On Thu, Jan 5, 2023 at 6:51 PM Bharath Rupireddy <bharath.rupireddyforpostg...@gmail.com> wrote: > > > I'm also wondering if it would make sense to extend the test coverage of it > > (and pg_waldump) to "validate" that both > > extracted images are the same and matches the one modified right after the > > checkpoint. > > > > What do you think? (could be done later in another patch though). > > I think pageinspect can be used here. We can fetch the raw page from > the table after the checkpoint and raw FPI from the WAL record logged > as part of the update. I've tried to do so [1], but I see a slight > difference in the raw output. The expectation is that they both be the > same. It might be that the update operation logs the FPI with some > more info set (prune_xid). I'll try to see why it is so. > > I'm attaching the v2 patch for further review. > > [1] > SELECT * FROM page_header(:'page_from_table'); > lsn | checksum | flags | lower | upper | special | pagesize | > version | prune_xid > -----------+----------+-------+-------+-------+---------+----------+---------+----------- > 0/1891D78 | 0 | 0 | 40 | 8064 | 8192 | 8192 | > 4 | 0 > (1 row) > > SELECT * FROM page_header(:'page_from_wal'); > lsn | checksum | flags | lower | upper | special | pagesize | > version | prune_xid > -----------+----------+-------+-------+-------+---------+----------+---------+----------- > 0/1891D78 | 0 | 0 | 44 | 8032 | 8192 | 8192 | > 4 | 735 > (1 row)
Ugh, v2 patch missed the new file added, I'm attaching v3 patch for further review. Sorry for the noise. -- Bharath Rupireddy PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
v3-0001-Add-FPI-extract-function-to-pg_walinspect.patch
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