On 2021-Aug-25, Peter Geoghegan wrote: > That way the overall structure starts with details of the physical > data structures (the table and its indexes), then goes into buffers > > 1. Heap pages > 2. Heap tuples > 3. Index stuff > 4. I/O timings (only when track_io_timing is on) > 5. avg read rate (always) > 6. buffer usage > 7. WAL usage. > 8. system usage > > This would mean that I'd be flipping the order of 7 and 8 relative to > Postgres 13 -- meaning there'd be one difference between Postgres 14 > and some existing stable release. But I think that putting WAL usage > last of all (after system usage) makes little sense -- commit > b7ce6de93b shouldn't have done it that way. I always expect to see the > getrusage() stuff last.
You mean: LOG: automatic vacuum of table "regression.public.bmsql_order_line": index scans: 1 pages: 0 removed, 8810377 remain, 0 skipped due to pins, 3044924 frozen tuples: 16819838 removed, 576364686 remain, 2207444 are dead but not yet removable, oldest xmin: 88197949 index scan needed: 1959301 pages from table (22.24% of total) had 11745226 dead item identifiers removed index "bmsql_order_line_pkey": pages: 2380261 in total, 0 newly deleted, 0 currently deleted, 0 reusable I/O timings: read: 65813.666 ms, write: 11310.689 ms avg read rate: 65.621 MB/s, avg write rate: 48.403 MB/s buffer usage: 174505 hits, 7630386 misses, 5628271 dirtied WAL usage: 7387358 records, 4051205 full page images, 28472185998 bytes system usage: CPU: user: 72.55 s, system: 52.07 s, elapsed: 908.42 s I like it better than the current layout, so +1. I think the "index scan needed" line (introduced very late in the 14 cycle, commit 5100010ee4d5 dated April 7 2021) is a bit odd. It is telling us stuff about the table -- how many pages had TIDs removed, am I reading that right? -- and it is also telling us whether indexes were scanned. But the fact that it starts with "index scan needed" suggests that it's talking about indexes. I think we should reword this line. I don't have any great ideas; what do you think of this? dead items: 1959301 pages from table (22.24% of total) had 11745226 dead item identifiers removed; index scan {needed, not needed, bypassed, bypassed by failsafe} I have to say that I am a bit bothered about the coding pattern used to build this sentence from two parts. I'm not sure it'll work okay in languages that build sentences in different ways. Maybe we should split this in two lines, one to give the numbers and the other to talk about the decision taken about indexes. -- Álvaro Herrera Valdivia, Chile — https://www.EnterpriseDB.com/ "This is what I like so much about PostgreSQL. Most of the surprises are of the "oh wow! That's cool" Not the "oh shit!" kind. :)" Scott Marlowe, http://archives.postgresql.org/pgsql-admin/2008-10/msg00152.php