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* pgindent run before PG 9.1 beta 1.Bruce Momjian2011-04-10
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* Avoid potential deadlock in InitCatCachePhase2().Tom Lane2011-03-22
| | | | | | | | | | | | | | | Opening a catcache's index could require reading from that cache's own catalog, which of course would acquire AccessShareLock on the catalog. So the original coding here risks locking index before heap, which could deadlock against another backend trying to get exclusive locks in the normal order. Because InitCatCachePhase2 is only called when a backend has to start up without a relcache init file, the deadlock was seldom seen in the field. (And by the same token, there's no need to worry about any performance disadvantage; so not much point in trying to distinguish exactly which catalogs have the risk.) Bug report, diagnosis, and patch by Nikhil Sontakke. Additional commentary by me. Back-patch to all supported branches.
* Per-column collation supportPeter Eisentraut2011-02-08
| | | | | | | | This adds collation support for columns and domains, a COLLATE clause to override it per expression, and B-tree index support. Peter Eisentraut reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch
* Stamp copyrights for year 2011.Bruce Momjian2011-01-01
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* Support unlogged tables.Robert Haas2010-12-29
| | | | | | | The contents of an unlogged table are WAL-logged; thus, they are not available on standby servers and are truncated whenever the database system enters recovery. Indexes on unlogged tables are also unlogged. Unlogged GiST indexes are not currently supported.
* Generalize concept of temporary relations to "relation persistence".Robert Haas2010-12-13
| | | | | | | | | | | | | | | This commit replaces pg_class.relistemp with pg_class.relpersistence; and also modifies the RangeVar node type to carry relpersistence rather than istemp. It also removes removes rd_istemp from RelationData and instead performs the correct computation based on relpersistence. For clarity, we add three new macros: RelationNeedsWAL(), RelationUsesLocalBuffers(), and RelationUsesTempNamespace(), so that we can clarify the purpose of each check that previous depended on rd_istemp. This is intended as infrastructure for the upcoming unlogged tables patch, as well as for future possible work on global temporary tables.
* Simplify and speed up mapping of index opfamilies to pathkeys.Tom Lane2010-11-29
| | | | | | | | | | | | | | | | | | | | | | Formerly we looked up the operators associated with each index (caching them in relcache) and then the planner looked up the btree opfamily containing such operators in order to build the btree-centric pathkey representation that describes the index's sort order. This is quite pointless for btree indexes: we might as well just use the index's opfamily information directly. That saves syscache lookup cycles during planning, and furthermore allows us to eliminate the relcache's caching of operators altogether, which may help in reducing backend startup time. I added code to plancat.c to perform the same type of double lookup on-the-fly if it's ever faced with a non-btree amcanorder index AM. If such a thing actually becomes interesting for production, we should replace that logic with some more-direct method for identifying the corresponding btree opfamily; but it's not worth spending effort on now. There is considerably more to do pursuant to my recent proposal to get rid of sort-operator-based representations of sort orderings, but this patch grabs some of the low-hanging fruit. I'll look at the remainder of that work after the current commitfest.
* Make TRUNCATE ... RESTART IDENTITY restart sequences transactionally.Tom Lane2010-11-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the previous coding, we simply issued ALTER SEQUENCE RESTART commands, which do not roll back on error. This meant that an error between truncating and committing left the sequences out of sync with the table contents, with potentially bad consequences as were noted in a Warning on the TRUNCATE man page. To fix, create a new storage file (relfilenode) for a sequence that is to be reset due to RESTART IDENTITY. If the transaction aborts, we'll automatically revert to the old storage file. This acts just like a rewriting ALTER TABLE operation. A penalty is that we have to take exclusive lock on the sequence, but since we've already got exclusive lock on its owning table, that seems unlikely to be much of a problem. The interaction of this with usual nontransactional behaviors of sequence operations is a bit weird, but it's hard to see what would be completely consistent. Our choice is to discard cached-but-unissued sequence values both when the RESTART is executed, and at rollback if any; but to not touch the currval() state either time. In passing, move the sequence reset operations to happen before not after any AFTER TRUNCATE triggers are fired. The previous ordering was not logically sensible, but was forced by the need to minimize inconsistency if the triggers caused an error. Transactional rollback is a much better solution to that. Patch by Steve Singer, rather heavily adjusted by me.
