Re: Improve WALRead() to suck data directly from WAL buffers when possible

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

To: Nitin Jadhav <nitinjadhavpostgres@gmail.com>

Cc: Nathan Bossart <nathandbossart@gmail.com>, Dilip Kumar <dilipbalaut@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, pgsql-hackers@lists.postgresql.org

Date: 2023-03-14T03:32:23Z

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 →

Add XLogCtl->logInsertResult
- f3ff7bf83bce 17.0 cited
Add assert to WALReadFromBuffers().
- 9ecbf54075a9 17.0 landed
Read WAL directly from WAL buffers.
- 91f2cae7a4e6 17.0 landed
Additional write barrier in AdvanceXLInsertBuffer().
- 766571be1659 17.0 landed
Use 64-bit atomics for xlblocks array elements.
- c3a8e2a7cb16 17.0 landed
Don't trust unvalidated xl_tot_len.
- bae868caf222 17.0 cited

Attachments

v9-0001-Improve-WALRead-to-suck-data-directly-from-WAL-bu.patch (application/octet-stream) patch v9-0001
v9-0002-Add-test-module-for-verifying-WAL-read-from-WAL-b.patch (application/octet-stream) patch v9-0002

On Sun, Mar 12, 2023 at 11:00 PM Bharath Rupireddy
<bharath.rupireddyforpostgres@gmail.com> wrote:
>
> I have some review comments to fix on
> v8-0001, so, I'll be sending out v9 patch-set soon.

Please find the attached v9 patch set for further review. I moved the
check for just-initialized WAL buffer pages before reading the page.
Up until now, it's the other way around, meaning, read the page and
then check the header if it is just-initialized, which is wrong. The
attached v9 patch set corrects it.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com