HnswElement element)
-{
-	HnswElementPtr ptr;
-
-	HnswPtrStore(base, ptr, element);
-
-	if (base == NULL)
-		element->hash = hash_pointer((uintptr_t) HnswPtrPointer(ptr));
-	else
-		element->hash = hash_offset(HnswPtrOffset(ptr));
-}
-#endif
-
 /*
 * Algorithm 1 from paper
 */
 void
-HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint, Relation index, FmgrInfo *procinfo, Oid collation, int m, int efConstruction, bool existing)
+HnswInsertElement(HnswElement element, HnswElement entryPoint, Relation index, FmgrInfo *procinfo, Oid collation, int m, int efConstruction, bool existing)
 {
 	List	   *ep;
 	List	   *w;
 	int			level = element->level;
 	int			entryLevel;
-	Datum		q = HnswGetValue(base, element);
+	Datum		q = element->value;
 	HnswElement skipElement = existing ? element : NULL;

 #if PG_VERSION_NUM >= 130000
 	/* Precompute hash */
 	if (index == NULL)
-		PrecomputeHash(base, element);
+		element->hash = hash_pointer((uintptr_t) element);
 #endif

 	/* No neighbors if no entry point */
@@ -1215,13 +1052,13 @@ HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint
 		return;

 	/* Get entry point and level */
-	ep = list_make1(HnswEntryCandidate(base, entryPoint, q, index, procinfo, collation, true));
+	ep = list_make1(HnswEntryCandidate(entryPoint, q, index, procinfo, collation, true));
 	entryLevel = entryPoint->level;

 	/* 1st phase: greedy search to insert level */
 	for (int lc = entryLevel; lc >= level + 1; lc--)
 	{
-		w = HnswSearchLayer(base, q, ep, 1, lc, index, procinfo, collation, m, true, skipElement);
+		w = HnswSearchLayer(q, ep, 1, lc, index, procinfo, collation, m, true, skipElement);
 		ep = w;
 	}

@@ -1239,12 +1076,12 @@ HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint
 		List	   *neighbors;
 		List	   *lw;

-		w = HnswSearchLayer(base, q, ep, efConstruction, lc, index, procinfo, collation, m, true, skipElement);
+		w = HnswSearchLayer(q, ep, efConstruction, lc, index, procinfo, collation, m, true, skipElement);

 		/* Elements being deleted or skipped can help with search */
 		/* but should be removed before selecting neighbors */
 		if (index != NULL)
-			lw = RemoveElements(base, w, skipElement);
+			lw = RemoveElements(w, skipElement);
 		else
 			lw = w;

@@ -1253,9 +1090,9 @@ HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint
 		 * sortCandidates to true for in-memory builds to enable closer
 		 * caching, but there does not seem to be a difference in performance.
 		 */
-		neighbors = SelectNeighbors(base, lw, lm, lc, procinfo, collation, element, NULL, NULL, false);
+		neighbors = SelectNeighbors(lw, lm, lc, procinfo, collation, element, NULL, NULL, false);

-		AddConnections(base, element, neighbors, lc);
+		AddConnections(element, neighbors, lm, lc);

 		ep = w;
 	}
--- a/src/hnswvacuum.c
+++ b/src/hnswvacuum.c
@@ -2,7 +2,6 @@

 #include <math.h>

-#include "access/generic_xlog.h"
 #include "commands/vacuum.h"
 #include "hnsw.h"
 #include "storage/bufmgr.h"
@@ -60,7 +59,8 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)
 		/* Iterate over nodes */
 		for (offno = FirstOffsetNumber; offno <= maxoffno; offno = OffsetNumberNext(offno))
 		{
-			HnswElementTuple etup = (HnswElementTuple) PageGetItem(page, PageGetItemId(page, offno));
+			ItemId		itemid = PageGetItemId(page, offno);
+			HnswElementTuple etup = (HnswElementTuple) PageGetItem(page, itemid);
 			int			idx = 0;
 			bool		itemUpdated = false;

@@ -91,10 +91,15 @@ RemoveHeapTids(HnswVacuumState * vacuumstate)

 				if (itemUpdated)
 				{
+					Size		etupSize = ItemIdGetLength(itemid);
+
 					/* Mark rest as invalid */
 					for (int i = idx; i < HNSW_HEAPTIDS; i++)
 						ItemPointerSetInvalid(&etup->heaptids[i]);

+					if (!PageIndexTupleOverwrite(page, offno, (Item) etup, etupSize))
+						elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
+
 					updated = true;
 				}
 			}
@@ -194,25 +199,21 @@ RepairGraphElement(HnswVacuumState * vacuumstate, HnswElement element, HnswEleme
 	BufferAccessStrategy bas = vacuumstate->bas;
 	HnswNeighborTuple ntup = vacuumstate->ntup;
 	Size		ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(element->level, m);
-	char	   *base = NULL;

 	/* Skip if element is entry point */
 	if (entryPoint != NULL && element->blkno == entryPoint->blkno && element->offno == entryPoint->offno)
 		return;

 	/* Init fields */
-	HnswInitNeighbors(base, element, m, NULL);
+	HnswInitNeighbors(element, m);
 	element->heaptidsLength = 0;

-	/* Find neighbors for element, skipping itself */
-	HnswFindElementNeighbors(base, element, entryPoint, index, procinfo, collation, m, efConstruction, true);
-
-	/* Zero memory for each element */
-	MemSet(ntup, 0, HNSW_TUPLE_ALLOC_SIZE);
+	/* Add element to graph, skipping itself */
+	HnswInsertElement(element, entryPoint, index, procinfo, collation, m, efConstruction, true);

 	/* Update neighbor tuple */
 	/* Do this before getting page to minimize locking */
-	HnswSetNeighborTuple(base, ntup, element, m);
+	HnswSetNeighborTuple(ntup, element, m);

 	/* Get neighbor page */
 	buf = ReadBufferExtended(index, MAIN_FORKNUM, element->neighborPage, RBM_NORMAL, bas);
@@ -229,7 +230,7 @@ RepairGraphElement(HnswVacuumState * vacuumstate, HnswElement element, HnswEleme
 	UnlockReleaseBuffer(buf);

 	/* Update neighbors */
-	HnswUpdateNeighborsOnDisk(index, procinfo, collation, element, m, true, false);
+	HnswUpdateNeighborPages(index, procinfo, collation, element, m, true, false);
 }

 /*
@@ -300,7 +301,7 @@ RepairGraphEntryPoint(HnswVacuumState * vacuumstate)
 			{
 				/* Reset neighbors from previous update */
 				if (highestPoint != NULL)
-					HnswPtrStore((char *) NULL, highestPoint->neighbors, (HnswNeighborArrayPtr *) NULL);
+					highestPoint->neighbors = NULL;

