Thread: Vacuum Cost Documentation?
Related to autovacuum work, I was looking into the new vacuum delay functionality. I might be missing something, but I can't find anything on it in the developer docs. Is that right? Also, in the default postgresql.conf there is: #vacuum_cost_naptime = 50 # 0-1000 milliseconds however psql reports this value as 0. I assume this is just postgresql.conf is just wrong. Can we fix this so it's consistent? Thanks, Matthew O'Connor
Matthew T. O'Connor wrote: > Related to autovacuum work, I was looking into the new vacuum delay > functionality. I might be missing something, but I can't find anything > on it in the developer docs. Is that right? > > Also, in the default postgresql.conf there is: > > #vacuum_cost_naptime = 50 # 0-1000 milliseconds > > however psql reports this value as 0. I assume this is just > postgresql.conf is just wrong. Can we fix this so it's consistent? I am not really fond of the term 'naptime'. Delay? Sleep? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
"Matthew T. O'Connor" <matthew@zeut.net> writes:
> Related to autovacuum work, I was looking into the new vacuum delay
> functionality. I might be missing something, but I can't find anything
> on it in the developer docs. Is that right?
You are not missing anything. I already nagged Jan about this once...
Of course, this is hardly the only seriously-underdocumented thing in
CVS tip ;-). We'll need to make a major push on docs soon.
regards, tom lane
On Sun, Jul 18, 2004 at 02:32:10AM -0400, Tom Lane wrote: > "Matthew T. O'Connor" <matthew@zeut.net> writes: > > Related to autovacuum work, I was looking into the new vacuum > > delay functionality. I might be missing something, but I can't > > find anything on it in the developer docs. Is that right? > > You are not missing anything. I already nagged Jan about this > once... > > Of course, this is hardly the only seriously-underdocumented thing > in CVS tip ;-). We'll need to make a major push on docs soon. Do tell. :) Cheers, D(oc writer ordinaire) -- David Fetter david@fetter.org http://fetter.org/ phone: +1 510 893 6100 mobile: +1 415 235 3778 Remember to vote!
Updated. Thanks. --------------------------------------------------------------------------- Matthew T. O'Connor wrote: > Related to autovacuum work, I was looking into the new vacuum delay > functionality. I might be missing something, but I can't find anything > on it in the developer docs. Is that right? > > Also, in the default postgresql.conf there is: > > #vacuum_cost_naptime = 50 # 0-1000 milliseconds > > however psql reports this value as 0. I assume this is just > postgresql.conf is just wrong. Can we fix this so it's consistent? > > Thanks, > > Matthew O'Connor > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On 8/6/2004 9:04 PM, Bruce Momjian wrote: > Updated. Thanks. I thought we want to have the feature activated ... I reversed your change and brought guc.c in sync instead. Jan > > --------------------------------------------------------------------------- > > Matthew T. O'Connor wrote: >> Related to autovacuum work, I was looking into the new vacuum delay >> functionality. I might be missing something, but I can't find anything >> on it in the developer docs. Is that right? >> >> Also, in the default postgresql.conf there is: >> >> #vacuum_cost_naptime = 50 # 0-1000 milliseconds >> >> however psql reports this value as 0. I assume this is just >> postgresql.conf is just wrong. Can we fix this so it's consistent? >> >> Thanks, >> >> Matthew O'Connor >> >> >> >> >> ---------------------------(end of broadcast)--------------------------- >> TIP 6: Have you searched our list archives? >> >> http://archives.postgresql.org >> > -- #======================================================================# # It's easier to get forgiveness for being wrong than for being right. # # Let's break this rule - forgive me. # #================================================== JanWieck@Yahoo.com #
Jan Wieck wrote: > On 8/6/2004 9:04 PM, Bruce Momjian wrote: > > > Updated. Thanks. > > I thought we want to have the feature activated ... I reversed your > change and brought guc.c in sync instead. OK. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Jan Wieck wrote: > On 8/6/2004 9:04 PM, Bruce Momjian wrote: > > > Updated. Thanks. > > I thought we want to have the feature activated ... I reversed your > change and brought guc.c in sync instead. Uh, if the guy is doing a vacuum at night, does he want the delay? Seems someone should have to enable the delay by default, or does your setup recoginize when it is being run on a lightly loaded system? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian wrote: > Jan Wieck wrote: > >>On 8/6/2004 9:04 PM, Bruce Momjian wrote: >> >> >>>Updated. Thanks. >> >>I thought we want to have the feature activated ... I reversed your >>change and brought guc.c in sync instead. > > > Uh, if the guy is doing a vacuum at night, does he want the delay? > Seems someone should have to enable the delay by default, or does your > setup recoginize when it is being run on a lightly loaded system? TODO: make vacuum_cost_naptime aware of system load :-) Regards Gaetano Mendola
On 8/6/2004 11:34 PM, Bruce Momjian wrote: > Jan Wieck wrote: >> On 8/6/2004 9:04 PM, Bruce Momjian wrote: >> >> > Updated. Thanks. >> >> I thought we want to have the feature activated ... I reversed your >> change and brought guc.c in sync instead. > > Uh, if the guy is doing a vacuum at night, does he want the delay? > Seems someone should have to enable the delay by default, or does your > setup recoginize when it is being run on a lightly loaded system? > > Good that autovacuum didn't make it then, those people would have had a big surprise :-) Jan -- #======================================================================# # It's easier to get forgiveness for being wrong than for being right. # # Let's break this rule - forgive me. # #================================================== JanWieck@Yahoo.com #
Jan Wieck <JanWieck@Yahoo.com> writes:
> Good that autovacuum didn't make it then, those people would have had a
> big surprise :-)
If autovacuum had made it, would you expect someone to have enabled it
by default? Without advance discussion?
regards, tom lane
Jan Wieck wrote: > On 8/6/2004 11:34 PM, Bruce Momjian wrote: > > > Jan Wieck wrote: > >> On 8/6/2004 9:04 PM, Bruce Momjian wrote: > >> > >> > Updated. Thanks. > >> > >> I thought we want to have the feature activated ... I reversed your > >> change and brought guc.c in sync instead. > > > > Uh, if the guy is doing a vacuum at night, does he want the delay? > > Seems someone should have to enable the delay by default, or does your > > setup recoginize when it is being run on a lightly loaded system? > > > > > > Those people will instantly realize what is going on and either change > the delay setting or start running vacuum at daytime too. > > What this buys us is that over time we will see less researches and > articles telling people that you have to bring down a PostgreSQL DB > frequently for vacuum maintenance because those "testers" run their fair > comparisions with out of the box configuration settings. I am not in favor of adding a delay in VACUUM unless people ask for it. Imagine either night vacuum or a vacuum you run in your application after you delete and just before you load a table. Neither want a vacuum. I think people who want a delay will think to ask for it while people who want a quick vacuum will just think that vacuum is slow. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073