Multi - table statistics - Mailing list pgsql-general

From Scara Maccai
Subject Multi - table statistics
Date
Msg-id 391885.88270.qm@web24608.mail.ird.yahoo.com
Whole thread Raw
Responses Re: Multi - table statistics
List pgsql-general
Hi,

I query is using Index scan instead of Bitmap Index Scan because it "thinks" that the number of rows returned will be
low(12). In fact, the number of rows returned is 120. 

This happens because there are some WHERE conditions that check cross-tables values (something like taba.col1 <
tabb.col2). Since Postgresql doesn't know (I guess) anything about cross-table values statistics, how are the "rows"
valuescalculated? 

Is there any way I can force the planner to use bitmap index scan?





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