 				RepairGraphElement(vacuumstate, entryPoint, highestPoint);
 			}
@@ -476,8 +477,11 @@ MarkDeleted(HnswVacuumState * vacuumstate)
 		/* Update element and neighbors together */
 		for (offno = FirstOffsetNumber; offno <= maxoffno; offno = OffsetNumberNext(offno))
 		{
-			HnswElementTuple etup = (HnswElementTuple) PageGetItem(page, PageGetItemId(page, offno));
+			ItemId		itemid = PageGetItemId(page, offno);
+			HnswElementTuple etup = (HnswElementTuple) PageGetItem(page, itemid);
 			HnswNeighborTuple ntup;
+			Size		etupSize;
+			Size		ntupSize;
 			Buffer		nbuf;
 			Page		npage;
 			BlockNumber neighborPage;
@@ -501,6 +505,10 @@ MarkDeleted(HnswVacuumState * vacuumstate)
 			if (ItemPointerIsValid(&etup->heaptids[0]))
 				continue;

+			/* Calculate sizes */
+			etupSize = ItemIdGetLength(itemid);
+			ntupSize = HNSW_NEIGHBOR_TUPLE_SIZE(etup->level, vacuumstate->m);
+
 			/* Get neighbor page */
 			neighborPage = ItemPointerGetBlockNumber(&etup->neighbortid);
 			neighborOffno = ItemPointerGetOffsetNumber(&etup->neighbortid);
@@ -527,10 +535,13 @@ MarkDeleted(HnswVacuumState * vacuumstate)
 			for (int i = 0; i < ntup->count; i++)
 				ItemPointerSetInvalid(&ntup->indextids[i]);

-			/*
-			 * We modified the tuples in place, no need to call
-			 * PageIndexTupleOverwrite
-			 */
+			/* Overwrite element tuple */
+			if (!PageIndexTupleOverwrite(page, offno, (Item) etup, etupSize))
+				elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));
+
+			/* Overwrite neighbor tuple */
+			if (!PageIndexTupleOverwrite(npage, neighborOffno, (Item) ntup, ntupSize))
+				elog(ERROR, "failed to add index item to \"%s\"", RelationGetRelationName(index));

 			/* Commit */
 			GenericXLogFinish(state);
@@ -575,7 +586,7 @@ InitVacuumState(HnswVacuumState * vacuumstate, IndexVacuumInfo *info, IndexBulkD
 	vacuumstate->bas = GetAccessStrategy(BAS_BULKREAD);
 	vacuumstate->procinfo = index_getprocinfo(index, 1, HNSW_DISTANCE_PROC);
 	vacuumstate->collation = index->rd_indcollation[0];
-	vacuumstate->ntup = palloc0(HNSW_TUPLE_ALLOC_SIZE);
+	vacuumstate->ntup = palloc0(BLCKSZ);
 	vacuumstate->tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
 												"Hnsw vacuum temporary context",
 												ALLOCSET_DEFAULT_SIZES);
--- a/src/ivfbuild.c
+++ b/src/ivfbuild.c
@@ -2,38 +2,58 @@

 #include <float.h>

-#include "access/table.h"
-#include "access/tableam.h"
 #include "access/parallel.h"
 #include "access/xact.h"
 #include "catalog/index.h"
 #include "catalog/pg_operator_d.h"
 #include "catalog/pg_type_d.h"
-#include "commands/progress.h"
 #include "ivfflat.h"
 #include "miscadmin.h"
-#include "optimizer/optimizer.h"
 #include "storage/bufmgr.h"
 #include "tcop/tcopprot.h"
 #include "utils/memutils.h"

 #if PG_VERSION_NUM >= 140000
 #include "utils/backend_progress.h"
-#else
+#elif PG_VERSION_NUM >= 120000
 #include "pgstat.h"
 #endif

+#if PG_VERSION_NUM >= 120000
+#include "access/tableam.h"
+#include "commands/progress.h"
+#else
+#define PROGRESS_CREATEIDX_SUBPHASE 0
+#define PROGRESS_CREATEIDX_TUPLES_TOTAL 0
+#define PROGRESS_CREATEIDX_TUPLES_DONE 0
+#endif
+
 #if PG_VERSION_NUM >= 130000
 #define CALLBACK_ITEM_POINTER ItemPointer tid
 #else
 #define CALLBACK_ITEM_POINTER HeapTuple hup
 #endif

+#if PG_VERSION_NUM >= 120000
+#define UpdateProgress(index, val) pgstat_progress_update_param(index, val)
+#else
+#define UpdateProgress(index, val) ((void)val)
+#endif
+
 #if PG_VERSION_NUM >= 140000
 #include "utils/backend_status.h"
 #include "utils/wait_event.h"
 #endif

+#if PG_VERSION_NUM >= 120000
+#include "access/table.h"
+#include "optimizer/optimizer.h"
+#else
+#include "access/heapam.h"
+#include "optimizer/planner.h"
+#include "pgstat.h"
+#endif
+
 #define PARALLEL_KEY_IVFFLAT_SHARED		UINT64CONST(0xA000000000000001)
 #define PARALLEL_KEY_TUPLESORT			UINT64CONST(0xA000000000000002)
 #define PARALLEL_KEY_IVFFLAT_CENTERS	UINT64CONST(0xA000000000000003)
@@ -130,8 +150,13 @@ SampleRows(IvfflatBuildState * buildstate)
 	{
 		BlockNumber targblock = BlockSampler_Next(&buildstate->bs);

+#if PG_VERSION_NUM >= 120000
 		table_index_build_range_scan(buildstate->heap, buildstate->index, buildstate->indexInfo,
 									 false, true, false, targblock, 1, SampleCallback, (void *) buildstate, NULL);
+#else
+		IndexBuildHeapRangeScan(buildstate->heap, buildstate->index, buildstate->indexInfo,
+								false, true, targblock, 1, SampleCallback, (void *) buildstate, NULL);
+#endif
 	}
 }

@@ -257,12 +282,16 @@ InsertTuples(Relation index, IvfflatBuildState * buildstate, ForkNumber forkNum)
 	IndexTuple	itup = NULL;	/* silence compiler warning */
 	int64		inserted = 0;

+#if PG_VERSION_NUM >= 120000
 	TupleTableSlot *slot = MakeSingleTupleTableSlot(buildstate->tupdesc, &TTSOpsMinimalTuple);
+#else
+	TupleTableSlot *slot = MakeSingleTupleTableSlot(buildstate->tupdesc);
+#endif
 	TupleDesc	tupdesc = RelationGetDescr(index);

