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2023-04-19Fix various typos and incorrect/outdated name referencesDavid Rowley
Author: Alexander Lakhin Discussion: https://postgr.es/m/[email protected]
2023-04-18Fix various typosDavid Rowley
This fixes many spelling mistakes in comments, but a few references to invalid parameter names, function names and option names too in comments and also some in string constants Also, fix an #undef that was undefining the incorrect definition Author: Alexander Lakhin Reviewed-by: Justin Pryzby Discussion: https://postgr.es/m/[email protected]
2023-04-14Support RBM_ZERO_AND_CLEANUP_LOCK in ExtendBufferedRelTo(), add testsAndres Freund
For some reason I had not implemented RBM_ZERO_AND_CLEANUP_LOCK support in ExtendBufferedRelTo(), likely thinking it not being reachable. But it is reachable, e.g. when replaying a WAL record for a page in a relation that subsequently is truncated (likely only reachable when doing crash recovery or PITR, not during ongoing streaming replication). As now all of the RBM_* modes are supported, remove assertions checking mode. As we had no test coverage for this scenario, add a new TAP test. There's plenty more that ought to be tested in this area... Reported-by: Tom Lane <[email protected]> Reported-by: Alexander Lakhin <[email protected]> Reviewed-by: Alexander Lakhin <[email protected]> Discussion: https://postgr.es/m/392271.1681238924%40sss.pgh.pa.us Discussion: https://postgr.es/m/[email protected]
2023-04-13Harmonize some more function parameter names.Peter Geoghegan
Make sure that function declarations use names that exactly match the corresponding names from function definitions in a few places. These inconsistencies were all introduced relatively recently, after the code base had parameter name mismatches fixed in bulk (see commits starting with commits 4274dc22 and 035ce1fe). pg_bsd_indent still has a couple of similar inconsistencies, which I (pgeoghegan) have left untouched for now. Like all earlier commits that cleaned up function parameter names, this commit was written with help from clang-tidy.
2023-04-08Handle logical slot conflicts on standbyAndres Freund
During WAL replay on the standby, when a conflict with a logical slot is identified, invalidate such slots. There are two sources of conflicts: 1) Using the information added in 6af1793954e, logical slots are invalidated if required rows are removed 2) wal_level on the primary server is reduced to below logical Uses the infrastructure introduced in the prior commit. FIXME: add commit reference. Change InvalidatePossiblyObsoleteSlot() to use a recovery conflict to interrupt use of a slot, if called in the startup process. The new recovery conflict is added to pg_stat_database_conflicts, as confl_active_logicalslot. See 6af1793954e for an overall design of logical decoding on a standby. Bumps catversion for the addition of the pg_stat_database_conflicts column. Bumps PGSTAT_FILE_FORMAT_ID for the same reason. Author: "Drouvot, Bertrand" <[email protected]> Author: Andres Freund <[email protected]> Author: Amit Khandekar <[email protected]> (in an older version) Reviewed-by: "Drouvot, Bertrand" <[email protected]> Reviewed-by: Andres Freund <[email protected]> Reviewed-by: Robert Haas <[email protected]> Reviewed-by: Fabrízio de Royes Mello <[email protected]> Reviewed-by: Bharath Rupireddy <[email protected]> Reviewed-by: Amit Kapila <[email protected]> Reviewed-by: Alvaro Herrera <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-04-08Add io_direct setting (developer-only).Thomas Munro
Provide a way to ask the kernel to use O_DIRECT (or local equivalent) where available for data and WAL files, to avoid or minimize kernel caching. This hurts performance currently and is not intended for end users yet. Later proposed work would introduce our own I/O clustering, read-ahead, etc to replace the facilities the kernel disables with this option. The only user-visible change, if the developer-only GUC is not used, is that this commit also removes the obscure logic that would activate O_DIRECT for the WAL when wal_sync_method=open_[data]sync and wal_level=minimal (which also requires max_wal_senders=0). Those are non-default and unlikely settings, and this behavior wasn't (correctly) documented. The same effect can be achieved with io_direct=wal. Author: Thomas Munro <[email protected]> Author: Andres Freund <[email protected]> Author: Bharath Rupireddy <[email protected]> Reviewed-by: Justin Pryzby <[email protected]> Reviewed-by: Bharath Rupireddy <[email protected]> Discussion: https://postgr.es/m/CA%2BhUKGK1X532hYqJ_MzFWt0n1zt8trz980D79WbjwnT-yYLZpg%40mail.gmail.com
