Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Tue, Mar 22, 2011 at 3:25 PM, Yeb Havinga wrote: > So the patch eats 4,5% from git master's syncrep performance in my setup. > Don't know how to measure it better than that. That's quite surprising, but I guess the way forward is clear: don't apply that patch. -- Robert Haas EnterpriseDB: ht

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-21 23:58, Yeb Havinga wrote: On Mon, Mar 21, 2011 at 7:51 PM, Yeb Havinga > wrote: On 2011-03-21 18:04, Robert Haas wrote: On Mon, Mar 21, 2011 at 12:29 PM, Yeb Havingamailto:yebhavi...@gmail.com>> wrote: pgbench

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Mon, Mar 21, 2011 at 7:51 PM, Yeb Havinga wrote: > On 2011-03-21 18:04, Robert Haas wrote: > >> On Mon, Mar 21, 2011 at 12:29 PM, Yeb Havinga >> wrote: >> >>> pgbench -i -s 50 test >>> Two runs of "pgbench -c 10 -M prepared -T 600 test" with 1 sync standby - >>> server configs etc were mailed

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-21 18:04, Robert Haas wrote: On Mon, Mar 21, 2011 at 12:29 PM, Yeb Havinga wrote: pgbench -i -s 50 test Two runs of "pgbench -c 10 -M prepared -T 600 test" with 1 sync standby - server configs etc were mailed upthread. - performance as of commit e148443ddd95cd29edf4cc1de6188eb9cee0

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Mon, Mar 21, 2011 at 12:29 PM, Yeb Havinga wrote: > pgbench -i -s 50 test > Two runs of "pgbench -c 10 -M prepared -T 600 test" with 1 sync standby - > server configs etc were mailed upthread. > >> - performance as of commit e148443ddd95cd29edf4cc1de6188eb9cee029c5 > > 1158 and 1306 (avg 1232)

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-21 02:05, Robert Haas wrote: On Sun, Mar 20, 2011 at 11:03 AM, Yeb Havinga wrote: On 2011-03-20 05:44, Robert Haas wrote: Hmm, I'm not going to be able to reproduce this here, and my test setup didn't show a clear regression. I can try beating on it some more, but... Any chance yo

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Sun, Mar 20, 2011 at 11:03 AM, Yeb Havinga wrote: > On 2011-03-20 05:44, Robert Haas wrote: >> >> Hmm, I'm not going to be able to reproduce this here, and my test >> setup didn't show a clear regression.  I can try beating on it some >> more, but...  Any chance you could rerun your test with t

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-20 05:44, Robert Haas wrote: Hmm, I'm not going to be able to reproduce this here, and my test setup didn't show a clear regression. I can try beating on it some more, but... Any chance you could rerun your test with the latest master-branch code, and perhaps also with the patch I p

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Sat, Mar 19, 2011 at 10:32 AM, Yeb Havinga wrote: > Testing 'methodology' sounds a bit heavy. I tested a number of patch > versions over time, with 30 second, hourly and nightly pgbench runs. The > nightly more for durability/memory leak testing than tps numbers, since I > gradually got the imp

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-18 18:25, Robert Haas wrote: On Fri, Mar 18, 2011 at 1:15 PM, Simon Riggs wrote: On Thu, 2011-03-17 at 09:33 -0400, Robert Haas wrote: Thanks for the review! Lets have a look here... You've added a test inside the lock to see if there is a standby, which I took out for performance

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

Responding to this again, somewhat out of order... On Fri, Mar 18, 2011 at 1:15 PM, Simon Riggs wrote: > Together that's about a >20% hit in performance in Yeb's tests. I think > you should spend a little time thinking how to retune that. I've spent some time playing around with pgbench and so f

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Fri, Mar 18, 2011 at 2:55 PM, Alvaro Herrera wrote: > Excerpts from Robert Haas's message of vie mar 18 14:25:16 -0300 2011: >> On Fri, Mar 18, 2011 at 1:15 PM, Simon Riggs wrote: > >> > SyncRepUpdateSyncStandbysDefined() is added into walwriter, which means >> > waiters won't be released if w

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

Excerpts from Robert Haas's message of vie mar 18 14:25:16 -0300 2011: > On Fri, Mar 18, 2011 at 1:15 PM, Simon Riggs wrote: > > SyncRepUpdateSyncStandbysDefined() is added into walwriter, which means > > waiters won't be released if we do a sighup during a fast shutdown, > > since the walwriter