-	pgstat_progress_update_param(PROGRESS_CREATEIDX_SUBPHASE, PROGRESS_IVFFLAT_PHASE_LOAD);
+	UpdateProgress(PROGRESS_CREATEIDX_SUBPHASE, PROGRESS_IVFFLAT_PHASE_LOAD);

-	pgstat_progress_update_param(PROGRESS_CREATEIDX_TUPLES_TOTAL, buildstate->indtuples);
+	UpdateProgress(PROGRESS_CREATEIDX_TUPLES_TOTAL, buildstate->indtuples);

 	GetNextTuple(buildstate->sortstate, tupdesc, slot, &itup, &list);

@@ -298,7 +327,7 @@ InsertTuples(Relation index, IvfflatBuildState * buildstate, ForkNumber forkNum)

 			pfree(itup);

-			pgstat_progress_update_param(PROGRESS_CREATEIDX_TUPLES_DONE, ++inserted);
+			UpdateProgress(PROGRESS_CREATEIDX_TUPLES_DONE, ++inserted);

 			GetNextTuple(buildstate->sortstate, tupdesc, slot, &itup, &list);
 		}
@@ -346,12 +375,20 @@ InitBuildState(IvfflatBuildState * buildstate, Relation heap, Relation index, In
 		elog(ERROR, "dimensions must be greater than one for this opclass");

 	/* Create tuple description for sorting */
+#if PG_VERSION_NUM >= 120000
 	buildstate->tupdesc = CreateTemplateTupleDesc(3);
+#else
+	buildstate->tupdesc = CreateTemplateTupleDesc(3, false);
+#endif
 	TupleDescInitEntry(buildstate->tupdesc, (AttrNumber) 1, "list", INT4OID, -1, 0);
 	TupleDescInitEntry(buildstate->tupdesc, (AttrNumber) 2, "tid", TIDOID, -1, 0);
 	TupleDescInitEntry(buildstate->tupdesc, (AttrNumber) 3, "vector", RelationGetDescr(index)->attrs[0].atttypid, -1, 0);

+#if PG_VERSION_NUM >= 120000
 	buildstate->slot = MakeSingleTupleTableSlot(buildstate->tupdesc, &TTSOpsVirtual);
+#else
+	buildstate->slot = MakeSingleTupleTableSlot(buildstate->tupdesc);
+#endif

 	buildstate->centers = VectorArrayInit(buildstate->lists, buildstate->dimensions);
 	buildstate->listInfo = palloc(sizeof(ListInfo) * buildstate->lists);
@@ -398,7 +435,7 @@ ComputeCenters(IvfflatBuildState * buildstate)
 {
 	int			numSamples;

-	pgstat_progress_update_param(PROGRESS_CREATEIDX_SUBPHASE, PROGRESS_IVFFLAT_PHASE_KMEANS);
+	UpdateProgress(PROGRESS_CREATEIDX_SUBPHASE, PROGRESS_IVFFLAT_PHASE_KMEANS);

 	/* Target 50 samples per list, with at least 10000 samples */
 	/* The number of samples has a large effect on index build time */
@@ -473,7 +510,7 @@ CreateListPages(Relation index, VectorArray centers, int dimensions,
 	IvfflatList list;

 	listSize = MAXALIGN(IVFFLAT_LIST_SIZE(dimensions));
-	list = palloc0(listSize);
+	list = palloc(listSize);

 	buf = IvfflatNewBuffer(index, forkNum);
 	IvfflatInitRegisterPage(index, &buf, &page, &state);
@@ -594,7 +631,11 @@ IvfflatParallelScanAndSort(IvfflatSpool * ivfspool, IvfflatShared * ivfshared, S
 {
 	SortCoordinate coordinate;
 	IvfflatBuildState buildstate;
+#if PG_VERSION_NUM >= 120000
 	TableScanDesc scan;
+#else
+	HeapScanDesc scan;
+#endif
 	double		reltuples;
 	IndexInfo  *indexInfo;

@@ -618,11 +659,18 @@ IvfflatParallelScanAndSort(IvfflatSpool * ivfspool, IvfflatShared * ivfshared, S
 	buildstate.centers->length = buildstate.centers->maxlen;
 	ivfspool->sortstate = tuplesort_begin_heap(buildstate.tupdesc, 1, attNums, sortOperators, sortCollations, nullsFirstFlags, sortmem, coordinate, false);
 	buildstate.sortstate = ivfspool->sortstate;
+#if PG_VERSION_NUM >= 120000
 	scan = table_beginscan_parallel(ivfspool->heap,
 									ParallelTableScanFromIvfflatShared(ivfshared));
 	reltuples = table_index_build_scan(ivfspool->heap, ivfspool->index, indexInfo,
 									   true, progress, BuildCallback,
 									   (void *) &buildstate, scan);
+#else
+	scan = heap_beginscan_parallel(ivfspool->heap, &ivfshared->heapdesc);
+	reltuples = IndexBuildHeapScan(ivfspool->heap, ivfspool->index, indexInfo,
+								   true, BuildCallback,
+								   (void *) &buildstate, scan);
+#endif

 	/* Execute this worker's part of the sort */
 	tuplesort_performsort(ivfspool->sortstate);
@@ -692,7 +740,11 @@ IvfflatParallelBuildMain(dsm_segment *seg, shm_toc *toc)
 	}

 	/* Open relations within worker */
+#if PG_VERSION_NUM >= 120000
 	heapRel = table_open(ivfshared->heaprelid, heapLockmode);
+#else
+	heapRel = heap_open(ivfshared->heaprelid, heapLockmode);
+#endif
 	indexRel = index_open(ivfshared->indexrelid, indexLockmode);

 	/* Initialize worker's own spool */
@@ -712,7 +764,11 @@ IvfflatParallelBuildMain(dsm_segment *seg, shm_toc *toc)

 	/* Close relations within worker */
 	index_close(indexRel, indexLockmode);
+#if PG_VERSION_NUM >= 120000
 	table_close(heapRel, heapLockmode);
+#else
+	heap_close(heapRel, heapLockmode);
+#endif
 }

 /*
@@ -737,7 +793,19 @@ IvfflatEndParallel(IvfflatLeader * ivfleader)
 static Size
 ParallelEstimateShared(Relation heap, Snapshot snapshot)
 {
+#if PG_VERSION_NUM >= 120000
 	return add_size(BUFFERALIGN(sizeof(IvfflatShared)), table_parallelscan_estimate(heap, snapshot));
+#else
+	if (!IsMVCCSnapshot(snapshot))
+	{
+		Assert(snapshot == SnapshotAny);
+		return sizeof(IvfflatShared);
+	}
+
+	return add_size(offsetof(IvfflatShared, heapdesc) +
+					offsetof(ParallelHeapScanDescData, phs_snapshot_data),
+					EstimateSnapshotSpace(snapshot));
+#endif
 }

