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* Improve comment for GetStableLatestTransactionId().Tom Lane2012-05-31
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* Only throw recovery conflicts when InHotStandby. Bug fix to recentSimon Riggs2012-05-31
| | | | | | patch to allow Index Only Scans on Hot Standby. Bug report from Jaime Casanova
* Change the way parent pages are tracked during buffered GiST build.Heikki Linnakangas2012-05-30
| | | | | | | | | | | | | | | | | | We used to mimic the way a stack is constructed when descending the tree during normal GiST inserts, but that was quite complicated during a buffered build. It was also wrong: in GiST, the left-to-right relationships on different levels might not match each other, so that when you know the parent of a child page, you won't necessarily find the parent of the page to the right of the child page by following the rightlinks at the parent level. This sometimes led to "could not re-find parent" errors while building a GiST index. We now use a simple hash table to track the parent of every internal page. Whenever a page is split, and downlinks are moved from one page to another, we update the hash table accordingly. This is also better for performance than the old method, as we never need to move right to re-find the parent page, which could take a significant amount of time for buffers that were created much earlier in the index build.
* Delete the temporary file used in buffered GiST build, after the build.Heikki Linnakangas2012-05-30
| | | | | | There were two bugs here: We forgot to call gistFreeBuildBuffers() function at the end of build, and we passed interXact == true to BufFileCreateTemp, so the file wasn't automatically cleaned up at end-of-transaction either.
* Fix integer overflow bug in GiST buffering build calculations.Heikki Linnakangas2012-05-29
| | | | | | | The result of (maintenance_work_mem * 1024) / BLCKSZ doesn't fit in a signed 32-bit integer, if maintenance_work_mem >= 2GB. Use double instead. And while we're at it, write the calculations in an easier to understand form, with the intermediary steps written out and commented.
* Teach AbortOutOfAnyTransaction to clean up partially-started transactions.Tom Lane2012-05-28
| | | | | | | | | | | | AbortOutOfAnyTransaction failed to do anything if the state it saw on entry corresponded to failing partway through StartTransaction. I fixed AbortCurrentTransaction to cope with that case way back in commit 60b2444cc3ba037630c9b940c3c9ef01b954b87b, but evidently overlooked that AbortOutOfAnyTransaction should do likewise. Back-patch to all supported branches. It's not clear that this omission has any more-than-cosmetic consequences, but it's also not clear that it doesn't, so back-patching seems the least risky choice.
* Prevent synchronized scanning when systable_beginscan chooses a heapscan.Tom Lane2012-05-26
| | | | | | | | | | | | | | | The only interesting-for-performance case wherein we force heapscan here is when we're rebuilding the relcache init file, and the only such case that is likely to be examining a catalog big enough to be syncscanned is RelationBuildTupleDesc. But the early-exit optimization in that code gets broken if we start the scan at a random place within the catalog, so that allowing syncscan is actually a big deoptimization if pg_attribute is large (at least for the normal case where the rows for core system catalogs have never been changed since initdb). Hence, prevent syncscan here. Per my testing pursuant to complaints from Jeff Frost and Greg Sabino Mullane, though neither of them seem to have actually hit this specific problem. Back-patch to 8.3, where syncscan was introduced.
* Ensure that seqscans check for interrupts at least once per page.Tom Lane2012-05-22
| | | | | | | | | | | | | If a seqscan encounters many consecutive pages containing only dead tuples, it can remain in the loop in heapgettup for a long time, and there was no CHECK_FOR_INTERRUPTS anywhere in that loop. This meant there were real-world situations where a query would be effectively uncancelable for long stretches. Add a check placed to occur once per page, which should be enough to provide reasonable response time without adding any measurable overhead. Report and patch by Merlin Moncure (though I tweaked it a bit). Back-patch to all supported branches.
