Which is faster — INSTR or LIKE?

Question

If your goal is to test if a string exists in a MySQL column (of type \'varchar\', \'text\', \'blob\', etc) which of the following is faster / more efficient / better to use

Answer 1

There is little to add to razzed's test. But apparently using regexp does incur a much heavier processing load, unlike what Seth points out in his comment.

The following tests assume that you set query_caching to On in my.ini

query_cache_type = 1
query_cache_size = 64M

Tests

• The timings show the average performance, out of three measurements (with the cache cleared intermittently):

• LIKE

  SELECT * FROM `domain_model_offers` WHERE `description` LIKE '%inform%' LIMIT 0 , 30
  

  Initial: 0.0035s
  Cached: 0.0005s

• REGEXP

  SELECT * FROM `domain_model_offers` WHERE `description` REGEXP 'inform' LIMIT 0 , 30
  

  Initial: 0.01s
  Cached: 0.0004s

Result

LIKE or INSTR is definitely faster than REGEXP.

Though minimal, the cache timing difference is probably sufficient to warrant further investigation.

On a probably configured MySQL system, fulltext indexing should generally be always faster or at least on par with a nonindexed search. So use indexing, especially on long human language texts, regardless of intermittent markup code.