* Correct poor grammar in comment.Robert Haas2010-11-14
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* Remove cvs keywords from all files.Magnus Hagander2010-09-20
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* Fix up flushing of composite-type typcache entries to be driven directly byTom Lane2010-09-02
| | | | | | | | | | | | | | | | | | | | | | SI invalidation events, rather than indirectly through the relcache. In the previous coding, we had to flush a composite-type typcache entry whenever we discarded the corresponding relcache entry. This caused problems at least when testing with RELCACHE_FORCE_RELEASE, as shown in recent report from Jeff Davis, and might result in real-world problems given the kind of unexpected relcache flush that that test mechanism is intended to model. The new coding decouples relcache and typcache management, which is a good thing anyway from a structural perspective. The cost is that we have to search the typcache linearly to find entries that need to be flushed. There are a couple of ways we could avoid that, but at the moment it's not clear it's worth any extra trouble, because the typcache contains very few entries in typical operation. Back-patch to 8.2, the same as some other recent fixes in this general area. The patch could be carried back to 8.0 with some additional work, but given that it's only hypothetical whether we're fixing any problem observable in the field, it doesn't seem worth the work now.
* Include the backend ID in the relpath of temporary relations.Robert Haas2010-08-13
| | | | | | | | | | | | | | | | | This allows us to reliably remove all leftover temporary relation files on cluster startup without reference to system catalogs or WAL; therefore, we no longer include temporary relations in XLOG_XACT_COMMIT and XLOG_XACT_ABORT WAL records. Since these changes require including a backend ID in each SharedInvalSmgrMsg, the size of the SharedInvalidationMessage.id field has been reduced from two bytes to one, and the maximum number of connections has been reduced from INT_MAX / 4 to 2^23-1. It would be possible to remove these restrictions by increasing the size of SharedInvalidationMessage by 4 bytes, but right now that doesn't seem like a good trade-off. Review by Jaime Casanova and Tom Lane.
* pgindent run for 9.0, second runBruce Momjian2010-07-06
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* Arrange for client authentication to occur before we select a specificTom Lane2010-04-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | database to connect to. This is necessary for the walsender code to work properly (it was previously using an untenable assumption that template1 would always be available to connect to). This also gets rid of a small security shortcoming that was introduced in the original patch to eliminate the flat authentication files: before, you could find out whether or not the requested database existed even if you couldn't pass the authentication checks. The changes needed to support this are mainly just to treat pg_authid and pg_auth_members as nailed relations, so that we can read them without having to be able to locate real pg_class entries for them. This mechanism was already debugged for pg_database, but we hadn't recognized the value of applying it to those catalogs too. Since the current code doesn't have support for accessing toast tables before we've brought up all of the relcache, remove pg_authid's toast table to ensure that no one can store an out-of-line toasted value of rolpassword. The case seems quite unlikely to occur in practice, and was effectively unsupported anyway in the old "flatfiles" implementation. Update genbki.pl to actually implement the same rules as bootstrap.c does for not-nullability of catalog columns. The previous coding was a bit cheesy but worked all right for the previous set of bootstrap catalogs. It does not work for pg_authid, where rolvaliduntil needs to be nullable. Initdb forced due to minor catalog changes (mainly the toast table removal).
* Fix a problem introduced by my patch of 2010-01-12 that revised the wayTom Lane2010-04-14
| | | | | | | | | | | | | | | | | | | | | relcache reload works. In the patched code, a relcache entry in process of being rebuilt doesn't get unhooked from the relcache hash table; which means that if a cache flush occurs due to sinval queue overrun while we're rebuilding it, the entry could get blown away by RelationCacheInvalidate, resulting in crash or misbehavior. Fix by ensuring that an entry being rebuilt has positive refcount, so it won't be seen as a target for removal if a cache flush occurs. (This will mean that the entry gets rebuilt twice in such a scenario, but that's okay.) It appears that the problem can only arise within a transaction that has previously reassigned the relfilenode of a pre-existing table, via TRUNCATE or a similar operation. Per bug #5412 from Rusty Conover. Back-patch to 8.2, same as the patch that introduced the problem. I think that the failure can't actually occur in 8.2, since it lacks the rd_newRelfilenodeSubid optimization, but let's make it work like the later branches anyway. Patch by Heikki, slightly editorialized on by me.