 /*
@@ -788,7 +856,11 @@ IvfflatBeginParallel(IvfflatBuildState * buildstate, bool isconcurrent, int requ
 	/* Enter parallel mode and create context */
 	EnterParallelMode();
 	Assert(request > 0);
+#if PG_VERSION_NUM >= 120000
 	pcxt = CreateParallelContext("vector", "IvfflatParallelBuildMain", request);
+#else
+	pcxt = CreateParallelContext("vector", "IvfflatParallelBuildMain", request, true);
+#endif

 	scantuplesortstates = leaderparticipates ? request + 1 : request;

@@ -846,9 +918,13 @@ IvfflatBeginParallel(IvfflatBuildState * buildstate, bool isconcurrent, int requ
 #ifdef IVFFLAT_KMEANS_DEBUG
 	ivfshared->inertia = 0;
 #endif
+#if PG_VERSION_NUM >= 120000
 	table_parallelscan_initialize(buildstate->heap,
 								  ParallelTableScanFromIvfflatShared(ivfshared),
 								  snapshot);
+#else
+	heap_parallelscan_initialize(&ivfshared->heapdesc, buildstate->heap, snapshot);
+#endif

 	/* Store shared tuplesort-private state, for which we reserved space */
 	sharedsort = (Sharedsort *) shm_toc_allocate(pcxt->toc, estsort);
@@ -919,7 +995,7 @@ AssignTuples(IvfflatBuildState * buildstate)
 	Oid			sortCollations[] = {InvalidOid};
 	bool		nullsFirstFlags[] = {false};

-	pgstat_progress_update_param(PROGRESS_CREATEIDX_SUBPHASE, PROGRESS_IVFFLAT_PHASE_ASSIGN);
+	UpdateProgress(PROGRESS_CREATEIDX_SUBPHASE, PROGRESS_IVFFLAT_PHASE_ASSIGN);

 	/* Calculate parallel workers */
 	if (buildstate->heap != NULL)
@@ -947,8 +1023,15 @@ AssignTuples(IvfflatBuildState * buildstate)
 		if (buildstate->ivfleader)
 			buildstate->reltuples = ParallelHeapScan(buildstate);
 		else
+		{
+#if PG_VERSION_NUM >= 120000
 			buildstate->reltuples = table_index_build_scan(buildstate->heap, buildstate->index, buildstate->indexInfo,
 														   true, true, BuildCallback, (void *) buildstate, NULL);
+#else
+			buildstate->reltuples = IndexBuildHeapScan(buildstate->heap, buildstate->index, buildstate->indexInfo,
+													   true, BuildCallback, (void *) buildstate, NULL);
+#endif
+		}

 #ifdef IVFFLAT_KMEANS_DEBUG
 		PrintKmeansMetrics(buildstate);
--- a/src/ivfflat.c
+++ b/src/ivfflat.c
@@ -3,16 +3,14 @@
 #include <float.h>

 #include "access/amapi.h"
-#include "access/reloptions.h"
-#include "commands/progress.h"
 #include "commands/vacuum.h"
 #include "ivfflat.h"
 #include "utils/guc.h"
 #include "utils/selfuncs.h"
 #include "utils/spccache.h"

-#if PG_VERSION_NUM < 150000
-#define MarkGUCPrefixReserved(x) EmitWarningsOnPlaceholders(x)
+#if PG_VERSION_NUM >= 120000
+#include "commands/progress.h"
 #endif

 int			ivfflat_probes;
@@ -35,13 +33,12 @@ IvfflatInit(void)
 	DefineCustomIntVariable("ivfflat.probes", "Sets the number of probes",
 							"Valid range is 1..lists.", &ivfflat_probes,
 							IVFFLAT_DEFAULT_PROBES, IVFFLAT_MIN_LISTS, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL);
-
-	MarkGUCPrefixReserved("ivfflat");
 }

 /*
 * Get the name of index build phase
 */
+#if PG_VERSION_NUM >= 120000
 static char *
 ivfflatbuildphasename(int64 phasenum)
 {
@@ -59,6 +56,7 @@ ivfflatbuildphasename(int64 phasenum)
 			return NULL;
 	}
 }
+#endif

 /*
 * Estimate the cost of an index scan
@@ -74,6 +72,9 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	double		ratio;
 	double		spc_seq_page_cost;
 	Relation	index;
+#if PG_VERSION_NUM < 120000
+	List	   *qinfos;
+#endif

 	/* Never use index without order */
 	if (path->indexorderbys == NULL)
@@ -104,7 +105,26 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	 */
 	costs.numIndexTuples = path->indexinfo->tuples * ratio;

+	/*
+	 * Do not use index if no limit or limit + offset > expected tuples unless
+	 * enable_seqscan = off
+	 */
+	if (root->limit_tuples < 0 || root->limit_tuples > costs.numIndexTuples)
+	{
+		*indexStartupCost = 1.0e10 - 1;
+		*indexTotalCost = 1.0e10 - 1;
+		*indexSelectivity = 0;
+		*indexCorrelation = 0;
+		*indexPages = 0;
+		return;
+	}
+
+#if PG_VERSION_NUM >= 120000
 	genericcostestimate(root, path, loop_count, &costs);
+#else
+	qinfos = deconstruct_indexquals(path);
+	genericcostestimate(root, path, loop_count, qinfos, &costs);
+#endif

 	get_tablespace_page_costs(path->indexinfo->reltablespace, NULL, &spc_seq_page_cost);

@@ -221,7 +241,9 @@ ivfflathandler(PG_FUNCTION_ARGS)
 	amroutine->amcostestimate = ivfflatcostestimate;
 	amroutine->amoptions = ivfflatoptions;
 	amroutine->amproperty = NULL;	/* TODO AMPROP_DISTANCE_ORDERABLE */
+#if PG_VERSION_NUM >= 120000
 	amroutine->ambuildphasename = ivfflatbuildphasename;
+#endif
 	amroutine->amvalidate = ivfflatvalidate;
 #if PG_VERSION_NUM >= 140000
 	amroutine->amadjustmembers = NULL;
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -3,10 +3,9 @@

 #include "postgres.h"

