RE: row filtering for logical replication

From: "wangw(dot)fnst(at)fujitsu(dot)com" <wangw(dot)fnst(at)fujitsu(dot)com>
To: Peter Smith <smithpb2250(at)gmail(dot)com>
Cc: "houzj(dot)fnst(at)fujitsu(dot)com" <houzj(dot)fnst(at)fujitsu(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Euler Taveira <euler(at)eulerto(dot)com>, Greg Nancarrow <gregn4422(at)gmail(dot)com>, vignesh C <vignesh21(at)gmail(dot)com>, Ajin Cherian <itsajin(at)gmail(dot)com>, "tanghy(dot)fnst(at)fujitsu(dot)com" <tanghy(dot)fnst(at)fujitsu(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, Rahila Syed <rahilasyed90(at)gmail(dot)com>, Peter Eisentraut <peter(dot)eisentraut(at)enterprisedb(dot)com>, Önder Kalacı <onderkalaci(at)gmail(dot)com>, japin <japinli(at)hotmail(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz>, David Steele <david(at)pgmasters(dot)net>, Craig Ringer <craig(at)2ndquadrant(dot)com>, Amit Langote <amitlangote09(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: RE: row filtering for logical replication
Date: 2022-01-05 02:05:08
Message-ID: OS3PR01MB6275ADE2B0EDED067C136D539E4B9@OS3PR01MB6275.jpnprd01.prod.outlook.com
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On Thu, Jan 4, 2022 at 00:54 PM Peter Smith <smithpb2250(at)gmail(dot)com> wrote:
> Modified in v58 [1] as suggested
Thanks for updating the patches.
A few comments about v58-0001 and v58-0002.

v58-0001
1.
How about modifying the following loop in copy_table by using for_each_from
instead of foreach?
Like the invocation of for_each_from in function get_rule_expr.
from:
if (qual != NIL)
{
ListCell *lc;
bool first = true;

appendStringInfoString(&cmd, " WHERE ");
foreach(lc, qual)
{
char *q = strVal(lfirst(lc));

if (first)
first = false;
else
appendStringInfoString(&cmd, " OR ");
appendStringInfoString(&cmd, q);
}
list_free_deep(qual);
}
change to:
if (qual != NIL)
{
ListCell *lc;
char *q = strVal(linitial(qual));

appendStringInfo(&cmd, " WHERE %s", q);
for_each_from(lc, qual, 1)
{
q = strVal(lfirst(lc));
appendStringInfo(&cmd, " OR %s", q);
}
list_free_deep(qual);
}

2.
I find the API of get_rel_sync_entry is modified.
-get_rel_sync_entry(PGOutputData *data, Oid relid)
+get_rel_sync_entry(PGOutputData *data, Relation relation)
It looks like just moving the invocation of RelationGetRelid from outside into
function get_rel_sync_entry. I am not sure whether this modification is
necessary to this feature or not.

v58-0002
1.
In function pgoutput_row_filter_init, if no_filter is set, I think we do not
need to add row filter to list(rfnodes).
So how about changing three conditions when add row filter to rfnodes like this:
- if (pub->pubactions.pubinsert)
+ if (pub->pubactions.pubinsert && !no_filter[idx_ins])
{
rfnode = stringToNode(TextDatumGetCString(rfdatum));
rfnodes[idx_ins] = lappend(rfnodes[idx_ins], rfnode);
}

Regards,
Wang wei

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