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12 Commits

Author SHA1 Message Date
Andrew Kane
e4ac05f044 Limit max probes [skip ci] 2024-09-22 11:20:28 -07:00
Andrew Kane
25f97fd91d Updated cost estimation [skip ci] 2024-09-22 11:17:29 -07:00
Andrew Kane
cd3f9a38ae Added max_probes option [skip ci] 2024-09-21 20:19:26 -07:00
Andrew Kane
ff6267917e Improved approach [skip ci] 2024-09-21 19:55:55 -07:00
Andrew Kane
c950c5ffaa Merge branch 'master' into ivfflat-streaming 2024-09-21 19:26:12 -07:00
Andrew Kane
88f56dc234 Merge branch 'master' into ivfflat-streaming 2024-09-21 18:37:31 -07:00
Andrew Kane
e2ba6cf38f Updated comment [skip ci] 2024-09-20 21:33:46 -07:00
Andrew Kane
689f9c4659 Added cost estimation [skip ci] 2024-09-20 21:30:52 -07:00
Andrew Kane
88889f5a4c Fixed CI [skip ci] 2024-09-20 12:52:08 -07:00
Andrew Kane
79851729f1 Improved streaming test 2024-09-20 11:13:03 -07:00
Andrew Kane
3fd6a29c49 Added test for streaming recall [skip ci] 2024-09-20 10:50:53 -07:00
Andrew Kane
2c58804756 Added streaming option for IVFFlat [skip ci] 2024-09-20 10:20:40 -07:00
20 changed files with 246 additions and 647 deletions

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@@ -1,8 +1,6 @@
## 0.8.0 (unreleased) ## 0.8.0 (unreleased)
- Added support for iterative index scans
- Added casts for arrays to `sparsevec` - Added casts for arrays to `sparsevec`
- Improved cost estimation
- Reduced memory usage for HNSW index scans - Reduced memory usage for HNSW index scans
- Dropped support for Postgres 12 - Dropped support for Postgres 12

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@@ -445,63 +445,6 @@ Use [partitioning](https://www.postgresql.org/docs/current/ddl-partitioning.html
CREATE TABLE items (embedding vector(3), category_id int) PARTITION BY LIST(category_id); CREATE TABLE items (embedding vector(3), category_id int) PARTITION BY LIST(category_id);
``` ```
## Streaming Queries [unreleased]
*Added in 0.8.0*
With approximate indexes, you can end up with less results than expected due to filtering conditions in the query.
Starting with 0.8.0, you can enable streaming queries. If too few results from the initial index scan match the query filters, it will resume scanning until enough results are found. This can significantly improve recall (at the cost of speed).
```tsql
SET hnsw.streaming = on;
-- or
SET ivfflat.streaming = on;
```
### Streaming Options
Since scanning a large portion of the index is expensive, there are options to control when the scan ends.
#### HNSW
Specify the max number of additional tuples visited
```sql
SET hnsw.ef_stream = 10000;
```
The scan will also end if reaches `work_mem`, at which point a notice is shown
```text
NOTICE: hnsw index scan exceeded work_mem after 50000 tuples
HINT: Increase work_mem to scan more tuples.
```
Adjust this with:
```sql
SET work_mem = '8MB';
```
#### IVFFlat
Specify the max number of probes
```sql
SET ivfflat.max_probes = 100;
```
### Streaming Order
With streaming queries, its possible for rows to be slightly out of order by distance. For strict ordering, use:
```sql
WITH approx_order AS MATERIALIZED (
SELECT *, embedding <-> '[1,2,3]' AS distance FROM items WHERE ... ORDER BY distance LIMIT 5
) SELECT * FROM approx_order ORDER BY distance;
```
## Half-Precision Vectors ## Half-Precision Vectors
*Added in 0.7.0* *Added in 0.7.0*

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@@ -159,6 +159,24 @@ CheckStateArray(ArrayType *statearray, const char *caller)
return (float8 *) ARR_DATA_PTR(statearray); return (float8 *) ARR_DATA_PTR(statearray);
} }
#if PG_VERSION_NUM < 120003
static pg_noinline void
float_overflow_error(void)
{
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("value out of range: overflow")));
}
static pg_noinline void
float_underflow_error(void)
{
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("value out of range: underflow")));
}
#endif
/* /*
* Convert textual representation to internal representation * Convert textual representation to internal representation
*/ */

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@@ -12,15 +12,12 @@
#include "utils/float.h" #include "utils/float.h"
#include "utils/guc.h" #include "utils/guc.h"
#include "utils/selfuncs.h" #include "utils/selfuncs.h"
#include "utils/spccache.h"
#if PG_VERSION_NUM < 150000 #if PG_VERSION_NUM < 150000
#define MarkGUCPrefixReserved(x) EmitWarningsOnPlaceholders(x) #define MarkGUCPrefixReserved(x) EmitWarningsOnPlaceholders(x)
#endif #endif
int hnsw_ef_search; int hnsw_ef_search;
int hnsw_ef_stream;
bool hnsw_streaming;
int hnsw_lock_tranche_id; int hnsw_lock_tranche_id;
static relopt_kind hnsw_relopt_kind; static relopt_kind hnsw_relopt_kind;
@@ -71,17 +68,6 @@ HnswInit(void)
"Valid range is 1..1000.", &hnsw_ef_search, "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); HNSW_DEFAULT_EF_SEARCH, HNSW_MIN_EF_SEARCH, HNSW_MAX_EF_SEARCH, PGC_USERSET, 0, NULL, NULL, NULL);
/* TODO Figure out name */
DefineCustomBoolVariable("hnsw.streaming", "Use streaming mode",
NULL, &hnsw_streaming,
HNSW_DEFAULT_STREAMING, PGC_USERSET, 0, NULL, NULL, NULL);
/* TODO Figure out name */
/* TODO Use same value as ivfflat.max_probes for "all" */
DefineCustomIntVariable("hnsw.ef_stream", "Sets the max number of additional candidates to visit for streaming search",
"-1 means all", &hnsw_ef_stream,
HNSW_DEFAULT_EF_STREAM, HNSW_MIN_EF_STREAM, HNSW_MAX_EF_STREAM, PGC_USERSET, 0, NULL, NULL, NULL);
MarkGUCPrefixReserved("hnsw"); MarkGUCPrefixReserved("hnsw");
} }
@@ -102,33 +88,6 @@ hnswbuildphasename(int64 phasenum)
} }
} }
/*
* Estimate ef needed for iterative scans
*/
static int
EstimateEf(PlannerInfo *root, IndexPath *path)
{
double selectivity = 1;
ListCell *lc;
/* Cannot estimate without limit */
/* limit_tuples includes offset */
if (root->limit_tuples < 0)
return 0;
/* Get the selectivity of non-index conditions */
foreach(lc, path->indexinfo->indrestrictinfo)
{
RestrictInfo *rinfo = lfirst(lc);
/* Skip DEFAULT_INEQ_SEL since it may be a distance filter */
if (rinfo->norm_selec >= 0 && rinfo->norm_selec <= 1 && rinfo->norm_selec != (Selectivity) DEFAULT_INEQ_SEL)
selectivity *= rinfo->norm_selec;
}
return root->limit_tuples / Max(selectivity, 0.00001);
}
/* /*
* Estimate the cost of an index scan * Estimate the cost of an index scan
*/ */
@@ -140,12 +99,7 @@ hnswcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
{ {
GenericCosts costs; GenericCosts costs;
int m; int m;
int ef;
int entryLevel; int entryLevel;
int layer0TuplesMax;
double layer0Selectivity;
double scalingFactor = 0.55;
double spc_seq_page_cost;
Relation index; Relation index;
/* Never use index without order */ /* Never use index without order */
@@ -165,57 +119,15 @@ hnswcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
HnswGetMetaPageInfo(index, &m, NULL); HnswGetMetaPageInfo(index, &m, NULL);
index_close(index, NoLock); index_close(index, NoLock);
ef = hnsw_streaming ? Max(hnsw_ef_search, EstimateEf(root, path)) : hnsw_ef_search; /* Approximate entry level */
entryLevel = (int) -log(1.0 / path->indexinfo->tuples) * HnswGetMl(m);
/* /* TODO Improve estimate of visited tuples (currently underestimates) */
* HNSW cost estimation follows a formula that accounts for the total /* Account for number of tuples (or entry level), m, and ef_search */
* number of tuples indexed combined with the parameters that most costs.numIndexTuples = (entryLevel + 2) * m;
* influence the duration of the index scan, namely: m - the number of
* tuples that are scanned in each step of the HNSW graph traversal
* ef_search - which influences the total number of steps taken at layer 0
*
* The source of the vector data can impact how many steps it takes to
* converge on the set of vectors to return to the executor. Currently, we
* use a hardcoded scaling factor (HNSWScanScalingFactor) to help
* influence that, but this could later become a configurable parameter
* based on the cost estimations.