* Fix bug in gistRelocateBuildBuffersOnSplit().Heikki Linnakangas2012-05-18
| | | | | | | | | | | | | | | | | | | When we create a temporary copy of the old node buffer, in stack, we mustn't leak that into any of the long-lived data structures. Before this patch, when we called gistPopItupFromNodeBuffer(), it got added to the array of "loaded buffers". After gistRelocateBuildBuffersOnSplit() exits, the pointer added to the loaded buffers array points to garbage. Often that goes unnotied, because when we go through the array of loaded buffers to unload them, buffers with a NULL pageBuffer are ignored, which can often happen by accident even if the pointer points to garbage. This patch fixes that by marking the temporary copy in stack explicitly as temporary, and refrain from adding buffers marked as temporary to the array of loaded buffers. While we're at it, initialize nodeBuffer->pageBlocknum to InvalidBlockNumber and improve comments a bit. This isn't strictly necessary, but makes debugging easier.
* Fix bug in freespace calculation in heap_multi_insert().Heikki Linnakangas2012-05-16
| | | | | | | If the amount of freespace on page was less than the amount reserved by fillfactor, the calculation would underflow. This fixes bug #6643 reported by Tomonari Katsumata.
* Update comments that became out-of-date with the PGXACT struct.Heikki Linnakangas2012-05-14
| | | | | | | | | | | When the "hot" members of PGPROC were split off to separate PGXACT structs, many PGPROC fields referred to in comments were moved to PGXACT, but the comments were neglected in the commit. Mostly this is just a search/replace of PGPROC with PGXACT, but the way the dummy PGPROC entries are created for prepared transactions changed more, making some of the comments totally bogus. Noah Misch
* Ensure backwards compatibility for GetStableLatestTransactionId()Simon Riggs2012-05-12
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* Fix obsolescent C declaration syntaxPeter Eisentraut2012-05-12
| | | | | gcc -Wextra/-Wold-style-declaration thinks that "inline" should go before the function return type.
* Ensure age() returns a stable value rather than the latest valueSimon Riggs2012-05-11
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* On GiST page split, release the locks on child pages before recursing up.Heikki Linnakangas2012-05-11
| | | | | | | | | | | | | | | | | | When inserting the downlinks for a split gist page, we used hold the locks on the child pages until the insertion into the parent - and recursively its parent if it had to be split too - were all completed. Change that so that the locks on child pages are released after the insertion in the immediate parent is done, before recursing further up the tree. This reduces the number of lwlocks that are held simultaneously. Holding many locks is bad for concurrency, and in extreme cases you can even hit the limit of 100 simultaneously held lwlocks in a backend. If you're really unlucky, you can hit the limit while in a critical section, which brings down the whole system. This fixes bug #6629 reported by Tom Forbes. Backpatch to 9.1. The page splitting code was rewritten in 9.1, and the old code did not have this problem.
* Fix an issue in recent walwriter hibernation patch.Tom Lane2012-05-08
| | | | | | | | | Users of asynchronous-commit mode expect there to be a guaranteed maximum delay before an async commit's WAL records get flushed to disk. The original version of the walwriter hibernation patch broke that. Add an extra shared-memory flag to allow async commits to kick the walwriter out of hibernation mode, without adding any noticeable overhead in cases where no action is needed.
* Reduce idle power consumption of walwriter and checkpointer processes.Tom Lane2012-05-08
| | | | | | | | | | | | | | | | | | | | | | | This patch modifies the walwriter process so that, when it has not found anything useful to do for many consecutive wakeup cycles, it extends its sleep time to reduce the server's idle power consumption. It reverts to normal as soon as it's done any successful flushes. It's still true that during any async commit, backends check for completed, unflushed pages of WAL and signal the walwriter if there are any; so that in practice the walwriter can get awakened and returned to normal operation sooner than the sleep time might suggest. Also, improve the checkpointer so that it uses a latch and a computed delay time to not wake up at all except when it has something to do, replacing a previous hardcoded 0.5 sec wakeup cycle. This also is primarily useful for reducing the server's power consumption when idle. In passing, get rid of the dedicated latch for signaling the walwriter in favor of using its procLatch, since that comports better with possible generic signal handlers using that latch. Also, fix a pre-existing bug with failure to save/restore errno in walwriter's signal handlers. Peter Geoghegan, somewhat simplified by Tom
* Avoid repeated CLOG access from heap_hot_search_buffer.Robert Haas2012-05-02
| | | | | | | | | | | At the time we check whether the tuple is dead to all running transactions, we've already verified that it isn't visible to our scan, setting hint bits if appropriate. So there's no need to recheck CLOG for the all-dead test we do just a moment later. So, add HeapTupleIsSurelyDead() to test the appropriate condition under the assumption that all relevant hit bits are already set. Review by Tom Lane.
