On Mon, Jul 22, 2024 at 10:59 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> The first line would vary depending on whether an autovacuum worker or
> not. And the above suggestion includes a change of term "row" to
> "tuple" for better consistency with VACUUM VERBOSE outputs. I think it
> would be great if autoanalyze also writes logs in the same format.
> IIUC with the patch, autoanalyze logs don't include the page and tuple
> statistics.
One issue is that the number of scanned pages, live tuples and dead
tuples is only available in acquire_sample_rows which is where the log
containing those stats is emitted. I've tried to implement the
following in 0003:
- Sampling functions now accept an AcquireSampleStats struct to store
pages and tuples stats
- Log is removed from sampling functions
- do_analyze_rel now outputs scanned and tuples statistics when
relevant. sampling from fdw doesn't provide those statistics so they
are not displayed in those cases.
This ensures that analyze logs are only emitted in do_analyze_rel,
allowing to display the same output for both autoanalyze and ANALYZE
VERBOSE. With those changes, we have the following output for analyze
verbose of a table:
analyze (verbose) pgbench_accounts ;
INFO: analyzing "public.pgbench_accounts"
INFO: analyze of table "postgres.public.pgbench_accounts"
pages: 1640 of 1640 scanned
tuples: 100000 live tuples, 0 are dead; 30000 tuples in samples,
100000 estimated total tuples
avg read rate: 174.395 MB/s, avg write rate: 0.000 MB/s
buffer usage: 285 hits, 1384 reads, 0 dirtied
WAL usage: 14 records, 0 full page images, 1343 bytes
system usage: CPU: user: 0.05 s, system: 0.00 s, elapsed: 0.06 s
For a file_fdw, the output will look like:
analyze (verbose) pglog;
INFO: analyzing "public.pglog"
INFO: analyze of table "postgres.public.pglog"
tuples: 30000 tuples in samples, 60042 estimated total tuples
avg read rate: 0.000 MB/s, avg write rate: 0.000 MB/s
buffer usage: 182 hits, 0 reads, 0 dirtied
WAL usage: 118 records, 0 full page images, 13086 bytes
system usage: CPU: user: 0.40 s, system: 0.00 s, elapsed: 0.41 s
I've also slightly modified 0002 to display "automatic analyze" when
we're inside an autovacuum worker, similar to what's done with vacuum
output.
Regards,
Anthonin