Debug [skip ci]

README.md

@@ -109,7 +109,10 @@ Specify the number of inverted lists (100 by default)
 CREATE INDEX ON items USING ivfflat (embedding vector_l2_ops) WITH (lists = 100);
 ```
 
-A [good place to start](https://github.com/facebookresearch/faiss/issues/112) is `4 * sqrt(rows)`
+A lower value provides better recall at the cost of speed. A good place to start is:
+
+- `rows / 1000` for up to 1M rows
+- `sqrt(rows)` for over 1M rows
 
 ### Query Options
 
@@ -119,7 +122,7 @@ Specify the number of probes (1 by default)
 SET ivfflat.probes = 1;
 ```
 
-A higher value improves recall at the cost of speed, and it can be set to the number of lists for exact nearest neighbor search (at which point the planner won’t use the index)
+A higher value provides better recall at the cost of speed, and it can be set to the number of lists for exact nearest neighbor search (at which point the planner won’t use the index)
 
 Use `SET LOCAL` inside a transaction to set it for a single query
 
@@ -201,6 +204,7 @@ Java, Scala | [pgvector-java](https://github.com/pgvector/pgvector-java)
 Julia | [pgvector-julia](https://github.com/pgvector/pgvector-julia)
 Lua | [pgvector-lua](https://github.com/pgvector/pgvector-lua)
 Node.js | [pgvector-node](https://github.com/pgvector/pgvector-node)
+Perl | [pgvector-perl](https://github.com/pgvector/pgvector-perl)
 PHP | [pgvector-php](https://github.com/pgvector/pgvector-php)
 Python | [pgvector-python](https://github.com/pgvector/pgvector-python)
 R | [pgvector-r](https://github.com/pgvector/pgvector-r)
@@ -281,7 +285,7 @@ docker build -t pgvector .
 With Homebrew Postgres, you can use:
 
 ```sh
-brew install pgvector/brew/pgvector
+brew install pgvector
 ```
 
 ### PGXN
@@ -310,8 +314,9 @@ To request a new extension on other providers:
 
 - Amazon RDS - follow the instructions on [this page](https://aws.amazon.com/rds/postgresql/faqs/)
 - Google Cloud SQL - vote or comment on [this page](https://issuetracker.google.com/issues/265172065)
-- DigitalOcean Managed Databases - vote or comment on [this page](https://ideas.digitalocean.com/app-framework-services/p/pgvector-extension-for-postgresql)
 - Azure Database - vote or comment on [this page](https://feedback.azure.com/d365community/idea/7b423322-6189-ed11-a81b-000d3ae49307)
+- DigitalOcean Managed Databases - vote or comment on [this page](https://ideas.digitalocean.com/app-framework-services/p/pgvector-extension-for-postgresql)
+- Render - vote or comment on [this page](https://feedback.render.com/features/p/add-pgvector-extension-to-postgresql)
 
 ## Upgrading
 

src/ivfflat.c

@@ -103,7 +103,13 @@ ivfflatcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 	if (ratio > 1)
 		ratio = 1;
 
+	// cost estimates for parallel workers applied outside of amcostestimate
+	elog(INFO, "parallel_workers = %d, parallel aware = %d", path->path.parallel_workers, path->path.parallel_aware);
+
 	costs.indexTotalCost *= ratio;
+	costs.numIndexPages *= ratio;
+
+	elog(INFO, "ivfflatcostestimate = %f", costs.indexTotalCost);
 
 	/* Startup cost and total cost are same */
 	*indexStartupCost = costs.indexTotalCost;
@@ -151,6 +157,25 @@ ivfflatvalidate(Oid opclassoid)
 	return true;
 }
 
+static Size
+ivfflatestimateparallelscan()
+{
+	elog(INFO, "ivfflatestimateparallelscan");
+	return 0;
+}
+
+static void
+ivfflatinitparallelscan(void *target)
+{
+	elog(INFO, "ivfflatinitparallelscan");
+}
+
+static void
+ivfflatparallelrescan(IndexScanDesc scan)
+{
+	elog(INFO, "ivfflatparallelrescan");
+}
+
 /*
  * Define index handler
  *
@@ -178,7 +203,7 @@ ivfflathandler(PG_FUNCTION_ARGS)
 	amroutine->amstorage = false;
 	amroutine->amclusterable = false;
 	amroutine->ampredlocks = false;
-	amroutine->amcanparallel = false;
+	amroutine->amcanparallel = true;
 	amroutine->amcaninclude = false;
 #if PG_VERSION_NUM >= 130000
 	amroutine->amusemaintenanceworkmem = false; /* not used during VACUUM */
@@ -212,9 +237,9 @@ ivfflathandler(PG_FUNCTION_ARGS)
 	amroutine->amrestrpos = NULL;
 