* pgindent run for 9.0Bruce Momjian2010-02-26
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* Stamp HEAD as 9.0devel, and update various places that were referring to 8.5Tom Lane2010-02-17
| | | | (hope I got 'em all). Per discussion, this release will be 9.0 not 8.5.
* Wrap calls to SearchSysCache and related functions using macros.Robert Haas2010-02-14
| | | | | | | | | | | | The purpose of this change is to eliminate the need for every caller of SearchSysCache, SearchSysCacheCopy, SearchSysCacheExists, GetSysCacheOid, and SearchSysCacheList to know the maximum number of allowable keys for a syscache entry (currently 4). This will make it far easier to increase the maximum number of keys in a future release should we choose to do so, and it makes the code shorter, too. Design and review by Tom Lane.
* Fix up rickety handling of relation-truncation interlocks.Tom Lane2010-02-09
| | | | | | | | | | | | | | | | | | | | Move rd_targblock, rd_fsm_nblocks, and rd_vm_nblocks from relcache to the smgr relation entries, so that they will get reset to InvalidBlockNumber whenever an smgr-level flush happens. Because we now send smgr invalidation messages immediately (not at end of transaction) when a relation truncation occurs, this ensures that other backends will reset their values before they next access the relation. We no longer need the unreliable assumption that a VACUUM that's doing a truncation will hold its AccessExclusive lock until commit --- in fact, we can intentionally release that lock as soon as we've completed the truncation. This patch therefore reverts (most of) Alvaro's patch of 2009-11-10, as well as my marginal hacking on it yesterday. We can also get rid of assorted no-longer-needed relcache flushes, which are far more expensive than an smgr flush because they kill a lot more state. In passing this patch fixes smgr_redo's failure to perform visibility-map truncation, and cleans up some rather dubious assumptions in freespace.c and visibilitymap.c about when rd_fsm_nblocks and rd_vm_nblocks can be out of date.
* Remove CatalogCacheFlushRelation, and the reloidattr infrastructure that wasTom Lane2010-02-08
| | | | | | | | | | | | | | | | | | | needed by nothing else. The restructuring I just finished doing on cache management exposed to me how silly this routine was. Its function was to go into the catcache and blow away all entries related to a given relation when there was a relcache flush on that relation. However, there is no point in removing a catcache entry if the catalog row it represents is still valid --- and if it isn't valid, there must have been a catcache entry flush on it, because that's triggered directly by heap_update or heap_delete on the catalog row. So this routine accomplished nothing except to blow away valid cache entries that we'd very likely be wanting in the near future to help reconstruct the relcache entry. Dumb. On top of which, it required a subtle and easy-to-get-wrong attribute in syscache definitions, ie, the column containing the OID of the related relation if any. Removing that is a very useful maintenance simplification.
* Create a "relation mapping" infrastructure to support changing the relfilenodesTom Lane2010-02-07
| | | | | | | | | | | | | | | | | | | | | | | of shared or nailed system catalogs. This has two key benefits: * The new CLUSTER-based VACUUM FULL can be applied safely to all catalogs. * We no longer have to use an unsafe reindex-in-place approach for reindexing shared catalogs. CLUSTER on nailed catalogs now works too, although I left it disabled on shared catalogs because the resulting pg_index.indisclustered update would only be visible in one database. Since reindexing shared system catalogs is now fully transactional and crash-safe, the former special cases in REINDEX behavior have been removed; shared catalogs are treated the same as non-shared. This commit does not do anything about the recently-discussed problem of deadlocks between VACUUM FULL/CLUSTER on a system catalog and other concurrent queries; will address that in a separate patch. As a stopgap, parallel_schedule has been tweaked to run vacuum.sql by itself, to avoid such failures during the regression tests.