* More duplicate word removal.Robert Haas2012-05-02
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* Remove duplicate words in comments.Heikki Linnakangas2012-05-02
| | | | Found these with grep -r "for for ".
* Converge all SQL-level statistics timing values to float8 milliseconds.Tom Lane2012-04-30
| | | | | | | | | | | | | | | | | | | | | | | | | This patch adjusts the core statistics views to match the decision already taken for pg_stat_statements, that values representing elapsed time should be represented as float8 and measured in milliseconds. By using float8, we are no longer tied to a specific maximum precision of timing data. (Internally, it's still microseconds, but we could now change that without needing changes at the SQL level.) The columns affected are pg_stat_bgwriter.checkpoint_write_time pg_stat_bgwriter.checkpoint_sync_time pg_stat_database.blk_read_time pg_stat_database.blk_write_time pg_stat_user_functions.total_time pg_stat_user_functions.self_time pg_stat_xact_user_functions.total_time pg_stat_xact_user_functions.self_time The first four of these are new in 9.2, so there is no compatibility issue from changing them. The others require a release note comment that they are now double precision (and can show a fractional part) rather than bigint as before; also their underlying statistics functions now match the column definitions, instead of returning bigint microseconds.
* Remove duplicate word in comment.Robert Haas2012-04-30
| | | | Noted by Peter Geoghegan.
* Prevent index-only scans from returning wrong answers under Hot Standby.Robert Haas2012-04-26
| | | | | | | | | The alternative of disallowing index-only scans in HS operation was discussed, but the consensus was that it was better to treat marking a page all-visible as a recovery conflict for snapshots that could still fail to see XIDs on that page. We may in the future try to soften this, so that we simply force index scans to do heap fetches in cases where this may be an issue, rather than throwing a hard conflict.
* Another trivial comment-typo fix.Tom Lane2012-04-25
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* Lots of doc corrections.Robert Haas2012-04-23
| | | | Josh Kupershmidt
* Fix some typosPeter Eisentraut2012-04-22
| | | | Josh Kupershmidt
* Tighten up error recovery for fast-path locking.Robert Haas2012-04-18
| | | | | | | | | The previous code could cause a backend crash after BEGIN; SAVEPOINT a; LOCK TABLE foo (interrupted by ^C or statement timeout); ROLLBACK TO SAVEPOINT a; LOCK TABLE foo, and might have leaked strong-lock counts in other situations. Report by Zoltán Böszörményi; patch review by Jeff Davis.
* Don't wait for the commit record to be replicated if we wrote no WAL.Heikki Linnakangas2012-04-17
| | | | | | | | When using synchronous replication, we waited for the commit record to be replicated, but if we our transaction didn't write any other WAL records, that's not required because we don't even flush the WAL locally to disk in that case. This lead to long waits when committing a transaction that only modified a temporary table. Bug spotted by Thom Brown.
* Fix typoPeter Eisentraut2012-04-16
| | | | Kyotaro HORIGUCHI
* Teach SLRU code to avoid replacing I/O-busy pages.Robert Haas2012-04-08
| | | | Patch by me; review by Tom Lane and others.
* Fix misleading output from gin_desc().Tom Lane2012-04-06
| | | | | | | | | | | XLOG_GIN_UPDATE_META_PAGE and XLOG_GIN_DELETE_LISTPAGE records were printed with a list link field labeled as "blkno", which was confusing, especially when the link was empty (InvalidBlockNumber). Print the metapage block number instead, since that's what's actually being updated. We could include the link values too as a separate field, but not clear it's worth the trouble. Back-patch to 8.4 where the dubious code was added.
