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Author: Sawada Masahiko Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CAD21AoA7ZEfsOXQ9HQqMv3QYGsEm2H5Wk5ic5S=mvzDf-3a3SA@mail.gmail.com
Otherwise we risk "leaking" deleted pages by making them non-recyclable indefinitely. Commit 6655a729 did the same thing for deleted pages in GiST indexes. That work was used as a starting point here. Stop storing an XID indicating the oldest bpto.xact across all deleted though unrecycled pages in nbtree metapages. There is no longer any reason to care about that condition/the oldest XID. It only ever made sense when wraparound was something _bt_vacuum_needs_cleanup() had to consider. The btm_oldest_btpo_xact metapage field has been repurposed and renamed. It is now btm_last_cleanup_num_delpages, which is used to remember how many non-recycled deleted pages remain from the last VACUUM (in practice its value is usually the precise number of pages that were _newly deleted_ during the specific VACUUM operation that last set the field). The general idea behind storing btm_last_cleanup_num_delpages is to use it to give _some_ consideration to non-recycled deleted pages inside _bt_vacuum_needs_cleanup() -- though never too much. We only really need to avoid leaving a truly excessive number of deleted pages in an unrecycled state forever. We only do this to cover certain narrow cases where no other factor makes VACUUM do a full scan, and yet the index continues to grow (and so actually misses out on recycling existing deleted pages). These metapage changes result in a clear user-visible benefit: We no longer trigger full index scans during VACUUM operations solely due to the presence of only 1 or 2 known deleted (though unrecycled) blocks from a very large index. All that matters now is keeping the costs and benefits in balance over time. Fix an issue that has been around since commit 857f9c3, which added the "skip full scan of index" mechanism (i.e. the _bt_vacuum_needs_cleanup() logic). The accuracy of btm_last_cleanup_num_heap_tuples accidentally hinged upon _when_ the source value gets stored. We now always store btm_last_cleanup_num_heap_tuples in btvacuumcleanup(). This fixes the issue because IndexVacuumInfo.num_heap_tuples (the source field) is expected to accurately indicate the state of the table _after_ the VACUUM completes inside btvacuumcleanup(). A backpatchable fix cannot easily be extracted from this commit. A targeted fix for the issue will follow in a later commit, though that won't happen today. I (pgeoghegan) have chosen to remove any mention of deleted pages in the documentation of the vacuum_cleanup_index_scale_factor GUC/param, since the presence of deleted (though unrecycled) pages is no longer of much concern to users. The vacuum_cleanup_index_scale_factor description in the docs now seems rather unclear in any case, and it should probably be rewritten in the near future. Perhaps some passing mention of page deletion will be added back at the same time. Bump XLOG_PAGE_MAGIC due to nbtree WAL records using full XIDs now. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com> Discussion: https://postgr.es/m/CAH2-WznpdHvujGUwYZ8sihX=d5u-tRYhi-F4wnV2uN2zHpMUXw@mail.gmail.com
PGHOST, PGPORT and PGUSER were already mentioned, but not PGDATABASE. Like 5aaa584, backpatch down to 12. Reported-by: Christophe Courtois Discussion: https://postgr.es/m/161399398648.21711.15387267201764682579@wrigleys.postgresql.org Backpatch-through: 12
Author: Kota Miyake Reviewed-by: Muhammad Usama Discussion: https://postgr.es/m/f5d30053d00dcafda3280c9e267ecb0f@oss.nttdata.com
The complement-class escapes \D, \S, \W are now allowed within bracket expressions. There is no semantic difficulty with doing that, but the rather hokey macro-expansion-based implementation previously used here couldn't cope. Also, invent "word" as an allowed character class name, thus "\w" is now equivalent to "[[:word:]]" outside brackets, or "[:word:]" within brackets. POSIX allows such implementation-specific extensions, and the same name is used in e.g. bash. One surprising compatibility issue this raises is that constructs such as "[\w-_]" are now disallowed, as our documentation has always said they should be: character classes can't be endpoints of a range. Previously, because \w was just a macro for "[:alnum:]_", such a construct was read as "[[:alnum:]_-_]", so it was accepted so long as the character after "-" was numerically greater than or equal to "_". Some implementation cleanup along the way: * Remove the lexnest() hack, and in consequence clean up wordchrs() to not interact with the lexer. * Fix colorcomplement() to not be O(N^2) in the number of colors involved. * Get rid of useless-as-far-as-I-can-see calls of element() on single-character character element names in brackpart(). element() always maps these to the character itself, and things would be quite broken if it didn't --- should "[a]" match something different than "a" does? Besides, the shortcut path in brackpart() wasn't doing this anyway, making it even more inconsistent. Discussion: https://postgr.es/m/2845172.1613674385@sss.pgh.pa.us Discussion: https://postgr.es/m/3220564.1613859619@sss.pgh.pa.us
Newline is certainly not a digit, nor a word character, so it is
sensible that it should match these complemented character classes.
Previously, \D and \W acted that way by default, but in
newline-sensitive mode ('n' or 'p' flag) they did not match newlines.
This behavior was previously forced because explicit complemented
character classes don't match newlines in newline-sensitive mode;
but as of the previous commit that implementation constraint no
longer exists. It seems useful to change this because the primary
real-world use for newline-sensitive mode seems to be to match the
default behavior of other regex engines such as Perl and Javascript
... and their default behavior is that these match newlines.
The old behavior can be kept by writing an explicit complemented
character class, i.e. [^[:digit:]] or [^[:word:]]. (This means
that \D and \W are not exactly equivalent to those strings, but
they weren't anyway.)
Discussion: https://postgr.es/m/3220564.1613859619@sss.pgh.pa.us
We aren't publishing this file as documentation, and it's been much more haphazardly maintained than the real docs in func.sgml, so let's just drop it. I think the only reason I included it in commit 7bcc6d9 was that the Berkeley-era sources had had a man page in this directory. Discussion: https://postgr.es/m/4099447.1614186542@sss.pgh.pa.us
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