... to avoid the LIKE operator where INSTR is sufficient
Some databases do even better: in postgres there is the option to index on regular expressions (or any string)
via the pg_trgm contrib extension.
Its disadvantage is huge index size but the gain can be enormous, as indeed in this, the OP's example:
-- table t is 112 MB, 1 million rows. The index is 190 MB (!)
-- all queries measured on second run (to avoid uninteresting cold cac
-- no index:
SELECT * FROM t WHERE name like '%Franklin%' and name like '%Linsey%';
Time: 118.004 ms
SELECT * FROM t WHERE position('Franklin' in name)>0 AND position('Lin
+sey' in name)>0;
Time: 444.716 ms
create index t_trgm_re_idx on t using gin (name gin_trgm_ops);
-- with index:
SELECT * FROM t WHERE name like '%Franklin%' and name like '%Linsey%'
Time: 1.582 ms
-- postgres specific regex-search syntax with '~'
SELECT * FROM t WHERE name ~ 'Franklin' and name ~ 'Linsey';
Time: 1.895 ms
The latter syntax has the added advantage that one can use regex like 'Frankl[iy]n' (it will use the trgm index as well).
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