Horton

Re: row filtering for logical replication

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.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: 2022-01-14T11:30:58Z
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 Thu, Jan 13, 2022 at 6:46 PM houzj.fnst@fujitsu.com
<houzj.fnst@fujitsu.com> wrote:
>
> Attach the V64 patch set which addressed Alvaro, Amit and Peter's comments.
>

Few more comments:
===================
1.
"SELECT DISTINCT pg_get_expr(pr.prqual, pr.prrelid)"
+ "  FROM pg_publication p"
+ "  LEFT OUTER JOIN pg_publication_rel pr"
+ "       ON (p.oid = pr.prpubid AND pr.prrelid = %u),"
+ "  LATERAL pg_get_publication_tables(p.pubname) GPT"
+ " WHERE GPT.relid = %u"
+ "   AND p.pubname IN ( %s );",

Use all aliases either in CAPS or in lower case. Seeing the nearby
code, it is better to use lower case for aliases.

2.
-
+extern Oid GetTopMostAncestorInPublication(Oid puboid, List *ancestors);

It seems like a spurious line removal. I think you should declare it
immediately after GetPubPartitionOptionRelations() to match the order
of functions as they are in pg_publication.c

3.
+ * 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

There is no need for a comma after REPLICA IDENTITY.

4.
+ /*
+ * Find what are the cols that are part of the REPLICA IDENTITY.

Let's change this comment as: "Remember columns that are part of the
REPLICA IDENTITY."

5. The function name rowfilter_column_walker sounds goo generic for
its purpose. Can we rename it contain_invalid_rfcolumn_walker() and
move it to publicationcmds.c? Also, can we try to rearrange the code
in GetRelationPublicationInfo() such that row filter validation
related code is moved to a new function contain_invalid_rfcolumn()
which will internally call contain_invalid_rfcolumn_walker(). This new
functions can also be defined in publicationcmds.c.

6.
+ *
+ * If the cached validation result is true, we assume that the cached
+ * publication actions are also valid.
+ */
+AttrNumber
+GetRelationPublicationInfo(Relation relation, bool validate_rowfilter)

Instead of having the above comment, can we have an Assert for valid
relation->rd_pubactions when we are returning in the function due to
rd_rfcol_valid. Then, you can add a comment (publication actions must
be valid) before Assert.

7. I think we should have a function check_simple_rowfilter_expr()
which internally should call rowfilter_walker. See
check_nested_generated/check_nested_generated_walker. If you agree
with this, we can probably change the name of row_filter function to
check_simple_rowfilter_expr_walker().

8.
+ if (pubobj->pubtable && pubobj->pubtable->whereClause)
+ ereport(ERROR,
+ errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("WHERE clause for schema not allowed"),

Will it be better to write the above message as: "WHERE clause not
allowed for schema"?

9.
--- a/src/backend/replication/logical/proto.c
+++ b/src/backend/replication/logical/proto.c
@@ -15,6 +15,7 @@
 #include "access/sysattr.h"
 #include "catalog/pg_namespace.h"
 #include "catalog/pg_type.h"
+#include "executor/executor.h"

Do we really need this include now? Please check includes in other
files as well and remove if anything is not required.

10.
 /*
- * Get information about remote relation in similar fashion the RELATION
- * message provides during replication.
+ * Get information about a remote relation, in a similar fashion to how the
+ * RELATION message provides information during replication.

Why this part of the comment needs to be changed?

11.
/*
  * For non-tables, we need to do COPY (SELECT ...), but we can't just
- * do SELECT * because we need to not copy generated columns.
+ * do SELECT * because we need to not copy generated columns.

I think here comment should say: "For non-tables and tables with row
filters, we need to do...."

Apart from the above, I have modified a few comments which you can
find in the attached patch v64-0002-Modify-comments. Kindly, review
those and if you are okay with them then merge those into the main
patch.

-- 
With Regards,
Amit Kapila.