* Restructure CLUSTER/newstyle VACUUM FULL/ALTER TABLE support so that swappingTom Lane2010-02-04
| | | | | | | | | | | | | | | | | | | of old and new toast tables can be done either at the logical level (by swapping the heaps' reltoastrelid links) or at the physical level (by swapping the relfilenodes of the toast tables and their indexes). This is necessary infrastructure for upcoming changes to support CLUSTER/VAC FULL on shared system catalogs, where we cannot change reltoastrelid. The physical swap saves a few catalog updates too. We unfortunately have to keep the logical-level swap logic because in some cases we will be adding or deleting a toast table, so there's no possibility of a physical swap. However, that only happens as a consequence of schema changes in the table, which we do not need to support for system catalogs, so such cases aren't an obstacle for that. In passing, refactor the cluster support functions a little bit to eliminate unnecessarily-duplicated code; and fix the problem that while CLUSTER had been taught to rename the final toast table at need, ALTER TABLE had not.
* Assorted cleanups in preparation for using a map file to support alteringTom Lane2010-02-03
| | | | | | | | | | | | | | | | | | | | | | the relfilenode of currently-not-relocatable system catalogs. 1. Get rid of inval.c's dependency on relfilenode, by not having it emit smgr invalidations as a result of relcache flushes. Instead, smgr sinval messages are sent directly from smgr.c when an actual relation delete or truncate is done. This makes considerably more structural sense and allows elimination of a large number of useless smgr inval messages that were formerly sent even in cases where nothing was changing at the physical-relation level. Note that this reintroduces the concept of nontransactional inval messages, but that's okay --- because the messages are sent by smgr.c, they will be sent in Hot Standby slaves, just from a lower logical level than before. 2. Move setNewRelfilenode out of catalog/index.c, where it never logically belonged, into relcache.c; which is a somewhat debatable choice as well but better than before. (I considered catalog/storage.c, but that seemed too low level.) Rename to RelationSetNewRelfilenode. 3. Cosmetic cleanups of some other relfilenode manipulations.
* When loading critical system indexes into the relcache, ensure we lock theTom Lane2010-01-13
| | | | | | | | | | | | | underlying catalog not only the index itself. Otherwise, if the cache load process touches the catalog (which will happen for many though not all of these indexes), we are locking index before parent table, which can result in a deadlock against processes that are trying to lock them in the normal order. Per today's failure on buildfarm member gothic_moth; it's surprising the problem hadn't been identified before. Back-patch to 8.2. Earlier releases didn't have the issue because they didn't try to lock these indexes during load (instead assuming that they couldn't change schema at all during multiuser operation).
* Fix relcache reload mechanism to be more robust in the face of errorsTom Lane2010-01-12
| | | | | | | | | | | | | | | | | | | | occurring during a reload, such as query-cancel. Instead of zeroing out an existing relcache entry and rebuilding it in place, build a new relcache entry, then swap its contents with the old one, then free the new entry. This avoids problems with code believing that a previously obtained pointer to a cache entry must still reference a valid entry, as seen in recent failures on buildfarm member jaguar. (jaguar is using CLOBBER_CACHE_ALWAYS which raises the probability of failure substantially, but the problem could occur in the field without that.) The previous design was okay when it was made, but subtransactions and the ResourceOwner mechanism make it unsafe now. Also, make more use of the already existing rd_isvalid flag, so that we remember that the entry requires rebuilding even if the first attempt fails. Back-patch as far as 8.2. Prior versions have enough issues around relcache reload anyway (due to inadequate locking) that fixing this one doesn't seem worthwhile.
* Please tablespace directories in their own subdirectory so pg_migratorBruce Momjian2010-01-12
| | | | | | | can upgrade clusters without renaming the tablespace directories. New directory structure format is, e.g.: $PGDATA/pg_tblspc/20981/PG_8.5_201001061/719849/83292814
* Document why we copy reloptions into CacheMemoryContext after-the-fact.Robert Haas2010-01-07
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* Get rid of the need for manual maintenance of the initial contents ofTom Lane2010-01-05
| | | | | | | | | | | | | | | | | | pg_attribute, by having genbki.pl derive the information from the various catalog header files. This greatly simplifies modification of the "bootstrapped" catalogs. This patch finally kills genbki.sh and Gen_fmgrtab.sh; we now rely entirely on Perl scripts for those build steps. To avoid creating a Perl build dependency where there was not one before, the output files generated by these scripts are now treated as distprep targets, ie, they will be built and shipped in tarballs. But you will need a reasonably modern Perl (probably at least 5.6) if you want to build from a CVS pull. The changes to the MSVC build process are untested, and may well break --- we'll soon find out from the buildfarm. John Naylor, based on ideas from Robert Haas and others
* Update copyright for the year 2010.Bruce Momjian2010-01-02
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* Remove a couple of unnecessary calls of CreateCacheMemoryContext. TheseTom Lane2009-12-27
| | | | | | | probably got there via blind copy-and-paste from one of the legitimate callers, so rearrange and comment that code a bit to make it clearer that this isn't a necessary prerequisite to hash_create. Per observation from Robert Haas.
