Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-09-01 Thread Heikki Linnakangas
Abhijit Menon-Sen wrote: At 2008-08-25 10:24:01 +0300, [EMAIL PROTECTED] wrote: My original plan was to enable index-only-scans using the DSM as well for 8.4, but it's pretty clear at this point that I don't have the time to finish that :-(. I wonder how hard that would be. It's doable, for

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-25 Thread Heikki Linnakangas
Tom Lane wrote: [ off-list ] Matthew T. O'Connor [EMAIL PROTECTED] writes: Tom Lane wrote: I'm not sure how important it will really be once we have support for dead-space-map-driven vacuum. Is that something we can expect any time soon? I haven't heard much about it really happening for

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-24 Thread Merlin Moncure
On Fri, Aug 22, 2008 at 11:36 PM, Bruce Momjian [EMAIL PROTECTED] wrote: I assume there is no TODO here. Well, there doesn't seem to be a TODO for partial/restartable vacuums, which were mentioned upthread. This is a really desirable feature for big databases and removes one of the reasons to

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-24 Thread Joshua D. Drake
Merlin Moncure wrote: On Fri, Aug 22, 2008 at 11:36 PM, Bruce Momjian [EMAIL PROTECTED] wrote: I assume there is no TODO here. Well, there doesn't seem to be a TODO for partial/restartable vacuums, which were mentioned upthread. This is a really desirable feature for big databases and

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-24 Thread Matthew T. O'Connor
Joshua D. Drake wrote: Merlin Moncure wrote: Well, there doesn't seem to be a TODO for partial/restartable vacuums, which were mentioned upthread. This is a really desirable feature for big databases and removes one of the reasons to partition large tables. I would agree that partial vacuums

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-24 Thread Tom Lane
Matthew T. O'Connor [EMAIL PROTECTED] writes: I think everyone agrees that partial vacuums would be useful / *A Good Thing* but it's the implementation that is the issue. I'm not sure how important it will really be once we have support for dead-space-map-driven vacuum.

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-24 Thread Matthew T. O'Connor
Tom Lane wrote: Matthew T. O'Connor [EMAIL PROTECTED] writes: I think everyone agrees that partial vacuums would be useful / *A Good Thing* but it's the implementation that is the issue. I'm not sure how important it will really be once we have support for dead-space-map-driven

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-08-22 Thread Bruce Momjian
I assume there is no TODO here. --- Pavan Deolasee wrote: (taking the discussions to -hackers) On Sat, Jul 12, 2008 at 11:02 PM, Tom Lane [EMAIL PROTECTED] wrote: (2) It achieves speedup of VACUUM by pushing work

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-07-15 Thread Heikki Linnakangas
Gregory Stark wrote: I thought we only pruned when we wanted to insert a new tuple and found not enough space. Nope, we prune on any access to the page, if the page is full enough, and the pd_prune_xid field suggests that there is something to prune. The problem with only pruning on inserts

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-07-14 Thread Tom Lane
Pavan Deolasee [EMAIL PROTECTED] writes: (taking the discussions to -hackers) On Sat, Jul 12, 2008 at 11:02 PM, Tom Lane [EMAIL PROTECTED] wrote: (2) It achieves speedup of VACUUM by pushing work onto subsequent regular accesses of the page, which is exactly the wrong thing. Worse, once you

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-07-14 Thread Gregory Stark
Tom Lane [EMAIL PROTECTED] writes: It strikes me that what you are trying to do here is compensate for a bad decision in the HOT patch, which was to have VACUUM's first pass prune/defrag a page even when we know we are going to have to come back to that page later. What about trying to fix

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-07-14 Thread Tom Lane
Gregory Stark [EMAIL PROTECTED] writes: I like the idea of only having to do a single pass through the table though. Well, that argument was already overstated: we're not re-reading all of the table now. Just the pages containing dead line pointers. Couldn't Pavan's original plan still work

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-07-14 Thread Gregory Stark
Tom Lane [EMAIL PROTECTED] writes: Gregory Stark [EMAIL PROTECTED] writes: I like the idea of only having to do a single pass through the table though. Well, that argument was already overstated: we're not re-reading all of the table now. Just the pages containing dead line pointers.

Re: [HACKERS] [PATCHES] VACUUM Improvements - WIP Patch

2008-07-13 Thread Pavan Deolasee
(taking the discussions to -hackers) On Sat, Jul 12, 2008 at 11:02 PM, Tom Lane [EMAIL PROTECTED] wrote: (2) It achieves speedup of VACUUM by pushing work onto subsequent regular accesses of the page, which is exactly the wrong thing. Worse, once you count the disk writes those accesses will