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* Make fast promotion the default promotion mode.Simon Riggs2013-04-24
| | | | | Continue to allow a request for synchronous checkpoints as a mechanism in case of problems.
* Remove some unused and seldom used fields from RelationAmInfo.Heikki Linnakangas2013-04-16
| | | | | | | This saves some memory from each index relcache entry. At least on a 64-bit machine, it saves just enough to shrink a typical relcache entry's memory usage from 2k to 1k. That's nice if you have a lot of backends and a lot of indexes.
* Remove duplicate initialization in XLogReadRecord.Robert Haas2013-04-09
| | | | Per a note from Dickson S. Guedes.
* Fix calculation of how many segments to retain for wal_keep_segments.Heikki Linnakangas2013-04-08
| | | | | | | KeepLogSeg function was broken when we switched to use a 64-bit int for the segment number. Per report from Jeff Janes.
* Skip extraneous locking in XLogCheckBuffer().Simon Riggs2013-04-08
| | | | | | | Heikki reported comment was wrong, so fixed code to match the comment: we only need to take additional locking precautions when we have a shared lock on the buffer.
* Avoid tricky race condition recording XLOG_HINTSimon Riggs2013-04-08
| | | | | | | | | | | | | | | | | | We copy the buffer before inserting an XLOG_HINT to avoid WAL CRC errors caused by concurrent hint writes to buffer while share locked. To make this work we refactor RestoreBackupBlock() to allow an XLOG_HINT to avoid the normal path for backup blocks, which assumes the underlying buffer is exclusive locked. Resulting code completely changes layout of XLOG_HINT WAL records, but this isn't even beta code, so this is a low impact change. In passing, avoid taking WALInsertLock for full page writes on checksummed hints, remove related cruft from XLogInsert() and improve xlog_desc record for XLOG_HINT. Andres Freund Bug report by Fujii Masao, testing by Jeff Janes and Jaime Casanova, review by Jeff Davis and Simon Riggs. Applied with changes from review and some comment editing.
* Fix checksums for CLUSTER, VACUUM FULL etc.Simon Riggs2013-04-07
| | | | | | | | | In CLUSTER, VACUUM FULL and ALTER TABLE SET TABLESPACE I erroneously set checksum before log_newpage, which sets the LSN and invalidates the checksum. So set checksum immediately *after* log_newpage. Bug report Fujii Masao, Fix and patch by Jeff Davis
* Make REPLICATION privilege checks test current user not authenticated user.Tom Lane2013-04-01
| | | | | | | | | | | The pg_start_backup() and pg_stop_backup() functions checked the privileges of the initially-authenticated user rather than the current user, which is wrong. For example, a user-defined index function could successfully call these functions when executed by ANALYZE within autovacuum. This could allow an attacker with valid but low-privilege database access to interfere with creation of routine backups. Reported and fixed by Noah Misch. Security: CVE-2013-1901
* Revoke bc5334d8679c428a709d150666b288171795bd76Simon Riggs2013-03-28
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* Fix buffer pin leak in heap update redo routine.Heikki Linnakangas2013-03-27
| | | | | | | | | | | | | | In a heap update, if the old and new tuple were on different pages, and the new page no longer existed (because it was subsequently truncated away by vacuum), heap_xlog_update forgot to release the pin on the old buffer. This bug was introduced by the "Fix multiple problems in WAL replay" patch, commit 3bbf668de9f1bc172371681e80a4e769b6d014c8 (on master branch). With full_page_writes=off, this triggered an "incorrect local pin count" error later in replay, if the old page was vacuumed. This fixes bug #7969, reported by Yunong Xiao. Backpatch to 9.0, like the commit that introduced this bug.
* Allow external recovery_config_directorySimon Riggs2013-03-27
| | | | | If required, recovery.conf can now be located outside of the data directory. Server needs read/write permissions on this directory.