*
* The tuple estimator formula is below:
*
* numIndexTuples = entryLevel * m + layer0TuplesMax * layer0Selectivity
*
* "entryLevel * m" represents the floor of tuples we need to scan to get
* to layer 0 (L0).
*
* "layer0TuplesMax" is the estimated total number of tuples we'd scan at
* L0 if we weren't discarding already visited tuples as part of the scan.
*
* "layer0Selectivity" estimates the percentage of tuples that are scanned
* at L0, accounting for previously visited tuples, multiplied by the
* "scalingFactor" (currently hardcoded).
*/
entryLevel = (int) (log(path->indexinfo->tuples + 1) * HnswGetMl(m));
layer0TuplesMax = HnswGetLayerM(m, 0) * ef;
layer0Selectivity = (scalingFactor * log(path->indexinfo->tuples + 1)) /
(log(m) * (1 + log(ef)));
costs.numIndexTuples = (entryLevel * m) +
(layer0TuplesMax * layer0Selectivity);
genericcostestimate(root, path, loop_count, &costs); genericcostestimate(root, path, loop_count, &costs);
get_tablespace_page_costs(path->indexinfo->reltablespace, NULL, &spc_seq_page_cost);
/* Adjust cost if needed since TOAST not included in seq scan cost */
if (costs.numIndexPages > path->indexinfo->rel->pages)
{
/* Change all page cost from random to sequential */
costs.indexTotalCost -= costs.numIndexPages * (costs.spc_random_page_cost - spc_seq_page_cost);
/* Remove cost of extra pages */
costs.indexTotalCost -= (costs.numIndexPages - path->indexinfo->rel->pages) * spc_seq_page_cost;
}
/* Use total cost since most work happens before first tuple is returned */ /* Use total cost since most work happens before first tuple is returned */
*indexStartupCost = costs.indexTotalCost; *indexStartupCost = costs.indexTotalCost;
*indexTotalCost = costs.indexTotalCost; *indexTotalCost = costs.indexTotalCost;

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@@ -12,10 +12,6 @@
#include "utils/sampling.h" #include "utils/sampling.h"
#include "vector.h" #include "vector.h"
#ifdef HNSW_BENCH
#include "portability/instr_time.h"
#endif
#define HNSW_MAX_DIM 2000 #define HNSW_MAX_DIM 2000
#define HNSW_MAX_NNZ 1000 #define HNSW_MAX_NNZ 1000
@@ -46,10 +42,6 @@
#define HNSW_DEFAULT_EF_SEARCH 40 #define HNSW_DEFAULT_EF_SEARCH 40
#define HNSW_MIN_EF_SEARCH 1 #define HNSW_MIN_EF_SEARCH 1
#define HNSW_MAX_EF_SEARCH 1000 #define HNSW_MAX_EF_SEARCH 1000
#define HNSW_DEFAULT_STREAMING false
#define HNSW_DEFAULT_EF_STREAM -1
#define HNSW_MIN_EF_STREAM -1
#define HNSW_MAX_EF_STREAM INT_MAX
/* Tuple types */ /* Tuple types */
#define HNSW_ELEMENT_TUPLE_TYPE 1 #define HNSW_ELEMENT_TUPLE_TYPE 1
@@ -76,21 +68,6 @@
#define HnswPageGetOpaque(page) ((HnswPageOpaque) PageGetSpecialPointer(page)) #define HnswPageGetOpaque(page) ((HnswPageOpaque) PageGetSpecialPointer(page))
#define HnswPageGetMeta(page) ((HnswMetaPageData *) PageGetContents(page)) #define HnswPageGetMeta(page) ((HnswMetaPageData *) PageGetContents(page))
#ifdef HNSW_BENCH
#define HnswBench(name, code) \
do { \
instr_time start; \
instr_time duration; \
INSTR_TIME_SET_CURRENT(start); \
(code); \
INSTR_TIME_SET_CURRENT(duration); \
INSTR_TIME_SUBTRACT(duration, start); \
elog(INFO, "%s: %.3f ms", name, INSTR_TIME_GET_MILLISEC(duration)); \
} while (0)
#else
#define HnswBench(name, code) (code)
#endif
#if PG_VERSION_NUM >= 150000 #if PG_VERSION_NUM >= 150000
#define RandomDouble() pg_prng_double(&pg_global_prng_state) #define RandomDouble() pg_prng_double(&pg_global_prng_state)
#define SeedRandom(seed) pg_prng_seed(&pg_global_prng_state, seed) #define SeedRandom(seed) pg_prng_seed(&pg_global_prng_state, seed)
@@ -129,8 +106,6 @@
/* Variables */ /* Variables */
extern int hnsw_ef_search; extern int hnsw_ef_search;
extern int hnsw_ef_stream;
extern bool hnsw_streaming;
extern int hnsw_lock_tranche_id; extern int hnsw_lock_tranche_id;
typedef struct HnswElementData HnswElementData; typedef struct HnswElementData HnswElementData;
@@ -154,7 +129,6 @@ struct HnswElementData
uint8 heaptidsLength; uint8 heaptidsLength;
uint8 level; uint8 level;
uint8 deleted; uint8 deleted;
uint8 version;
uint32 hash; uint32 hash;
HnswNeighborsPtr neighbors; HnswNeighborsPtr neighbors;
BlockNumber blkno; BlockNumber blkno;
@@ -189,9 +163,6 @@ typedef struct HnswSearchCandidate
float distance; float distance;
} HnswSearchCandidate; } HnswSearchCandidate;
#define HnswGetSearchCandidate(membername, ptr) pairingheap_container(HnswSearchCandidate, membername, ptr)
#define HnswGetSearchCandidateConst(membername, ptr) pairingheap_const_container(HnswSearchCandidate, membername, ptr)
/* HNSW index options */ /* HNSW index options */
typedef struct HnswOptions typedef struct HnswOptions
{ {
@@ -335,10 +306,10 @@ typedef struct HnswElementTupleData
uint8 type; uint8 type;
uint8 level; uint8 level;
uint8 deleted; uint8 deleted;
uint8 version; uint8 unused;
ItemPointerData heaptids[HNSW_HEAPTIDS]; ItemPointerData heaptids[HNSW_HEAPTIDS];
ItemPointerData neighbortid; ItemPointerData neighbortid;
uint16 unused; uint16 unused2;
Vector data; Vector data;
} HnswElementTupleData; } HnswElementTupleData;
@@ -347,31 +318,18 @@ typedef HnswElementTupleData * HnswElementTuple;
typedef struct HnswNeighborTupleData typedef struct HnswNeighborTupleData
{ {
uint8 type; uint8 type;
uint8 version; uint8 unused;
uint16 count; uint16 count;
ItemPointerData indextids[FLEXIBLE_ARRAY_MEMBER]; ItemPointerData indextids[FLEXIBLE_ARRAY_MEMBER];
} HnswNeighborTupleData; } HnswNeighborTupleData;
typedef HnswNeighborTupleData * HnswNeighborTuple; typedef HnswNeighborTupleData * HnswNeighborTuple;
typedef union
{
struct pointerhash_hash *pointers;
struct offsethash_hash *offsets;
struct tidhash_hash *tids;
} visited_hash;
typedef struct HnswScanOpaqueData typedef struct HnswScanOpaqueData
{ {
const HnswTypeInfo *typeInfo; const HnswTypeInfo *typeInfo;
bool first; bool first;
List *w; List *w;
visited_hash v;
pairingheap *discarded;
Datum q;
int m;
int64 tuples;
double previousDistance;
MemoryContext tmpCtx; MemoryContext tmpCtx;
/* Support functions */ /* Support functions */
@@ -417,7 +375,7 @@ bool HnswCheckNorm(FmgrInfo *procinfo, Oid collation, Datum value);
Buffer HnswNewBuffer(Relation index, ForkNumber forkNum); Buffer HnswNewBuffer(Relation index, ForkNumber forkNum);
void HnswInitPage(Buffer buf, Page page); void HnswInitPage(Buffer buf, Page page);
void HnswInit(void); 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, visited_hash * v, pairingheap **discarded, bool initVisited, int64 *tuples); List *HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement);
HnswElement HnswGetEntryPoint(Relation index); HnswElement HnswGetEntryPoint(Relation index);
void HnswGetMetaPageInfo(Relation index, int *m, HnswElement * entryPoint); void HnswGetMetaPageInfo(Relation index, int *m, HnswElement * entryPoint);
void *HnswAlloc(HnswAllocator * allocator, Size size); void *HnswAlloc(HnswAllocator * allocator, Size size);

View File

@@ -36,7 +36,7 @@ GetInsertPage(Relation index)
* Check for a free offset * Check for a free offset
*/ */
static bool static bool
HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size etupSize, Size ntupSize, Buffer *nbuf, Page *npage, OffsetNumber *freeOffno, OffsetNumber *freeNeighborOffno, BlockNumber *newInsertPage, uint8 *tupleVersion) HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size etupSize, Size ntupSize, Buffer *nbuf, Page *npage, OffsetNumber *freeOffno, OffsetNumber *freeNeighborOffno, BlockNumber *newInsertPage)
{ {
OffsetNumber offno; OffsetNumber offno;
OffsetNumber maxoffno = PageGetMaxOffsetNumber(page); OffsetNumber maxoffno = PageGetMaxOffsetNumber(page);
@@ -98,7 +98,6 @@ HnswFreeOffset(Relation index, Buffer buf, Page page, HnswElement element, Size
{ {
*freeOffno = offno; *freeOffno = offno;
*freeNeighborOffno = neighborOffno; *freeNeighborOffno = neighborOffno;
*tupleVersion = etup->version;
return true; return true;
} }
else if (*nbuf != buf) else if (*nbuf != buf)
@@ -154,7 +153,6 @@ AddElementOnDisk(Relation index, HnswElement e, int m, BlockNumber insertPage, B
OffsetNumber freeOffno = InvalidOffsetNumber; OffsetNumber freeOffno = InvalidOffsetNumber;
OffsetNumber freeNeighborOffno = InvalidOffsetNumber; OffsetNumber freeNeighborOffno = InvalidOffsetNumber;
BlockNumber newInsertPage = InvalidBlockNumber; BlockNumber newInsertPage = InvalidBlockNumber;
uint8 tupleVersion;
char *base = NULL; char *base = NULL;
/* Calculate sizes */ /* Calculate sizes */
@@ -204,7 +202,7 @@ AddElementOnDisk(Relation index, HnswElement e, int m, BlockNumber insertPage, B
} }
/* Next, try space from a deleted element */ /* Next, try space from a deleted element */
if (HnswFreeOffset(index, buf, page, e, etupSize, ntupSize, &nbuf, &npage, &freeOffno, &freeNeighborOffno, &newInsertPage, &tupleVersion)) if (HnswFreeOffset(index, buf, page, e, etupSize, ntupSize, &nbuf, &npage, &freeOffno, &freeNeighborOffno, &newInsertPage))
{ {
if (nbuf != buf) if (nbuf != buf)
{ {
@@ -214,10 +212,6 @@ AddElementOnDisk(Relation index, HnswElement e, int m, BlockNumber insertPage, B
npage = GenericXLogRegisterBuffer(state, nbuf, 0); npage = GenericXLogRegisterBuffer(state, nbuf, 0);
} }
/* Set tuple version */
etup->version = tupleVersion;
ntup->version = tupleVersion;
break; break;
} }

View File

@@ -1,7 +1,5 @@
#include "postgres.h" #include "postgres.h"
#include <float.h>
#include "access/relscan.h" #include "access/relscan.h"
#include "hnsw.h" #include "hnsw.h"
#include "pgstat.h" #include "pgstat.h"
@@ -28,9 +26,6 @@ GetScanItems(IndexScanDesc scan, Datum q)
/* Get m and entry point */ /* Get m and entry point */
HnswGetMetaPageInfo(index, &m, &entryPoint); HnswGetMetaPageInfo(index, &m, &entryPoint);
so->q = q;
so->m = m;
if (entryPoint == NULL) if (entryPoint == NULL)
return NIL; return NIL;
@@ -38,44 +33,11 @@ GetScanItems(IndexScanDesc scan, Datum q)
for (int lc = entryPoint->level; lc >= 1; lc--) for (int lc = entryPoint->level; lc >= 1; lc--)
{ {
w = HnswSearchLayer(base, q, ep, 1, lc, index, procinfo, collation, m, false, NULL, NULL, NULL, true, NULL); w = HnswSearchLayer(base, q, ep, 1, lc, index, procinfo, collation, m, false, NULL);
ep = w; ep = w;
} }
return HnswSearchLayer(base, q, ep, hnsw_ef_search, 0, index, procinfo, collation, m, false, NULL, &so->v, hnsw_streaming ? &so->discarded : NULL, true, &so->tuples); return HnswSearchLayer(base, q, ep, hnsw_ef_search, 0, index, procinfo, collation, m, false, NULL);
}
/*
* Resume scan at ground level with discarded candidates
*/
static List *
ResumeScanItems(IndexScanDesc scan)
{
HnswScanOpaque so = (HnswScanOpaque) scan->opaque;
Relation index = scan->indexRelation;
FmgrInfo *procinfo = so->procinfo;
Oid collation = so->collation;
List *ep = NIL;
char *base = NULL;
int batch_size = hnsw_ef_search;
if (pairingheap_is_empty(so->discarded))
return NIL;
/* Get next batch of candidates */
for (int i = 0; i < batch_size; i++)
{
HnswSearchCandidate *hc;
if (pairingheap_is_empty(so->discarded))
break;
hc = HnswGetSearchCandidate(w_node, pairingheap_remove_first(so->discarded));
ep = lappend(ep, hc);
}
return HnswSearchLayer(base, so->q, ep, batch_size, 0, index, procinfo, collation, so->m, false, NULL, &so->v, &so->discarded, false, &so->tuples);
} }
/* /*
@@ -119,8 +81,6 @@ hnswbeginscan(Relation index, int nkeys, int norderbys)
so = (HnswScanOpaque) palloc(sizeof(HnswScanOpaqueData)); so = (HnswScanOpaque) palloc(sizeof(HnswScanOpaqueData));
so->typeInfo = HnswGetTypeInfo(index); so->typeInfo = HnswGetTypeInfo(index);
so->first = true; so->first = true;
so->v.tids = NULL;
so->discarded = NULL;
so->tmpCtx = AllocSetContextCreate(CurrentMemoryContext, so->tmpCtx = AllocSetContextCreate(CurrentMemoryContext,
"Hnsw scan temporary context", "Hnsw scan temporary context",
ALLOCSET_DEFAULT_SIZES); ALLOCSET_DEFAULT_SIZES);
@@ -143,15 +103,7 @@ hnswrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int no
{ {
HnswScanOpaque so = (HnswScanOpaque) scan->opaque; HnswScanOpaque so = (HnswScanOpaque) scan->opaque;
if (so->v.tids != NULL)
tidhash_reset(so->v.tids);
if (so->discarded != NULL)
pairingheap_reset(so->discarded);
so->first = true; so->first = true;
so->tuples = 0;
so->previousDistance = -INFINITY;
MemoryContextReset(so->tmpCtx); MemoryContextReset(so->tmpCtx);
if (keys && scan->numberOfKeys > 0) if (keys && scan->numberOfKeys > 0)
@@ -201,7 +153,7 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
*/ */
LockPage(scan->indexRelation, HNSW_SCAN_LOCK, ShareLock); LockPage(scan->indexRelation, HNSW_SCAN_LOCK, ShareLock);
HnswBench("scan iteration", so->w = GetScanItems(scan, value)); so->w = GetScanItems(scan, value);
/* Release shared lock */ /* Release shared lock */
UnlockPage(scan->indexRelation, HNSW_SCAN_LOCK, ShareLock); UnlockPage(scan->indexRelation, HNSW_SCAN_LOCK, ShareLock);
@@ -213,97 +165,22 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
#endif #endif
} }
for (;;) while (list_length(so->w) > 0)
{ {
char *base = NULL; char *base = NULL;
HnswSearchCandidate *hc; HnswSearchCandidate *hc = llast(so->w);
HnswElement element; HnswElement element = HnswPtrAccess(base, hc->element);
ItemPointer heaptid; ItemPointer heaptid;
if (list_length(so->w) == 0)
{
if (!hnsw_streaming)
break;
/* Empty index */
if (so->discarded == NULL)
break;
/* Reached max number of additional tuples */
if (hnsw_ef_stream != -1 && so->tuples >= hnsw_ef_search + hnsw_ef_stream)
{
if (pairingheap_is_empty(so->discarded))
break;
/* Return remaining tuples */
so->w = lappend(so->w, HnswGetSearchCandidate(w_node, pairingheap_remove_first(so->discarded)));
}
/* Prevent scans from consuming too much memory */
else if (MemoryContextMemAllocated(so->tmpCtx, false) > (Size) work_mem * 1024L)
{
if (pairingheap_is_empty(so->discarded))
{
ereport(NOTICE,
(errmsg("hnsw index scan exceeded work_mem after " INT64_FORMAT " tuples", so->tuples),
errhint("Increase work_mem to scan more tuples.")));
break;
}
/* Return remaining tuples */
so->w = lappend(so->w, HnswGetSearchCandidate(w_node, pairingheap_remove_first(so->discarded)));
}
else
{
/*
* Locking ensures when neighbors are read, the elements they
* reference will not be deleted (and replaced) during the
* iteration.