* Publish checkpoint timing information to pg_stat_bgwriter.Robert Haas2012-04-05
| | | | Greg Smith, Peter Geoghegan, and Robert Haas
* Correct epoch of txid_current() when executed on a Hot Standby server.Simon Riggs2012-03-29
| | | | | | | | | Initialise ckptXidEpoch from starting checkpoint and maintain the correct value as we roll forwards. This allows GetNextXidAndEpoch() to return the correct epoch when executed during recovery. Backpatch to 9.0 when the problem is first observable by a user. Bug report from Daniel Farina
* Code cleanup for heap_freeze_tuple.Robert Haas2012-03-26
| | | | | | | It used to be case that lazy vacuum could call this function with only a shared lock on the buffer, but neither lazy vacuum nor any other code path does that any more. Simplify the code accordingly and clean up some related, obsolete comments.
* Clean up compiler warnings from unused variables with asserts disabledPeter Eisentraut2012-03-21
| | | | | | For those variables only used when asserts are enabled, use a new macro PG_USED_FOR_ASSERTS_ONLY, which expands to __attribute__((unused)) when asserts are not enabled.
* Add additional safety check against invalid backup label filePeter Eisentraut2012-03-14
| | | | | | | It was already checking for invalid data after "BACKUP FROM", but would possibly crash if "BACKUP FROM" was missing altogether. found by Coverity
* Fix SPGiST vacuum algorithm to handle concurrent tuple motion properly.Tom Lane2012-03-12
| | | | | | | | | | | | | A leaf tuple that we need to delete could get moved as a consequence of an insertion happening concurrently with the VACUUM scan. If it moves from a page past the current scan point to a page before, we'll miss it, which is not acceptable. Hence, when we see a leaf-page REDIRECT that could have been made since our scan started, chase down the redirection pointer much as if we were doing a normal index search, and be sure to vacuum every page it leads to. This fixes the issue because, if the tuple was on page N at the instant we start our scan, we will surely find it as a consequence of chasing the redirect from page N, no matter how much it moves around in between. Problem noted by Takashi Yamamoto.
* Teach SPGiST to store nulls and do whole-index scans.Tom Lane2012-03-11
| | | | | | | | | | | | | | | | | | | | | This patch fixes the other major compatibility-breaking limitation of SPGiST, that it didn't store anything for null values of the indexed column, and so could not support whole-index scans or "x IS NULL" tests. The approach is to create a wholly separate search tree for the null entries, and use fixed "allTheSame" insertion and search rules when processing this tree, instead of calling the index opclass methods. This way the opclass methods do not need to worry about dealing with nulls. Catversion bump is for pg_am updates as well as the change in on-disk format of SPGiST indexes; there are some tweaks in SPGiST WAL records as well. Heavily rewritten version of a patch by Oleg Bartunov and Teodor Sigaev. (The original also stored nulls separately, but it reused GIN code to do so; which required undesirable compromises in the on-disk format, and would likely lead to bugs due to the GIN code being required to work in two very different contexts.)
* Restructure SPGiST opclass interface API to support whole-index scans.Tom Lane2012-03-10
| | | | | | | | | | | | | | | | | | | | The original API definition was incapable of supporting whole-index scans because there was no way to invoke leaf-value reconstruction without checking any qual conditions. Also, it was inefficient for multiple-qual-condition scans because value reconstruction got done over again for each qual condition, and because other internal work in the consistent functions likewise had to be done for each qual. To fix these issues, pass the whole scankey array to the opclass consistent functions, instead of only letting them see one item at a time. (Essentially, the loop over scankey entries is now inside the consistent functions not outside them. This makes the consistent functions a bit more complicated, but not unreasonably so.) In itself this commit does nothing except save a few cycles in multiple-qual-condition index scans, since we can't support whole-index scans on SPGiST indexes until nulls are included in the index. However, I consider this a must-fix for 9.2 because once we release it will get very much harder to change the opclass API definition.
