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, Mar 31, 2021 at 7:17 AM Euler Taveira <euler@eulerto.com> wrote:
>
> On Tue, Mar 30, 2021, at 8:23 AM, Amit Kapila wrote:
>
> On Mon, Mar 29, 2021 at 6:47 PM Euler Taveira <euler@eulerto.com> wrote:
> >
> Few comments:
> ==============
> 1. How can we specify row filters for multiple tables for a
> publication? Consider a case as below:
>
> It is not possible. Row filter is a per table option. Isn't it clear from the
> synopsis?
>
Sorry, it seems I didn't read it properly earlier, now I got it.
>
> 2.
> + /*
> + * Although ALTER PUBLICATION grammar allows WHERE clause to be specified
> + * for DROP TABLE action, it doesn't make sense to allow it. We implement
> + * this restriction here, instead of complicating the grammar to enforce
> + * it.
> + */
> + if (stmt->tableAction == DEFELEM_DROP)
> + {
> + ListCell *lc;
> +
> + foreach(lc, stmt->tables)
> + {
> + PublicationTable *t = lfirst(lc);
> +
> + if (t->whereClause)
> + ereport(ERROR,
> + (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
> + errmsg("cannot use a WHERE clause when removing table from
> publication \"%s\"",
> + NameStr(pubform->pubname))));
> + }
> + }
>
> Is there a reason to deal with this here separately rather than in the
> ALTER PUBLICATION grammar?
>
> Good question. IIRC the issue is that AlterPublicationStmt->tables has a list
> element that was a relation_expr_list and was converted to
> publication_table_list. If we share 'tables' with relation_expr_list (for ALTER
> PUBLICATION ... DROP TABLE) and publication_table_list (for the other ALTER
> PUBLICATION ... ADD|SET TABLE), the OpenTableList() has to know what list
> element it is dealing with. I think I came to the conclusion that it is less
> uglier to avoid changing OpenTableList() and CloseTableList().
>
> [Doing some experimentation...]
>
> Here is a patch that remove the referred code.
>
Thanks, few more comments:
1. In pgoutput_change, we are always sending schema even though we
don't send actual data because of row filters. It may not be a problem
in many cases but I guess for some odd cases we can avoid sending
extra information.
2. In get_rel_sync_entry(), we are caching the qual for rel_sync_entry
even though we won't publish it which seems unnecessary?
3.
@@ -1193,5 +1365,11 @@ rel_sync_cache_publication_cb(Datum arg, int
cacheid, uint32 hashvalue)
entry->pubactions.pubupdate = false;
entry->pubactions.pubdelete = false;
entry->pubactions.pubtruncate = false;
+
+ if (entry->qual != NIL)
+ list_free_deep(entry->qual);
Seeing one previous comment in this thread [1], I am wondering if
list_free_deep is enough here?
4. Can we write explicitly in the docs that row filters won't apply
for Truncate operation?
5. Getting some whitespace errors:
git am /d/PostgreSQL/Patches/logical_replication/row_filter/v14-0001-Row-filter-for-logical-replication.patch
.git/rebase-apply/patch:487: trailing whitespace.
warning: 1 line adds whitespace errors.
Applying: Row filter for logical replication
[1] - https://www.postgresql.org/message-id/20181123161933.jpepibtyayflz2xg%40alvherre.pgsql
--
With Regards,
Amit Kapila.