| From: | Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com> |
|---|---|
| To: | Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> |
| Cc: | PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: How to generate a WAL record spanning multiple WAL files? |
| Date: | 2022-04-05 13:39:04 |
| Message-ID: | CAEze2WhZME=N1KgvFgJS+G78PDA1hq0o+pNEc_gLVrjqQk-efQ@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, 5 Apr 2022 at 15:13, Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
>
> Hi,
>
> I wanted to have a WAL record spanning multiple WAL files of size, say
> 16MB. I'm wondering if the Full Page Images (FPIs) of a TOAST table
> would help here. Please let me know if there's any way to generate
> such large WAL records.
The function pg_logical_emit_message (callable with REPLICATION
permissions from SQL) allows you to emit records of arbitrary length <
2GB - 2B (for now), which should be enough.
Other than that, you could try to generate 16MB of subtransaction IDs;
the commit record would contain all subxids and thus be at least 16MB
in size.
-Matthias
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Robert Haas | 2022-04-05 14:01:56 | Re: API stability [was: pgsql: Fix possible recovery trouble if TRUNCATE overlaps a checkpoint.] |
| Previous Message | Ashutosh Bapat | 2022-04-05 13:36:18 | Re: Handle infinite recursion in logical replication setup |