-#include "access/genam.h"
 #include "access/generic_xlog.h"
 #include "access/parallel.h"
-#include "lib/pairingheap.h"
+#include "access/reloptions.h"
 #include "nodes/execnodes.h"
 #include "port.h"				/* for random() */
 #include "utils/sampling.h"
@@ -17,6 +16,10 @@
 #include "common/pg_prng.h"
 #endif

+#if PG_VERSION_NUM < 120000
+#include "access/relscan.h"
+#endif
+
 #ifdef IVFFLAT_BENCH
 #include "portability/instr_time.h"
 #endif
@@ -132,10 +135,16 @@ typedef struct IvfflatShared
 #ifdef IVFFLAT_KMEANS_DEBUG
 	double		inertia;
 #endif
+
+#if PG_VERSION_NUM < 120000
+	ParallelHeapScanDescData heapdesc;	/* must come last */
+#endif
 }			IvfflatShared;

+#if PG_VERSION_NUM >= 120000
 #define ParallelTableScanFromIvfflatShared(shared) \
 	(ParallelTableScanDesc) ((char *) (shared) + BUFFERALIGN(sizeof(IvfflatShared)))
+#endif

 typedef struct IvfflatLeader
 {
--- a/src/ivfinsert.c
+++ b/src/ivfinsert.c
@@ -2,7 +2,6 @@

 #include <float.h>

-#include "access/generic_xlog.h"
 #include "ivfflat.h"
 #include "storage/bufmgr.h"
 #include "storage/lmgr.h"
--- a/src/ivfscan.c
+++ b/src/ivfscan.c
@@ -5,7 +5,6 @@
 #include "access/relscan.h"
 #include "catalog/pg_operator_d.h"
 #include "catalog/pg_type_d.h"
-#include "lib/pairingheap.h"
 #include "ivfflat.h"
 #include "miscadmin.h"
 #include "pgstat.h"
@@ -106,7 +105,12 @@ GetScanItems(IndexScanDesc scan, Datum value)
 	IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque;
 	TupleDesc	tupdesc = RelationGetDescr(scan->indexRelation);
 	double		tuples = 0;
+
+#if PG_VERSION_NUM >= 120000
 	TupleTableSlot *slot = MakeSingleTupleTableSlot(so->tupdesc, &TTSOpsVirtual);
+#else
+	TupleTableSlot *slot = MakeSingleTupleTableSlot(so->tupdesc);
+#endif

 	/*
 	 * Reuse same set of shared buffers for scan
@@ -212,14 +216,22 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
 	so->collation = index->rd_indcollation[0];

 	/* Create tuple description for sorting */
+#if PG_VERSION_NUM >= 120000
 	so->tupdesc = CreateTemplateTupleDesc(2);
+#else
+	so->tupdesc = CreateTemplateTupleDesc(2, false);
+#endif
 	TupleDescInitEntry(so->tupdesc, (AttrNumber) 1, "distance", FLOAT8OID, -1, 0);
 	TupleDescInitEntry(so->tupdesc, (AttrNumber) 2, "heaptid", TIDOID, -1, 0);

 	/* Prep sort */
 	so->sortstate = tuplesort_begin_heap(so->tupdesc, 1, attNums, sortOperators, sortCollations, nullsFirstFlags, work_mem, NULL, false);

+#if PG_VERSION_NUM >= 120000
 	so->slot = MakeSingleTupleTableSlot(so->tupdesc, &TTSOpsMinimalTuple);
+#else
+	so->slot = MakeSingleTupleTableSlot(so->tupdesc);
+#endif

 	so->listQueue = pairingheap_allocate(CompareLists, scan);

@@ -309,8 +321,12 @@ ivfflatgettuple(IndexScanDesc scan, ScanDirection dir)
 	{
 		ItemPointer heaptid = (ItemPointer) DatumGetPointer(slot_getattr(so->slot, 2, &so->isnull));

+#if PG_VERSION_NUM >= 120000
 		scan->xs_heaptid = *heaptid;
-		scan->xs_recheck = false;
+#else
+		scan->xs_ctup.t_self = *heaptid;
+#endif
+
 		scan->xs_recheckorderby = false;
 		return true;
 	}
--- a/src/ivfutils.c
+++ b/src/ivfutils.c
@@ -1,6 +1,5 @@
 #include "postgres.h"

-#include "access/generic_xlog.h"
 #include "ivfflat.h"
 #include "storage/bufmgr.h"
 #include "vector.h"
--- a/src/ivfvacuum.c
+++ b/src/ivfvacuum.c
@@ -1,6 +1,5 @@
 #include "postgres.h"

-#include "access/generic_xlog.h"
 #include "commands/vacuum.h"
 #include "ivfflat.h"
 #include "storage/bufmgr.h"
--- a/src/vector.c
+++ b/src/vector.c
@@ -3,7 +3,6 @@
 #include <math.h>

 #include "catalog/pg_type.h"
-#include "common/shortest_dec.h"
 #include "fmgr.h"
 #include "hnsw.h"
 #include "ivfflat.h"
@@ -12,7 +11,6 @@
 #include "port.h"				/* for strtof() */
 #include "utils/array.h"
 #include "utils/builtins.h"
-#include "utils/float.h"
 #include "utils/lsyscache.h"
 #include "utils/numeric.h"
 #include "vector.h"
@@ -21,6 +19,13 @@
 #include "varatt.h"
 #endif

+#if PG_VERSION_NUM >= 120000
+#include "common/shortest_dec.h"
+#include "utils/float.h"
+#else
+#include <float.h>
+#endif
+
 #if PG_VERSION_NUM < 130000
 #define TYPALIGN_DOUBLE 'd'
 #define TYPALIGN_INT 'i'
@@ -288,6 +293,15 @@ vector_out(PG_FUNCTION_ARGS)
 	char	   *ptr;
 	int			n;

+#if PG_VERSION_NUM < 120000
+	int			ndig = FLT_DIG + extra_float_digits;
+
+	if (ndig < 1)
+		ndig = 1;
+
+#define FLOAT_SHORTEST_DECIMAL_LEN (ndig + 10)
+#endif
+
 	/*
 	 * Need:
 	 *
@@ -311,7 +325,11 @@ vector_out(PG_FUNCTION_ARGS)
 			ptr++;
 		}

+#if PG_VERSION_NUM >= 120000
 		n = float_to_shortest_decimal_bufn(vector->x[i], ptr);
+#else
+		n = sprintf(ptr, "%.*g", ndig, vector->x[i]);
+#endif
 		ptr += n;
 	}
 	*ptr = ']';
@@ -866,10 +884,9 @@ vector_mul(PG_FUNCTION_ARGS)
 int
 vector_cmp_internal(Vector * a, Vector * b)
 {
-	int			dim = Min(a->dim, b->dim);
+	CheckDims(a, b);

