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path: root/src/backend/storage/buffer/bufmgr.c
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* Repair a low-probability race condition identified by Qingqing Zhou.Tom Lane2006-04-14
| | | | | | | | | | | | If a process abandons a wait in LockBufferForCleanup (in practice, only happens if someone cancels a VACUUM) just before someone else sends it a signal indicating the buffer is available, it was possible for the wakeup to remain in the process' semaphore, causing misbehavior next time the process waited for an lmgr lock. Rather than try to prevent the race condition directly, it seems best to make the lock manager robust against leftover wakeups, by having it repeat waiting on the semaphore if the lock has not actually been granted or denied yet.
* Clean up WAL/buffer interactions as per my recent proposal. Get rid of theTom Lane2006-03-31
| | | | | | | | | | | | | | | | misleadingly-named WriteBuffer routine, and instead require routines that change buffer pages to call MarkBufferDirty (which does exactly what it says). We also require that they do so before calling XLogInsert; this takes care of the synchronization requirement documented in SyncOneBuffer. Note that because bufmgr takes the buffer content lock (in shared mode) while writing out any buffer, it doesn't matter whether MarkBufferDirty is executed before the buffer content change is complete, so long as the content change is completed before releasing exclusive lock on the buffer. So it's OK to set the dirtybit before we fill in the LSN. This eliminates the former kluge of needing to set the dirtybit in LockBuffer. Aside from making the code more transparent, we can also add some new debugging assertions, in particular that the caller of MarkBufferDirty must hold the buffer content lock, not merely a pin.
* Clean up and document the API for XLogOpenRelation and XLogReadBuffer.Tom Lane2006-03-29
| | | | | | | | This commit doesn't make much functional change, but it does eliminate some duplicated code --- for instance, PageIsNew tests are now done inside XLogReadBuffer rather than by each caller. The GIST xlog code still needs a lot of love, but I'll worry about that separately.
* Update copyright for 2006. Update scripts.Bruce Momjian2006-03-05
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* Arrange to call AbsorbFsyncRequests every so often while performing aTom Lane2006-03-03
| | | | | | | checkpoint in the bgwriter. This forestalls overflow of the fsync request queue, which is not fatal but causes considerable performance degradation when it occurs (because backends then have to do their own fsyncs). Per patch from Itagaki Takahiro, modified a little bit by me.
* Fix ReadBuffer() to correctly handle the case where it's trying to extendTom Lane2006-01-06
| | | | | | | | | the relation but it finds a pre-existing valid buffer. The buffer does not correspond to any page known to the kernel, so we *must* do smgrextend to ensure that the space becomes allocated. The 7.x branches all do this correctly, but the corner case got lost somewhere during 8.0 bufmgr rewrites. (My fault no doubt :-( ... I think I assumed that such a buffer must be not-BM_VALID, which is not so.)
* Get rid of the SpinLockAcquire/SpinLockAcquire_NoHoldoff distinctionTom Lane2005-12-29
| | | | | | | | | | in favor of having just one set of macros that don't do HOLD/RESUME_INTERRUPTS (hence, these correspond to the old SpinLockAcquire_NoHoldoff case). Given our coding rules for spinlock use, there is no reason to allow CHECK_FOR_INTERRUPTS to be done while holding a spinlock, and also there is no situation where ImmediateInterruptOK will be true while holding a spinlock. Therefore doing HOLD/RESUME_INTERRUPTS while taking/releasing a spinlock is just a waste of cycles. Qingqing Zhou and Tom Lane.
* Re-run pgindent, fixing a problem where comment lines after a blankBruce Momjian2005-11-22
| | | | | | | | | comment line where output as too long, and update typedefs for /lib directory. Also fix case where identifiers were used as variable names in the backend, but as typedefs in ecpg (favor the backend for indenting). Backpatch to 8.1.X.
* DropRelFileNodeBuffers failed to fix the state of the lookup hash tableTom Lane2005-11-17
| | | | | | | | that was added to localbuf.c in 8.1; therefore, applying it to a temp table left corrupt lookup state in memory. The only case where this had a significant chance of causing problems was an ON COMMIT DELETE ROWS temp table; the other possible paths left bogus state that was unlikely to be used again. Per report from Csaba Nagy.
