Re: Minimal logical decoding on standbys

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

To: Andres Freund <andres@anarazel.de>

Cc: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, Amit Khandekar <amitdkhan.pg@gmail.com>, fabriziomello@gmail.com, tushar <tushar.ahuja@enterprisedb.com>, Rahila Syed <rahila.syed@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2022-12-20T20:39:26Z

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 →

Reduce the log level in 035_standby_logical_decoding.pl.
- 3034dc56ef4b 16.0 landed
035_standby_logical_decoding: Add missing waits for replication
- 57411c82ce86 16.0 landed
For cascading replication, wake physical and logical walsenders separately
- e101dfac3a53 16.0 landed
Handle logical slot conflicts on standby
- 26669757b6a7 16.0 landed
Support invalidating replication slots due to horizon and wal_level
- be87200efd93 16.0 landed
Prevent use of invalidated logical slot in CreateDecodingContext()
- 4397abd0a2af 16.0 landed
Replace replication slot's invalidated_at LSN with an enum
- 15f8203a5975 16.0 landed
Pass down table relation into more index relation functions
- 61b313e47eb9 16.0 landed
Assert only valid flag bits are passed to visibilitymap_set()
- a88a18b1250b 16.0 landed
Remove unused _bt_delitems_delete() argument.
- dc43492e46c7 14.0 cited
Add xl_btree_delete optimization.
- d2e5e20e5711 13.0 cited

Attachments

kpt_hash_setup.sql (application/octet-stream)
kpt_hash_pgbench.sql (application/octet-stream)

On Tue, Dec 20, 2022 at 1:25 PM Robert Haas <robertmhaas@gmail.com> wrote:
> I'm going to go through all the record types one by one before
> commenting further.

OK, so xl_hash_vacuum_one_page, at least, is a live issue. To reproduce:

./configure <whatever your usual options are>
echo 'COPT=-fsanitize=alignment -fno-sanitize-recover=all' > src/Makefile.custom
make -j8
make install
initdb
postgres

Then in another window:

pg_basebackup -D pgstandby -R
# edit postgresql.conf, change port number
postgres -D pgstandby

Then in a third window, using the attached files:

pgbench -i -s 10
psql -f kpt_hash_setup.sql
pgbench -T 10 -c 4 -j 4 -f kpt_hash_pgbench.sql

With the patch, the standby falls over:

bufpage.c:1194:31: runtime error: load of misaligned address
0x7fa62f05d119 for type 'OffsetNumber' (aka 'unsigned short'), which
requires 2 byte alignment
0x7fa62f05d119: note: pointer points here
 00 00 00  00 e5 00 8f 00 00 00 00  87 00 ab 20 20 20 20 20  20 20 20
20 20 20 20 20  20 20 20 20 20
              ^

Without the patch, this doesn't occur.

I think this might be the only WAL record type where there's a
problem, but I haven't fully confirmed that yet.

-- 
Robert Haas
EDB: http://www.enterprisedb.com