2023-04-08Introduce PG_IO_ALIGN_SIZE and align all I/O buffers.Thomas Munro
In order to have the option to use O_DIRECT/FILE_FLAG_NO_BUFFERING in a later commit, we need the addresses of user space buffers to be well aligned. The exact requirements vary by OS and file system (typically sectors and/or memory pages). The address alignment size is set to 4096, which is enough for currently known systems: it matches modern sectors and common memory page size. There is no standard governing O_DIRECT's requirements so we might eventually have to reconsider this with more information from the field or future systems. Aligning I/O buffers on memory pages is also known to improve regular buffered I/O performance. Three classes of I/O buffers for regular data pages are adjusted: (1) Heap buffers are now allocated with the new palloc_aligned() or MemoryContextAllocAligned() functions introduced by commit 439f6175. (2) Stack buffers now use a new struct PGIOAlignedBlock to respect PG_IO_ALIGN_SIZE, if possible with this compiler. (3) The buffer pool is also aligned in shared memory. WAL buffers were already aligned on XLOG_BLCKSZ. It's possible for XLOG_BLCKSZ to be configured smaller than PG_IO_ALIGNED_SIZE and thus for O_DIRECT WAL writes to fail to be well aligned, but that's a pre-existing condition and will be addressed by a later commit. BufFiles are not yet addressed (there's no current plan to use O_DIRECT for those, but they could potentially get some incidental speedup even in plain buffered I/O operations through better alignment). If we can't align stack objects suitably using the compiler extensions we know about, we disable the use of O_DIRECT by setting PG_O_DIRECT to 0. This avoids the need to consider systems that have O_DIRECT but can't align stack objects the way we want; such systems could in theory be supported with more work but we don't currently know of any such machines, so it's easier to pretend there is no O_DIRECT support instead. That's an existing and tested class of system. Add assertions that all buffers passed into smgrread(), smgrwrite() and smgrextend() are correctly aligned, unless PG_O_DIRECT is 0 (= stack alignment tricks may be unavailable) or the block size has been set too small to allow arrays of buffers to be all aligned. Author: Thomas Munro <[email protected]> Author: Andres Freund <[email protected]> Reviewed-by: Justin Pryzby <[email protected]> Discussion: https://postgr.es/m/CA+hUKGK1X532hYqJ_MzFWt0n1zt8trz980D79WbjwnT-yYLZpg@mail.gmail.com
2023-04-08Track IO times in pg_stat_ioAndres Freund
a9c70b46dbe and 8aaa04b32S added counting of IO operations to a new view, pg_stat_io. Now, add IO timing for reads, writes, extends, and fsyncs to pg_stat_io as well. This combines the tracking for pgBufferUsage with the tracking for pg_stat_io into a new function pgstat_count_io_op_time(). This should make it a bit easier to avoid the somewhat costly instr_time conversion done for pgBufferUsage. Author: Melanie Plageman <[email protected]> Reviewed-by: Andres Freund <[email protected]> Reviewed-by: Bertrand Drouvot <[email protected]> Discussion: https://postgr.es/m/flat/CAAKRu_ay5iKmnbXZ3DsauViF3eMxu4m1oNnJXqV_HyqYeg55Ww%40mail.gmail.com
2023-04-07Improve IO accounting for temp relation writesAndres Freund
Both pgstat_database and pgBufferUsage count IO timing for reads of temporary relation blocks into local buffers. However, both failed to count write IO timing for flushes of dirty local buffers. Fix. Additionally, FlushRelationBuffers() seems to have omitted counting write IO (both count and timing) stats for both pgstat_database and pgBufferUsage. Fix. Author: Melanie Plageman <[email protected]> Reviewed-by: Andres Freund <[email protected]> Discussion: https://postgr.es/m/20230321023451.7rzy4kjj2iktrg2r%40awork3.anarazel.de
2023-04-07Fix copy-paste bug in 12f3867f553 triggering an assert after a write errorAndres Freund
The same condition accidentally was copied to both branches. Manual testing confirms that otherwise the error recovery path works fine. Found while reviewing the logical-decoding-on-standby patch.
