Re: row filtering for logical replication
Amit Kapila <amit.kapila16@gmail.com>
Commits
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the thread's linked commits as JSON, with link sources.
API reference →
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Release cache tuple when no longer needed
- ed0fbc8e5ac9 15.0 landed
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Add some additional tests for row filters in logical replication.
- ceb57afd3ce1 15.0 landed
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Fix one of the tests introduced in commit 52e4f0cd47.
- cfb4e209ec15 15.0 landed
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Allow specifying row filters for logical replication of tables.
- 52e4f0cd472d 15.0 landed
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Move scanint8() to numutils.c
- cfc7191dfea3 15.0 cited
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Replace Test::More plans with done_testing
- 549ec201d613 15.0 cited
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Reduce relcache access in WAL sender streaming logical changes
- 6ce16088bfed 15.0 cited
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Small cleanups related to PUBLICATION framework code
- c9105dd3660f 15.0 cited
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Add a view to show the stats of subscription workers.
- 8d74fc96db5f 15.0 cited
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Allow publishing the tables of schema.
- 5a2832465fd8 15.0 cited
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Doc: improve documentation of CREATE/ALTER SUBSCRIPTION.
- 1882d6cca161 15.0 cited
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Add PublicationTable and PublicationRelInfo structs
- 0c6828fa987b 15.0 cited
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Remove unused argument "txn" in maybe_send_schema().
- 93d573d86571 15.0 cited
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Add prepare API support for streaming transactions in logical replication.
- 63cf61cdeb7b 15.0 cited
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Unify PostgresNode's new() and get_new_node() methods
- 201a76183e20 15.0 cited
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Use l*_node() family of functions where appropriate
- 2b00db4fb0c7 15.0 cited
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Add support for prepared transactions to built-in logical replication.
- a8fd13cab0ba 15.0 cited
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Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.
- ef9480509622 11.13 cited
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Rename a parse node to be more general
- 91d1f2d30210 14.0 landed
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Remove unused column atttypmod from initial tablesync query
- 4ad31bb2ef25 14.0 landed
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SEARCH and CYCLE clauses
- 3696a600e229 14.0 cited
On Wed, Sep 1, 2021 at 8:29 PM Euler Taveira <euler@eulerto.com> wrote: > > On Wed, Sep 1, 2021, at 9:36 AM, Amit Kapila wrote: > > I think this or any other similar solution for row filters (on > updates) won't work till we solve the problem reported by Hou-San [1]. > The main reason is that we don't have data for unchanged toast columns > in WAL. For that, we have discussed some probable solutions in email > [2], however, that also required us to solve one of the existing > bugs[3]. > > I didn't mention but I'm working on it in parallel. > > I agree with you that including TOAST values in the WAL is a possible solution > for this issue. This is a popular request for wal2json [1][2][3] and I think > other output plugins have the same request too. It is useful for CDC solutions. > > I'm experimenting 2 approaches: (i) always include unchanged TOAST values to > new tuple if a GUC is set and (ii) include unchanged TOAST values to new tuple > iif it wasn't include in the old tuple. > In the second approach, we will always end up having unchanged toast columns for non-key columns in the WAL which will be a significant overhead, so not sure if that can be acceptable if we want to do it by default. > The advantage of the first option is > that you fix the problem adjusting a parameter in your configuration file. > However, the disadvantage is that, depending on your setup -- REPLICA IDENTITY > FULL, you might have the same TOAST value for a single change twice in the WAL. > The second option solves the disadvantage of (i) but it only works if you have > REPLICA IDENTITY FULL and Dilip's patch applied [4] (I expect to review it > soon). > Thanks for offering the review of that patch. I think it will be good to get it committed. > In the output plugin, (i) requires a simple modification (remove > restriction for unchanged TOAST values) but (ii) needs a more complex surgery. > I think if get Dilip's patch then we can have a rule for filter columns such that it can contain only replica identity key columns. This rule is anyway required for Deletes and we can have it for Updates. At this stage, I haven't checked what it takes to implement such a solution but it would be worth investigating it. -- With Regards, Amit Kapila.