* Tweak buffer manager so that 'internal' accesses to a buffer do notTom Lane2005-10-27
| | | | | | | | advance its usage_count. This includes writes of dirty buffers triggered by bgwriter, checkpoint, or FlushRelationBuffers, as well as various corner cases that really ought not count as accesses to the page. Should make for some marginal improvement in the quality of our decisions about when to recycle buffers. Per suggestion from ITAGAKI Takahiro.
* Standard pgindent run for 8.1.Bruce Momjian2005-10-15
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* Do all accesses to shared buffer headers through volatile-qualifiedTom Lane2005-10-12
| | | | | | | pointers, to ensure that compilers won't rearrange accesses to occur while we're not holding the buffer header spinlock. It's probably not necessary to mark volatile in every single place in bufmgr.c, but better safe than sorry. Per trouble report from Kevin Grittner.
* Reverse out Assert addition.Bruce Momjian2005-08-12
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* Improve documention on loading large data sets into plperl.Bruce Momjian2005-08-12
| | | | David Fetter
* Remove BufferBlockPointers array in favor of a base + (bufnum) * BLCKSZTom Lane2005-08-12
| | | | | | | | computation. On modern machines this is as fast if not faster, and we don't have to clog the CPU's L2 cache with a tens-of-KB pointer array. If we ever decide to adopt a more dynamic allocation method for shared buffers, we'll probably have to revert this patch, but in the meantime we might as well save a few bytes and nanoseconds. Per Qingqing Zhou.
* Avoid useless loop overhead in AtEOXact routines when the backend isTom Lane2005-08-08
| | | | compiled with USE_ASSERT_CHECKING but is running with assert_enabled false.
* Cause ShutdownPostgres to do a normal transaction abort during backendTom Lane2005-08-08
| | | | | | | | exit, instead of trying to take shortcuts. Introduce some additional shutdown callback routines to eliminate kluges like having ProcKill be responsible for shutting down the buffer manager. Ensure that the order of operations during shutdown is predictable and what you would expect given the module layering.
* Tweak BgBufferSync() so that a persistent write error on a dirty bufferTom Lane2005-08-02
| | | | | | | doesn't block the bgwriter from making progress writing out other buffers. This was a hard problem in the context of the ARC/2Q design, but it's trivial in the context of clock sweep ... just advance the sweep counter before we try to write not after.
* Split the shared-memory array of PGPROC pointers out of the sinvalTom Lane2005-05-19
| | | | | | communication structure, and make it its own module with its own lock. This should reduce contention at least a little, and it definitely makes the code seem cleaner. Per my recent proposal.
* Remove unnecessary calls of FlushRelationBuffers: there is no needTom Lane2005-03-20
| | | | | | | | | | to write out data that we are about to tell the filesystem to drop. smgr_internal_unlink already had a DropRelFileNodeBuffers call to get rid of dead buffers without a write after it's no longer possible to roll back the deleting transaction. Adding a similar call in smgrtruncate simplifies callers and makes the overall division of labor clearer. This patch removes the former behavior that VACUUM would write all dirty buffers of a relation unconditionally.
* Avoid infinite loop in InvalidateBuffer if we ourselves are holdingTom Lane2005-03-18
| | | | a pin on the victim buffer.
* Replace the BufMgrLock with separate locks on the lookup hashtable andTom Lane2005-03-04
| | | | | | | | the freelist, plus per-buffer spinlocks that protect access to individual shared buffer headers. This requires abandoning a global freelist (since the freelist is a global contention point), which shoots down ARC and 2Q as well as plain LRU management. Adopt a clock sweep algorithm instead. Preliminary results show substantial improvement in multi-backend situations.
* Phase 1 of fix for 'SMgrRelation hashtable corrupted' problem. ThisTom Lane2005-01-10
| | | | | | is the minimum required fix. I want to look next at taking advantage of it by simplifying the message semantics in the shared inval message queue, but that part can be held over for 8.1 if it turns out too ugly.
* Repair bufmgr deadlock problem reported by Michael Wildpaner. Must takeTom Lane2005-01-03
| | | | | | | | | | | share lock on a buffer being written out before releasing BufMgrLock in the BufferAlloc code path; if we do it later we might block on someone who's re-pinned the buffer. I believe this is only an issue for BufferAlloc and not the other places that call FlushBuffer. BufferSync must continue to do it the old way since it may well be trying to write buffers that other backends have pinned; but it should not be holding any conflicting locks. FlushRelationBuffers is okay since it's got exclusive lock at the relation level.
