Horton

Re: Parallel Append implementation

Amit Khandekar <amitdkhan.pg@gmail.com>

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From: Amit Khandekar <amitdkhan.pg@gmail.com>
To: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-03-10T09:06:12Z
Lists: pgsql-hackers 
On 10 March 2017 at 14:05, Ashutosh Bapat
<ashutosh.bapat@enterprisedb.com> wrote:
>> The need for
>> num_workers=-1 will still be there for partial plans, because we need
>> to set it to -1 once a worker finishes a plan.
>>
>
> IIRC, we do that so that no other workers are assigned to it when
> scanning the array of plans. But with the new scheme we don't need to
> scan the non-parallel plans for when assigning plan to workers so -1
> may not be needed. I may be wrong though.
>

Still, when a worker finishes a partial subplan , it marks it as -1,
so that no new workers pick this, even if there are other workers
already executing it.

-- 
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company

Commits

  1. Update parallel.sgml for Parallel Append

  2. Support Parallel Append plan nodes.

  3. Remove BufFile's isTemp flag.

  4. Improve comments for parallel executor estimation functions.

  5. Separate reinitialization of shared parallel-scan state from ExecReScan.

  6. Eat XIDs more efficiently in recovery TAP test.

  7. Avoid syntax error on platforms that have neither LOCALE_T nor ICU.

  8. Preparatory refactoring for parallel merge join support.