* Fix grammatical errors in some new message strings.Tom Lane2013-03-26
| | | | Daniele Varrazzo
* Allow I/O reliability checks using 16-bit checksumsSimon Riggs2013-03-22
| | | | | | | | | | | | | | | | | | | Checksums are set immediately prior to flush out of shared buffers and checked when pages are read in again. Hint bit setting will require full page write when block is dirtied, which causes various infrastructure changes. Extensive comments, docs and README. WARNING message thrown if checksum fails on non-all zeroes page; ERROR thrown but can be disabled with ignore_checksum_failure = on. Feature enabled by an initdb option, since transition from option off to option on is long and complex and has not yet been implemented. Default is not to use checksums. Checksum used is WAL CRC-32 truncated to 16-bits. Simon Riggs, Jeff Davis, Greg Smith Wide input and assistance from many community members. Thank you.
* Remove PageSetTLI and rename pd_tli to pd_checksumSimon Riggs2013-03-18
| | | | | | | | | | | | | | Remove use of PageSetTLI() from all page manipulation functions and adjust README to indicate change in the way we make changes to pages. Repurpose those bytes into the pd_checksum field and explain how that works in comments about page header. Refactoring ahead of actual feature patch which would make use of the checksum field, arriving later. Jeff Davis, with comments and doc changes by Simon Riggs Direction suggested by Robert Haas; many others providing review comments.
* Move pqsignal() to libpgport.Tom Lane2013-03-17
| | | | | | | | | We had two copies of this function in the backend and libpq, which was already pretty bogus, but it turns out that we need it in some other programs that don't use libpq (such as pg_test_fsync). So put it where it probably should have been all along. The signal-mask-initialization support in src/backend/libpq/pqsignal.c stays where it is, though, since we only need that in the backend.
* Fix tli history file fetching, broken by the archive after crash recevery patch.Heikki Linnakangas2013-03-07
| | | | | | | | | | | | | | If we were about to enter archive recovery after crash recovery, we scanned the archive for the latest tli history file, and set the recovery target timeline to that. However, when we actually tried to read the history file, we would not fetch the file from the archive, because we were not in archive recovery yet. To fix, make readTimeLineHistory and existsTimeLineHistory to always fetch the file from archive if archive recovery is requested, even if we're not in archive recovery yet. Backpatch to 9.2. Mitsumasa KONDO
* Add a materialized view relations.Kevin Grittner2013-03-03
| | | | | | | | | | | | | | | | | | | | | | A materialized view has a rule just like a view and a heap and other physical properties like a table. The rule is only used to populate the table, references in queries refer to the materialized data. This is a minimal implementation, but should still be useful in many cases. Currently data is only populated "on demand" by the CREATE MATERIALIZED VIEW and REFRESH MATERIALIZED VIEW statements. It is expected that future releases will add incremental updates with various timings, and that a more refined concept of defining what is "fresh" data will be developed. At some point it may even be possible to have queries use a materialized in place of references to underlying tables, but that requires the other above-mentioned features to be working first. Much of the documentation work by Robert Haas. Review by Noah Misch, Thom Brown, Robert Haas, Marko Tiikkaja Security review by KaiGai Kohei, with a decision on how best to implement sepgsql still pending.
* Fix SQL function execution to be safe with long-lived FmgrInfos.Tom Lane2013-03-03
| | | | | | | | | | | | fmgr_sql had been designed on the assumption that the FmgrInfo it's called with has only query lifespan. This is demonstrably unsafe in connection with range types, as shown in bug #7881 from Andrew Gierth. Fix things so that we re-generate the function's cache data if the (sub)transaction it was made in is no longer active. Back-patch to 9.2. This might be needed further back, but it's not clear whether the case can realistically arise without range types, so for now I'll desist from back-patching further.
* Fix thinko in previous commit.Heikki Linnakangas2013-02-22
| | | | | | We must still initialize minRecoveryPoint if we start straight with archive recovery, e.g when recovering from a normal base backup taken with pg_start/stop_backup. Otherwise we never consider the system consistent.
