It appears it scanes the type_idx once per opereator. IN gets broken down into ORs
Is this what the TODO entry 'Make IN / NOT IN have similar performance as EXISTS' means? -- Rod ----- Original Message ----- From: "Oleg Bartunov" <[EMAIL PROTECTED]> To: "Pgsql Hackers" <[EMAIL PROTECTED]>; "Tom Lane" <[EMAIL PROTECTED]> Sent: Monday, May 13, 2002 9:42 AM Subject: [HACKERS] strange explain > Hi, > > > I've got performance problem and while I'dont ready to describe it > I'd like to ask about strange explain: > > tour=# explain analyze select * from tours where > ( operator_id in (2,3,4,5,7) and type_id = 2 ) or > ( operator_id = 8 and type_id=4 ); > > NOTICE: QUERY PLAN: > > Index Scan using type_idx, type_idx, type_idx, type_idx, type_idx, type_idx on tours (cost=0.00..12.25 rows=1 width=1091) (actual time=0.26..0.26 rows=0 loops=1) > Total runtime: 0.45 msec > > EXPLAIN > > What does many 'type_idx' means ? > > Theare are 2 indices - operator_idx and type_idx. > > > Regards, > Oleg > _____________________________________________________________ > Oleg Bartunov, sci.researcher, hostmaster of AstroNet, > Sternberg Astronomical Institute, Moscow University (Russia) > Internet: [EMAIL PROTECTED], http://www.sai.msu.su/~megera/ > phone: +007(095)939-16-83, +007(095)939-23-83 > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED]) > ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
