On Mon, Jan 4, 2021 at 3:35 AM Tomas Vondra
wrote:
> Seems this commit left behind a couple unnecessary prototypes in a bunch
> of header files. In particular, it removed these functions
>
> - ShutdownCLOG();
> - ShutdownCommitTs();
> - ShutdownSUBTRANS();
> - ShutdownMultiXact();
Thanks.
On 9/25/20 9:09 AM, Thomas Munro wrote:
On Fri, Sep 25, 2020 at 12:53 PM Thomas Munro wrote:
Here's a new version. The final thing I'm contemplating before
pushing this is whether there may be hidden magical dependencies in
the order of operations in CheckPointGuts(), which I've changed
On Fri, Sep 25, 2020 at 12:53 PM Thomas Munro wrote:
> Here's a new version. The final thing I'm contemplating before
> pushing this is whether there may be hidden magical dependencies in
> the order of operations in CheckPointGuts(), which I've changed
> around. Andres, any comments?
I nagged
On Fri, Sep 25, 2020 at 12:05 PM Tom Lane wrote:
> Thomas Munro writes:
> > Tom, do you have any thoughts on ShutdownCLOG() etc?
>
> Hm, if we cannot reach that without first completing a shutdown checkpoint,
> it does seem a little pointless.
Thanks for the sanity check.
> It'd likely be a
Thomas Munro writes:
> Tom, do you have any thoughts on ShutdownCLOG() etc?
Hm, if we cannot reach that without first completing a shutdown checkpoint,
it does seem a little pointless.
It'd likely be a good idea to add a comment to CheckPointCLOG et al
explaining that we expect $what-exactly to
On Wed, Sep 23, 2020 at 1:56 PM Thomas Munro wrote:
> As for the ShutdownXXX() functions, I haven't yet come up with any
> reason for this code to exist. Emboldened by a colleague's inability
> to explain to me what that code is doing for us, here is a new version
> that just rips it all out.
On Tue, Sep 22, 2020 at 9:08 AM Thomas Munro wrote:
> On Mon, Sep 21, 2020 at 2:19 PM Thomas Munro wrote:
> > While scanning for comments and identifier names that needed updating,
> > I realised that this patch changed the behaviour of the ShutdownXXX()
> > functions, since they currently flush
On Mon, Sep 21, 2020 at 2:19 PM Thomas Munro wrote:
> While scanning for comments and identifier names that needed updating,
> I realised that this patch changed the behaviour of the ShutdownXXX()
> functions, since they currently flush the SLRUs but are not followed
> by a checkpoint. I'm not
On Sun, Sep 20, 2020 at 12:40 PM Thomas Munro wrote:
> On Sat, Sep 19, 2020 at 5:06 PM Thomas Munro wrote:
> > In the meantime, from the low-hanging-fruit department, here's a new
> > version of the SLRU-fsync-offload patch. The only changes are a
> > tweaked commit message, and adoption of C99
On Sat, Sep 19, 2020 at 5:06 PM Thomas Munro wrote:
> In the meantime, from the low-hanging-fruit department, here's a new
> version of the SLRU-fsync-offload patch. The only changes are a
> tweaked commit message, and adoption of C99 designated initialisers
> for the function table, so {
On Mon, Aug 31, 2020 at 8:50 PM Jakub Wartak wrote:
> - IO_URING - gives a lot of promise here I think, is it even planned to be
> shown for PgSQL14 cycle ? Or it's more like PgSQL15?
I can't answer that, but I've played around with the prototype quite a
bit, and thought quite a lot about how
Hi Thomas, hackers,
>> ... %CPU ... COMMAND
>> ... 97.4 ... postgres: startup recovering 00010089
> So, what else is pushing this thing off CPU, anyway? For one thing, I
> guess it might be stalling while reading the WAL itself, because (1)
> we only read it 8KB at a time,
On Sat, Aug 29, 2020 at 12:43 AM Jakub Wartak wrote:
> ... %CPU ... COMMAND
> ... 97.4 ... postgres: startup recovering 00010089
So, what else is pushing this thing off CPU, anyway? For one thing, I
guess it might be stalling while reading the WAL itself, because (1)
we only
On Sat, Aug 29, 2020 at 12:43 AM Jakub Wartak wrote:
> USERPID %CPU %MEMVSZ RSS TTY STAT START TIME COMMAND
> postgres 120935 0.9 0.0 866052 3824 ?Ss 09:47 0:00 postgres:
> checkpointer
> postgres 120936 61.9 0.0 865796 3824 ?Rs 09:47 0:22
Hi Thomas, hackers,
>> > To move these writes out of recovery's way, we should probably just
>> > run the bgwriter process during crash recovery. I'm going to look
>> > into that.
>>
>> Sounds awesome.