* If recovery.conf is created after "pg_ctl stop -m i", do crash recovery.Heikki Linnakangas2013-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If you create a base backup using an atomic filesystem snapshot, and try to perform PITR starting from that base backup, or if you just kill a master server and create recovery.conf to put it into standby mode, we don't know how far we need to recover before reaching consistency. Normally in crash recovery, we replay all the WAL present in pg_xlog, and assume that we're consistent after that. And normally in archive recovery, minRecoveryPoint, backupEndRequired, or backupEndPoint is set in the control file, indicating how far we need to replay to reach consistency. But if the server was previously up and running normally, and you kill -9 it or take an atomic filesystem snapshot, none of those fields are set in the control file. The solution is to perform crash recovery first, replaying all the WAL in pg_xlog. After that's done, we assume that the system is consistent like in normal crash recovery, and switch to archive recovery mode after that. Per report from Kyotaro HORIGUCHI. In his scenario, recovery.conf was created after "pg_ctl stop -m i". I'm not sure we need to support that exact scenario, but we should support backing up using a filesystem snapshot, which looks identical. This issue goes back to at least 9.0, where hot standby was introduced and we started to track when consistency is reached. In 9.1 and 9.2, we would open up for hot standby too early, and queries could briefly see an inconsistent state. But 9.2 made it more visible, as we started to PANIC if we see a reference to a non-existing page during recovery, if we've already reached consistency. This is a fairly big patch, so back-patch to 9.2 only, where the issue is more visible. We can consider back-patching further after this has received some more testing in 9.2 and master.
* Move relpath() to libpgcommonAlvaro Herrera2013-02-21
| | | | | | | This enables non-backend code, such as pg_xlogdump, to use it easily. The previous location, in src/backend/catalog/catalog.c, made that essentially impossible because that file depends on many backend-only facilities; so this needs to live separately.
* Better fix for "unarchived WAL files get deleted on crash recovery" bug.Heikki Linnakangas2013-02-15
| | | | | | | | | | Revert my earlier fix for the bug that unarchived WAL files get deleted on crash recovery, commit c9cc7e05c6d82a9781883a016c70d95aa4923122. We create a .done file for files streamed or restored from archive, so the WAL file recycling logic used during normal operation works just as well during archive recovery. Per Fujii Masao's suggestion.
* Force archive_status of .done for xlogs created by dearchival/replication.Simon Riggs2013-02-15
| | | | | | | | | This is a forward-patch of commit 6f4b8a4f4f7a2d683ff79ab59d3693714b965e3d, applied to 9.2 back in August. The plan was to do something else in master, but it looks like it's not going to happen, so let's just apply the 9.2 solution to master as well. Fujii Masao
* Don't delete unarchived WAL files during crash recovery.Heikki Linnakangas2013-02-15
| | | | | Bug reported by Jehan-Guillaume (ioguix) de Rorthais. This was introduced with the change to keep WAL files restored from archive in pg_xlog, in 9.2.
* Invent pre-commit/pre-prepare/pre-subcommit events for xact callbacks.Tom Lane2013-02-14
| | | | | | | | | | | | | | Currently it's only possible for loadable modules to get control during post-commit cleanup of a transaction. That doesn't work too well if they want to do something that could throw an error; for example, an FDW might need to issue a remote commit, which could well fail. To improve matters, extend the existing APIs for XactCallback and SubXactCallback functions to provide new pre-commit events for this purpose. The release notes will need to mention that existing callback functions should be checked to make sure they don't do something unwanted when one of the new event types occurs. In the examples within our source tree, contrib/sepgsql was fine but plpgsql had been a bit too cute.
* Support unlogged GiST index.Heikki Linnakangas2013-02-11
| | | | | | | | | | | | | | | The reason this wasn't supported before was that GiST indexes need an increasing sequence to detect concurrent page-splits. In a regular WAL- logged GiST index, the LSN of the page-split record is used for that purpose, and in a temporary index, we can get away with a backend-local counter. Neither of those methods works for an unlogged relation. To provide such an increasing sequence of numbers, create a "fake LSN" counter that is saved and restored across shutdowns. On recovery, unlogged relations are blown away, so the counter doesn't need to survive that either. Jeevan Chalke, based on discussions with Robert Haas, Tom Lane and me.