*
* Elements loaded into memory on previous iterations may have
* been deleted (and replaced), so when reading neighbors, the
* element version must be checked.
*/
LockPage(scan->indexRelation, HNSW_SCAN_LOCK, ShareLock);
HnswBench("scan iteration", so->w = ResumeScanItems(scan));
UnlockPage(scan->indexRelation, HNSW_SCAN_LOCK, ShareLock);
#if defined(HNSW_MEMORY)
elog(INFO, "memory: %zu KB", MemoryContextMemAllocated(so->tmpCtx, false) / 1024);
#endif
}
if (list_length(so->w) == 0)
break;
}
hc = llast(so->w);
element = HnswPtrAccess(base, hc->element);
/* Move to next element if no valid heap TIDs */ /* Move to next element if no valid heap TIDs */
if (element->heaptidsLength == 0) if (element->heaptidsLength == 0)
{ {
so->w = list_delete_last(so->w); so->w = list_delete_last(so->w);
/* Mark memory as free for next iteration */
if (hnsw_streaming)
{
pfree(element);
pfree(hc);
}
continue; continue;
} }
heaptid = &element->heaptids[--element->heaptidsLength]; heaptid = &element->heaptids[--element->heaptidsLength];
if (hc->distance < so->previousDistance)
continue;
so->previousDistance = hc->distance;
MemoryContextSwitchTo(oldCtx); MemoryContextSwitchTo(oldCtx);
scan->xs_heaptid = *heaptid; scan->xs_heaptid = *heaptid;

View File

@@ -100,6 +100,13 @@ hash_offset(Size offset)
#define SH_DEFINE #define SH_DEFINE
#include "lib/simplehash.h" #include "lib/simplehash.h"
typedef union
{
pointerhash_hash *pointers;
offsethash_hash *offsets;
tidhash_hash *tids;
} visited_hash;
typedef union typedef union
{ {
HnswElement element; HnswElement element;
@@ -246,8 +253,6 @@ HnswInitElement(char *base, ItemPointer heaptid, int m, double ml, int maxLevel,
element->level = level; element->level = level;
element->deleted = 0; element->deleted = 0;
/* Start at one to make it easier to find issues */
element->version = 1;
HnswInitNeighbors(base, element, m, allocator); HnswInitNeighbors(base, element, m, allocator);
@@ -400,7 +405,6 @@ HnswSetElementTuple(char *base, HnswElementTuple etup, HnswElement element)
etup->type = HNSW_ELEMENT_TUPLE_TYPE; etup->type = HNSW_ELEMENT_TUPLE_TYPE;
etup->level = element->level; etup->level = element->level;
etup->deleted = 0; etup->deleted = 0;
etup->version = element->version;
for (int i = 0; i < HNSW_HEAPTIDS; i++) for (int i = 0; i < HNSW_HEAPTIDS; i++)
{ {
if (i < element->heaptidsLength) if (i < element->heaptidsLength)
@@ -443,7 +447,6 @@ HnswSetNeighborTuple(char *base, HnswNeighborTuple ntup, HnswElement e, int m)
} }
ntup->count = idx; ntup->count = idx;
ntup->version = e->version;
} }
/* /*
@@ -517,7 +520,6 @@ HnswLoadElementFromTuple(HnswElement element, HnswElementTuple etup, bool loadHe
{ {
element->level = etup->level; element->level = etup->level;
element->deleted = etup->deleted; element->deleted = etup->deleted;
element->version = etup->version;
element->neighborPage = ItemPointerGetBlockNumber(&etup->neighbortid); element->neighborPage = ItemPointerGetBlockNumber(&etup->neighbortid);
element->neighborOffno = ItemPointerGetOffsetNumber(&etup->neighbortid); element->neighborOffno = ItemPointerGetOffsetNumber(&etup->neighbortid);
element->heaptidsLength = 0; element->heaptidsLength = 0;
@@ -619,6 +621,9 @@ HnswEntryCandidate(char *base, HnswElement entryPoint, Datum q, Relation index,
return hc; return hc;
} }
#define HnswGetSearchCandidate(membername, ptr) pairingheap_container(HnswSearchCandidate, membername, ptr)
#define HnswGetSearchCandidateConst(membername, ptr) pairingheap_const_container(HnswSearchCandidate, membername, ptr)
/* /*
* Compare candidate distances * Compare candidate distances
*/ */
@@ -634,21 +639,6 @@ CompareNearestCandidates(const pairingheap_node *a, const pairingheap_node *b, v
return 0; return 0;
} }
/*
* Compare discarded candidate distances
*/
static int
CompareNearestDiscardedCandidates(const pairingheap_node *a, const pairingheap_node *b, void *arg)
{
if (HnswGetSearchCandidateConst(w_node, a)->distance < HnswGetSearchCandidateConst(w_node, b)->distance)
return 1;
if (HnswGetSearchCandidateConst(w_node, a)->distance > HnswGetSearchCandidateConst(w_node, b)->distance)
return -1;
return 0;
}
/* /*
* Compare candidate distances * Compare candidate distances
*/ */
@@ -764,30 +754,20 @@ HnswLoadUnvisitedFromDisk(HnswElement element, HnswUnvisited * unvisited, int *u
int start; int start;
ItemPointerData indextids[HNSW_MAX_M * 2]; ItemPointerData indextids[HNSW_MAX_M * 2];
*unvisitedLength = 0;
buf = ReadBuffer(index, element->neighborPage); buf = ReadBuffer(index, element->neighborPage);
LockBuffer(buf, BUFFER_LOCK_SHARE); LockBuffer(buf, BUFFER_LOCK_SHARE);
page = BufferGetPage(buf); page = BufferGetPage(buf);
ntup = (HnswNeighborTuple) PageGetItem(page, PageGetItemId(page, element->neighborOffno)); ntup = (HnswNeighborTuple) PageGetItem(page, PageGetItemId(page, element->neighborOffno));
start = (element->level - lc) * m;
/*
* Ensure the neighbor tuple has not been deleted or replaced between
* index scan iterations
*/
if (ntup->version != element->version || ntup->count != (element->level + 2) * m)
{
UnlockReleaseBuffer(buf);
return;
}
/* Copy to minimize lock time */ /* Copy to minimize lock time */
start = (element->level - lc) * m;
memcpy(&indextids, ntup->indextids + start, lm * sizeof(ItemPointerData)); memcpy(&indextids, ntup->indextids + start, lm * sizeof(ItemPointerData));
UnlockReleaseBuffer(buf); UnlockReleaseBuffer(buf);
*unvisitedLength = 0;
for (int i = 0; i < lm; i++) for (int i = 0; i < lm; i++)
{ {
ItemPointer indextid = &indextids[i]; ItemPointer indextid = &indextids[i];
@@ -807,13 +787,13 @@ HnswLoadUnvisitedFromDisk(HnswElement element, HnswUnvisited * unvisited, int *u
* Algorithm 2 from paper * Algorithm 2 from paper
*/ */
List * List *
HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement, visited_hash * v, pairingheap **discarded, bool initVisited, int64 *tuples) HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, FmgrInfo *procinfo, Oid collation, int m, bool inserting, HnswElement skipElement)
{ {
List *w = NIL; List *w = NIL;
pairingheap *C = pairingheap_allocate(CompareNearestCandidates, NULL); pairingheap *C = pairingheap_allocate(CompareNearestCandidates, NULL);
pairingheap *W = pairingheap_allocate(CompareFurthestCandidates, NULL); pairingheap *W = pairingheap_allocate(CompareFurthestCandidates, NULL);
int wlen = 0; int wlen = 0;
visited_hash vh; visited_hash v;
ListCell *lc2; ListCell *lc2;
HnswNeighborArray *localNeighborhood = NULL; HnswNeighborArray *localNeighborhood = NULL;
Size neighborhoodSize = 0; Size neighborhoodSize = 0;
@@ -821,19 +801,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
HnswUnvisited *unvisited = palloc(lm * sizeof(HnswUnvisited)); HnswUnvisited *unvisited = palloc(lm * sizeof(HnswUnvisited));
int unvisitedLength; int unvisitedLength;
if (v == NULL) InitVisited(base, &v, index, ef, m);
{
v = &vh;
initVisited = true;
}
if (initVisited)
{
InitVisited(base, v, index, ef, m);
if (discarded != NULL)
*discarded = pairingheap_allocate(CompareNearestDiscardedCandidates, NULL);
}
/* Create local memory for neighborhood if needed */ /* Create local memory for neighborhood if needed */
if (index == NULL) if (index == NULL)
@@ -848,13 +816,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
HnswSearchCandidate *hc = (HnswSearchCandidate *) lfirst(lc2); HnswSearchCandidate *hc = (HnswSearchCandidate *) lfirst(lc2);
