Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions

Amit Kapila <amit.kapila16@gmail.com>

From: Amit Kapila <amit.kapila16@gmail.com>

To: Craig Ringer <craig@2ndquadrant.com>

Cc: Dilip Kumar <dilipbalaut@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>

Date: 2019-10-14T02:11:23Z

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 →

Tighten the concurrent abort check during decoding.
- 2ce353fc1902 14.0 landed
Improve hash_create()'s API for some added robustness.
- b3817f5f7746 14.0 landed
Use HASH_BLOBS for xidhash.
- a1b8aa1e4eec 14.0 landed
Fix initialization of RelationSyncEntry for streaming transactions.
- 69bd60672af6 14.0 landed
Remove unused function declaration in logicalproto.h.
- ddd5f6d2609b 14.0 landed
Add additional tests to test streaming of in-progress transactions.
- 58b5ae9d62bd 14.0 landed
Fix inline marking introduced in commit 464824323e.
- ac15b499f7f9 14.0 landed
Add support for streaming to built-in logical replication.
- 464824323e57 14.0 landed
Fix the SharedFileSetUnregister API.
- 4ab77697f67a 14.0 landed
Fix comment in procarray.c
- 77c7267c37f7 14.0 cited
Suppress compiler warning in non-cassert builds.
- e942af7b8261 14.0 cited
Extend the BufFile interface.
- 808e13b282ef 14.0 landed
Mark a few logical decoding related variables with PGDLLIMPORT.
- b48cac3b10a0 14.0 landed
Implement streaming mode in ReorderBuffer.
- 7259736a6e5b 14.0 landed
Extend the logical decoding output plugin API with stream methods.
- 45fdc9738b36 14.0 landed
WAL Log invalidations at command end with wal_level=logical.
- c55040ccd017 14.0 landed
Immediately WAL-log subtransaction and top-level XID association.
- 0bead9af484c 14.0 landed
Allow logical replication to transfer data in binary format.
- 9de77b545313 14.0 cited
Only superuser can set sslcert/sslkey in postgres_fdw user mappings
- cebf9d6e6ee1 13.0 cited
Track statistics for spilling of changes from ReorderBuffer.
- 9290ad198b15 13.0 landed
Add logical_decoding_work_mem to limit ReorderBuffer memory usage.
- cec2edfa7859 13.0 landed
logical decoding: process ASSIGNMENT during snapshot build
- bac2fae05c77 13.0 cited
Emit invalidations to standby for transactions without xid.
- c6ff84b06a68 9.6.0 cited

On Mon, Oct 14, 2019 at 6:51 AM Craig Ringer <craig@2ndquadrant.com> wrote:
>
> On Sun, 13 Oct 2019 at 19:50, Amit Kapila <amit.kapila16@gmail.com> wrote:
>>
>
>
> Does anyone object if we add the reorder buffer total size & in-memory size to struct WalSnd too, so we can report it in pg_stat_replication?
>

There is already a patch
(0011-Track-statistics-for-streaming-spilling) in this series posted
by Tomas[1] which tracks important statistics in WalSnd which I think
are good enough.  Have you checked that?  I am not sure if adding
additional size will help, but I might be missing something.

> I can follow up with a patch to add on top of this one if you think it's reasonable. I'll also take the opportunity to add a number of tracepoints across the walsender and logical decoding, since right now it's very opaque in production systems ... and everyone just LOVES hunting down debug syms and attaching gdb to production DBs.
>

Sure, adding tracepoints can be helpful, but isn't it better to start
that as a separate thread?

[1] - https://www.postgresql.org/message-id/20190928190917.hrpknmq76v3ts3lj%40development

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com