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* Improve concurrency of foreign key lockingAlvaro Herrera2013-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
* Fix more issues with cascading replication and timeline switches.Heikki Linnakangas2013-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | When a standby server follows the master using WAL archive, and it chooses a new timeline (recovery_target_timeline='latest'), it only fetches the timeline history file for the chosen target timeline, not any other history files that might be missing from pg_xlog. For example, if the current timeline is 2, and we choose 4 as the new recovery target timeline, the history file for timeline 3 is not fetched, even if it's part of this server's history. That's enough for the standby itself - the history file for timeline 4 includes timeline 3 as well - but if a cascading standby server wants to recover to timeline 3, it needs the history file. To fix, when a new recovery target timeline is chosen, try to copy any missing history files from the archive to pg_xlog between the old and new target timeline. A second similar issue was with the WAL files. When a standby recovers from archive, and it reaches a segment that contains a switch to a new timeline, recovery fetches only the WAL file labelled with the new timeline's ID. The file from the new timeline contains a copy of the WAL from the old timeline up to the point where the switch happened, and recovery recovers it from the new file. But in streaming replication, walsender only tries to read it from the old timeline's file. To fix, change walsender to read it from the new file, so that it behaves the same as recovery in that sense, and doesn't try to open the possibly nonexistent file with the old timeline's ID.
* Fix off-by-one bug in xlog reading logicAlvaro Herrera2013-01-18
| | | | | | Bug reported by Michael Paquier Author: Andres Freund
* Use the right timeline when beginning to stream from master.Heikki Linnakangas2013-01-18
| | | | | | | | | | | | | | | | | | | | | The xlogreader refactoring broke the logic to decide which timeline to start streaming from. XLogPageRead() uses the timeline history to check which timeline the requested WAL position falls into. However, after the refactoring, XLogPageRead() is always first called with the first page in the segment, to verify the segment header, and only then with the actual WAL position we're interested in. That first read of the segment's header made XLogPageRead() to always start streaming from the old timeline containing the segment header, not the timeline containing the actual record, if there was a timeline switch within the segment. I thought I fixed this yesterday, but that fix was too narrow and only fixed this for the corner-case that the timeline switch happened in the first page of the segment. To fix this more robustly, pass explicitly the position of the record we're actually interested in to XLogPageRead, and use that to decide which timeline to read from, rather than deduce it from the page and offset. Per report from Fujii Masao.
* Make pg_receivexlog and pg_basebackup -X stream work across timeline switches.Heikki Linnakangas2013-01-17
| | | | | | | | | | | | | | | | | | | | | | This mirrors the changes done earlier to the server in standby mode. When receivelog reaches the end of a timeline, as reported by the server, it fetches the timeline history file of the next timeline, and restarts streaming from the new timeline by issuing a new START_STREAMING command. When pg_receivexlog crosses a timeline, it leaves the .partial suffix on the last segment on the old timeline. This helps you to tell apart a partial segment left in the directory because of a timeline switch, and a completed segment. If you just follow a single server, it won't make a difference, but it can be significant in more complicated scenarios where new WAL is still generated on the old timeline. This includes two small changes to the streaming replication protocol: First, when you reach the end of timeline while streaming, the server now sends the TLI of the next timeline in the server's history to the client. pg_receivexlog uses that as the next timeline, so that it doesn't need to parse the timeline history file like a standby server does. Second, when BASE_BACKUP command sends the begin and end WAL positions, it now also sends the timeline IDs corresponding the positions.
* Fix a couple of error-handling bugs in the xlogreader patch.Heikki Linnakangas2013-01-17
| | | | | | | | | | | | XLogReadRecord should reset its state on every error, to make sure it re-reads the page on next call. It was inconsistent in that some errors did that, but some did not. In ReadRecord(), don't give up on an error if we're in standby mode. The loop was set up to retry, but the checks within the loop broke out of the loop on any error. Andres Freund, with some tweaking by me.
* Split out XLog reading as an independent facilityAlvaro Herrera2013-01-16
| | | | | | | | | | | | | | | | | This new facility can not only be used by xlog.c to carry out crash recovery, but also by external programs. By supplying a function to read XLog pages from somewhere, all the WAL reading can be used for completely different purposes. For the standard backend use, the behavior should be pretty much the same as previously. As for non-backend programs, an hypothetical pg_xlogdump program is now closer to reality, but some more backend support is still necessary. This patch was originally submitted by Andres Freund in a different form, but Heikki Linnakangas opted for and authored another design of the concept. Andres has advanced the patch since Heikki's initial version. Review and some (mostly cosmetics) changes by me.
