Re: [HACKERS] bitmap scan and explain analyze

2005-05-04 Thread Tatsuo Ishii
Why actual rows=0? I couldn't think of any reasonably cheap way to count the actual rows (especially in the presence of lossy bitmaps), so I just punted. I see. BTW is it possible to let BitmapHeapScan fetch tuples by TID order? It would make heap acccess in sequential manner and would

Re: [HACKERS] bitmap scan and explain analyze

2005-05-04 Thread Tom Lane
Tatsuo Ishii [EMAIL PROTECTED] writes: BTW is it possible to let BitmapHeapScan fetch tuples by TID order? It already does ... regards, tom lane ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose

Re: [HACKERS] bitmap scan and explain analyze

2005-05-04 Thread Tatsuo Ishii
BTW is it possible to let BitmapHeapScan fetch tuples by TID order? It already does ... Oh great. It seems tbm_begin_iterate() does the trick... -- Tatsuo Ishii ---(end of broadcast)--- TIP 7: don't forget to increase your free space map

[HACKERS] bitmap scan and explain analyze

2005-05-03 Thread Tatsuo Ishii
I noticed that explain analyze emits a little bit funny reslut for bitmap scans: BitmapOr (cost=157.36..157.36 rows=18894 width=0) (actual time=9.406..9.406 rows=0 loops=1) Why actual rows=0? -- Tatsuo Ishii ---(end of broadcast)--- TIP 8:

Re: [HACKERS] bitmap scan and explain analyze

2005-05-03 Thread Tom Lane
Tatsuo Ishii [EMAIL PROTECTED] writes: Why actual rows=0? I couldn't think of any reasonably cheap way to count the actual rows (especially in the presence of lossy bitmaps), so I just punted. regards, tom lane ---(end of