* Add exclusion constraints, which generalize the concept of uniqueness toTom Lane2009-12-07
| | | | | | | | support any indexable commutative operator, not just equality. Two rows violate the exclusion constraint if "row1.col OP row2.col" is TRUE for each of the columns in the constraint. Jeff Davis, reviewed by Robert Haas
* Revert my ill-considered change that made formrdesc not insert the correctTom Lane2009-09-26
| | | | | | | | relation rowtype OID into the relcache entries it builds. This ensures that catcache copies of the relation tupdescs will be fully correct. While the deficiency doesn't seem to have any effect in the current sources, we have been bitten by not-quite-right catcache tupdescs before, so it seems like a good idea to maintain the rule that they should be right.
* Fix RelationCacheInitializePhase2 (Phase3, in HEAD) to cope with theTom Lane2009-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | possibility of shared-inval messages causing a relcache flush while it tries to fill in missing data in preloaded relcache entries. There are actually two distinct failure modes here: 1. The flush could delete the next-to-be-processed cache entry, causing the subsequent hash_seq_search calls to go off into the weeds. This is the problem reported by Michael Brown, and I believe it also accounts for bug #5074. The simplest fix is to restart the hashtable scan after we've read any new data from the catalogs. It appears that pre-8.4 branches have not suffered from this failure, because by chance there were no other catalogs sharing the same hash chains with the catalogs that RelationCacheInitializePhase2 had work to do for. However that's obviously pretty fragile, and it seems possible that derivative versions with additional system catalogs might be vulnerable, so I'm back-patching this part of the fix anyway. 2. The flush could delete the *current* cache entry, in which case the pointer to the newly-loaded data would end up being stored into an already-deleted Relation struct. As long as it was still deleted, the only consequence would be some leaked space in CacheMemoryContext. But it seems possible that the Relation struct could already have been recycled, in which case this represents a hard-to-reproduce clobber of cached data structures, with unforeseeable consequences. The fix here is to pin the entry while we work on it. In passing, also change RelationCacheInitializePhase2 to Assert that formrdesc() set up the relation's cached TupleDesc (rd_att) with the correct type OID and hasoids values. This is more appropriate than silently updating the values, because the original tupdesc might already have been copied into the catcache. However this part of the patch is not in HEAD because it fails due to some questionable recent changes in formrdesc :-(. That will be cleaned up in a subsequent patch.
* Remove some useless assignments of the result of fread(). Quiets warningsTom Lane2009-08-30
| | | | from clang static checker, and makes the code more readable anyway IMO.
* Allow backends to start up without use of the flat-file copy of pg_database.Tom Lane2009-08-12
| | | | | | | | | | | | | | | | | | | | | | To make this work in the base case, pg_database now has a nailed-in-cache relation descriptor that is initialized using hardwired knowledge in relcache.c. This means pg_database is added to the set of relations that need to have a Schema_pg_xxx macro maintained in pg_attribute.h. When this path is taken, we'll have to do a seqscan of pg_database to find the row we need. In the normal case, we are able to do an indexscan to find the database's row by name. This is made possible by storing a global relcache init file that describes only the shared catalogs and their indexes (and therefore is usable by all backends in any database). A new backend loads this cache file, finds its database OID after an indexscan on pg_database, and then loads the local relcache init file for that database. This change should effectively eliminate number of databases as a factor in backend startup time, even with large numbers of databases. However, the real reason for doing it is as a first step towards getting rid of the flat files altogether. There are still several other sub-projects to be tackled before that can happen.
* Support deferrable uniqueness constraints.Tom Lane2009-07-29
| | | | | | | | | | The current implementation fires an AFTER ROW trigger for each tuple that looks like it might be non-unique according to the index contents at the time of insertion. This works well as long as there aren't many conflicts, but won't scale to massive unique-key reassignments. Improving that case is a TODO item. Dean Rasheed
* 8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef listBruce Momjian2009-06-11
| | | | provided by Andrew.