* Tolerate timeline switches while "pg_basebackup -X fetch" is running.Heikki Linnakangas2013-01-03
| | | | | | | | | | | | | | | | | | | | | | If you take a base backup from a standby server with "pg_basebackup -X fetch", and the timeline switches while the backup is being taken, the backup used to fail with an error "requested WAL segment %s has already been removed". This is because the server-side code that sends over the required WAL files would not construct the WAL filename with the correct timeline after a switch. Fix that by using readdir() to scan pg_xlog for all the WAL segments in the range, regardless of timeline. Also, include all timeline history files in the backup, if taken with "-X fetch". That fixes another related bug: If a timeline switch happened just before the backup was initiated in a standby, the WAL segment containing the initial checkpoint record contains WAL from the older timeline too. Recovery will not accept that without a timeline history file that lists the older timeline. Backpatch to 9.2. Versions prior to that were not affected as you could not take a base backup from a standby before 9.2.
* Delay reading timeline history file until it's fetched from master.Heikki Linnakangas2013-01-03
| | | | | | | | | | | | | | | | | | Streaming replication can fetch any missing timeline history files from the master, but recovery would read the timeline history file for the target timeline before reading the checkpoint record, and before walreceiver has had a chance to fetch it from the master. Delay reading it, and the sanity checks involving timeline history, until after reading the checkpoint record. There is at least one scenario where this makes a difference: if you take a base backup from a standby server right after a timeline switch, the WAL segment containing the initial checkpoint record will begin with an older timeline ID. Without the timeline history file, recovering that file will fail as the older timeline ID is not recognized to be an ancestor of the target timeline. If you try to recover from such a backup, using only streaming replication to fetch the WAL, this patch is required for that to work.
* Fix bug in streaming replication over multiple tli switches.Heikki Linnakangas2013-01-02
| | | | | | | | After receiving some WAL over streaming replication, try to open the file from the timeline we're currently recieving, not recoveryTargetTLI. They are usually the same, which is why wasn't noticed before, but you'd get an error if there have been more than one timeline switch between the current point in WAL and the recovery target.
* Fix silly typo in code, which broke the check for reaching consistency.Heikki Linnakangas2013-01-02
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* Update copyrights for 2013Bruce Momjian2013-01-01
| | | | | Fully update git head, and update back branches in ./COPYRIGHT and legal.sgml files.
* Keep timeline history files restored from archive in pg_xlog.Heikki Linnakangas2012-12-30
| | | | | | | | | | | | | | | | | | | | | | | The cascading standby patch in 9.2 changed the way WAL files are treated when restored from the archive. Before, they were restored under a temporary filename, and not kept in pg_xlog, but after the patch, they were copied under pg_xlog. This is necessary for a cascading standby to find them, but it also means that if the archive goes offline and a standby is restarted, it can recover back to where it was using the files in pg_xlog. It also means that if you take an offline backup from a standby server, it includes all the required WAL files in pg_xlog. However, the same change was not made to timeline history files, so if the WAL segment containing the checkpoint record contains a timeline switch, you will still get an error if you try to restart recovery without the archive, or recover from an offline backup taken from the standby. With this patch, timeline history files restored from archive are copied into pg_xlog like WAL files are, so that pg_xlog contains all the files required to recover. This is a corner-case pre-existing issue in 9.2, but even more important in master where it's possible for a standby to follow a timeline switch through streaming replication. To make that possible, the timeline history files must be present in pg_xlog.