bool found; bool found;
if (initVisited) AddToVisited(base, &v, hc->element, index, &found);
{
AddToVisited(base, v, hc->element, index, &found);
if (tuples != NULL)
(*tuples)++;
}
pairingheap_add(C, &hc->c_node); pairingheap_add(C, &hc->c_node);
pairingheap_add(W, &hc->w_node); pairingheap_add(W, &hc->w_node);
@@ -880,12 +842,9 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
cElement = HnswPtrAccess(base, c->element); cElement = HnswPtrAccess(base, c->element);
if (index == NULL) if (index == NULL)
HnswLoadUnvisitedFromMemory(base, cElement, unvisited, &unvisitedLength, v, lc, localNeighborhood, neighborhoodSize); HnswLoadUnvisitedFromMemory(base, cElement, unvisited, &unvisitedLength, &v, lc, localNeighborhood, neighborhoodSize);
else else
HnswLoadUnvisitedFromDisk(cElement, unvisited, &unvisitedLength, v, index, m, lm, lc); HnswLoadUnvisitedFromDisk(cElement, unvisited, &unvisitedLength, &v, index, m, lm, lc);
if (tuples != NULL)
(*tuples) += unvisitedLength;
for (int i = 0; i < unvisitedLength; i++) for (int i = 0; i < unvisitedLength; i++)
{ {
@@ -909,22 +868,16 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
/* Avoid any allocations if not adding */ /* Avoid any allocations if not adding */
eElement = NULL; eElement = NULL;
HnswLoadElementImpl(blkno, offno, &eDistance, &q, index, procinfo, collation, inserting, alwaysAdd || discarded != NULL ? NULL : &f->distance, &eElement); HnswLoadElementImpl(blkno, offno, &eDistance, &q, index, procinfo, collation, inserting, alwaysAdd ? NULL : &f->distance, &eElement);
if (eElement == NULL)
continue;
} }
if (eElement == NULL || !(eDistance < f->distance || alwaysAdd)) if (!(eDistance < f->distance || alwaysAdd))
{
if (discarded != NULL)
{
/* Create a new candidate */
e = palloc(sizeof(HnswSearchCandidate));
HnswPtrStore(base, e->element, eElement);
e->distance = eDistance;
pairingheap_add(*discarded, &e->w_node);
}
continue; continue;
}
Assert(!eElement->deleted);
/* Make robust to issues */ /* Make robust to issues */
if (eElement->level < lc) if (eElement->level < lc)
@@ -948,12 +901,7 @@ HnswSearchLayer(char *base, Datum q, List *ep, int ef, int lc, Relation index, F
/* No need to decrement wlen */ /* No need to decrement wlen */
if (wlen > ef) if (wlen > ef)
{ pairingheap_remove_first(W);
HnswSearchCandidate *d = HnswGetSearchCandidate(w_node, pairingheap_remove_first(W));
if (discarded != NULL)
pairingheap_add(*discarded, &d->w_node);
}
} }
} }
} }
@@ -1326,7 +1274,7 @@ HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint
/* 1st phase: greedy search to insert level */ /* 1st phase: greedy search to insert level */
for (int lc = entryLevel; lc >= level + 1; lc--) for (int lc = entryLevel; lc >= level + 1; lc--)
{ {
w = HnswSearchLayer(base, q, ep, 1, lc, index, procinfo, collation, m, true, skipElement, NULL, NULL, true, NULL); w = HnswSearchLayer(base, q, ep, 1, lc, index, procinfo, collation, m, true, skipElement);
ep = w; ep = w;
} }
@@ -1345,7 +1293,7 @@ HnswFindElementNeighbors(char *base, HnswElement element, HnswElement entryPoint
List *lw = NIL; List *lw = NIL;
ListCell *lc2; ListCell *lc2;
w = HnswSearchLayer(base, q, ep, efConstruction, lc, index, procinfo, collation, m, true, skipElement, NULL, NULL, true, NULL); w = HnswSearchLayer(base, q, ep, efConstruction, lc, index, procinfo, collation, m, true, skipElement);
/* Convert search candidates to candidates */ /* Convert search candidates to candidates */
foreach(lc2, w) foreach(lc2, w)

View File

@@ -527,14 +527,6 @@ MarkDeleted(HnswVacuumState * vacuumstate)
for (int i = 0; i < ntup->count; i++) for (int i = 0; i < ntup->count; i++)
ItemPointerSetInvalid(&ntup->indextids[i]); ItemPointerSetInvalid(&ntup->indextids[i]);
/* Increment version */
/* This is used to avoid incorrect reads for iterative scans */
/* Reserve some bits for future use */
etup->version++;
if (etup->version > 15)
etup->version = 1;
ntup->version = etup->version;
/* /*
* We modified the tuples in place, no need to call * We modified the tuples in place, no need to call
* PageIndexTupleOverwrite * PageIndexTupleOverwrite

View File

@@ -17,6 +17,8 @@
#endif #endif
int ivfflat_probes; int ivfflat_probes;
int ivfflat_max_probes;
bool ivfflat_streaming;
static relopt_kind ivfflat_relopt_kind; static relopt_kind ivfflat_relopt_kind;
/* /*
@@ -33,6 +35,14 @@ IvfflatInit(void)
"Valid range is 1..lists.", &ivfflat_probes, "Valid range is 1..lists.", &ivfflat_probes,
IVFFLAT_DEFAULT_PROBES, IVFFLAT_MIN_LISTS, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL); IVFFLAT_DEFAULT_PROBES, IVFFLAT_MIN_LISTS, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL);
DefineCustomIntVariable("ivfflat.max_probes", "Sets the max number of probes for iterative scans",
NULL, &ivfflat_max_probes,
-1, IVFFLAT_MIN_LISTS, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL);
DefineCustomBoolVariable("ivfflat.streaming", "Use streaming mode",
NULL, &ivfflat_streaming,
IVFFLAT_DEFAULT_STREAMING, PGC_USERSET, 0, NULL, NULL, NULL);
MarkGUCPrefixReserved("ivfflat"); MarkGUCPrefixReserved("ivfflat");
} }
@@ -57,6 +67,35 @@ ivfflatbuildphasename(int64 phasenum)
} }
} }
/*
* Estimate the number of probes for iterative scans
*/
static int
EstimateProbes(PlannerInfo *root, IndexPath *path, int lists)
{
double selectivity = 1;
ListCell *lc;
double tuplesPerList;
/* Cannot estimate without limit */
/* limit_tuples includes offset */
if (root->limit_tuples < 0)
return 0;
/* Get the selectivity of non-index conditions */
foreach(lc, path->indexinfo->indrestrictinfo)
{
RestrictInfo *rinfo = lfirst(lc);
/* Skip DEFAULT_INEQ_SEL since it may be a distance filter */
if (rinfo->norm_selec >= 0 && rinfo->norm_selec <= 1 && rinfo->norm_selec != (Selectivity) DEFAULT_INEQ_SEL)
selectivity *= rinfo->norm_selec;
}
tuplesPerList = path->indexinfo->tuples / (double) lists;
return root->limit_tuples / (tuplesPerList * selectivity);
}
/* /*
* Estimate the cost of an index scan * Estimate the cost of an index scan
*/ */
@@ -68,6 +107,7 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
{ {
GenericCosts costs; GenericCosts costs;
int lists; int lists;
int probes;
double ratio; double ratio;
double spc_seq_page_cost; double spc_seq_page_cost;
Relation index; Relation index;
@@ -89,8 +129,17 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
IvfflatGetMetaPageInfo(index, &lists, NULL); IvfflatGetMetaPageInfo(index, &lists, NULL);
index_close(index, NoLock); index_close(index, NoLock);
probes = ivfflat_probes;
if (ivfflat_streaming)
{
probes = Max(probes, EstimateProbes(root, path, lists));
if (ivfflat_max_probes != -1)
probes = Min(probes, ivfflat_max_probes);
}
/* Get the ratio of lists that we need to visit */ /* Get the ratio of lists that we need to visit */
ratio = ((double) ivfflat_probes) / lists; ratio = ((double) probes) / lists;
if (ratio > 1.0) if (ratio > 1.0)
ratio = 1.0; ratio = 1.0;
@@ -120,6 +169,13 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
costs.indexTotalCost -= 0.5 * costs.numIndexPages * (costs.spc_random_page_cost - spc_seq_page_cost); costs.indexTotalCost -= 0.5 * costs.numIndexPages * (costs.spc_random_page_cost - spc_seq_page_cost);
} }
/*
* If the list selectivity is lower than what is returned from the generic
* cost estimator, use that.