* Tag appropriate files for rc3PostgreSQL Daemon2004-12-31
| | | | | | | | Also performed an initial run through of upgrading our Copyright date to extend to 2005 ... first run here was very simple ... change everything where: grep 1996-2004 && the word 'Copyright' ... scanned through the generated list with 'less' first, and after, to make sure that I only picked up the right entries ...
* Assert that BufferIsPinned() in IncrBufferRefCount(), rather than usingNeil Conway2004-11-24
| | | | | a home-brewed combination of assertions that boiled down to the same thing.
* Allow background writing to be shut down by setting limit values to zero.Tom Lane2004-10-17
| | | | | | | This does not disable the bgwriter process: it still has to wake up often enough to collect fsync requests from backends in a timely fashion. But it responds to the recent gripe about not being able to prevent the disk from being spun up constantly.
* Give the ResourceOwner mechanism full responsibility for releasing bufferTom Lane2004-10-16
| | | | | | | | pins at end of transaction, and reduce AtEOXact_Buffers to an Assert cross-check that this was done correctly. When not USE_ASSERT_CHECKING, AtEOXact_Buffers is a complete no-op. This gets rid of an O(NBuffers) bottleneck during transaction commit/abort, which recent testing has shown becomes significant above a few tens of thousands of shared buffers.
* Remove BufferLocks[] array in favor of a single pointer to the bufferTom Lane2004-10-16
| | | | | | (if any) currently waited for by LockBufferForCleanup(), which is all that we were using it for anymore. Saves some space and eliminates proportional-to-NBuffers slowdown in UnlockBuffers().
* Repair possible failure to update hint bits back to disk, perTom Lane2004-10-15
| | | | | | | | | | http://archives.postgresql.org/pgsql-hackers/2004-10/msg00464.php. This fix is intended to be permanent: it moves the responsibility for calling SetBufferCommitInfoNeedsSave() into the tqual.c routines, eliminating the requirement for callers to test whether t_infomask changed. Also, tighten validity checking on buffer IDs in bufmgr.c --- several routines were paranoid about out-of-range shared buffer numbers but not about out-of-range local ones, which seems a tad pointless.
* I can't see any good reason for DropRelFileNodeBuffers to be issuingTom Lane2004-09-06
| | | | FATAL when it detects a nonzero reference count. Reduce to ERROR.
* FlushRelationBuffers was also being a bit cavalier about whether theTom Lane2004-08-31
| | | | relation is already opened by smgr.
* Pgindent run for 8.0.Bruce Momjian2004-08-29
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* Update copyright to 2004.Bruce Momjian2004-08-29
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* Invent ResourceOwner mechanism as per my recent proposal, and use it toTom Lane2004-07-17
| | | | | | | | keep track of portal-related resources separately from transaction-related resources. This allows cursors to work in a somewhat sane fashion with nested transactions. For now, cursor behavior is non-subtransactional, that is a cursor's state does not roll back if you abort a subtransaction that fetched from the cursor. We might want to change that later.
* Nested transactions. There is still much left to do, especially on theTom Lane2004-07-01
| | | | | | | performance front, but with feature freeze upon us I think it's time to drive a stake in the ground and say that this will be in 7.5. Alvaro Herrera, with some help from Tom Lane.
* Tablespaces. Alternate database locations are dead, long live tablespaces.Tom Lane2004-06-18
| | | | | | | | | There are various things left to do: contrib dbsize and oid2name modules need work, and so does the documentation. Also someone should think about COMMENT ON TABLESPACE and maybe RENAME TABLESPACE. Also initlocation is dead, it just doesn't know it yet. Gavin Sherry and Tom Lane.
* Add some code to Assert that when we release pin on a buffer, we areTom Lane2004-06-11
| | | | | | | not holding the buffer's cntx_lock or io_in_progress_lock. A recent report from Litao Wu makes me wonder whether it is ever possible for us to drop a buffer and forget to release its cntx_lock. The Assert does not fire in the regression tests, but that proves little ...
* Additional mop-up for sync-to-fsync changes: avoid issuing fsyncs forTom Lane2004-05-31
| | | | | | temp tables, and avoid WAL-logging truncations of temp tables. Do issue fsync on truncated files (not sure this is necessary but it seems like a good idea).