* Remove obsolete XLogRecPtr macrosAlvaro Herrera2012-12-28
| | | | | | | | | | | | | | | | | This gets rid of XLByteLT, XLByteLE, XLByteEQ and XLByteAdvance. These were useful for brevity when XLogRecPtrs were split in xlogid/xrecoff; but now that they are simple uint64's, they are just clutter. The only downside to making this change would be ease of backporting patches, but that has been negated by other substantive changes to the involved code anyway. The clarity of simpler expressions makes the change worthwhile. Most of the changes are mechanical, but in a couple of places, the patch author chose to invert the operator sense, making the code flow more logical (and more in line with preceding comments). Author: Andres Freund Eyeballed by Dimitri Fontaine and Alvaro Herrera
* Assign InvalidXLogRecPtr instead of MemSet(0)Alvaro Herrera2012-12-27
| | | | | | For consistency. Author: Andres Freund
* Fix grammatical mistake in error messagePeter Eisentraut2012-12-20
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* Fix recycling of WAL segments after switching timeline during recovery.Heikki Linnakangas2012-12-20
| | | | | | | | | | | | | | | | | | | | | | | | This was broken before, we would recycle old WAL segments on wrong timeline after the recovery target timeline had changed, but my recent commit to not initialize ThisTimeLineID at all in a standby's checkpointer process broke this completely. The problem is that when installing a recycled WAL segment as a future one, ThisTimeLineID is used to construct the filename. To fix, always update ThisTimeLineID to the current timeline being recovered, before recycling WAL segments at a restartpoint. This still leaves a small window where we might install WAL segments under wrong timeline ID, if the timeline is changed just as we're about to start recycling. Also, even if we're replaying timeline X at the momnent, there's no guarantee that we'll need as many WAL segments on that timeline as we recycle. We might be just about to reach the point where we switch to next timeline, so might only need one more WAL segment on the current timeline. We'll live with the waste in that situation. Bug pointed out by Fujii Masao. 9.1 and 9.2 had the same issue, when recovery target timeline was changed, but I committed a slightly different version of this patch on those branches.
* Follow TLI of last replayed record, not recovery target TLI, in walsenders.Heikki Linnakangas2012-12-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the time, the last replayed record comes from the recovery target timeline, but there is a corner case where it makes a difference. When the startup process scans for a new timeline, and decides to change recovery target timeline, there is a window where the recovery target TLI has already been bumped, but there are no WAL segments from the new timeline in pg_xlog yet. For example, if we have just replayed up to point 0/30002D8, on timeline 1, there is a WAL file called 000000010000000000000003 in pg_xlog that contains the WAL up to that point. When recovery switches recovery target timeline to 2, a walsender can immediately try to read WAL from 0/30002D8, from timeline 2, so it will try to open WAL file 000000020000000000000003. However, that doesn't exist yet - the startup process hasn't copied that file from the archive yet nor has the walreceiver streamed it yet, so walsender fails with error "requested WAL segment 000000020000000000000003 has already been removed". That's harmless, in that the standby will try to reconnect later and by that time the segment is already created, but error messages that should be ignored are not good. To fix that, have walsender track the TLI of the last replayed record, instead of the recovery target timeline. That way walsender will not try to read anything from timeline 2, until the WAL segment has been created and at least one record has been replayed from it. The recovery target timeline is now xlog.c's internal affair, it doesn't need to be exposed in shared memory anymore. This fixes the error reported by Thom Brown. depesz the same error message, but I'm not sure if this fixes his scenario.
* Don't set ThisTimeLineID in checkpointer & bgwriter during recovery.Heikki Linnakangas2012-12-20
| | | | | | | | | | | We used to set it to the current recovery target timeline, but the recovery target timeline can change during recovery, leaving ThisTimeLineID at an old value. That seems worse than always leaving it at zero to begin with. AFAICS there was no good reason to set it in the first place. ThisTimeLineID is not needed in checkpointer or bgwriter process, until it's time to write the end-of-recovery checkpoint, and at that point ThisTimeLineID is updated anyway.
* Check if we've reached end-of-backup point also if no redo is required.Heikki Linnakangas2012-12-19
| | | | | | | | | | | | | If you restored from a backup taken from a standby, and the last record in the backup is the checkpoint record, ie. there is no redo required except for the checkpoint record, we would fail to notice that we've reached the end-of-backup point, and the database is consistent. The result was an error "WAL ends before end of online backup". To fix, move the have-we-reached-end-of-backup check into CheckRecoveryConsistency(), which is already responsible for similar checks with minRecoveryPoint, and is called in the right places. Backpatch to 9.2, this check and bug did not exist before that.
