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: Dilip Kumar <dilipbalaut@gmail.com>

Cc: Erik Rijkers <er@xs4all.nl>, Kuntal Ghosh <kuntalghosh.2007@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>

Date: 2020-06-10T10:30:26Z

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 →

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 Wed, Jun 10, 2020 at 2:30 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
>
> Currently, I am done with a working prototype of using the BufFile
> infrastructure for the tempfile.  Meanwhile, I want to discuss a few
> interface changes required for the BufFIle infrastructure.
>
> 1. Support read-write mode for "BufFileOpenShared",  Basically, in
> workers we will be opening the xid's changes and subxact files per
> stream, so we need an RW mode even in the open.  I have passed a flag
> for the same.
>

Generally file open APIs have mode as a parameter to indicate
read_only or read_write.  Using flag here seems a bit odd to me.

> 2. Files should not be closed at the end of the transaction:
> Currently, files opened with BufFileCreateShared/BufFileOpenShared are
> registered to be closed on EOXACT.  Basically, we need to open the
> changes file on the stream start and keep it open until stream stop,
> so we can not afford to get it closed on the EOXACT.  I have added a
> flag for the same.
>

But where do we end the transaction before the stream stop which can
lead to closure of this file?

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