* Fix checkpoint after fast promotion.Heikki Linnakangas2013-02-11
| | | | | | | | | | The intention was to request a regular online checkpoint immediately after end of recovery, when performing "fast promotion". However, because the checkpoint was requested before other backends were allowed to write WAL, the checkpointer process performed a restartpoint rather than a checkpoint. Delay the RequestCheckPoint call until after recovery has truly ended, so that you get a real checkpoint.
* Include previous TLI in end-of-recovery and shutdown checkpoint records.Heikki Linnakangas2013-02-11
| | | | | | This isn't used for anything but a sanity check at the moment, but it could be highly valuable for debugging purposes. It could also be used to recreate timeline history by traversing WAL, which seems useful.
* Further cleanup of gistsplit.c.Tom Lane2013-02-10
| | | | | | | | | | | | | | | | | | | | After further reflection I was unconvinced that the existing coding is guaranteed to return valid union datums in every code path for multi-column indexes. Fix that by forcing a gistunionsubkey() call at the end of the recursion. Having done that, we can remove some clearly-redundant calls elsewhere. This should be a little faster for multi-column indexes (since the previous coding would uselessly do such a call for each column while unwinding the recursion), as well as much harder to break. Also, simplify the handling of cases where one side or the other of a primary split contains only don't-care tuples. The previous coding used a very ugly hack in removeDontCares() that essentially forced one random tuple to be treated as non-don't-care, providing a random initial choice of seed datum for the secondary split. It seems unlikely that that method will give better-than-random splits. Instead, treat such a split as degenerate and just let the next column determine the split, the same way that we handle fully degenerate cases where the two sides produce identical union datums.
* Remove useless picksplit-doesn't-support-secondary-split log spam.Tom Lane2013-02-10
| | | | | | | | | | | | | | This LOG message was put in over five years ago with the evident expectation that we'd make all GiST opclasses support secondary split directly. However, no such thing ever happened, and indeed the number of opclasses supporting it decreased to zero in 9.2. The reason is that improving on the default implementation isn't that easy --- the opclass-specific code that did exist, before 9.2, doesn't appear to have been any improvement over the default. Hence, remove the message altogether. There's certainly no point in nagging users about this in released branches, but I doubt that we'll ever implement complete opclass-specific support anyway.
* Remove vestigial secondary-split support in gist_box_picksplit().Tom Lane2013-02-10
| | | | | | | | | | | | | | | | | | | | | | | Not only is this implementation of secondary-split not better than the default implementation in gistsplit.c, it's actually worse. The gistsplit.c code at least looks to see if switching the left and right sides would make a better merge with the previously-split tuples, while this doesn't. In any case it's rather useless to support secondary split only in an edge case. There used to be more complete support for it here (in chooseLR()), but that was removed in commit 7f3bd86843e5aad84585a57d3f6b80db3c609916. It appears to me though that the chooseLR() code was really isomorphic to the default implementation, since it was still based on choosing the cheaper way of adding two sub-split vectors that had been chosen without regard to the primary split initially. I think an implementation of secondary split that could beat the default implementation would have to be pretty fully integrated into the split algorithm, not plastered on at the end. Back-patch to 9.2, but not further; previous branches have the chooseLR() code which I don't feel a great need to mess with. This is mainly so we just have two behaviors and not three among the various branches (IOW, this patch is cleanup for commit 7f3bd86843e5aad84585a57d3f6b80db3c609916's incomplete removal of secondary-split support).
* Document and clean up gistsplit.c.Tom Lane2013-02-10
| | | | | | | | | | Improve comments, rename some variables and functions, slightly simplify a couple of APIs, in an attempt to make this code readable by people other than its original author. Even though this is essentially just cosmetic, back-patch to all active branches, because otherwise it's going to make back-patching future fixes in this file very painful.