-	/* Check values before dimensions to be consistent with Postgres arrays */
-	for (int i = 0; i < dim; i++)
+	for (int i = 0; i < a->dim; i++)
 	{
 		if (a->x[i] < b->x[i])
 			return -1;
@@ -877,13 +894,6 @@ vector_cmp_internal(Vector * a, Vector * b)
 		if (a->x[i] > b->x[i])
 			return 1;
 	}
-
-	if (a->dim < b->dim)
-		return -1;
-
-	if (a->dim > b->dim)
-		return 1;
-
 	return 0;
 }

@@ -897,9 +907,6 @@ vector_lt(PG_FUNCTION_ARGS)
 	Vector	   *a = PG_GETARG_VECTOR_P(0);
 	Vector	   *b = PG_GETARG_VECTOR_P(1);

-	/* TODO Remove in 0.7.0 */
-	CheckDims(a, b);
-
 	PG_RETURN_BOOL(vector_cmp_internal(a, b) < 0);
 }

@@ -913,9 +920,6 @@ vector_le(PG_FUNCTION_ARGS)
 	Vector	   *a = PG_GETARG_VECTOR_P(0);
 	Vector	   *b = PG_GETARG_VECTOR_P(1);

-	/* TODO Remove in 0.7.0 */
-	CheckDims(a, b);
-
 	PG_RETURN_BOOL(vector_cmp_internal(a, b) <= 0);
 }

@@ -929,9 +933,6 @@ vector_eq(PG_FUNCTION_ARGS)
 	Vector	   *a = PG_GETARG_VECTOR_P(0);
 	Vector	   *b = PG_GETARG_VECTOR_P(1);

-	/* TODO Remove in 0.7.0 */
-	CheckDims(a, b);
-
 	PG_RETURN_BOOL(vector_cmp_internal(a, b) == 0);
 }

@@ -945,9 +946,6 @@ vector_ne(PG_FUNCTION_ARGS)
 	Vector	   *a = PG_GETARG_VECTOR_P(0);
 	Vector	   *b = PG_GETARG_VECTOR_P(1);

-	/* TODO Remove in 0.7.0 */
-	CheckDims(a, b);
-
 	PG_RETURN_BOOL(vector_cmp_internal(a, b) != 0);
 }

@@ -961,9 +959,6 @@ vector_ge(PG_FUNCTION_ARGS)
 	Vector	   *a = PG_GETARG_VECTOR_P(0);
 	Vector	   *b = PG_GETARG_VECTOR_P(1);

-	/* TODO Remove in 0.7.0 */
-	CheckDims(a, b);
-
 	PG_RETURN_BOOL(vector_cmp_internal(a, b) >= 0);
 }

@@ -977,9 +972,6 @@ vector_gt(PG_FUNCTION_ARGS)
 	Vector	   *a = PG_GETARG_VECTOR_P(0);
 	Vector	   *b = PG_GETARG_VECTOR_P(1);

-	/* TODO Remove in 0.7.0 */
-	CheckDims(a, b);
-
 	PG_RETURN_BOOL(vector_cmp_internal(a, b) > 0);
 }

--- a/test/expected/functions.out
+++ b/test/expected/functions.out
@@ -24,56 +24,6 @@ SELECT '[1e37]'::vector * '[1e37]';
 ERROR:  value out of range: overflow
 SELECT '[1e-37]'::vector * '[1e-37]';
 ERROR:  value out of range: underflow
-SELECT '[1,2,3]'::vector = '[1,2,3]';
- ?column? 
----------
- t
-(1 row)
-
-SELECT '[1,2,3]'::vector = '[1,2]';
-ERROR:  different vector dimensions 3 and 2
-SELECT vector_cmp('[1,2,3]', '[1,2,3]');
- vector_cmp 
------------
-          0
-(1 row)
-
-SELECT vector_cmp('[1,2,3]', '[0,0,0]');
- vector_cmp 
------------
-          1
-(1 row)
-
-SELECT vector_cmp('[0,0,0]', '[1,2,3]');
- vector_cmp 
------------
-         -1
-(1 row)
-
-SELECT vector_cmp('[1,2]', '[1,2,3]');
- vector_cmp 
------------
-         -1
-(1 row)
-
-SELECT vector_cmp('[1,2,3]', '[1,2]');
- vector_cmp 
------------
-          1
-(1 row)
-
-SELECT vector_cmp('[1,2]', '[2,3,4]');
- vector_cmp 
------------
-         -1
-(1 row)
-
-SELECT vector_cmp('[2,3]', '[1,2,3]');
- vector_cmp 
------------
-          1
-(1 row)
-
 SELECT vector_dims('[1,2,3]');
 vector_dims 
 -------------
--- a/test/sql/functions.sql
+++ b/test/sql/functions.sql
@@ -6,17 +6,6 @@ SELECT '[1,2,3]'::vector * '[4,5,6]';
 SELECT '[1e37]'::vector * '[1e37]';
 SELECT '[1e-37]'::vector * '[1e-37]';

-SELECT '[1,2,3]'::vector = '[1,2,3]';
-SELECT '[1,2,3]'::vector = '[1,2]';
-
-SELECT vector_cmp('[1,2,3]', '[1,2,3]');
-SELECT vector_cmp('[1,2,3]', '[0,0,0]');
-SELECT vector_cmp('[0,0,0]', '[1,2,3]');
-SELECT vector_cmp('[1,2]', '[1,2,3]');
-SELECT vector_cmp('[1,2,3]', '[1,2]');
-SELECT vector_cmp('[1,2]', '[2,3,4]');
-SELECT vector_cmp('[2,3]', '[1,2,3]');
-
 SELECT vector_dims('[1,2,3]');

 SELECT round(vector_norm('[1,1]')::numeric, 5);
--- a/test/t/012_hnsw_build_recall.pl
+++ b/test/t/012_hnsw_build_recall.pl
@@ -95,10 +95,11 @@ for my $i (0 .. $#operators)

 	$node->safe_psql("postgres", "DROP INDEX idx;");

-	# Build index in parallel in memory
+	# Build index in parallel
 	my ($ret, $stdout, $stderr) = $node->psql("postgres", qq(
 		SET client_min_messages = DEBUG;
 		SET min_parallel_table_scan_size = 1;
+		SET hnsw.enable_parallel_build = on;
 		CREATE INDEX idx ON tst USING hnsw (v $opclass);
 	));
 	is($ret, 0, $stderr);
@@ -108,21 +109,6 @@ for my $i (0 .. $#operators)
 	test_recall($min, $operator);