* Allow a streaming replication standby to follow a timeline switch.Heikki Linnakangas2012-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this patch, streaming replication would refuse to start replicating if the timeline in the primary doesn't exactly match the standby. The situation where it doesn't match is when you have a master, and two standbys, and you promote one of the standbys to become new master. Promoting bumps up the timeline ID, and after that bump, the other standby would refuse to continue. There's significantly more timeline related logic in streaming replication now. First of all, when a standby connects to primary, it will ask the primary for any timeline history files that are missing from the standby. The missing files are sent using a new replication command TIMELINE_HISTORY, and stored in standby's pg_xlog directory. Using the timeline history files, the standby can follow the latest timeline present in the primary (recovery_target_timeline='latest'), just as it can follow new timelines appearing in an archive directory. START_REPLICATION now takes a TIMELINE parameter, to specify exactly which timeline to stream WAL from. This allows the standby to request the primary to send over WAL that precedes the promotion. The replication protocol is changed slightly (in a backwards-compatible way although there's little hope of streaming replication working across major versions anyway), to allow replication to stop when the end of timeline reached, putting the walsender back into accepting a replication command. Many thanks to Amit Kapila for testing and reviewing various versions of this patch.
* Consistency check should compare last record replayed, not last record read.Heikki Linnakangas2012-12-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | EndRecPtr is the last record that we've read, but not necessarily yet replayed. CheckRecoveryConsistency should compare minRecoveryPoint with the last replayed record instead. This caused recovery to think it's reached consistency too early. Now that we do the check in CheckRecoveryConsistency correctly, we have to move the call of that function to after redoing a record. The current place, after reading a record but before replaying it, is wrong. In particular, if there are no more records after the one ending at minRecoveryPoint, we don't enter hot standby until one extra record is generated and read by the standby, and CheckRecoveryConsistency is called. These two bugs conspired to make the code appear to work correctly, except for the small window between reading the last record that reaches minRecoveryPoint, and replaying it. In the passing, rename recoveryLastRecPtr, which is the last record replayed, to lastReplayedEndRecPtr. This makes it slightly less confusing with replayEndRecPtr, which is the last record read that we're about to replay. Original report from Kyotaro HORIGUCHI, further diagnosis by Fujii Masao. Backpatch to 9.0, where Hot Standby subtly changed the test from "minRecoveryPoint < EndRecPtr" to "minRecoveryPoint <= EndRecPtr". The former works because where the test is performed, we have always read one more record than we've replayed.
* Fix the tracking of min recovery point timeline.Heikki Linnakangas2012-12-10
| | | | | | | | Forgot to update it at the right place. Also, consider checkpoint record that switches to new timelne to be on the new timeline. This fixes erroneous "requested timeline 2 does not contain minimum recovery point" errors, pointed out by Amit Kapila while testing another patch.
* Ensure recovery pause feature doesn't pause unless users can connect.Tom Lane2012-12-05
| | | | | | | | | | | | | | | | | | | | | | | | | | If we're not in hot standby mode, then there's no way for users to connect to reset the recoveryPause flag, so we shouldn't pause. The code was aware of this but the test to see if pausing was safe was seriously inadequate: it wasn't paying attention to reachedConsistency, and besides what it was testing was that we could legally enter hot standby, not that we have done so. Get rid of that in favor of checking LocalHotStandbyActive, which because of the coding in CheckRecoveryConsistency is tantamount to checking that we have told the postmaster to enter hot standby. Also, move the recoveryPausesHere() call that reacts to asynchronous recoveryPause requests so that it's not in the middle of application of a WAL record. I put it next to the recoveryStopsHere() call --- in future those are going to need to interact significantly, so this seems like a good waystation. Also, don't bother trying to read another WAL record if we've already decided not to continue recovery. This was no big deal when the code was written originally, but now that reading a record might entail actions like fetching an archive file, it seems a bit silly to do it like that. Per report from Jeff Janes and subsequent discussion. The pause feature needs quite a lot more work, but this gets rid of some indisputable bugs, and seems safe enough to back-patch.
* Oops, meant to change the comment in writeTimeLineHistory.Heikki Linnakangas2012-12-05
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* Must not reach consistency before XLOG_BACKUP_RECORDSimon Riggs2012-12-05
| | | | | | | | | | When waiting for an XLOG_BACKUP_RECORD the minRecoveryPoint will be incorrect, so we must not declare recovery as consistent before we have seen the record. Major bug allowing recovery to end too early in some cases, allowing people to see inconsistent db. This patch to HEAD and 9.2, other fix required for 9.1 and 9.0 Simon Riggs and Andres Freund, bug report by Jeff Janes
* Downgrade a status message from LOG to DEBUG2.Heikki Linnakangas2012-12-04
| | | | | I never intended this to be anything other than a debugging aid, but forgot to change the level before committing.
