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* 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.
* 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.
* 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.
* 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
* 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
* Remove spurious spaceAlvaro Herrera2013-01-14
| | | | Andres Freund
* Update copyrights for 2013Bruce Momjian2013-01-01
| | | | | Fully update git head, and update back branches in ./COPYRIGHT and legal.sgml files.
* Make xlog_internal.h includable in frontend context.Heikki Linnakangas2012-12-13
| | | | | | | This makes unnecessary the ugly hack used to #include postgres.h in pg_basebackup. Based on Alvaro Herrera's patch
* 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.