2023-04-06Add VACUUM/ANALYZE BUFFER_USAGE_LIMIT optionDavid Rowley
Add new options to the VACUUM and ANALYZE commands called BUFFER_USAGE_LIMIT to allow users more control over how large to make the buffer access strategy that is used to limit the usage of buffers in shared buffers. Larger rings can allow VACUUM to run more quickly but have the drawback of VACUUM possibly evicting more buffers from shared buffers that might be useful for other queries running on the database. Here we also add a new GUC named vacuum_buffer_usage_limit which controls how large to make the access strategy when it's not specified in the VACUUM/ANALYZE command. This defaults to 256KB, which is the same size as the access strategy was prior to this change. This setting also controls how large to make the buffer access strategy for autovacuum. Per idea by Andres Freund. Author: Melanie Plageman Reviewed-by: David Rowley Reviewed-by: Andres Freund Reviewed-by: Justin Pryzby Reviewed-by: Bharath Rupireddy Discussion: https://postgr.es/m/[email protected]
2023-04-06Use ExtendBufferedRelTo() in {vm,fsm}_extend()Andres Freund
This uses ExtendBufferedRelTo(), introduced in 31966b151e6, to extend the visibilitymap and freespacemap to the size needed. It also happens to fix a warning introduced in 3d6a98457d8, reported by Tom Lane. Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2023-04-05bufmgr: Introduce infrastructure for faster relation extensionAndres Freund
The primary bottlenecks for relation extension are: 1) The extension lock is held while acquiring a victim buffer for the new page. Acquiring a victim buffer can require writing out the old page contents including possibly needing to flush WAL. 2) When extending via ReadBuffer() et al, we write a zero page during the extension, and then later write out the actual page contents. This can nearly double the write rate. 3) The existing bulk relation extension infrastructure in hio.c just amortized the cost of acquiring the relation extension lock, but none of the other costs. Unfortunately 1) cannot currently be addressed in a central manner as the callers to ReadBuffer() need to acquire the extension lock. To address that, this this commit moves the responsibility for acquiring the extension lock into bufmgr.c functions. That allows to acquire the relation extension lock for just the required time. This will also allow us to improve relation extension further, without changing callers. The reason we write all-zeroes pages during relation extension is that we hope to get ENOSPC errors earlier that way (largely works, except for CoW filesystems). It is easier to handle out-of-space errors gracefully if the page doesn't yet contain actual tuples. This commit addresses 2), by using the recently introduced smgrzeroextend(), which extends the relation, without dirtying the kernel page cache for all the extended pages. To address 3), this commit introduces a function to extend a relation by multiple blocks at a time. There are three new exposed functions: ExtendBufferedRel() for extending the relation by a single block, ExtendBufferedRelBy() to extend a relation by multiple blocks at once, and ExtendBufferedRelTo() for extending a relation up to a certain size. To avoid duplicating code between ReadBuffer(P_NEW) and the new functions, ReadBuffer(P_NEW) now implements relation extension with ExtendBufferedRel(), using a flag to tell ExtendBufferedRel() that the relation lock is already held. Note that this commit does not yet lead to a meaningful performance or scalability improvement - for that uses of ReadBuffer(P_NEW) will need to be converted to ExtendBuffered*(), which will be done in subsequent commits. Reviewed-by: Heikki Linnakangas <[email protected]> Reviewed-by: Melanie Plageman <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-04-05bufmgr: Support multiple in-progress IOs by using resownerAndres Freund
