Re: row filtering for logical replication
Peter Smith <smithpb2250@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
The current PG docs text for CREATE PUBLICATION (in the v54-0001 patch) has a part that says + A nullable column in the <literal>WHERE</literal> clause could cause the + expression to evaluate to false; avoid using columns without not-null + constraints in the <literal>WHERE</literal> clause. I felt that the caution to "avoid using" nullable columns is too strongly worded. AFAIK nullable columns will work perfectly fine so long as you take due care of them in the WHERE clause. In fact, it might be very useful sometimes to filter on nullable columns. Here is a small test example: // publisher test_pub=# create table t1 (id int primary key, msg text null); test_pub=# create publication p1 for table t1 where (msg != 'three'); // subscriber test_sub=# create table t1 (id int primary key, msg text null); test_sub=# CREATE SUBSCRIPTION sub1 CONNECTION 'host=localhost dbname=test_pub application_name=sub1' PUBLICATION p1; // insert some data test_pub=# insert into t1 values (1, 'one'), (2, 'two'), (3, 'three'), (4, null), (5, 'five'); test_pub=# select * from t1; id | msg ----+------- 1 | one 2 | two 3 | three 4 | 5 | five (5 rows) // data at sub test_sub=# select * from t1; id | msg ----+------ 1 | one 2 | two 5 | five (3 rows) Notice the row 4 with the NULL is also not replicated. But, perhaps we were expecting it to be replicated (because NULL is not 'three'). To do this, simply rewrite the WHERE clause to properly account for nulls. // truncate both sides test_pub=# truncate table t1; test_sub=# truncate table t1; // alter the WHERE clause test_pub=# alter publication p1 set table t1 where (msg is null or msg != 'three'); // insert data at pub test_pub=# insert into t1 values (1, 'one'), (2, 'two'), (3, 'three'), (4, null), (5, 'five'); INSERT 0 5 test_pub=# select * from t1; id | msg ----+------- 1 | one 2 | two 3 | three 4 | 5 | five (5 rows) // data at sub (not it includes the row 4) test_sub=# select * from t1; id | msg ----+------ 1 | one 2 | two 4 | 5 | five (4 rows) ~~ So, IMO the PG docs wording for this part should be relaxed a bit. e.g. BEFORE: + A nullable column in the <literal>WHERE</literal> clause could cause the + expression to evaluate to false; avoid using columns without not-null + constraints in the <literal>WHERE</literal> clause. AFTER: + A nullable column in the <literal>WHERE</literal> clause could cause the + expression to evaluate to false. To avoid unexpected results, any possible + null values should be accounted for. Thoughts? ------ Kind Regards, Peter Smith. Fujitsu Australia