Horton

RE: row filtering for logical replication

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

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From: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Peter Smith <smithpb2250@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, Euler Taveira <euler@eulerto.com>, Greg Nancarrow <gregn4422@gmail.com>, vignesh C <vignesh21@gmail.com>, Ajin Cherian <itsajin@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Rahila Syed <rahilasyed90@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Önder Kalacı <onderkalaci@gmail.com>, japin <japinli@hotmail.com>, Michael Paquier <michael@paquier.xyz>, David Steele <david@pgmasters.net>, Craig Ringer <craig@2ndquadrant.com>, Amit Langote <amitlangote09@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-01-13T13:16:33Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Release cache tuple when no longer needed

  2. Add some additional tests for row filters in logical replication.

  3. Fix one of the tests introduced in commit 52e4f0cd47.

  4. Allow specifying row filters for logical replication of tables.

  5. Move scanint8() to numutils.c

  6. Replace Test::More plans with done_testing

  7. Reduce relcache access in WAL sender streaming logical changes

  8. Small cleanups related to PUBLICATION framework code

  9. Add a view to show the stats of subscription workers.

  10. Allow publishing the tables of schema.

  11. Doc: improve documentation of CREATE/ALTER SUBSCRIPTION.

  12. Add PublicationTable and PublicationRelInfo structs

  13. Remove unused argument "txn" in maybe_send_schema().

  14. Add prepare API support for streaming transactions in logical replication.

  15. Unify PostgresNode's new() and get_new_node() methods

  16. Use l*_node() family of functions where appropriate

  17. Add support for prepared transactions to built-in logical replication.

  18. Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.

  19. Rename a parse node to be more general

  20. Remove unused column atttypmod from initial tablesync query

  21. SEARCH and CYCLE clauses

Attachments

On Thursday, January 13, 2022 6:23 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Wed, Jan 12, 2022 at 7:19 PM houzj.fnst@fujitsu.com
> <houzj.fnst@fujitsu.com> wrote:
> >
> > On Wed, Jan 12, 2022 5:38 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > Attach the v63 patch set which include the following changes.
> >

Thanks for the comments !

> Few comments:
> =============
> 1.
> +
> +     <row>
> +      <entry role="catalog_table_entry"><para role="column_definition">
> +      <structfield>prqual</structfield> <type>pg_node_tree</type>
> +      </para>
> +      <para>Expression tree (in <function>nodeToString()</function>
> +      representation) for the relation's qualifying condition</para></entry>
> +     </row>
> 
> Let's slightly modify this as: "Expression tree (in
> <function>nodeToString()</function> representation) for the relation's
> qualifying condition. Null if there is no qualifying condition."

Changed.

> 2.
> +   A <literal>WHERE</literal> clause allows simple expressions. The simple
> +   expression cannot contain any aggregate or window functions,
> non-immutable
> +   functions, user-defined types, operators or functions.
> 
> This part in the docs should be updated to say something similar to what we
> have in the commit message for this part or maybe additionally in some way we
> can say which other forms of expressions are not allowed.

Temporally used the description in commit message.

> 3.
> +   for which the <replaceable
> class="parameter">expression</replaceable> returns
> +   false or null will not be published.
> +   If the subscription has several publications in which
> +   the same table has been published with different
> + <literal>WHERE</literal>
> 
> In the above text line spacing appears a bit odd to me. There doesn't seem to be
> a need for extra space after line-2 and line-3 in above-quoted text.

I adjusted these text lines.

> 4.
> /*
> + * Return the relid of the topmost ancestor that is published via this
> 
> We normally seem to use Returns in similar places.

Changed

> 
> 6.
> +static void
> +transformPubWhereClauses(List *tables, const char *queryString)
> 
> To keep the function naming similar to other nearby functions, it is better to
> name this as TransformPubWhereClauses.

Changed.

> 7. In AlterPublicationTables(), won't it better if we
> transformPubWhereClauses() after
> CheckObjSchemaNotAlreadyInPublication() to avoid extra processing in case of
> errors.

Changed.

> 8.
> + /*
> + * Check if the relation is member of the existing schema in the
> + * publication or member of the schema list specified.
> + */
>   CheckObjSchemaNotAlreadyInPublication(rels, schemaidlist,
>     PUBLICATIONOBJ_TABLE);
> 
> I don't see the above comment addition has anything to do with this patch. Can
> we remove it?

Removed.

> 9.
>  CheckCmdReplicaIdentity(Relation rel, CmdType cmd)  {
>   PublicationActions *pubactions;
> + AttrNumber bad_rfcolnum;
> 
>   /* We only need to do checks for UPDATE and DELETE. */
>   if (cmd != CMD_UPDATE && cmd != CMD_DELETE)
>   return;
> 
> + if (rel->rd_rel->relreplident == REPLICA_IDENTITY_FULL) return;
> +
> + /*
> + * It is only safe to execute UPDATE/DELETE when all columns referenced
> + in
> + * the row filters from publications which the relation is in are valid
> + -
> + * i.e. when all referenced columns are part of REPLICA IDENTITY, or
> + the
> + * table does not publish UPDATES or DELETES.
> + */
> + bad_rfcolnum = GetRelationPublicationInfo(rel, true);
> 
> Can we name this variable as invalid_rf_column?
Changed.

Attach the V64 patch set which addressed Alvaro, Amit and Peter's comments.

The new version patch also include some other changes:
- Fix a table sync bug[1] by using the SQL suggested by Tang[1]
- Adjust the row filter initialize code related to FOR ALL TABLE IN SCHEMA to
  make sure it gets the correct row filter.
- Update the documents.
- Rebased the patch based on recent commit 025b92

[1] https://www.postgresql.org/message-id/OS0PR01MB6113BB510435B16E9F0B2A59FB519%40OS0PR01MB6113.jpnprd01.prod.outlook.com

Best regards,
Hou zj