Horton

RE: Data is copied twice when specifying both child and parent table in publication

Zhijie Hou (Fujitsu) <houzj.fnst@fujitsu.com>

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From: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
To: Peter Smith <smithpb2250@gmail.com>, "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, "shiy.fnst@fujitsu.com" <shiy.fnst@fujitsu.com>, Amit Langote <amitlangote09@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, Dilip Kumar <dilipbalaut@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, vignesh C <vignesh21@gmail.com>
Date: 2022-08-04T11:26:18Z
Lists: pgsql-hackers 
On Thursday, July 28, 2022 5:17 PM Peter Smith <smithpb2250@gmail.com> wrote:
> Here are some review comments for the HEAD_v7-0001 patch:
> 
> ======
> 
> 1. <General>
> 
> I have a fundamental question about this patch.
> 
> IIUC the purpose of this patch is to ensure that (when
> publish_via_root = true) the copy of the partition data will happen
> only once (e.g. from one parent table on one of the publishers). But I
> think there is no guarantee that those 2 publishers even had the same
> data, right? Therefore it seems to me you could get different results
> if the data were copied from pub1 or from pub2. (I have not tried it -
> this is just my suspicion).
> 
> Am I correct or mistaken?

Since the subscribed publishers are combined with OR and are from the same database.
And we are trying to copy the data from the top most parent table, so I think the results
should be as expected.

Best regards,
Hou zj

Commits

  1. Avoid syncing data twice for the 'publish_via_partition_root' option.

  2. Fix partition table's REPLICA IDENTITY checking on the subscriber.

  3. Prohibit combining publications with different column lists.

  4. Fix double publish of child table's data.

  5. Support adding partitioned tables to publication