 	/* Interface functions to support parallel index scans */
-	amroutine->amestimateparallelscan = NULL;
-	amroutine->aminitparallelscan = NULL;
-	amroutine->amparallelrescan = NULL;
+	amroutine->amestimateparallelscan = ivfflatestimateparallelscan;
+	amroutine->aminitparallelscan = ivfflatinitparallelscan;
+	amroutine->amparallelrescan = ivfflatparallelrescan;
 
 	PG_RETURN_POINTER(amroutine);
 }

test/expected/functions.out

@@ -22,10 +22,28 @@ SELECT round(vector_norm('[1,1]')::numeric, 5);
  1.41421
 (1 row)
 
-SELECT round(l2_distance('[1,2]', '[0,0]')::numeric, 5);
-  round  
----------
- 2.23607
+SELECT vector_norm('[3,4]');
+ vector_norm 
+-------------
+           5
+(1 row)
+
+SELECT vector_norm('[0,1]');
+ vector_norm 
+-------------
+           1
+(1 row)
+
+SELECT l2_distance('[0,0]', '[3,4]');
+ l2_distance 
+-------------
+           5
+(1 row)
+
+SELECT l2_distance('[0,0]', '[0,1]');
+ l2_distance 
+-------------
+           1
 (1 row)
 
 SELECT l2_distance('[1,2]', '[3]');
@@ -38,10 +56,10 @@ SELECT inner_product('[1,2]', '[3,4]');
 
 SELECT inner_product('[1,2]', '[3]');
 ERROR:  different vector dimensions 2 and 1
-SELECT round(cosine_distance('[1,2]', '[2,4]')::numeric, 5);
-  round  
----------
- 0.00000
+SELECT cosine_distance('[1,2]', '[2,4]');
+ cosine_distance 
+-----------------
+               0
 (1 row)
 
 SELECT cosine_distance('[1,2]', '[0,0]');

test/sql/functions.sql

@@ -2,15 +2,19 @@ SELECT '[1,2,3]'::vector + '[4,5,6]';
 SELECT '[1,2,3]'::vector - '[4,5,6]';
 
 SELECT vector_dims('[1,2,3]');
-SELECT round(vector_norm('[1,1]')::numeric, 5);
 
-SELECT round(l2_distance('[1,2]', '[0,0]')::numeric, 5);
+SELECT round(vector_norm('[1,1]')::numeric, 5);
+SELECT vector_norm('[3,4]');
+SELECT vector_norm('[0,1]');
+
+SELECT l2_distance('[0,0]', '[3,4]');
+SELECT l2_distance('[0,0]', '[0,1]');
 SELECT l2_distance('[1,2]', '[3]');
 
 SELECT inner_product('[1,2]', '[3,4]');
 SELECT inner_product('[1,2]', '[3]');
 
-SELECT round(cosine_distance('[1,2]', '[2,4]')::numeric, 5);
+SELECT cosine_distance('[1,2]', '[2,4]');
 SELECT cosine_distance('[1,2]', '[0,0]');
 SELECT cosine_distance('[1,1]', '[1,1]');
 SELECT cosine_distance('[1,1]', '[-1,-1]');

test/sql/ivfflat_parallel.sql

@@ -0,0 +1,15 @@
+-- SET force_parallel_mode = on;
+SET parallel_setup_cost = 10;
+SET parallel_tuple_cost = 0.001;
+SET min_parallel_table_scan_size = 1;
+SET min_parallel_index_scan_size = 1;
+
+CREATE TABLE t (id integer, val vector(3));
+INSERT INTO t (id, val) SELECT n, ARRAY[random(), random(), random()] FROM generate_series(1,1000000) n;
+CREATE INDEX ON t USING ivfflat (val) WITH (lists = 10);
+SET ivfflat.probes = 2;
+
+EXPLAIN SELECT * FROM t ORDER BY val <-> '[0.5,0.5,0.5]' LIMIT 5;
+SELECT * FROM t ORDER BY val <-> '[0.5,0.5,0.5]' LIMIT 5;
+
+DROP TABLE t;