10 Commits (b098abf90537edf0ce9c70e8eb55320baf6e445d)

Author	SHA1	Message	Date
Tom Lane	ee4af347ba	Measure Bloom index signature-length reloption in bits, not words. ... Per discussion, this is a more understandable and future-proof way of exposing the setting to users. On-disk, we can still store it in words, so as to not break on-disk compatibility with beta1. Along the way, clean up the code associated with Bloom reloptions. Provide explicit macros for default and maximum lengths rather than having magic numbers buried in multiple places in the code. Drop the adjustBloomOptions() code altogether: it was useless in view of the fact that reloptions.c already performed default-substitution and range checking for the options. Rename a couple of macros and types for more clarity. Discussion: <23767.1464926580@sss.pgh.pa.us>	9 years ago
Tom Lane	e13ac5586c	Avoid possible crash in contrib/bloom's blendscan(). ... It's possible to begin and end an indexscan without ever calling amrescan. contrib/bloom, unlike every other index AM, allocated its "scan->opaque" storage at amrescan time, and thus would crash in amendscan if amrescan hadn't been called. We could fix this by putting in a null-pointer check in blendscan, but I see no very good reason why contrib/bloom should march to its own drummer in this respect. Let's move that initialization to blbeginscan instead. Per report from Jeff Janes.	9 years ago
Tom Lane	14216649f3	PGDLLIMPORT-ify old_snapshot_threshold. ... Revert commit 7cb1db1d95, which represented a misunderstanding of the problem (if snapmgr.h weren't already included in bufmgr.h, things wouldn't compile anywhere). Instead install what I think is the real fix.	10 years ago
Kevin Grittner	7cb1db1d95	Include snapmgr.h in blscan.c ... Windows builds on buildfarm are failing because old_snapshot_threshold is not found in the bloom filter contrib module.	10 years ago
Kevin Grittner	a343e223a5	Revert no-op changes to BufferGetPage() ... The reverted changes were intended to force a choice of whether any newly-added BufferGetPage() calls needed to be accompanied by a test of the snapshot age, to support the "snapshot too old" feature. Such an accompanying test is needed in about 7% of the cases, where the page is being used as part of a scan rather than positioning for other purposes (such as DML or vacuuming). The additional effort required for back-patching, and the doubt whether the intended benefit would really be there, have indicated it is best just to rely on developers to do the right thing based on comments and existing usage, as we do with many other conventions. This change should have little or no effect on generated executable code. Motivated by the back-patching pain of Tom Lane and Robert Haas	10 years ago
Kevin Grittner	848ef42bb8	Add the "snapshot too old" feature ... This feature is controlled by a new old_snapshot_threshold GUC. A value of -1 disables the feature, and that is the default. The value of 0 is just intended for testing. Above that it is the number of minutes a snapshot can reach before pruning and vacuum are allowed to remove dead tuples which the snapshot would otherwise protect. The xmin associated with a transaction ID does still protect dead tuples. A connection which is using an "old" snapshot does not get an error unless it accesses a page modified recently enough that it might not be able to produce accurate results. This is similar to the Oracle feature, and we use the same SQLSTATE and error message for compatibility.	10 years ago
Kevin Grittner	8b65cf4c5e	Modify BufferGetPage() to prepare for "snapshot too old" feature ... This patch is a no-op patch which is intended to reduce the chances of failures of omission once the functional part of the "snapshot too old" patch goes in. It adds parameters for snapshot, relation, and an enum to specify whether the snapshot age check needs to be done for the page at this point. This initial patch passes NULL for the first two new parameters and BGP_NO_SNAPSHOT_TEST for the third. The follow-on patch will change the places where the test needs to be made.	10 years ago
Tom Lane	8f75fd1f40	Fix contrib/bloom to not fail under CLOBBER_CACHE_ALWAYS. ... The code was supposing that rd_amcache wouldn't disappear from under it during a scan; which is wrong. Copy the data out of the relcache rather than trying to reference it there.	10 years ago
Tom Lane	a9284849b4	Clean up some stuff in new contrib/bloom module. ... Coverity complained about implicit sign-extension in the BloomPageGetFreeSpace macro, probably because sizeOfBloomTuple isn't wide enough for size calculations. No overflow is really possible as long as maxoff and sizeOfBloomTuple are small enough to represent a realistic situation, but it seems like a good idea to declare sizeOfBloomTuple as Size not int32. Add missing check on BloomPageAddItem() result, again from Coverity. Avoid core dump due to not allocating so->sign array when scan->numberOfKeys is zero. Also thanks to Coverity. Use FLEXIBLE_ARRAY_MEMBER rather than declaring an array as size 1 when it isn't necessarily. Very minor beautification of related code. Unfortunately, none of the Coverity-detected mistakes look like they could account for the remaining buildfarm unhappiness with this module. It's barely possible that the FLEXIBLE_ARRAY_MEMBER mistake does account for that, if it's enabling bogus compiler optimizations; but I'm not terribly optimistic. We probably still have bugs to find here.	10 years ago
Teodor Sigaev	9ee014fc89	Bloom index contrib module ... Module provides new access method. It is actually a simple Bloom filter implemented as pgsql's index. It could give some benefits on search with large number of columns. Module is a single way to test generic WAL interface committed earlier. Author: Teodor Sigaev, Alexander Korotkov Reviewers: Aleksander Alekseev, Michael Paquier, Jim Nasby	10 years ago