pg_hint_plan

pig repo add pgdg -u    # add pgdg repo and update cache

pig install pg_hint_plan;		# install via package name, for the active PG version

pig install pg_hint_plan -v 18;   # install for PG 18
pig install pg_hint_plan -v 17;   # install for PG 17
pig install pg_hint_plan -v 16;   # install for PG 16
pig install pg_hint_plan -v 15;   # install for PG 15
pig install pg_hint_plan -v 14;   # install for PG 14

shared_preload_libraries = 'pg_hint_plan';

CREATE EXTENSION pg_hint_plan;

/*+
  HashJoin(a b)
  SeqScan(a)
*/
SELECT *
FROM pgbench_branches b
JOIN pgbench_accounts a ON b.bid = a.bid
ORDER BY a.aid;

-- Simple left-deep join order
/*+ Leading(a b c) */

-- Explicit join tree with nesting
/*+ Leading((a (b c))) */

/*+ Rows(a b #100) */    -- Set to absolute number
/*+ Rows(a b +100) */    -- Add to estimate
/*+ Rows(a b -100) */    -- Subtract from estimate
/*+ Rows(a b *2.0) */    -- Multiply estimate

/*+ Parallel(table 4 hard) */   -- Force 4 parallel workers
/*+ Parallel(table 0 hard) */   -- Disable parallelism

/*+ Set(random_page_cost 1.0) Set(seq_page_cost 1.0) */
SELECT * FROM my_table WHERE id = 42;