 	$node->safe_psql("postgres", "DROP INDEX idx;");
-
-	# Build index in parallel on disk
-	# Set parallel_workers on table to use workers with low maintenance_work_mem
-	($ret, $stdout, $stderr) = $node->psql("postgres", qq(
-		ALTER TABLE tst SET (parallel_workers = 2);
-		SET client_min_messages = DEBUG;
-		SET maintenance_work_mem = '4MB';
-		CREATE INDEX idx ON tst USING hnsw (v $opclass);
-		ALTER TABLE tst RESET (parallel_workers);
-	));
-	is($ret, 0, $stderr);
-	like($stderr, qr/using \d+ parallel workers/);
-	like($stderr, qr/hnsw graph no longer fits into maintenance_work_mem/);
-
-	$node->safe_psql("postgres", "DROP INDEX idx;");
 }

 done_testing();
--- a/test/t/018_hnsw_filtering.pl
+++ b/test/t/018_hnsw_filtering.pl
@@ -1,114 +0,0 @@
-use strict;
-use warnings;
-use PostgresNode;
-use TestLib;
-use Test::More;
-
-my $dim = 3;
-my $nc = 50;
-my $limit = 20;
-
-my $array_sql = join(",", ('random()') x $dim);
-
-# Initialize node
-my $node = get_new_node('node');
-$node->init;
-$node->start;
-
-# Create table and index
-$node->safe_psql("postgres", "CREATE EXTENSION vector;");
-$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim), c int4, t text);");
-$node->safe_psql("postgres",
-	"INSERT INTO tst SELECT i, ARRAY[$array_sql], i % $nc, 'test ' || i FROM generate_series(1, 10000) i;"
-);
-$node->safe_psql("postgres", "CREATE INDEX idx ON tst USING hnsw (v vector_l2_ops);");
-$node->safe_psql("postgres", "ANALYZE tst;");
-
-# Generate query
-my @r = ();
-for (1 .. $dim)
-{
-	push(@r, rand());
-}
-my $query = "[" . join(",", @r) . "]";
-my $c = int(rand() * $nc);
-
-# Test attribute filtering
-my $explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with few rows removed
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c != $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with few rows removed comparison
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c >= 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with many rows removed comparison
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c < 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with few rows removed like
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE t LIKE '%%test%%' ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with many rows removed like
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE t LIKE '%%other%%' ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Seq Scan/);
-
-# Test distance filtering
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test distance filtering greater than distance
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' > 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test distance filtering without order
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1;
-));
-like($explain, qr/Seq Scan/);
-
-# Test distance filtering without limit
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1 ORDER BY v <-> '$query';
-));
-like($explain, qr/Seq Scan/);
-
-# Test attribute index
-$node->safe_psql("postgres", "CREATE INDEX attribute_idx ON tst (c);");
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Use attribute index
-like($explain, qr/Index Scan using idx/);
-
-# Test partial index
-$node->safe_psql("postgres", "CREATE INDEX partial_idx ON tst USING hnsw (v vector_l2_ops) WHERE (c = $c);");
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using partial_idx/);
-
-done_testing();
--- a/test/t/019_ivfflat_filtering.pl
+++ b/test/t/019_ivfflat_filtering.pl
@@ -1,116 +0,0 @@
-use strict;
-use warnings;
-use PostgresNode;
-use TestLib;
-use Test::More;
-
-my $dim = 3;
-my $nc = 50;
-my $limit = 20;
-
-my $array_sql = join(",", ('random()') x $dim);
-
-# Initialize node
-my $node = get_new_node('node');
-$node->init;
-$node->start;
-
-# Create table and index
-$node->safe_psql("postgres", "CREATE EXTENSION vector;");
-$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim), c int4, t text);");
-$node->safe_psql("postgres",
-	"INSERT INTO tst SELECT i, ARRAY[$array_sql], i % $nc, 'test ' || i FROM generate_series(1, 10000) i;"
-);
-$node->safe_psql("postgres", "CREATE INDEX idx ON tst USING ivfflat (v vector_l2_ops) WITH (lists = 100);");
-$node->safe_psql("postgres", "ANALYZE tst;");
-
-# Generate query
-my @r = ();
-for (1 .. $dim)
-{
-	push(@r, rand());
-}
-my $query = "[" . join(",", @r) . "]";
-my $c = int(rand() * $nc);
-
-# Test attribute filtering
-my $explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with few rows removed
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c != $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with few rows removed comparison
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c >= 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with many rows removed comparison
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c < 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with few rows removed like
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE t LIKE '%%test%%' ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute filtering with many rows removed like
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE t LIKE '%%other%%' ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Seq Scan/);
-
-# Test distance filtering
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-like($explain, qr/Index Scan using idx/);
-
-# Test distance filtering greater than distance
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' > 1 ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test distance filtering without order
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1;
-));
-like($explain, qr/Seq Scan/);
-
-# Test distance filtering without limit
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1 ORDER BY v <-> '$query';
-));
-# TODO Do not use index
-like($explain, qr/Index Scan using idx/);
-
-# Test attribute index
-$node->safe_psql("postgres", "CREATE INDEX attribute_idx ON tst (c);");
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Use attribute index
-like($explain, qr/Index Scan using idx/);
-
-# Test partial index
-$node->safe_psql("postgres", "CREATE INDEX partial_idx ON tst USING ivfflat (v vector_l2_ops) WITH (lists = 5) WHERE (c = $c);");
-$explain = $node->safe_psql("postgres", qq(
-	EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
-));
-# TODO Use partial index
-like($explain, qr/Index Scan using idx/);
-
-done_testing();
--- a/test/t/019_ivfflat_limit.pl
+++ b/test/t/019_ivfflat_limit.pl