* Write exact xlog position of timeline switch in the timeline history file.Heikki Linnakangas2012-12-04
| | | | | | | This allows us to do some more rigorous sanity checking for various incorrect point-in-time recovery scenarios, and provides more information for debugging purposes. It will also come handy in the upcoming patch to allow timeline switches to be replicated by streaming replication.
* Track the timeline associated with minRecoveryPoint, for more sanity checks.Heikki Linnakangas2012-12-04
| | | | | | | | | | | | | This allows recovery to notice certain incorrect recovery scenarios. If a server has recovered to point X on timeline 5, and you restart recovery, it better be on timeline 5 when it reaches point X again, not on some timeline with a higher ID. This can happen e.g if you a standby server is shut down, a new timeline appears in the WAL archive, and the standby server is restarted. It will try to follow the new timeline, which is wrong because some WAL on the old timeline was already replayed before shutdown. Requires an initdb (or at least pg_resetxlog), because this adds a field to the control file.
* Attempt to unbreak MSVC builds broken by ↵Andrew Dunstan2012-12-03
| | | | | | f21bb9cfb5646e1793dcc9c0ea697bab99afa523. We can't use type uint, so use uint32.
* Refactor inCommit flag into generic delayChkpt flag.Simon Riggs2012-12-03
| | | | | | | | | | Rename PGXACT->inCommit flag into delayChkpt flag, and generalise comments to allow use in other situations, such as the forthcoming potential use in checksum patch. Replace wait loop to look for VXIDs with delayChkpt set. No user visible changes, not behaviour changes at present. Simon Riggs, reviewed and rebased by Jeff Davis
* Clarify locking for PageGetLSN() in XLogCheckBuffer()Simon Riggs2012-12-03
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* Refactor the code implementing standby-mode logic.Heikki Linnakangas2012-12-03
| | | | | It is now easier to see that it's a state machine, making the code easier to understand overall.
* Don't advance checkPoint.nextXid near the end of a checkpoint sequence.Tom Lane2012-12-02
| | | | | | | | | | | | | | | | | | | | | | This reverts commit c11130690d6dca64267201a169cfb38c1adec5ef in favor of actually fixing the problem: namely, that we should never have been modifying the checkpoint record's nextXid at this point to begin with. The nextXid should match the state as of the checkpoint's logical WAL position (ie the redo point), not the state as of its physical position. It's especially bogus to advance it in some wal_levels and not others. In any case there is no need for the checkpoint record to carry the same nextXid shown in the XLOG_RUNNING_XACTS record just emitted by LogStandbySnapshot, as any replay operation will already have adopted that value as current. This fixes bug #7710 from Tarvi Pillessaar, and probably also explains bug #6291 from Daniel Farina, in that if a checkpoint were in progress at the instant of XID wraparound, the epoch bump would be lost as reported. (And, of course, these days there's at least a 50-50 chance of a checkpoint being in progress at any given instant.) Diagnosed by me and independently by Andres Freund. Back-patch to all branches supporting hot standby.
* Rearrange storage of data in xl_running_xacts.Simon Riggs2012-12-02
| | | | | | | | | | | | | Previously we stored all xids mixed together. Now we store top-level xids first, followed by all subxids. Also skip logging any subxids if the snapshot is suboverflowed, since there are potentially large numbers of them and they are not useful in that case anyway. Has value in the envisaged design for decoding of WAL. No planned effect on Hot Standby. Andres Freund, reviewed by me
* XidEpoch++ if wraparound during checkpoint.Simon Riggs2012-12-02
| | | | | | | | | | | | | | | | If wal_level = hot_standby we update the checkpoint nextxid, though in the case where a wraparound occurred half-way through a checkpoint we would neglect updating the epoch also. Updating the nextxid is arguably the wrong thing to do, but changing that may introduce subtle bugs into hot standby startup, while updating the value doesn't cause any known bugs yet. Minimal fix now to HEAD and backbranches, wider fix later in HEAD. Bug reported in #6291 by Daniel Farina and slightly differently in Cause analysis and recommended fixes from Tom Lane and Andres Freund. Applied patch is minimal version of Andres Freund's work.
