On Thur, Mar 10, 2021 at 10:08 AM houzj.f...@fujitsu.com wrote: > Hi, > > When reviewing some logical replication related features. I noticed another > possible problem if the subscriber subscribes multiple publications which > publish parent and child table. > > For example: > > ----pub > create table t (a int, b int, c int) partition by range (a); > create table t_1 partition of t for values from (1) to (10); > > create publication pub1 for table t > with (PUBLISH_VIA_PARTITION_ROOT); > create publication pub2 for table t_1 > with (PUBLISH_VIA_PARTITION_ROOT); > > ----sub > ---- prepare table t and t_1 > CREATE SUBSCRIPTION sub CONNECTION 'port=10000 dbname=postgres' > PUBLICATION pub1, pub2; > > select * from pg_subscription_rel ; > srsubid | srrelid | srsubstate | srsublsn > ---------+---------+------------+----------- > 16391 | 16385(t) | r | 0/150D100 > 16391 | 16388(t_1) | r | 0/150D138 > > If subscribe two publications one of them publish parent table with > (pubviaroot=true) and another publish child table. Both the parent table and > child table will exist in pg_subscription_rel which also means we will do > initial copy for both tables. > > But after initial copy, we only publish change with the schema of the parent > table(t). It looks a bit inconsistent. > > Based on the document of PUBLISH_VIA_PARTITION_ROOT option. I think the > expected behavior could be we only store the top most parent(table t) in > pg_subscription_rel and do initial copy for it if pubviaroot is on. I haven't > thought about how to fix this and will investigate this later. Hi, I try to fix this bug. Attach the patch.
The current HEAD get table list for one publication by invoking function pg_get_publication_tables. If multiple publications are subscribed, then this function is invoked multiple times. So option PUBLISH_VIA_PARTITION_ROOT works independently on every publication, I think it does not work correctly on different publications of the same subscription. So I fix this bug by the following two steps: First step, I get oids of subscribed tables by publication list. Then for tables with the same topmost root table, I filter them base on the option PUBLISH_VIA_PARTITION_ROOT(see new function filter_partitions_oids). After filtering, I get the final oid list. Second step, I get the required informations(nspname and relname) base on the oid list of first step. Regards, Wang wei
v1-0001-Fix-data-replicated-twice-when-specifying-PUBLISH.patch
Description: v1-0001-Fix-data-replicated-twice-when-specifying-PUBLISH.patch
