Re: [HACKERS] Planner question

2008-09-23 Thread Bruce Momjian
Tom Raney wrote: RELOPTINFO (tenk1): rows=1 width=244 path list: SeqScan(tenk1) rows=1 cost=0.00..434.00 IdxScan(tenk1) rows=1 cost=0.00..583.25 pathkeys: ((tenk1.unique2, onek.unique2)) --- cheapest startup path:

Re: [HACKERS] Planner question

2008-09-10 Thread Tom Raney
Tom Lane wrote: Tom Raney [EMAIL PROTECTED] writes: Why does the planner consider both input variations of each symmetric merge join? The README says there is not a lot of difference between the two options. When are there any differences? The righthand side needs to support mark/restore,

Re: [HACKERS] Planner question

2008-09-10 Thread Tom Lane
Tom Raney [EMAIL PROTECTED] writes: Why does the index scan for tenk1 include a path key from onek.unique2? Is it implying an equivalence there? bench=# explain select * from tenk1 JOIN onek ON tenk1.unique2=onek.unique2; Yes, for an example like that the planner knows that tenk1.unique2

Re: [HACKERS] Planner question

2008-09-10 Thread Tom Raney
Tom Lane wrote: Tom Raney [EMAIL PROTECTED] writes: Why does the index scan for tenk1 include a path key from onek.unique2? Is it implying an equivalence there? bench=# explain select * from tenk1 JOIN onek ON tenk1.unique2=onek.unique2; Yes, for an example like that the planner knows

[HACKERS] Planner question

2008-09-05 Thread Tom Raney
Why does the planner consider both input variations of each symmetric merge join? The README says there is not a lot of difference between the two options. When are there any differences? -Tom Raney -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to

Re: [HACKERS] Planner question

2008-09-05 Thread Jeff Davis
On Fri, 2008-09-05 at 11:21 -0700, Tom Raney wrote: Why does the planner consider both input variations of each symmetric merge join? The README says there is not a lot of difference between the two options. When are there any differences? -Tom Raney

Re: [HACKERS] Planner question

2008-09-05 Thread Tom Lane
Tom Raney [EMAIL PROTECTED] writes: Why does the planner consider both input variations of each symmetric merge join? The README says there is not a lot of difference between the two options. When are there any differences? The righthand side needs to support mark/restore, the left

[HACKERS] Planner question

2008-08-12 Thread Tom Raney
I've been working on a client application (based on the Red Hat Visual Explain tool) to display all plans the planner considers graphically and it does that. But, the trace functionality in the planner is always on (and thus, taking up cycles and resources) whether or not it is requested by

Re: [HACKERS] Planner question

2008-08-12 Thread Tom Lane
Tom Raney [EMAIL PROTECTED] writes: My question is: How would I let the planner know when a planner session has been invoked by the explain command? If I can slip a flag into PlannerInfo or PlannerGlobal, that would be perfect. But, I'm a bit stuck on how to get explain context to that