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Fri, Mar 18, 2011 at 1:15 PM, Simon Riggs wrote: > On Thu, 2011-03-17 at 09:33 -0400, Robert Haas wrote: >> Thanks for the review! > > Lets have a look here... > > You've added a test inside the lock to see if there is a standby, which > I took out for performance reasons. Maybe there's another

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Thu, 2011-03-17 at 09:33 -0400, Robert Haas wrote: > Thanks for the review! Lets have a look here... You've added a test inside the lock to see if there is a standby, which I took out for performance reasons. Maybe there's another way, I know that code is fiddly. You've also added back in th

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Fri, Mar 18, 2011 at 11:58 AM, Heikki Linnakangas wrote: > On 18.03.2011 17:38, Jeff Davis wrote: >> >> On Fri, 2011-03-18 at 10:27 -0400, Robert Haas wrote: >>> >>> ERRCODE_(WARNING_?)REPLICATION_WAIT_CANCELLED >>> >>> ...which might have something to recommend it. >> >> Works for me. > > Yes,

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 18.03.2011 17:38, Jeff Davis wrote: On Fri, 2011-03-18 at 10:27 -0400, Robert Haas wrote: ERRCODE_(WARNING_?)REPLICATION_WAIT_CANCELLED ...which might have something to recommend it. Works for me. Yes, sounds reasonable. Without "WARNING_", please. -- Heikki Linnakangas EnterpriseDB

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Fri, 2011-03-18 at 10:27 -0400, Robert Haas wrote: > ERRCODE_(WARNING_?)REPLICATION_WAIT_CANCELLED > > ...which might have something to recommend it. Works for me. Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subs

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Fri, Mar 18, 2011 at 10:17 AM, Jeff Davis wrote: > On Fri, 2011-03-18 at 08:27 -0400, Robert Haas wrote: >> On Thu, Mar 17, 2011 at 6:00 PM, Jeff Davis wrote: >> > On Wed, 2011-03-16 at 13:35 -0400, Robert Haas wrote: >> >> 2. If a query cancel interrupt is received (pg_cancel_backend or ^C),

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Fri, 2011-03-18 at 08:27 -0400, Robert Haas wrote: > On Thu, Mar 17, 2011 at 6:00 PM, Jeff Davis wrote: > > On Wed, 2011-03-16 at 13:35 -0400, Robert Haas wrote: > >> 2. If a query cancel interrupt is received (pg_cancel_backend or ^C), > >> then cancel the sync rep wait and issue a warning bef

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Thu, Mar 17, 2011 at 6:00 PM, Jeff Davis wrote: > On Wed, 2011-03-16 at 13:35 -0400, Robert Haas wrote: >> 2. If a query cancel interrupt is received (pg_cancel_backend or ^C), >> then cancel the sync rep wait and issue a warning before acknowledging >> the commit. > > When I saw this commit, I

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, 2011-03-16 at 13:35 -0400, Robert Haas wrote: > 2. If a query cancel interrupt is received (pg_cancel_backend or ^C), > then cancel the sync rep wait and issue a warning before acknowledging > the commit. When I saw this commit, I noticed that the WARNING doesn't have an errcode(). It seem

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Thu, Mar 17, 2011 at 8:24 AM, Heikki Linnakangas wrote: > Hmm, so setting synchronous_standby_names to '' takes effect immediately, > but other changes to it don't apply to already-blocked commits. That seems a > bit inconsistent. Perhaps walwriter should store the parsed list of > standby-name

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Thu, Mar 17, 2011 at 2:08 AM, Fujii Masao wrote: > This occurs to me; we should ensure that, in shutdown case, walwriter > should exit after all the backends have gone out? I'm not sure if it's worth > thinking of the case, but what if synchronous_standby_names is unset > and config file is rel

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 16.03.2011 19:35, Robert Haas wrote: 3. If synchronous_standby_names is changed to '' by editing postgresql.conf and issuing pg_ctl reload, then cancel all waits in progress and wake everybody up. As I mentioned before, reloading the config file from within the waiting backend (which can't sa

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Thu, Mar 17, 2011 at 2:35 AM, Robert Haas wrote: > 1. If a die interrupt is received (pg_terminate_backend or fast > shutdown), then terminate the sync rep wait and arrange for the > connection to be closed without acknowledging the commit (but do send > a warning message back).  The commit sti

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 16, 2011 at 8:30 PM, Robert Haas wrote: > I think the most important part of all this is that it is logged. > Anyone who is running synchronous replication should also be doing > careful monitoring; if not, shame on them, because if your data is > important enough that you need synchr