>
>I wrote a quick and dirty experimental patch to try that. I can't see
>any benefit from it
On Thu, Aug 27, 2020 at 8:48 PM Jakub Wartak wrote:
> >> 29.62% postgres [kernel.kallsyms] [k]
> >> copy_user_enhanced_fast_string
> >> ---copy_user_enhanced_fast_string
> >>|--17.98%--copyin
> >> [..]
> >>| __pwrite_nocancel
> >>
On Thu, Aug 27, 2020 at 8:48 PM Jakub Wartak wrote:
> I've tried to get cache misses ratio via PMCs, apparently on EC2 they are
> (even on bigger) reporting as not-supported or zeros.
I heard some of the counters are only allowed on their dedicated instance types.
> However interestingly the
Hi Alvaro, Thomas, hackers
>> 14.69% postgres postgres[.] hash_search_with_hash_value
>> ---hash_search_with_hash_value
>>|--9.80%--BufTableLookup
[..]
>> --4.90%--smgropen
>>
Hi Thomas / hackers,
>> The append-only bottleneck appears to be limited by syscalls/s due to small
>> block size even with everything in FS cache (but not in shared buffers,
>> please compare with TEST1 as there was no such bottleneck at all):
>>
>> 29.62% postgres [kernel.kallsyms]
On Thu, Aug 27, 2020 at 6:15 AM Alvaro Herrera wrote:
> > --4.90%--smgropen
> > |--2.86%--ReadBufferWithoutRelcache
>
> Looking at an earlier report of this problem I was thinking whether it'd
> make sense to replace SMgrRelationHash with a simplehash
On 2020-Aug-25, Jakub Wartak wrote:
> Turning on/off the defer SLRU patch and/or fsync doesn't seem to make
> any difference, so if anyone is curious the next sets of append-only
> bottlenecks is like below:
>
> 14.69% postgres postgres[.] hash_search_with_hash_value
>
On 2020-Aug-25, Andres Freund wrote:
> Hi,
>
> On 2020-08-26 15:58:14 +1200, Thomas Munro wrote:
> > > --12.51%--compactify_tuples
> > > PageRepairFragmentation
> > > heap2_redo
> > > StartupXLOG
> >
>
Hi,
On 2020-08-26 15:58:14 +1200, Thomas Munro wrote:
> > --12.51%--compactify_tuples
> > PageRepairFragmentation
> > heap2_redo
> > StartupXLOG
>
> I wonder if there is something higher level that
On Tue, Aug 25, 2020 at 9:16 PM Jakub Wartak wrote:
> I just wanted to help testing this patch (defer SLRU fsyncs during recovery)
> and also faster compactify_tuples() patch [2] as both are related to the WAL
> recovery performance in which I'm interested in. This is my first message to
>
On Wed, Aug 12, 2020 at 6:06 PM Thomas Munro wrote:
> [patch]
Hi Thomas / hackers,
I just wanted to help testing this patch (defer SLRU fsyncs during recovery)
and also faster compactify_tuples() patch [2] as both are related to the WAL
recovery performance in which I'm interested in. This is
On Wed, Aug 12, 2020 at 6:06 PM Thomas Munro wrote:
> [patch]
Bitrot, rebased, no changes.
> Yeah, the combined effect of these two patches is better than I
> expected. To be clear though, I was only measuring the time between
> the "redo starts at ..." and "redo done at ..." messages, since
On Sat, Aug 8, 2020 at 2:44 AM Robert Haas wrote:
> On Wed, Aug 5, 2020 at 2:01 AM Thomas Munro wrote:
> > * Master is around 11% faster than last week before commit c5315f4f
> > "Cache smgrnblocks() results in recovery."
> > * This patch gives a similar speedup, bringing the total to around 25%
On Wed, Aug 5, 2020 at 2:01 AM Thomas Munro wrote:
> * Master is around 11% faster than last week before commit c5315f4f
> "Cache smgrnblocks() results in recovery."
> * This patch gives a similar speedup, bringing the total to around 25%
> faster than last week (the time is ~20% less, the WAL
On Tue, Aug 4, 2020 at 6:02 PM Thomas Munro wrote:
> ... speedup of around 6% ...
I did some better testing. OS: Linux, storage: consumer SSD. I
repeatedly ran crash recovery on 3.3GB worth of WAL generated with 8M
pgbench transactions. I tested 3 different builds 7 times each and
used
On Wed, Feb 12, 2020 at 9:54 PM Thomas Munro wrote:
> In commit 3eb77eba we made it possible for any subsystem that wants a
> file to be flushed as part of the next checkpoint to ask the
> checkpointer to do that, as previously only md.c could do.
Hello,
While working on recovery performance, I
Hi,
In commit 3eb77eba we made it possible for any subsystem that wants a
file to be flushed as part of the next checkpoint to ask the
checkpointer to do that, as previously only md.c could do.
In the past, foreground CLOG flush stalls were a problem, but then
commit 33aaa139 cranked up the
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