* Clarify operation of online checkpoints.Simon Riggs2012-12-02
| | | | | Previous comments left, but were too obscure for such an important aspect of the system.
* Split out rmgr rm_desc functions into their own filesAlvaro Herrera2012-11-28
| | | | | This is necessary (but not sufficient) to have them compilable outside of a backend environment.
* If we don't have a backup-end-location, don't claim we've reached it.Heikki Linnakangas2012-11-28
| | | | | | | | This was apparently a typo, which caused recovery to think that it immediately reached the end of backup, and allowed the database to start up too early. Reported by Jeff Janes. Backpatch to 9.2, where this code was introduced.
* Add OpenTransientFile, with automatic cleanup at end-of-xact.Heikki Linnakangas2012-11-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | Files opened with BasicOpenFile or PathNameOpenFile are not automatically cleaned up on error. That puts unnecessary burden on callers that only want to keep the file open for a short time. There is AllocateFile, but that returns a buffered FILE * stream, which in many cases is not the nicest API to work with. So add function called OpenTransientFile, which returns a unbuffered fd that's cleaned up like the FILE* returned by AllocateFile(). This plugs a few rare fd leaks in error cases: 1. copy_file() - fixed by by using OpenTransientFile instead of BasicOpenFile 2. XLogFileInit() - fixed by adding close() calls to the error cases. Can't use OpenTransientFile here because the fd is supposed to persist over transaction boundaries. 3. lo_import/lo_export - fixed by using OpenTransientFile instead of PathNameOpenFile. In addition to plugging those leaks, this replaces many BasicOpenFile() calls with OpenTransientFile() that were not leaking, because the code meticulously closed the file on error. That wasn't strictly necessary, but IMHO it's good for robustness. The same leaks exist in older versions, but given the rarity of the issues, I'm not backpatching this. Not yet, anyway - it might be good to backpatch later, after this mechanism has had some more testing in master branch.
* Avoid bogus "out-of-sequence timeline ID" errors in standby-mode.Heikki Linnakangas2012-11-22
| | | | | | | | | | | | | | | | | | When startup process opens a WAL segment after replaying part of it, it validates the first page on the WAL segment, even though the page it's really interested in later in the file. As part of the validation, it checks that the TLI on the page header is >= the TLI it saw on the last page it read. If the segment contains a timeline switch, and we have already replayed it, and then re-open the WAL segment (because of streaming replication got disconnected and reconnected, for example), the TLI check will fail when the first page is validated. Fix that by relaxing the TLI check when re-opening a WAL segment. Backpatch to 9.0. Earlier versions had the same code, but before standby mode was introduced in 9.0, recovery never tried to re-read a segment after partially replaying it. Reported by Amit Kapila, while testing a new feature.
* Fix archive_cleanup_command.Heikki Linnakangas2012-11-19
| | | | | | | | | | | | | | | | When I moved ExecuteRecoveryCommand() from xlog.c to xlogarchive.c, I didn't realize that it's called from the checkpoint process, not the startup process. I tried to use InRedo variable to decide whether or not to attempt cleaning up the archive (must not do so before we have read the initial checkpoint record), but that variable is only valid within the startup process. Instead, let ExecuteRecoveryCommand() always clean up the archive, and add an explicit argument to RestoreArchivedFile() to say whether that's allowed or not. The caller knows better. Reported by Erik Rijkers, diagnosis by Fujii Masao. Only 9.3devel is affected.
