Horton

Re: Parallel copy

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: "Hou, Zhijie" <houzj.fnst@cn.fujitsu.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2020-12-09T10:41:16Z
Lists: pgsql-hackers

Commits

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  1. Allow WaitLatch() to be used without a latch.

  2. Add %P to log_line_prefix for parallel group leader

  3. Include replication origins in SQL functions for commit timestamp

  4. Avoid useless buffer allocations during binary COPY FROM.

On Mon, Dec 7, 2020 at 3:00 PM Hou, Zhijie <houzj.fnst@cn.fujitsu.com> wrote:
>
> > Attached v11 patch has the fix for this, it also includes the changes to
> > rebase on top of head.
>
> Thanks for the explanation.
>
> I think there is still chances we can know the size.
>
> +                * line_size will be set. Read the line_size again to be sure if it is
> +                * completed or partial block.
> +                */
> +               dataSize = pg_atomic_read_u32(&lineInfo->line_size);
> +               if (dataSize != -1)
> +               {
>
> If I am not wrong, this seems the branch that procsssing the populated block.
> I think we can check the copiedSize here, if copiedSize == 0, that means
> Datasizes is the size of the whole line and in this case we can do the enlarge.
>
>

Yes this optimization can be done, I will handle this in the next patch set.

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com