On Mar 13, 2011, at 12:05 PM, Dmitriy Igrishin wrote: > Hey Viktor, > > 2011/3/13 Viktor Nagy <viktor.n...@toolpart.hu> > hi, > > when trying to insert a long-long value, I get the following error: > > index row size 3120 exceeds maximum 2712 for index "ir_translation_ltns" > HINT: Values larger than 1/3 of a buffer page cannot be indexed. > Consider a function index of an MD5 hash of the value, or use full text > indexing. > > is there a way to generate this recommended function index of an md5 hash on > an already existing database and tables (filled with data)? > Just create index this way, e.g. > CREATE INDEX ir_translation_ltns ON tab ((md5(col))); > where "tab" and "col" are table and column of which you want > to create btree index.
This probably goes without saying, but you'll have to use col = md5('blahblahblahblah') in your qualifiers to get the benefit of the index. --brian