* Reduce log level of picksplit-doesn't-support-secondary-split whining.Tom Lane2013-02-09
| | | | | | This was agreed to back in 2007, but never actually done. Josh Hansen
* Fix gist_box_same and gist_point_consistent to handle fuzziness correctly.Tom Lane2013-02-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | While there's considerable doubt that we want fuzzy behavior in the geometric operators at all (let alone as currently implemented), nobody is stepping forward to redesign that stuff. In the meantime it behooves us to make sure that index searches agree with the behavior of the underlying operators. This patch fixes two problems in this area. First, gist_box_same was using fuzzy equality, but it really needs to use exact equality to prevent not-quite-identical upper index keys from being treated as identical, which for example would prevent an existing upper key from being extended by an amount less than epsilon. This would result in inconsistent indexes. (The next release notes will need to recommend that users reindex GiST indexes on boxes, polygons, circles, and points, since all four opclasses use gist_box_same.) Second, gist_point_consistent used exact comparisons for upper-page comparisons in ~= searches, when it needs to use fuzzy comparisons to ensure it finds all matches; and it used fuzzy comparisons for point <@ box searches, when it needs to use exact comparisons because that's what the <@ operator (rather inconsistently) does. The added regression test cases illustrate all three misbehaviors. Back-patch to all active branches. (8.4 did not have GiST point_ops, but it still seems prudent to apply the gist_box_same patch to it.) Alexander Korotkov, reviewed by Noah Misch
* Fix Xmax freeze conditionsAlvaro Herrera2013-02-08
| | | | | | | I broke this in 0ac5ad5134; previously, freezing a tuple marked with an IS_MULTI xmax was not necessary. Per brokenness report from Jeff Janes.
* Repair bugs in GiST page splitting code for multi-column indexes.Tom Lane2013-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When considering a non-last column in a multi-column GiST index, gistsplit.c tries to improve on the split chosen by the opclass-specific pickSplit function by considering penalties for the next column. However, there were two bugs in this code: it failed to recompute the union keys for the leftmost index columns, even though these might well change after reassigning tuples; and it included the old union keys in the recomputation for the columns it did recompute, so that those keys couldn't get smaller even if they should. The first problem could result in an invalid index in which searches wouldn't find index entries that are in fact present; the second would make the index less efficient to search. Both of these errors were caused by misuse of gistMakeUnionItVec, whose API was designed in a way that just begged such errors to be made. There is no situation in which it's safe or useful to compute the union keys for a subset of the index columns, and there is no caller that wants any previous union keys to be included in the computation; so the undocumented choice to treat the union keys as in/out rather than pure output parameters is a waste of code as well as being dangerous. Hence, rather than just making a minimal patch, I've changed the API of gistMakeUnionItVec to remove the "startkey" parameter (it now always processes all index columns) and treat the attr/isnull arrays as purely output parameters. In passing, also get rid of a couple of unnecessary and dangerous uses of static variables in gistutil.c. It's remarkable that the one in gistMakeUnionKey hasn't given us portability troubles before now, because in addition to posing a re-entrancy hazard, it was unsafely assuming that a static char[] array would have at least Datum alignment. Per investigation of a trouble report from Tomas Vondra. (There are also some bugs in contrib/btree_gist to be fixed, but that seems like material for a separate patch.) Back-patch to all supported branches.
* Rely only on checkpoint 1 at end of recovery.Simon Riggs2013-02-07
| | | | | | | Searching for checkpoint 2 (previous) is not correct in all cases. Bug report from Heikki Linnakangas
* Split out list of XLog resource managersAlvaro Herrera2013-02-06
| | | | | | | | | | The new rmgrlist.h header, containing all necessary data about built-in resource managers, allows other pieces of code to access them. In particular, this allows a future pg_xlogdump program to extract rm_desc function pointers, without having to keep a duplicate list of them.
* Fill tuple before HeapSatisfiesHOTAndKeyUpdateAlvaro Herrera2013-02-01
| | | | | | | | | | | | Failing to do this results in almost all updates to system catalogs being non-HOT updates, because the OID column would differ (not having been set for the new tuple), which is an indexed column. While at it, make sure to set the tableoid early in both old and new tuples as well. This isn't of much consequence, since that column is seldom (never?) indexed. Report and patch from Andres Freund.
