hydra/src/sql/upgrade-57.sql

CREATE EXTENSION pg_trgm;
CREATE INDEX IndexTrgmBuildsOnDrvpath ON builds USING gin (drvpath gin_trgm_ops);
Create a pg_trgm index on builds.drvpath The search query uses the LIKE operator which requires a sequential scan (it can't use the already existing B-tree index). This new index (trigram) avoids a sequential scan of the builds table when the LIKE operator is used. Here is the analyze of a request on the builds table with this index: explain analyze select * from builds where drvpath like '%k3r71gz0gv16ld8rhcp2bb8gb5w1xc4b%'; QUERY PLAN ----------------------------------------------------------------------------------------------------------------------------------- Bitmap Heap Scan on builds (cost=128.00..132.01 rows=1 width=492) (actual time=0.070..0.077 rows=1 loops=1) Recheck Cond: (drvpath ~~ '%k3r71gz0gv16ld8rhcp2bb8gb5w1xc4b%'::text) -> Bitmap Index Scan on indextrgmbuildsondrvpath (cost=0.00..128.00 rows=1 width=0) (actual time=0.047..0.047 rows=3 loops=1) Index Cond: (drvpath ~~ '%k3r71gz0gv16ld8rhcp2bb8gb5w1xc4b%'::text) Total runtime: 0.206 ms (5 rows) 2019-06-06 11:57:11 +02:00			`CREATE EXTENSION pg_trgm;`
			`CREATE INDEX IndexTrgmBuildsOnDrvpath ON builds USING gin (drvpath gin_trgm_ops);`