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: 2022-01-17T15:28:17Z
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 Mon, Jan 17, 2022 7:23 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> 
> On Mon, Jan 17, 2022 at 3:19 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > Some other comments:
> > ==================
> >
> 
> Few more comments:
> ==================
> 1.
> +pgoutput_row_filter_init_expr(Node *rfnode) {  ExprState  *exprstate;
> + Expr    *expr;
> +
> + /*
> + * This is the same code as ExecPrepareExpr() but that is not used
> + because
> + * we have no EState to pass it.
> 
> Isn't it better to say "This is the same code as ExecPrepareExpr() but that is not
> used because we want to cache the expression"? I feel if we want we can allocate
> Estate as the patch is doing in pgoutput_row_filter(), no?

Changed as suggested.

> 2.
> + elog(DEBUG3, "row filter evaluates to %s (isnull: %s)",
> + DatumGetBool(ret) ? "true" : "false",
> + isnull ? "true" : "false");
> +
> + if (isnull)
> + return false;
> 
> Won't the isnull condition's result in elog should be reversed?

Changed.

> 3.
> + /*
> + * If the publication is FOR ALL TABLES IN SCHEMA and it overlaps
> + * with the current relation in the same schema then this is also
> + * treated same as if this table has no row filters (even if for
> + * other publications it does).
> + */
> + else if (list_member_oid(schemaPubids, pub->oid)) pub_no_filter =
> + true;
> 
> The code will appear better if you can move the comments inside else if. There
> are other places nearby this comment where we can follow the same style.

Changed.

> 4.
> + * Multiple ExprState entries might be used if there are multiple
> + * publications for a single table. Different publication actions don't
> + * allow multiple expressions to always be combined into one, so there
> + is
> + * one ExprState per publication action. The exprstate array is indexed
> + by
> + * ReorderBufferChangeType.
> + */
> + bool exprstate_valid;
> +
> + /* ExprState array for row filter. One per publication action. */
> + ExprState  *exprstate[NUM_ROWFILTER_PUBACTIONS];
> 
> It is not clear from comments here or at other places as to why we need an array
> for row filter expressions? Can you please add comments to explain the same?
> IIRC, it is primarily due to the reason that we don't want to add the restriction
> that the publish operation 'insert'
> should also honor RI columns restriction. If there are other reasons then let's add
> those to comments as well.
I will think over this and update in next version.

Attach the V66 patch set which addressed Amit, Peter and Greg's comments.

Best regards,
Hou zj