*/
if (ratio < costs.indexSelectivity)
costs.indexSelectivity = ratio;
/* Use total cost since most work happens before first tuple is returned */ /* Use total cost since most work happens before first tuple is returned */
*indexStartupCost = costs.indexTotalCost; *indexStartupCost = costs.indexTotalCost;
*indexTotalCost = costs.indexTotalCost; *indexTotalCost = costs.indexTotalCost;

View File

@@ -43,6 +43,7 @@
#define IVFFLAT_MIN_LISTS 1 #define IVFFLAT_MIN_LISTS 1
#define IVFFLAT_MAX_LISTS 32768 #define IVFFLAT_MAX_LISTS 32768
#define IVFFLAT_DEFAULT_PROBES 1 #define IVFFLAT_DEFAULT_PROBES 1
#define IVFFLAT_DEFAULT_STREAMING false
/* Build phases */ /* Build phases */
/* PROGRESS_CREATEIDX_SUBPHASE_INITIALIZE is 1 */ /* PROGRESS_CREATEIDX_SUBPHASE_INITIALIZE is 1 */
@@ -80,6 +81,8 @@
/* Variables */ /* Variables */
extern int ivfflat_probes; extern int ivfflat_probes;
extern int ivfflat_max_probes;
extern bool ivfflat_streaming;
typedef struct VectorArrayData typedef struct VectorArrayData
{ {
@@ -247,8 +250,10 @@ typedef struct IvfflatScanOpaqueData
{ {
const IvfflatTypeInfo *typeInfo; const IvfflatTypeInfo *typeInfo;
int probes; int probes;
int maxProbes;
int dimensions; int dimensions;
bool first; bool first;
Datum value;
/* Sorting */ /* Sorting */
Tuplesortstate *sortstate; Tuplesortstate *sortstate;
@@ -265,6 +270,8 @@ typedef struct IvfflatScanOpaqueData
/* Lists */ /* Lists */
pairingheap *listQueue; pairingheap *listQueue;
BlockNumber *startPages;
int currentIndex;
IvfflatScanList lists[FLEXIBLE_ARRAY_MEMBER]; /* must come last */ IvfflatScanList lists[FLEXIBLE_ARRAY_MEMBER]; /* must come last */
} IvfflatScanOpaqueData; } IvfflatScanOpaqueData;

View File

@@ -65,7 +65,7 @@ GetScanLists(IndexScanDesc scan, Datum value)
/* Use procinfo from the index instead of scan key for performance */ /* Use procinfo from the index instead of scan key for performance */
distance = DatumGetFloat8(so->distfunc(so->procinfo, so->collation, PointerGetDatum(&list->center), value)); distance = DatumGetFloat8(so->distfunc(so->procinfo, so->collation, PointerGetDatum(&list->center), value));
if (listCount < so->probes) if (listCount < so->maxProbes)
{ {
IvfflatScanList *scanlist; IvfflatScanList *scanlist;
@@ -102,6 +102,11 @@ GetScanLists(IndexScanDesc scan, Datum value)
UnlockReleaseBuffer(cbuf); UnlockReleaseBuffer(cbuf);
} }
for (int i = listCount - 1; i >= 0; i--)
so->startPages[i] = GetScanList(pairingheap_remove_first(so->listQueue))->startPage;
Assert(pairingheap_is_empty(so->listQueue));
} }
/* /*
@@ -114,11 +119,14 @@ GetScanItems(IndexScanDesc scan, Datum value)
TupleDesc tupdesc = RelationGetDescr(scan->indexRelation); TupleDesc tupdesc = RelationGetDescr(scan->indexRelation);
double tuples = 0; double tuples = 0;
TupleTableSlot *slot = so->vslot; TupleTableSlot *slot = so->vslot;
int batchProbes = 0;
tuplesort_reset(so->sortstate);
/* Search closest probes lists */ /* Search closest probes lists */
while (!pairingheap_is_empty(so->listQueue)) while (so->currentIndex < so->maxProbes && (++batchProbes) <= so->probes)
{ {
BlockNumber searchPage = GetScanList(pairingheap_remove_first(so->listQueue))->startPage; BlockNumber searchPage = so->startPages[so->currentIndex++];
/* Search all entry pages for list */ /* Search all entry pages for list */
while (BlockNumberIsValid(searchPage)) while (BlockNumberIsValid(searchPage))
@@ -166,13 +174,17 @@ GetScanItems(IndexScanDesc scan, Datum value)
} }
} }
if (tuples < 100) if (tuples < 100 && !ivfflat_streaming)
ereport(DEBUG1, ereport(DEBUG1,
(errmsg("index scan found few tuples"), (errmsg("index scan found few tuples"),
errdetail("Index may have been created with little data."), errdetail("Index may have been created with little data."),
errhint("Recreate the index and possibly decrease lists."))); errhint("Recreate the index and possibly decrease lists.")));
tuplesort_performsort(so->sortstate); tuplesort_performsort(so->sortstate);
#if defined(IVFFLAT_MEMORY)
elog(INFO, "memory: %zu MB", MemoryContextMemAllocated(CurrentMemoryContext, true) / (1024 * 1024));
#endif
} }
/* /*
@@ -240,6 +252,7 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
int lists; int lists;
int dimensions; int dimensions;
int probes = ivfflat_probes; int probes = ivfflat_probes;
int maxProbes;
scan = RelationGetIndexScan(index, nkeys, norderbys); scan = RelationGetIndexScan(index, nkeys, norderbys);
@@ -249,10 +262,21 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
if (probes > lists) if (probes > lists)
probes = lists; probes = lists;
so = (IvfflatScanOpaque) palloc(offsetof(IvfflatScanOpaqueData, lists) + probes * sizeof(IvfflatScanList)); if (ivfflat_streaming)
{
if (ivfflat_max_probes == -1)
maxProbes = lists;
else
maxProbes = Min(ivfflat_max_probes, lists);
}
else
maxProbes = probes;
so = (IvfflatScanOpaque) palloc(offsetof(IvfflatScanOpaqueData, lists) + maxProbes * sizeof(IvfflatScanList));
so->typeInfo = IvfflatGetTypeInfo(index); so->typeInfo = IvfflatGetTypeInfo(index);
so->first = true; so->first = true;
so->probes = probes; so->probes = probes;
so->maxProbes = maxProbes;
so->dimensions = dimensions; so->dimensions = dimensions;
/* Set support functions */ /* Set support functions */
@@ -280,6 +304,8 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
so->bas = GetAccessStrategy(BAS_BULKREAD); so->bas = GetAccessStrategy(BAS_BULKREAD);
so->listQueue = pairingheap_allocate(CompareLists, scan); so->listQueue = pairingheap_allocate(CompareLists, scan);
so->startPages = palloc(maxProbes * sizeof(BlockNumber));
so->currentIndex = 0;
scan->opaque = so; scan->opaque = so;
@@ -294,11 +320,9 @@ ivfflatrescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int
{ {
IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque; IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque;
if (!so->first)
tuplesort_reset(so->sortstate);
so->first = true; so->first = true;
pairingheap_reset(so->listQueue); pairingheap_reset(so->listQueue);
so->currentIndex = 0;
if (keys && scan->numberOfKeys > 0) if (keys && scan->numberOfKeys > 0)
memmove(scan->keyData, keys, scan->numberOfKeys * sizeof(ScanKeyData)); memmove(scan->keyData, keys, scan->numberOfKeys * sizeof(ScanKeyData));
@@ -314,6 +338,8 @@ bool
ivfflatgettuple(IndexScanDesc scan, ScanDirection dir) ivfflatgettuple(IndexScanDesc scan, ScanDirection dir)
{ {
IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque; IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque;
ItemPointer heaptid;
bool isnull;
/* /*
* Index can be used to scan backward, but Postgres doesn't support * Index can be used to scan backward, but Postgres doesn't support
@@ -341,28 +367,25 @@ ivfflatgettuple(IndexScanDesc scan, ScanDirection dir)
IvfflatBench("GetScanLists", GetScanLists(scan, value)); IvfflatBench("GetScanLists", GetScanLists(scan, value));