* Fix multiple problems in WAL replay.Tom Lane2012-11-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the replay functions for WAL record types that modify more than one page failed to ensure that those pages were locked correctly to ensure that concurrent queries could not see inconsistent page states. This is a hangover from coding decisions made long before Hot Standby was added, when it was hardly necessary to acquire buffer locks during WAL replay at all, let alone hold them for carefully-chosen periods. The key problem was that RestoreBkpBlocks was written to hold lock on each page restored from a full-page image for only as long as it took to update that page. This was guaranteed to break any WAL replay function in which there was any update-ordering constraint between pages, because even if the nominal order of the pages is the right one, any mixture of full-page and non-full-page updates in the same record would result in out-of-order updates. Moreover, it wouldn't work for situations where there's a requirement to maintain lock on one page while updating another. Failure to honor an update ordering constraint in this way is thought to be the cause of bug #7648 from Daniel Farina: what seems to have happened there is that a btree page being split was rewritten from a full-page image before the new right sibling page was written, and because lock on the original page was not maintained it was possible for hot standby queries to try to traverse the page's right-link to the not-yet-existing sibling page. To fix, get rid of RestoreBkpBlocks as such, and instead create a new function RestoreBackupBlock that restores just one full-page image at a time. This function can be invoked by WAL replay functions at the points where they would otherwise perform non-full-page updates; in this way, the physical order of page updates remains the same no matter which pages are replaced by full-page images. We can then further adjust the logic in individual replay functions if it is necessary to hold buffer locks for overlapping periods. A side benefit is that we can simplify the handling of concurrency conflict resolution by moving that code into the record-type-specfic functions; there's no more need to contort the code layout to keep conflict resolution in front of the RestoreBkpBlocks call. In connection with that, standardize on zero-based numbering rather than one-based numbering for referencing the full-page images. In HEAD, I removed the macros XLR_BKP_BLOCK_1 through XLR_BKP_BLOCK_4. They are still there in the header files in previous branches, but are no longer used by the code. In addition, fix some other bugs identified in the course of making these changes: spgRedoAddNode could fail to update the parent downlink at all, if the parent tuple is in the same page as either the old or new split tuple and we're not doing a full-page image: it would get fooled by the LSN having been advanced already. This would result in permanent index corruption, not just transient failure of concurrent queries. Also, ginHeapTupleFastInsert's "merge lists" case failed to mark the old tail page as a candidate for a full-page image; in the worst case this could result in torn-page corruption. heap_xlog_freeze() was inconsistent about using a cleanup lock or plain exclusive lock: it did the former in the normal path but the latter for a full-page image. A plain exclusive lock seems sufficient, so change to that. Also, remove gistRedoPageDeleteRecord(), which has been dead code since VACUUM FULL was rewritten. Back-patch to 9.0, where hot standby was introduced. Note however that 9.0 had a significantly different WAL-logging scheme for GIST index updates, and it doesn't appear possible to make that scheme safe for concurrent hot standby queries, because it can leave inconsistent states in the index even between WAL records. Given the lack of complaints from the field, we won't work too hard on fixing that branch.
* Use correct text domain for translating errcontext() messages.Heikki Linnakangas2012-11-12
| | | | | | | | | | | | | | | | | | | errcontext() is typically used in an error context callback function, not within an ereport() invocation like e.g errmsg and errdetail are. That means that the message domain that the TEXTDOMAIN magic in ereport() determines is not the right one for the errcontext() calls. The message domain needs to be determined by the C file containing the errcontext() call, not the file containing the ereport() call. Fix by turning errcontext() into a macro that passes the TEXTDOMAIN to use for the errcontext message. "errcontext" was used in a few places as a variable or struct field name, I had to rename those out of the way, now that errcontext is a macro. We've had this problem all along, but this isn't doesn't seem worth backporting. It's a fairly minor issue, and turning errcontext from a function to a macro requires at least a recompile of any external code that calls errcontext().
* Fix erroneous choice of timeline variable, tooAlvaro Herrera2012-10-31
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* Fix erroneous choices of segNo variablesAlvaro Herrera2012-10-31
| | | | | | | | | | | | | | Commit dfda6eba (which changed segment numbers to use a single 64 bit variable instead of log/seg) introduced a couple of bogus choices of exactly which log segment number variable to use in each case. This is currently pretty harmless; in one place, the bogus number was only being used in an error message for a pretty unlikely condition (failure to fsync a WAL segment file). In the other, it was using a global variable instead of the local variable; but all callsites were passing the value of the global variable anyway. No need to backpatch because that commit is not on earlier branches.
* Fix silly bug in previous refactoring.Heikki Linnakangas2012-10-09
| | | | | I extracted the refactoring patch from a larger patch that contained other changes too, but missed one unintentional change and didn't test enough...
* Put the logic to wait for WAL in standby mode to a separate function.Heikki Linnakangas2012-10-09
| | | | | This is just refactoring with no user-visible effect, to make the code more readable.
* Fix typo in comment, and reword it slightly while we're at it.Heikki Linnakangas2012-10-04
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* Add #includes needed on some platforms in the new files.Heikki Linnakangas2012-10-02
| | | | Hopefully this makes the *BSD buildfarm animals happy.