20 Commits (7ed908be41fbca1635d34f97138abb13beab8b24)

Author	SHA1	Message	Date
Robert Haas	2e44770fa3	pgrowlocks: Use GetActiveSnapshot() rather than SnapshotNow. ... Per discussion, it's desirable to eliminate all remaining uses of SnapshotNow, because it has unpleasant semantics: race conditions can result in seeing multiple versions of a concurrently updated row, or none at all. By using GetActiveSnapshot() here, callers will see exactly those rows that would have been visible if the invoking query had scanned the table using, for example, a SELECT statement. This is slightly different from the old behavior, because commits that happen concurrently with the scan will not affect the results. In REPEATABLE READ or SERIALIZABLE modes, where transaction snapshots are used, commits that have happened since the start of the transaction will also not affect the results. It is hoped that this minor incompatibility will be thought an improvement, or at least no worse than what we did before.	12 years ago
Robert Haas	0518eceec3	Adjust HeapTupleSatisfies* routines to take a HeapTuple. ... Previously, these functions took a HeapTupleHeader, but upcoming patches for logical replication will introduce new a new snapshot type under which the tuple's TID will be used to lookup (CMIN, CMAX) for visibility determination purposes. This makes that information available. Code churn is minimal since HeapTupleSatisfiesVisibility took the HeapTuple anyway, and deferenced it before calling the satisfies function. Independently of logical replication, this allows t_tableOid and t_self to be cross-checked via assertions in tqual.c. This seems like a useful way to make sure that all callers are setting these values properly, which has been previously put forward as desirable. Andres Freund, reviewed by Álvaro Herrera	12 years ago
Bruce Momjian	9af4159fce	pgindent run for release 9.3 ... This is the first run of the Perl-based pgindent script. Also update pgindent instructions.	12 years ago
Alvaro Herrera	77a3082fc5	pgrowlocks: fix bogus lock strength output ... Per report from digoal@126.com	13 years ago
Alvaro Herrera	0ac5ad5134	Improve concurrency of foreign key locking ... 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	13 years ago
Bruce Momjian	6416a82a62	Remove unnecessary #include references, per pgrminclude script.	14 years ago
Alvaro Herrera	b93f5a5673	Move Trigger and TriggerDesc structs out of rel.h into a new reltrigger.h ... This lets us stop including rel.h into execnodes.h, which is a widely used header.	14 years ago
Magnus Hagander	9f2e211386	Remove cvs keywords from all files.	15 years ago
Bruce Momjian	d747140279	8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list ... provided by Andrew.	17 years ago
Alvaro Herrera	a3540b0f65	Improve our #include situation by moving pointer types away from the ... corresponding struct definitions. This allows other headers to avoid including certain highly-loaded headers such as rel.h and relscan.h, instead using just relcache.h, heapam.h or genam.h, which are more lightweight and thus cause less unnecessary dependencies.	17 years ago
Alvaro Herrera	f8c4d7db60	Restructure some header files a bit, in particular heapam.h, by removing some ... unnecessary #include lines in it. Also, move some tuple routine prototypes and macros to htup.h, which allows removal of heapam.h inclusion from some .c files. For this to work, a new header file access/sysattr.h needed to be created, initially containing attribute numbers of system columns, for pg_dump usage. While at it, make contrib ltree, intarray and hstore header files more consistent with our header style.	18 years ago
Alvaro Herrera	73b0300b2a	Move the HTSU_Result enum definition into snapshot.h, to avoid including ... tqual.h into heapam.h. This makes all inclusion of tqual.h explicit. I also sorted alphabetically the includes on some source files.	18 years ago
Tom Lane	895a94de6d	Avoid incrementing the CommandCounter when CommandCounterIncrement is called ... but no database changes have been made since the last CommandCounterIncrement. This should result in a significant improvement in the number of "commands" that can typically be performed within a transaction before hitting the 2^32 CommandId size limit. In particular this buys back (and more) the possible adverse consequences of my previous patch to fix plan caching behavior. The implementation requires tracking whether the current CommandCounter value has been "used" to mark any tuples. CommandCounter values stored into snapshots are presumed not to be used for this purpose. This requires some small executor changes, since the executor used to conflate the curcid of the snapshot it was using with the command ID to mark output tuples with. Separating these concepts allows some small simplifications in executor APIs. Something for the TODO list: look into having CommandCounterIncrement not do AcceptInvalidationMessages. It seems fairly bogus to be doing it there, but exactly where to do it instead isn't clear, and I'm disinclined to mess with asynchronous behavior during late beta.	18 years ago
Tom Lane	89fefd9416	Reduce the permissions check needed to use pgrowlocks() to having ... SELECT on the target table. Per discussion.	18 years ago
Tom Lane	56f3fb3ba1	Restrict pgrowlocks function to superusers. (This might be too strict, ... but no permissions check at all is certainly no good.) Clean up usage of some deprecated APIs.	18 years ago
Bruce Momjian	f99a569a2e	pgindent run for 8.2.	19 years ago
Bruce Momjian	66c15dfda1	Adjust /contrib for new include file contents.	19 years ago
Tom Lane	a0ffab351e	Magic blocks don't do us any good unless we use 'em ... so install one ... in every shared library.	20 years ago
Tatsuo Ishii	a34fd95977	Fix bug reported by Michael Fuhr on Sun, 23 Apr 2006 09:52:31 -0600 ... (pgsql-committers@postgresql.org).	20 years ago
Tatsuo Ishii	66126f9687	Add new contrib function pgrowlocks. See README.pgrowlocks for more details.	20 years ago