* Restrict infomask bits to set on multixactsAlvaro Herrera2013-01-31
| | | | | | | | | | | | | | | We must only set the bit(s) for the strongest lock held in the tuple; otherwise, a multixact containing members with exclusive lock and key-share lock will behave as though only a share lock is held. This bug was introduced in commit 0ac5ad5134, somewhere along development, when we allowed a singleton FOR SHARE lock to be implemented without a MultiXact by using a multi-bit pattern. I overlooked that GetMultiXactIdHintBits() needed to be tweaked as well. Previously, we could have the bits for FOR KEY SHARE and FOR UPDATE simultaneously set and it wouldn't cause a problem. Per report from digoal@126.com
* Switch timelines if we crash soon after promotion.Simon Riggs2013-01-31
| | | | | | | | | Previous patch to skip checkpoints at end of recovery didn't correctly perform crash recovery, fumbling the timeline switch. Now we record the minRecoveryPointTLI of the newly selected timeline, so that we crash recover to the correct timeline. Bug report from Fujii Masao, investigated by me.
* Provide database object names as separate fields in error messages.Tom Lane2013-01-29
| | | | | | | | | | | | | | | | | | This patch addresses the problem that applications currently have to extract object names from possibly-localized textual error messages, if they want to know for example which index caused a UNIQUE_VIOLATION failure. It adds new error message fields to the wire protocol, which can carry the name of a table, table column, data type, or constraint associated with the error. (Since the protocol spec has always instructed clients to ignore unrecognized field types, this should not create any compatibility problem.) Support for providing these new fields has been added to just a limited set of error reports (mainly, those in the "integrity constraint violation" SQLSTATE class), but we will doubtless add them to more calls in future. Pavel Stehule, reviewed and extensively revised by Peter Geoghegan, with additional hacking by Tom Lane.
* Fast promote mode skips checkpoint at end of recovery.Simon Riggs2013-01-29
| | | | | | | | | | | pg_ctl promote -m fast will skip the checkpoint at end of recovery so that we can achieve very fast failover when the apply delay is low. Write new WAL record XLOG_END_OF_RECOVERY to allow us to switch timeline correctly for downstream log readers. If we skip synchronous end of recovery checkpoint we request a normal spread checkpoint so that the window of re-recovery is low. Simon Riggs and Kyotaro Horiguchi, with input from Fujii Masao. Review by Heikki Linnakangas
* Add some randomness to the choice of which GiST page to insert to.Heikki Linnakangas2013-01-25
| | | | | | | | | | | | | | | | | When descending the tree for an insert, and there are multiple equally good pages we could insert to, make the choice in random. Previously, we would always choose the tuple with lowest offset number. That meant that when two non-leaf pages overlap - in the extreme case they might have exactly the same key - all but the first such page went unused. That wasn't optimal for space usage; if you deleted some tuples from the non-first pages, the space would never be reused. With this patch, the other pages are sometimes chosen too, although there's still a heavy bias towards low-offset tuples, so that we don't lose cache locality when doing a lot of inserts with similar keys. Original idea by Alexander Korotkov, although this patch version was written by me and copy-edited by Tom Lane.
* Fix rare missing cancellations in Hot Standby.Simon Riggs2013-01-24
| | | | | | | | | | | | The machinery around XLOG_HEAP2_CLEANUP_INFO failed to correctly pass through the necessary information on latestRemovedXid, avoiding cancellations in some infrequent concurrent update/cleanup scenarios. Backpatchable fix to 9.0 Detailed bug report and fix by Noah Misch, backpatchable version by me.
* 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.
* When xlogreader asks the callback function to read a page, make sure weHeikki Linnakangas2013-01-17
| | | | | | | | | get a large enough part of the page to include the beginning of the next record we're interested in. The XLogPageRead callback uses the requested length to decide which timeline to stream WAL from, and if the first call is short, and the page contains a timeline switch, we'll repeatedly try to stream that page from the old timeline, and never get across the timeline switch.