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 16, 2011 at 6:23 PM, Dimitri Fontaine wrote: > Robert Haas writes: >> 1. If a die interrupt is received (pg_terminate_backend or fast >> shutdown), then terminate the sync rep wait and arrange for the >> connection to be closed without acknowledging the commit (but do send >> a warnin

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

Robert Haas writes: > 1. If a die interrupt is received (pg_terminate_backend or fast > shutdown), then terminate the sync rep wait and arrange for the > connection to be closed without acknowledging the commit (but do send > a warning message back). The commit still happened, though, so other >

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 16, 2011 at 7:39 AM, Robert Haas wrote: >>> The only idea I have for allowing fast shutdown to still be fast, even >>> when sync rep is involved, is to shut down the system in two phases. >>> The postmaster would need to stop accepting new connections, and first >>> kill off all the ba

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 16, 2011 at 4:51 AM, Simon Riggs wrote: > On Tue, 2011-03-15 at 22:07 -0400, Robert Haas wrote: >> On Wed, Mar 9, 2011 at 11:11 PM, Fujii Masao wrote: >> > Same as above. I think that it's more problematic to leave the code >> > as it is. Because smart/fast shutdown can make the serve

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 16, 2011 at 1:43 AM, Fujii Masao wrote: > On Wed, Mar 16, 2011 at 11:07 AM, Robert Haas wrote: >> The problem is that there may be another backend B waiting on a lock >> held by A.  If backend A exits cleanly (without a PANIC), it will >> remove itself from the ProcArray and release l

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Tue, 2011-03-15 at 22:07 -0400, Robert Haas wrote: > On Wed, Mar 9, 2011 at 11:11 PM, Fujii Masao wrote: > > Same as above. I think that it's more problematic to leave the code > > as it is. Because smart/fast shutdown can make the server get stuck > > until immediate shutdown is requested. >

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 16, 2011 at 11:07 AM, Robert Haas wrote: > The problem is that there may be another backend B waiting on a lock > held by A.  If backend A exits cleanly (without a PANIC), it will > remove itself from the ProcArray and release locks.  That wakes up A, > which can now go do its thing.  

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 9, 2011 at 11:11 PM, Fujii Masao wrote: > Same as above. I think that it's more problematic to leave the code > as it is. Because smart/fast shutdown can make the server get stuck > until immediate shutdown is requested. I agree that the current state of affairs is a problem. However

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Thu, Mar 10, 2011 at 12:03 AM, Simon Riggs wrote: > On Wed, 2011-03-09 at 15:37 +0100, Yeb Havinga wrote: > >> The current situation is definately unsafe because it forces people >> that are in this state to do a fast shutdown.. but that fails as well, >> so they are only left with immediate.

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, 2011-03-09 at 15:37 +0100, Yeb Havinga wrote: > The current situation is definately unsafe because it forces people > that are in this state to do a fast shutdown.. but that fails as well, > so they are only left with immediate. All the more reason not to change anything, since we disagre

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-09 15:10, Simon Riggs wrote: On Wed, 2011-03-09 at 16:38 +0900, Fujii Masao wrote: On Wed, Mar 9, 2011 at 2:14 PM, Jaime Casanova wrote: On Tue, Mar 8, 2011 at 11:58 AM, Robert Haas wrote: The fast shutdown handling seems fine, but why not just handle smart shutdown the same way?

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, 2011-03-09 at 16:38 +0900, Fujii Masao wrote: > On Wed, Mar 9, 2011 at 2:14 PM, Jaime Casanova wrote: > > On Tue, Mar 8, 2011 at 11:58 AM, Robert Haas wrote: > >> > >> The fast shutdown handling seems fine, but why not just handle smart > >> shutdown the same way? > > > > currently, smart

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On Wed, Mar 9, 2011 at 08:38, Fujii Masao wrote: > On Wed, Mar 9, 2011 at 2:14 PM, Jaime Casanova wrote: >> On Tue, Mar 8, 2011 at 11:58 AM, Robert Haas wrote: >>> >>> The fast shutdown handling seems fine, but why not just handle smart >>> shutdown the same way? >> >> currently, smart shutdown

Re: Sync Rep and shutdown Re: [HACKERS] Sync Rep v19

On 2011-03-09 08:38, Fujii Masao wrote: On Wed, Mar 9, 2011 at 2:14 PM, Jaime Casanova wrote: On Tue, Mar 8, 2011 at 11:58 AM, Robert Haas wrote: The fast shutdown handling seems fine, but why not just handle smart shutdown the same way? currently, smart shutdown means no new connections, wa