* Minor code rationalization: FlushRelationBuffers just returns void,Tom Lane2004-05-31
| | | | | | | | rather than an error code, and does elog(ERROR) not elog(WARNING) when it detects a problem. All callers were simply elog(ERROR)'ing on failure return anyway, and I find it hard to envision a caller that would not, so we may as well simplify the callers and produce the more useful error message directly.
* Per previous discussions, get rid of use of sync(2) in favor ofTom Lane2004-05-31
| | | | | | | | | | | | | | | | | explicitly fsync'ing every (non-temp) file we have written since the last checkpoint. In the vast majority of cases, the burden of the fsyncs should fall on the bgwriter process not on backends. (To this end, we assume that an fsync issued by the bgwriter will force out blocks written to the same file by other processes using other file descriptors. Anyone have a problem with that?) This makes the world safe for WIN32, which ain't even got sync(2), and really makes the world safe for Unixen as well, because sync(2) never had the semantics we need: it offers no way to wait for the requested I/O to finish. Along the way, fix a bug I recently introduced in xlog recovery: file truncation replay failed to clear bufmgr buffers for the dropped blocks, which could result in 'PANIC: heap_delete_redo: no block' later on in xlog replay.
* Separate out bgwriter code into a logically separate module, ratherTom Lane2004-05-29
| | | | | | | | | than being random pieces of other files. Give bgwriter responsibility for all checkpoint activity (other than a post-recovery checkpoint); so this child process absorbs the functionality of the former transient checkpoint and shutdown subprocesses. While at it, create an actual include file for postmaster.c, which for some reason never had its own file before.
* Get rid of rd_nblocks field in relcache entries. Turns out this wasTom Lane2004-05-08
| | | | | | | | | costing us lots more to maintain than it was worth. On shared tables it was of exactly zero benefit because we couldn't trust it to be up to date. On temp tables it sometimes saved an lseek, but not often enough to be worth getting excited about. And the real problem was that we forced an lseek on every relcache flush in order to update the field. So all in all it seems best to lose the complexity.
* Tiny assorted fixes: correct a typo in a comment in vacuumlazy.c, removeNeil Conway2004-04-25
| | | | | some unused #include directives from bufmgr.c, and clarify comments in bufmgr.h and buf.h
* Make LocalRefCount and PrivateRefCount arrays of int32, rather than long.Neil Conway2004-04-22
| | | | This saves a small amount of per-backend memory for LP64 machines.
* Another round of code cleanup on bufmgr. Use BM_VALID flag to keep trackTom Lane2004-04-21
| | | | | | | | | of whether we have successfully read data into a buffer; this makes the error behavior a bit more transparent (IMHO anyway), and also makes it work correctly for local buffers which don't use Start/TerminateBufferIO. Collapse three separate functions for writing a shared buffer into one. This overlaps a bit with cleanups that Neil proposed awhile back, but seems not to have committed yet.
* Code review for ARC patch. Eliminate static variables, improve handlingTom Lane2004-04-19
| | | | | | | | of VACUUM cases so that VACUUM requests don't affect the ARC state at all, avoid corner case where BufferSync would uselessly rewrite a buffer that no longer contains the page that was to be flushed. Make some minor other cleanups in and around the bufmgr as well, such as moving PinBuffer and UnpinBuffer into bufmgr.c where they really belong.
* Avoid delaying postmaster shutdown by up to 10 seconds on platformsTom Lane2004-02-12
| | | | where signals do not terminate sleep() delays.
* Fixed bug where FlushRelationBuffers() did call StrategyInvalidateBuffer()Jan Wieck2004-02-12
| | | | | | | | | | | for already empty buffers because their buffer tag was not cleard out when the buffers have been invalidated before. Also removed the misnamed BM_FREE bufhdr flag and replaced the checks, which effectively ask if the buffer is unpinned, with checks against the refcount field. Jan
* Centralize implementation of delay code by creating a pg_usleep()Tom Lane2004-02-10
| | | | | | | | | subroutine in src/port/pgsleep.c. Remove platform dependencies from miscadmin.h and put them in port.h where they belong. Extend recent vacuum cost-based-delay patch to apply to VACUUM FULL, ANALYZE, and non-btree index vacuuming. By the way, where is the documentation for the cost-based-delay patch?
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