IvfflatBench("GetScanItems", GetScanItems(scan, value)); IvfflatBench("GetScanItems", GetScanItems(scan, value));
so->first = false; so->first = false;
so->value = value;
#if defined(IVFFLAT_MEMORY) /* TODO clean up if we allocated a new value */
elog(INFO, "memory: %zu MB", MemoryContextMemAllocated(CurrentMemoryContext, true) / (1024 * 1024));
#endif
/* Clean up if we allocated a new value */
if (value != scan->orderByData->sk_argument)
pfree(DatumGetPointer(value));
} }
if (tuplesort_gettupleslot(so->sortstate, true, false, so->mslot, NULL)) while (!tuplesort_gettupleslot(so->sortstate, true, false, so->mslot, NULL))
{ {
bool isnull; if (so->currentIndex == so->maxProbes)
ItemPointer heaptid = (ItemPointer) DatumGetPointer(slot_getattr(so->mslot, 2, &isnull)); return false;
scan->xs_heaptid = *heaptid; IvfflatBench("GetScanItems", GetScanItems(scan, so->value));
scan->xs_recheck = false;
scan->xs_recheckorderby = false;
return true;
} }
return false; heaptid = (ItemPointer) DatumGetPointer(slot_getattr(so->mslot, 2, &isnull));
scan->xs_heaptid = *heaptid;
scan->xs_recheck = false;
scan->xs_recheckorderby = false;
return true;
} }
/* /*
@@ -374,6 +397,7 @@ ivfflatendscan(IndexScanDesc scan)
IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque; IvfflatScanOpaque so = (IvfflatScanOpaque) scan->opaque;
pairingheap_free(so->listQueue); pairingheap_free(so->listQueue);
pfree(so->startPages);
tuplesort_end(so->sortstate); tuplesort_end(so->sortstate);
FreeAccessStrategy(so->bas); FreeAccessStrategy(so->bas);
FreeTupleDesc(so->tupdesc); FreeTupleDesc(so->tupdesc);

View File

@@ -155,6 +155,24 @@ CheckStateArray(ArrayType *statearray, const char *caller)
return (float8 *) ARR_DATA_PTR(statearray); return (float8 *) ARR_DATA_PTR(statearray);
} }
#if PG_VERSION_NUM < 120003
static pg_noinline void
float_overflow_error(void)
{
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("value out of range: overflow")));
}
static pg_noinline void
float_underflow_error(void)
{
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("value out of range: underflow")));
}
#endif
/* /*
* Convert textual representation to internal representation * Convert textual representation to internal representation
*/ */

View File

@@ -94,7 +94,8 @@ like($explain, qr/Seq Scan/);
$explain = $node->safe_psql("postgres", qq( $explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1 ORDER BY v <-> '$query'; EXPLAIN ANALYZE SELECT i FROM tst WHERE v <-> '$query' < 1 ORDER BY v <-> '$query';
)); ));
like($explain, qr/Seq Scan/); # TODO Do not use index
like($explain, qr/Index Scan using idx/);
# Test attribute index # Test attribute index
$node->safe_psql("postgres", "CREATE INDEX attribute_idx ON tst (c);"); $node->safe_psql("postgres", "CREATE INDEX attribute_idx ON tst (c);");
@@ -109,6 +110,7 @@ $node->safe_psql("postgres", "CREATE INDEX partial_idx ON tst USING ivfflat (v v
$explain = $node->safe_psql("postgres", qq( $explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit; EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
)); ));
like($explain, qr/Index Scan using partial_idx/); # TODO Use partial index
like($explain, qr/Index Scan using idx/);
done_testing(); done_testing();

View File

@@ -18,13 +18,9 @@ $node->start;
# Create table and index # Create table and index
$node->safe_psql("postgres", "CREATE EXTENSION vector;"); $node->safe_psql("postgres", "CREATE EXTENSION vector;");
$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim), c int4, t text);"); $node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim), c int4, t text);");
$node->safe_psql("postgres", "CREATE TABLE cat (i int4 PRIMARY KEY, t text, b boolean);");
$node->safe_psql("postgres", $node->safe_psql("postgres",
"INSERT INTO tst SELECT i, ARRAY[$array_sql], i % $nc, 'test ' || i FROM generate_series(1, 10000) i;" "INSERT INTO tst SELECT i, ARRAY[$array_sql], i % $nc, 'test ' || i FROM generate_series(1, 10000) i;"
); );
$node->safe_psql("postgres",
"INSERT INTO cat SELECT i, 'cat ' || i, i % 5 = 0 FROM generate_series(1, $nc) i;"
);
$node->safe_psql("postgres", "CREATE INDEX idx ON tst USING hnsw (v vector_l2_ops);"); $node->safe_psql("postgres", "CREATE INDEX idx ON tst USING hnsw (v vector_l2_ops);");
$node->safe_psql("postgres", "ANALYZE tst;"); $node->safe_psql("postgres", "ANALYZE tst;");
@@ -100,25 +96,13 @@ $explain = $node->safe_psql("postgres", qq(
)); ));
like($explain, qr/Seq Scan/); like($explain, qr/Seq Scan/);
# Test join
$explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT cat.t FROM cat INNER JOIN tst ON cat.i = tst.c ORDER BY v <-> '$query' LIMIT $limit;
));
like($explain, qr/Index Scan using idx/);
# Test join with attribute filtering
$explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT cat.t FROM cat INNER JOIN tst ON cat.i = tst.c WHERE cat.b = 't' ORDER BY v <-> '$query' LIMIT $limit;
));
like($explain, qr/Index Scan using idx/);
# Test attribute index # Test attribute index
$node->safe_psql("postgres", "CREATE INDEX attribute_idx ON tst (c);"); $node->safe_psql("postgres", "CREATE INDEX attribute_idx ON tst (c);");
$explain = $node->safe_psql("postgres", qq( $explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit; EXPLAIN ANALYZE SELECT i FROM tst WHERE c = $c ORDER BY v <-> '$query' LIMIT $limit;
)); ));
# Use attribute index # TODO Use attribute index
like($explain, qr/Bitmap Index Scan on attribute_idx/); like($explain, qr/Index Scan using idx/);
# Test partial index # Test partial index
$node->safe_psql("postgres", "CREATE INDEX partial_idx ON tst USING hnsw (v vector_l2_ops) WHERE (c = $c);"); $node->safe_psql("postgres", "CREATE INDEX partial_idx ON tst USING hnsw (v vector_l2_ops) WHERE (c = $c);");

View File

@@ -1,46 +0,0 @@
use strict;
use warnings FATAL => 'all';
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::Utils;
use Test::More;
my @dims = (384, 1536);
my $limit = 10;
# Initialize node
my $node = PostgreSQL::Test::Cluster->new('node');
$node->init;
$node->start;
$node->safe_psql("postgres", "CREATE EXTENSION vector;");
for my $dim (@dims)
{
my $array_sql = join(",", ('random()') x $dim);
my $n = $dim == 384 ? 2000 : 1000;
# Create table and index
$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim));");
$node->safe_psql("postgres",
"INSERT INTO tst SELECT i, ARRAY[$array_sql] FROM generate_series(1, $n) 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 $explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT i FROM tst ORDER BY v <-> '$query' LIMIT $limit;
));
like($explain, qr/Index Scan using idx/);
$node->safe_psql("postgres", "DROP TABLE tst;");
}
done_testing();

View File

@@ -0,0 +1,31 @@
use strict;
use warnings FATAL => 'all';
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::Utils;
use Test::More;
my $dim = 3;
my $array_sql = join(",", ('random()') x $dim);
# Initialize node
my $node = PostgreSQL::Test::Cluster->new('node');