* Modify the relcache to record the temp status of both local and nonlocalTom Lane2009-03-31
| | | | | | | | | | temp relations; this is no more expensive than before, now that we have pg_class.relistemp. Insert tests into bufmgr.c to prevent attempting to fetch pages from nonlocal temp relations. This provides a low-level defense against bugs-of-omission allowing temp pages to be loaded into shared buffers, as in the contrib/pgstattuple problem reported by Stuart Bishop. While at it, tweak a bunch of places to use new relcache tests (instead of expensive probes into pg_namespace) to detect local or nonlocal temp tables.
* Add a "relistemp" boolean column to pg_class, which is true for temporaryTom Lane2009-03-31
| | | | | | | relations (including a temp table's indexes and toast table/index), and false for normal relations. For ease of checking, this commit just adds the column and fills it correctly --- revising the relation access machinery to use it will come separately.
* Revert updatable viewsPeter Eisentraut2009-01-27
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* Allow extracting and parsing of reloptions from a bare pg_class tuple, andAlvaro Herrera2009-01-26
| | | | | | refactor the relcache code that used to do that. This allows other callers (particularly autovacuum) to do the same without necessarily having to open and lock a table.
* Support column-level privileges, as required by SQL standard.Tom Lane2009-01-22
| | | | Stephen Frost, with help from KaiGai Kohei and others
* Automatic view update rulesPeter Eisentraut2009-01-22
| | | | Bernd Helmle
* Update copyright for 2009.Bruce Momjian2009-01-01
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* Fix oversight in ALTER TABLE ENABLE/DISABLE RULE patch: the new enabledTom Lane2008-12-30
| | | | | | | field needs to be included in equalRuleLocks() comparisons, else updates will fail to propagate into relcache entries when they have positive reference count (ie someone is using the relcache entry). Per report from Alex Hunsaker.
* Introduce visibility map. The visibility map is a bitmap with one bit perHeikki Linnakangas2008-12-03
| | | | | | | | | | | | | | | | | | heap page, where a set bit indicates that all tuples on the page are visible to all transactions, and the page therefore doesn't need vacuuming. It is stored in a new relation fork. Lazy vacuum uses the visibility map to skip pages that don't need vacuuming. Vacuum is also responsible for setting the bits in the map. In the future, this can hopefully be used to implement index-only-scans, but we can't currently guarantee that the visibility map is always 100% up-to-date. In addition to the visibility map, there's a new PD_ALL_VISIBLE flag on each heap page, also indicating that all tuples on the page are visible to all transactions. It's important that this flag is kept up-to-date. It is also used to skip visibility tests in sequential scans, which gives a small performance gain on seqscans.
* Rely on relcache invalidation to update the cached size of the FSM.Heikki Linnakangas2008-11-26
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* Make relhasrules and relhastriggers work like relhasindex, namely we letTom Lane2008-11-10
| | | | VACUUM reset them to false rather than trying to clean 'em up during DROP.
* Replace pg_class.reltriggers with relhastriggers, which is just a boolean hintTom Lane2008-11-09
| | | | | | | | | | | | | ("there might be triggers") rather than an exact count. This is necessary catalog infrastructure for the upcoming patch to reduce the strength of locking needed for trigger addition/removal. Split out and committed separately for ease of reviewing/testing. In passing, also get rid of the unused pg_class columns relukeys, relfkeys, and relrefs, which haven't been maintained in many years and now have no chance of ever being maintained (because of wishing to avoid locking). Simon Riggs
* Rewrite the FSM. Instead of relying on a fixed-size shared memory segment, theHeikki Linnakangas2008-09-30
| | | | | | | | | | | | | free space information is stored in a dedicated FSM relation fork, with each relation (except for hash indexes; they don't use FSM). This eliminates the max_fsm_relations and max_fsm_pages GUC options; remove any trace of them from the backend, initdb, and documentation. Rewrite contrib/pg_freespacemap to match the new FSM implementation. Also introduce a new variant of the get_raw_page(regclass, int4, int4) function in contrib/pageinspect that let's you to return pages from any relation fork, and a new fsm_page_contents() function to inspect the new FSM pages.