SCNR - have to show off postgres' regex indexing on a quickly generated 10M row table.

-- table size: 1117 MB
-- regex index size: 1727 MB (big index = disadvantage)

  where txt like '%batman%'; -->  'like' means: search without regex; 
+uses the trgm index
                                      txt                             
+           
----------------------------------------------------------------------
+-----------
 zdfrcj batman igihbky bpwz hzzfmq plyazufcawovvjrlwow xkllfiovgktraw 
+ bmnuyjelj

Time: 9.911 ms

  where txt ~ '\ybatman\y'; -->  '~' means: regex search;  \y:  word b
+oundary
                                      txt                             
+           
----------------------------------------------------------------------
+-----------
 zdfrcj batman igihbky bpwz hzzfmq plyazufcawovvjrlwow xkllfiovgktraw 
+ bmnuyjelj

Time: 13.179 ms

[download]

(performance of these regex-indexes (via trigram matching from the pg_trgm extension) is good but the size can be reason not to use them.)

In reply to Re^4: Documentation of REGEXP support in DBD::SQLite? by erix
in thread Documentation of REGEXP support in DBD::SQLite? by ibm1620

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