$node->init;
$node->start;
# Create table
$node->safe_psql("postgres", "CREATE EXTENSION vector;");
$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim));");
$node->safe_psql("postgres",
"INSERT INTO tst SELECT i, ARRAY[$array_sql] FROM generate_series(1, 100000) i;"
);
$node->safe_psql("postgres", "CREATE INDEX ON tst USING ivfflat (v vector_l2_ops);");
my $count = $node->safe_psql("postgres", qq(
SET enable_seqscan = off;
SET ivfflat.probes = 10;
SET ivfflat.streaming = on;
SELECT COUNT(*) FROM (SELECT v FROM tst WHERE i % 10000 = 0 ORDER BY v <-> (SELECT v FROM tst LIMIT 1) LIMIT 11) t;
));
is($count, 10);
done_testing();

View File

@@ -1,45 +0,0 @@
use strict;
use warnings FATAL => 'all';
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::Utils;
use Test::More;
my @dims = (384, 1536);
my $limit = 10;
# Initialize node
my $node = PostgreSQL::Test::Cluster->new('node');
$node->init;
$node->start;
$node->safe_psql("postgres", "CREATE EXTENSION vector;");
for my $dim (@dims)
{
my $array_sql = join(",", ('random()') x $dim);
# Create table and index
$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim));");
$node->safe_psql("postgres",
"INSERT INTO tst SELECT i, ARRAY[$array_sql] FROM generate_series(1, 5000) i;"
);
$node->safe_psql("postgres", "CREATE INDEX idx ON tst USING ivfflat (v vector_l2_ops) WITH (lists = 5);");
$node->safe_psql("postgres", "ANALYZE tst;");
# Generate query
my @r = ();
for (1 .. $dim)
{
push(@r, rand());
}
my $query = "[" . join(",", @r) . "]";
my $explain = $node->safe_psql("postgres", qq(
EXPLAIN ANALYZE SELECT i FROM tst ORDER BY v <-> '$query' LIMIT $limit;
));
like($explain, qr/Index Scan using idx/);
$node->safe_psql("postgres", "DROP TABLE tst;");
}
done_testing();

View File

@@ -8,20 +8,18 @@ my $node;
my @queries = (); my @queries = ();
my @expected; my @expected;
my $limit = 20; my $limit = 20;
my $dim = 3;
my $array_sql = join(",", ('random()') x $dim);
my @cs = (100, 1000); my @cs = (100, 1000);
sub test_recall sub test_recall
{ {
my ($c, $ef_search, $min, $operator) = @_; my ($c, $probes, $min, $operator) = @_;
my $correct = 0; my $correct = 0;
my $total = 0; my $total = 0;
my $explain = $node->safe_psql("postgres", qq( my $explain = $node->safe_psql("postgres", qq(
SET enable_seqscan = off; SET enable_seqscan = off;
SET hnsw.ef_search = $ef_search; SET ivfflat.probes = $probes;
SET hnsw.streaming = on; SET ivfflat.streaming = on;
EXPLAIN ANALYZE SELECT i FROM tst WHERE i % $c = 0 ORDER BY v $operator '$queries[0]' LIMIT $limit; EXPLAIN ANALYZE SELECT i FROM tst WHERE i % $c = 0 ORDER BY v $operator '$queries[0]' LIMIT $limit;
)); ));
like($explain, qr/Index Scan using idx on tst/); like($explain, qr/Index Scan using idx on tst/);
@@ -30,8 +28,8 @@ sub test_recall
{ {
my $actual = $node->safe_psql("postgres", qq( my $actual = $node->safe_psql("postgres", qq(
SET enable_seqscan = off; SET enable_seqscan = off;
SET hnsw.ef_search = $ef_search; SET ivfflat.probes = $probes;
SET hnsw.streaming = on; SET ivfflat.streaming = on;
SELECT i FROM tst WHERE i % $c = 0 ORDER BY v $operator '$queries[$i]' LIMIT $limit; SELECT i FROM tst WHERE i % $c = 0 ORDER BY v $operator '$queries[$i]' LIMIT $limit;
)); ));
my @actual_ids = split("\n", $actual); my @actual_ids = split("\n", $actual);
@@ -60,20 +58,18 @@ $node->start;
# Create table # Create table
$node->safe_psql("postgres", "CREATE EXTENSION vector;"); $node->safe_psql("postgres", "CREATE EXTENSION vector;");
$node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector($dim));"); $node->safe_psql("postgres", "CREATE TABLE tst (i int4, v vector(3));");
$node->safe_psql("postgres", $node->safe_psql("postgres",
"INSERT INTO tst SELECT i, ARRAY[$array_sql] FROM generate_series(1, 100000) i;" "INSERT INTO tst SELECT i, ARRAY[random(), random(), random()] FROM generate_series(1, 100000) i;"
); );
# Generate queries # Generate queries
for (1 .. 20) for (1 .. 20)
{ {
my @r = (); my $r1 = rand();
for (1 .. $dim) my $r2 = rand();
{ my $r3 = rand();
push(@r, rand()); push(@queries, "[$r1,$r2,$r3]");
}
push(@queries, "[" . join(",", @r) . "]");
} }
# Check each index type # Check each index type
@@ -85,10 +81,7 @@ for my $i (0 .. $#operators)
my $operator = $operators[$i]; my $operator = $operators[$i];
my $opclass = $opclasses[$i]; my $opclass = $opclasses[$i];
$node->safe_psql("postgres", qq( $node->safe_psql("postgres", "CREATE INDEX idx ON tst USING ivfflat (v $opclass);");
SET maintenance_work_mem = '128MB';
CREATE INDEX idx ON tst USING hnsw (v $opclass);
));
foreach (@cs) foreach (@cs)
{ {
@@ -110,17 +103,18 @@ for my $i (0 .. $#operators)
if ($c == 100) if ($c == 100)
{ {
test_recall($c, 40, 0.99, $operator); test_recall($c, 1, 0.58, $operator);
test_recall($c, 10, 0.98, $operator);
} }
else else
{ {
if ($operator eq "<->") if ($operator eq "<->")
{ {
test_recall($c, 40, 0.99, $operator); test_recall($c, 1, 0.80, $operator);
} }
else else
{ {
test_recall($c, 40, 0.99, $operator); test_recall($c, 1, 0.88, $operator);
} }
} }
} }

View File

@@ -1,66 +0,0 @@
use strict;
use warnings FATAL => 'all';
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::Utils;
use Test::More;
my $dim = 3;
my $array_sql = join(",", ('random()') x $dim);
# Initialize node
my $node = PostgreSQL::Test::Cluster->new('node');
$node->init;
$node->start;
# Create table
$node->safe_psql("postgres", "CREATE EXTENSION vector;");
$node->safe_psql("postgres", "CREATE TABLE tst (i int4 PRIMARY KEY, v vector($dim));");
$node->safe_psql("postgres",
"INSERT INTO tst SELECT i, ARRAY[$array_sql] FROM generate_series(1, 100000) i;"
);
$node->safe_psql("postgres", qq(
SET maintenance_work_mem = '128MB';
SET max_parallel_maintenance_workers = 2;
CREATE INDEX ON tst USING hnsw (v vector_l2_ops)
));
my $count = $node->safe_psql("postgres", qq(
SET enable_seqscan = off;
SET hnsw.streaming = on;
SET work_mem = '8MB';
SELECT COUNT(*) FROM (SELECT v FROM tst WHERE i % 10000 = 0 ORDER BY v <-> (SELECT v FROM tst LIMIT 1) LIMIT 11) t;
));
is($count, 10);
foreach ((30000, 50000, 70000))
{
my $ef_stream = $_;
my $expected = $ef_stream / 10000;
my $sum = 0;
for my $i (1 .. 20)
{
$count = $node->safe_psql("postgres", qq(
SET enable_seqscan = off;
SET hnsw.streaming = on;
SET hnsw.ef_stream = $ef_stream;
SET work_mem = '8MB';
SELECT COUNT(*) FROM (SELECT v FROM tst WHERE i % 10000 = 0 ORDER BY v <-> (SELECT v FROM tst WHERE i = $i) LIMIT 11) t;
));
$sum += $count;
}
my $avg = $sum / 20;
cmp_ok($avg, '>', $expected - 2);
cmp_ok($avg, '<', $expected + 2);
}
my ($ret, $stdout, $stderr) = $node->psql("postgres", qq(
SET enable_seqscan = off;
SET hnsw.streaming = on;
SET work_mem = '2MB';
SELECT COUNT(*) FROM (SELECT v FROM tst WHERE i % 10000 = 0 ORDER BY v <-> (SELECT v FROM tst LIMIT 1) LIMIT 11) t;
));
like($stderr, qr/hnsw index scan exceeded work_mem after \d+ tuples/);
done_testing();