@@ -0,0 +1,64 @@
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+# Initialize node
+my $node = get_new_node('node');
+$node->init;
+$node->start;
+
+# Create table and index
+$node->safe_psql("postgres", "CREATE EXTENSION vector;");
+$node->safe_psql("postgres", "CREATE TABLE tst (v vector(3));");
+$node->safe_psql("postgres",
+	"INSERT INTO tst SELECT ARRAY[random(), random(), random()] FROM generate_series(1, 1000) i;"
+);
+$node->safe_psql("postgres", "CREATE INDEX ON tst USING ivfflat (v vector_l2_ops) WITH (lists = 10);");
+
+# Test limit
+my $explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 100;
+));
+like($explain, qr/Index Scan/);
+
+# Test limit with probes
+$explain = $node->safe_psql("postgres", qq(
+	SET ivfflat.probes = 2;
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 200;
+));
+like($explain, qr/Index Scan/);
+
+# Test limit + offset
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 90 OFFSET 10;
+));
+like($explain, qr/Index Scan/);
+
+# Test limit > expected tuples
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 101;
+));
+like($explain, qr/Seq Scan/);
+
+# Test limit > expected tuples with probes
+$explain = $node->safe_psql("postgres", qq(
+	SET ivfflat.probes = 2;
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 201;
+));
+like($explain, qr/Seq Scan/);
+
+# Test limit + offset > expected tuples
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 91 OFFSET 10;
+));
+like($explain, qr/Seq Scan/);
+
+# Test no limit
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]';
+));
+like($explain, qr/Seq Scan/);
+
+done_testing();
--- a/test/t/020_hnsw_array.pl
+++ b/test/t/020_hnsw_array.pl
@@ -1,113 +0,0 @@
-use strict;
-use warnings;
-use PostgresNode;
-use TestLib;
-use Test::More;
-
-my $node;
-my @queries = ();
-my @expected;
-my $limit = 20;
-
-sub test_recall
-{
-	my ($min, $operator) = @_;
-	my $correct = 0;
-	my $total = 0;
-
-	my $explain = $node->safe_psql("postgres", qq(
-		SET enable_seqscan = off;
-		EXPLAIN ANALYZE SELECT i FROM tst ORDER BY v $operator '$queries[0]' LIMIT $limit;
-	));
-	like($explain, qr/Index Scan/);
-
-	for my $i (0 .. $#queries)
-	{
-		my $actual = $node->safe_psql("postgres", qq(
-			SET enable_seqscan = off;
-			SELECT i FROM tst ORDER BY v $operator '$queries[$i]' LIMIT $limit;
-		));
-		my @actual_ids = split("\n", $actual);
-		my %actual_set = map { $_ => 1 } @actual_ids;
-
-		my @expected_ids = split("\n", $expected[$i]);
-
-		foreach (@expected_ids)
-		{
-			if (exists($actual_set{$_}))
-			{
-				$correct++;
-			}
-			$total++;
-		}
-	}
-
-	cmp_ok($correct / $total, ">=", $min, $operator);
-}
-
-# Initialize node
-$node = get_new_node('node');
-$node->init;
-$node->start;
-
-# Create table
-$node->safe_psql("postgres", "CREATE EXTENSION vector;");
-$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v float4[3]);");
-$node->safe_psql("postgres",
-	"INSERT INTO tst SELECT i, ARRAY[random(), random(), random()] FROM generate_series(1, 10000) i;"
-);
-
-$node->safe_psql("postgres", qq(
-	CREATE FUNCTION float4_l2_distance(float4[], float4[]) RETURNS float8
-		AS 'BEGIN RETURN l2_distance(\$1::vector, \$2::vector); END;'
-		LANGUAGE plpgsql IMMUTABLE STRICT PARALLEL SAFE;
-
-	CREATE FUNCTION float4_l2_squared_distance(float4[], float4[]) RETURNS float8
-		AS 'BEGIN RETURN vector_l2_squared_distance(\$1::vector, \$2::vector); END;'
-		LANGUAGE plpgsql IMMUTABLE STRICT PARALLEL SAFE;
-
-	CREATE OPERATOR <-> (
-		LEFTARG = float4[], RIGHTARG = float4[], PROCEDURE = float4_l2_distance,
-		COMMUTATOR = '<->'
-	);
-
-	CREATE OPERATOR CLASS float4_l2_ops
-		FOR TYPE float4[] USING hnsw AS
-		OPERATOR 1 <-> (float4[], float4[]) FOR ORDER BY float_ops,
-		FUNCTION 1 float4_l2_squared_distance(float4[], float4[]);
-));
-
-# Generate queries
-for (1 .. 20)
-{
-	my $r1 = rand();
-	my $r2 = rand();
-	my $r3 = rand();
-	push(@queries, "{$r1,$r2,$r3}");
-}
-
-# Check each index type
-my @operators = ("<->");
-my @opclasses = ("float4_l2_ops");
-
-for my $i (0 .. $#operators)
-{
-	my $operator = $operators[$i];
-	my $opclass = $opclasses[$i];
-
-	# Get exact results
-	@expected = ();
-	foreach (@queries)
-	{
-		my $res = $node->safe_psql("postgres", "SELECT i FROM tst ORDER BY v $operator '$_' LIMIT $limit;");
-		push(@expected, $res);
-	}
-
-	# Add index
-	$node->safe_psql("postgres", "CREATE INDEX ON tst USING hnsw (v $opclass);");
-
-	my $min = $operator eq "<#>" ? 0.80 : 0.99;
-	test_recall($min, $operator);
-}
-
-done_testing();
--- a/test/t/020_hnsw_limit.pl
+++ b/test/t/020_hnsw_limit.pl
@@ -0,0 +1,62 @@
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More;
+
+# Initialize node
+my $node = get_new_node('node');
+$node->init;
+$node->start;
+
+# Create table and index
+$node->safe_psql("postgres", "CREATE EXTENSION vector;");
+$node->safe_psql("postgres", "CREATE TABLE tst (v vector(3));");
+$node->safe_psql("postgres",
+	"INSERT INTO tst SELECT ARRAY[random(), random(), random()] FROM generate_series(1, 1000) i;"
+);
+$node->safe_psql("postgres", "CREATE INDEX ON tst USING hnsw (v vector_l2_ops);");
+
+# Test limit
+my $explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 40;
+));
+like($explain, qr/Index Scan/);
+
+# Test limit with CTE
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE WITH cte AS (SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 40) SELECT * FROM cte;
+));
+like($explain, qr/Index Scan/);
+
+# Test limit + offset
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 30 OFFSET 10;
+));
+like($explain, qr/Index Scan/);
+
+# Test limit > ef_search
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 41;
+));
+like($explain, qr/Seq Scan/);
+
+# Test limit > ef_search with CTE
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE WITH cte AS (SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 41) SELECT * FROM cte;
+));
+like($explain, qr/Seq Scan/);
+
+# Test limit + offset > ef_search
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]' LIMIT 31 OFFSET 10;
+));
+like($explain, qr/Seq Scan/);
+
+# Test no limit
+$explain = $node->safe_psql("postgres", qq(
+	EXPLAIN ANALYZE SELECT * FROM tst ORDER BY v <-> '[1,2,3]';
+));
+like($explain, qr/Seq Scan/);
+
+done_testing();
--- a/vector.control
+++ b/vector.control
@@ -1,4 +1,4 @@
 comment = 'vector data type and ivfflat and hnsw access methods'
-default_version = '0.6.0'
+default_version = '0.5.1'
 module_pathname = '$libdir/vector'
 relocatable = true