Tom Lane wrote:
"Jens-Wolfhard Schicke" <[EMAIL PROTECTED]> writes:
I an explain analyze I saw recently, a BitmapOr node of 5 Bitmap Index Scan
looked like this:
BitmapOr (cost=43.57..43.57 rows=1833 width=0) (actual time=0.146..0.146
rows=0 loops=1)
Can we do better than just saying 0? something indicating not
calculated, or the fact we can't calculate it?
BitmapOr and BitmapAnd don't attempt to count their result rows --- doing
so would involve an extra scan over the bitmap, and what would you do
for lossy pages?
regards, tom lane
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TIP 5: don't forget to increase your free space map settings
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