* Update outdated comment. HeapTupleHeader.t_natts field doesn't exist anymore.Heikki Linnakangas2012-03-09
| | | | Kevin Grittner
* Silence warning about unused variable, when building without assertions.Heikki Linnakangas2012-03-08
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* Typo fix.Robert Haas2012-03-06
| | | | Fujii Masao
* Make the comments more clear on the fact that UpdateFullPageWrites() is notHeikki Linnakangas2012-03-06
| | | | safe to call concurrently from multiple processes.
* Remove extra copies of LogwrtResult.Heikki Linnakangas2012-03-06
| | | | | | | | | | | | | | | This simplifies the code a little bit. The new rule is that to update XLogCtl->LogwrtResult, you must hold both WALWriteLock and info_lck, whereas before we had two copies, one that was protected by WALWriteLock and another protected by info_lck. The code that updates them was already holding both locks, so merging the two is trivial. The third copy, XLogCtl->Insert.LogwrtResult, was not totally redundant, it was used in AdvanceXLInsertBuffer to update the backend-local copy, before acquiring the info_lck to read the up-to-date value. But the value of that seems dubious; at best it's saving one spinlock acquisition per completed WAL page, which is not significant compared to all the other work involved. And in practice, it's probably not saving even that much.
* Simplify the way changes to full_page_writes are logged.Heikki Linnakangas2012-03-06
| | | | | | | | | | | | | | | It's harmless to do full page writes even when not strictly necessary, so when turning full_page_writes on, we can set the global flag first, and then call XLogInsert. Likewise, when turning it off, we can write the WAL record first, and then clear the flag. This way XLogInsert doesn't need any special handling of the XLOG_FPW_CHANGE record type. XLogInsert is complicated enough already, so anything we can keep away from there is a good thing. Actually I don't think the atomicity of the shared memory flag matters, anyway, because we only write the XLOG_FPW_CHANGE at the end of recovery, when there are no concurrent WAL insertions going on. But might as well make it safe, in case we allow changing full_page_writes on the fly in the future.
* More carefully validate xlog location string inputsMagnus Hagander2012-03-04
| | | | | | | Now that we have validate_xlog_location, call it from the previously existing functions taking xlog locatoins as a string input. Suggested by Fujii Masao
* Add function pg_xlog_location_diff to help comparisonsMagnus Hagander2012-03-04
| | | | | | | | Comparing two xlog locations are useful for example when calculating replication lag. Euler Taveira de Oliveira, reviewed by Fujii Masao, and some cleanups from me
* When a GiST page is split during index build, it might not have a buffer.Heikki Linnakangas2012-03-02
| | | | | | | | | | | | | Previously it was thought that it's impossible as the code stands, because insertions create buffers as tuples are cascaded downwards, and index split also creaters buffers eagerly for all halves. But the example from Jay Levitt demonstrates that it can happen, when the root page is split. It's in fact OK if the buffer doesn't exist, so we just need to remove the sanity check. In fact, we've been discussing the possibility of destroying empty buffers to conserve memory, which would render the sanity check completely useless anyway. Fix by Alexander Korotkov
* Add const qualifiers where they are accidentally cast awayPeter Eisentraut2012-02-28
| | | | | This only produces warnings under -Wcast-qual, but it's more correct and consistent in any case.
* Fix some more bugs in GIN's WAL replay logic.Tom Lane2012-02-26
| | | | | | | | | | | | | | | | | | In commit 4016bdef8aded77b4903c457050622a5a1815c16 I fixed a bunch of ginxlog.c bugs having to do with not handling XLogReadBuffer failures correctly. However, in ginRedoUpdateMetapage and ginRedoDeleteListPages, I unaccountably thought that failure to read the metapage would be impossible and just put in an elog(PANIC) call. This is of course wrong: failure is exactly what will happen if the index got dropped (or rebuilt) between creation of the WAL record and the crash we're trying to recover from. I believe this explains Nicholas Wilson's recent report of these errors getting reached. Also, fix memory leak in forgetIncompleteSplit. This wasn't of much concern when the code was written, but in a long-running standby server page split records could be expected to accumulate indefinitely. Back-patch to 8.4 --- before that, GIN didn't have a metapage.