From: Kyotaro Horiguchi
> If we can skip the table-copy when ALTER TABLE SET LOGGED on
> wal_level=minimal, is your objective achived?
I expect so, if we can skip the table copy during ALTER TABLE SET
LOGGED/UNLOGGED. On the other hand, both approaches have different pros and
cons. It's nice
At Fri, 11 Sep 2020 17:36:19 +0900 (JST), Kyotaro Horiguchi
wrote in
> At Fri, 11 Sep 2020 05:15:32 +, "tsunakawa.ta...@fujitsu.com"
> wrote in
> > From: Peter Smith
> > On Thu, Sep 10, 2020 at 7:16 PM tsunakawa.ta...@fujitsu.com
> > > wrote:
> > > > ALTER TABLE takes long time proporti
At Fri, 11 Sep 2020 05:15:32 +, "tsunakawa.ta...@fujitsu.com"
wrote in
> From: Peter Smith
> On Thu, Sep 10, 2020 at 7:16 PM tsunakawa.ta...@fujitsu.com
> > wrote:
> > > ALTER TABLE takes long time proportional to the amount of existing data,
> > while wal_level = none doesn't.
> >
> > Ri
From: Peter Smith
On Thu, Sep 10, 2020 at 7:16 PM tsunakawa.ta...@fujitsu.com
> wrote:
> > ALTER TABLE takes long time proportional to the amount of existing data,
> while wal_level = none doesn't.
>
> Right, but if wal_level=none is considered OK for that table with
> existing data, then why no
On Thu, Sep 10, 2020 at 7:16 PM tsunakawa.ta...@fujitsu.com
wrote:
> ALTER TABLE takes long time proportional to the amount of existing data,
> while wal_level = none doesn't.
Right, but if wal_level=none is considered OK for that table with
existing data, then why not just create the table UNL
From: Peter Smith
> Earlier, Osumi-san was rejecting the idea of using ALTER TABLE tbl SET
> UNLOGGED on basis that it is too time consuming for large data to
> switch the table modes [1].
> Doesn't wal_level=none essentially just behave as if every table was
> UNLOGGED; not just the ones we are
Hi.
I expect I have some basic misunderstanding because IMO now this
thread seems to have come full circle.
Earlier, Osumi-san was rejecting the idea of using ALTER TABLE tbl SET
UNLOGGED on basis that it is too time consuming for large data to
switch the table modes [1].
Now the latest idea is
From: Amit Kapila
> Sure, but on a daily basis, one requires only incremental WAL to
> complete the backup but in this case, it would require the entire
> database back up unless we have some form of block-level incremental
> backup method.
Regarding the backup time, I think users can shorten it
On Thu, Aug 27, 2020 at 7:04 AM tsunakawa.ta...@fujitsu.com
wrote:
>
> From: Amit Kapila
> > So you want your users to shutdown and restart the server before Copy
> > because that would be required if you want to change the wal_level.
>
> Yes. They seem to be fine with it, as far as I heard from
From: Amit Kapila
> So you want your users to shutdown and restart the server before Copy
> because that would be required if you want to change the wal_level.
Yes. They seem to be fine with it, as far as I heard from a person who is
involved in the system design.
> However, even if we do tha
On Wed, Aug 26, 2020 at 12:54 PM tsunakawa.ta...@fujitsu.com
wrote:
>
>
> Following this idea, what do you think about adding a new value "none" to
> wal_level, where no WAL is generated? The setting of wal_level is recorded
> in pg_control. The startup process can see the value and reject rec
Hello,
I think it's worth thinking about a sophisticated feature like Oracle's
UNRECOVERABLE data loading (because SQL Server's BCP load utility also has such
a feature, but for an empty table), how about an easier approach like MySQL? I
expect this won't complicate Postgres code much.
The c
On Thu, Aug 20, 2020 at 5:49 AM osumi.takami...@fujitsu.com
wrote:
>
> Hello.
> > > During the crash recovery, those points are helpful to recognize and
> > > detach such blocks in order to solve a situation that the loaded data is
> > > partially
> > synced to the disk and the rest isn't.
> >
>
At Thu, 20 Aug 2020 00:18:52 +, "osumi.takami...@fujitsu.com"
wrote in
> Hello.
>
> Apologies for the delay.
