>>>Tatsuo Ishii said:> > SELECT key FROM t WHERE key ~* '^somestring'> > > > returns no tuples and explain says it will
usethe index on key. Why is th is?> > That's strange. It should be seq scan in this case?
I forgot to mention, that if 'somestring' is all uppercase, everything works
(the key field in the table is all uppercase). It still says index scan will
be used.
To summarize the problem. If key contains (equivalent cyrillic letters) 'ABC',
'ABCD', 'DAB' and 'ABX' and the query is:
SELECT key FROM t WHERE key ~* '^AB';
index scan will be used and the correct tuples ('ABC', 'ABCD' and 'ABX') will
be returned. If the query is
SELECT key FROM t WHERE key ~* '^ab';
index scan will be used and no tuples will be returned. With the query
SELECT key FROM t WHERE key ~* 'ab';
sequential scan will be used and the correct tuples will be returned (all of
the above).
> Can you test following case:> > SELECT key FROM t WHERE key ~* '^Xsomestring'> > where X is one of an ASCII
character.
Explain says it will use sequential scan and if I insert proper key in the
table it will be returned.
Daniel