> > > When the server crash occurs during data loading of COPY UNLOGGED,
> > > it's a must to keep index consistent of course.
> > > I'm thinking that to rebuild the indexes on the t
Hello.
Apologies for the delay.
> > When the server crash occurs during data loading of COPY UNLOGGED,
> > it's a must to keep index consistent of course.
> > I'm thinking that to rebuild the indexes on the target table would work.
> >
> > In my opinion, UNLOGGED clause must be designed to guarant
On Fri, 17 Jul 2020 at 13:23, osumi.takami...@fujitsu.com
wrote:
>
> Hi,
>
> > AFAICS, we can already accomplish basically the same thing as what you want
> > to
> > do like this:
> >
> > alter table foo set unlogged;
> > copy foo from ...;
> > alter table foo set logged;
> This didn't satisfy wh
On Wed, Jul 22, 2020 at 11:11 AM osumi.takami...@fujitsu.com
wrote:
>
> > If you are going to suggest users not to replicate such tables then why
> > can't you
> > suggest them to create such tables as UNLOGGED in the first place? Another
> > idea could be that you create an 'unlogged'
> > table
Hi. Amit-san
> If you are going to suggest users not to replicate such tables then why can't
> you
> suggest them to create such tables as UNLOGGED in the first place? Another
> idea could be that you create an 'unlogged'
> table, copy the data to it. Then perform Alter Table .. SET Logged and
On Fri, Jul 17, 2020 at 9:53 AM osumi.takami...@fujitsu.com
wrote:
>
> Lastly, I have to admit that
> the status of target table where data is loaded by COPY UNLOGGED would be
> marked
> as invalid and notified to standbys under replication environment
> from the point in time when the operation
Hi,
> AFAICS, we can already accomplish basically the same thing as what you want to
> do like this:
>
> alter table foo set unlogged;
> copy foo from ...;
> alter table foo set logged;
This didn't satisfy what I wanted.
In case that 'foo' has huge amount of rows at the beginning,
this example wo
"osumi.takami...@fujitsu.com" writes:
>> Aside from that, though, how does this improve upon the existing capability
>> to copy into an unlogged temporary table?
> [>] unlogged temporary table can’t be inherited over sessions first of all.
Unlogged tables don't have to be temporary.
> And unlo
Hi David Johnston
Thank you for your comment.
Aside from that, though, how does this improve upon the existing capability to
copy into an unlogged temporary table?
[>] unlogged temporary table can’t be inherited over sessions first of all.
And unlogged table needs to be recreated due to startup
On 2020/07/09 15:17, osumi.takami...@fujitsu.com wrote:
Fujii-san
Thank you for your interest in this idea.
This feature can work safely with wal_level=replica or logical?
Or it can work only with wal_level=minimal?
If yes, what is the main difference
between this method and wal_skip_thresh
On Thu, Jul 9, 2020 at 11:47 AM osumi.takami...@fujitsu.com
wrote:
>
>
> In terms of streaming replication,
> I'd like to ask for advice of other members in this community.
> Now, I think this feature requires to re-create standby
> immediately after the COPY UNLOGGED like Oracle's clause
>
This
From: David G. Johnston
> This step seems to invalidate the idea outright. The checkpoint command is
> superuser only and isn’t table specific. This seems to require both those
> things to be changed.
Perhaps FlushRelationBuffers() followed by smgrsync() can be used instead. Or,
depending o
Fujii-san
Thank you for your interest in this idea.
> This feature can work safely with wal_level=replica or logical?
> Or it can work only with wal_level=minimal?
>If yes, what is the main difference
> between this method and wal_skip_threshold?
I'm thinking this feature can be used
when you set
On Wednesday, July 8, 2020, osumi.takami...@fujitsu.com <
osumi.takami...@fujitsu.com> wrote:
>
> 5. Sync the data to disk by performing checkpoint.
>
This step seems to invalidate the idea outright. The checkpoint command is
superuser only and isn’t table specific. This seems to require both th
On 2020/07/09 11:36, osumi.takami...@fujitsu.com wrote:
Hello, hackers.
I've been thinking to suggest
a peformance-oriented feature for COPY FROM.
It's UNLOGGED clause, which means data loading skipping WAL generation.
This feature can work safely with wal_level=replica or logical?
Or it c
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