A future patch will add support for extending relations by multiple blocks at once. To be concurrency safe, the buffers for those blocks need to be marked as BM_IO_IN_PROGRESS. Until now we only had infrastructure for recovering from an IO error for a single buffer. This commit extends that infrastructure to multiple buffers by using the resource owner infrastructure. This commit increases the size of the ResourceOwnerData struct, which appears to have a just about measurable overhead in very extreme workloads. Medium term we are planning to substantially shrink the size of ResourceOwnerData. Short term the increase is small enough to not worry about it for now. Reviewed-by: Melanie Plageman <[email protected]> Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2023-04-05bufmgr: Acquire and clean victim buffer separatelyAndres Freund
Previously we held buffer locks for two buffer mapping partitions at the same time to change the identity of buffers. Particularly for extending relations needing to hold the extension lock while acquiring a victim buffer is painful.But it also creates a bottleneck for workloads that just involve reads. Now we instead first acquire a victim buffer and write it out, if necessary. Then we remove that buffer from the old partition with just the old partition's partition lock held and insert it into the new partition with just that partition's lock held. By separating out the victim buffer acquisition, future commits will be able to change relation extensions to scale better. On my workstation, a micro-benchmark exercising buffered reads strenuously and under a lot of concurrency, sees a >2x improvement. Reviewed-by: Heikki Linnakangas <[email protected]> Reviewed-by: Melanie Plageman <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-04-05bufmgr: Add Pin/UnpinLocalBuffer()Andres Freund
So far these were open-coded in quite a few places, without a good reason. Reviewed-by: Melanie Plageman <[email protected]> Reviewed-by: David Rowley <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-04-05bufmgr: Add some more error checking [infrastructure] around pinningAndres Freund
This adds a few more assertions against a buffer being local in places we don't expect, and extracts the check for a buffer being pinned exactly once from LockBufferForCleanup() into its own function. Later commits will use this function. Reviewed-by: Heikki Linnakangas <[email protected]> Reviewed-by: Melanie Plageman <[email protected]> Discussion: http://postgr.es/m/[email protected]
2023-04-05Add smgrzeroextend(), FileZero(), FileFallocate()Andres Freund
smgrzeroextend() uses FileFallocate() to efficiently extend files by multiple blocks. When extending by a small number of blocks, use FileZero() instead, as using posix_fallocate() for small numbers of blocks is inefficient for some file systems / operating systems. FileZero() is also used as the fallback for FileFallocate() on platforms / filesystems that don't support fallocate. A big advantage of using posix_fallocate() is that it typically won't cause dirty buffers in the kernel pagecache. So far the most common pattern in our code is that we smgrextend() a page full of zeroes and put the corresponding page into shared buffers, from where we later write out the actual contents of the page. If the kernel, e.g. due to memory pressure or elapsed time, already wrote back the all-zeroes page, this can lead to doubling the amount of writes reaching storage. There are no users of smgrzeroextend() as of this commit. That will follow in future commits. Reviewed-by: Melanie Plageman <[email protected]> Reviewed-by: Heikki Linnakangas <[email protected]> Reviewed-by: Kyotaro Horiguchi <[email protected]> Reviewed-by: David Rowley <[email protected]> Reviewed-by: John Naylor <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-04-05Don't initialize page in {vm,fsm}_extend(), not neededAndres Freund
The read path needs to be able to initialize pages anyway, as relation extensions are not durable. By avoiding initializing pages, we can, in a future patch, extend the relation by multiple blocks at once. Using smgrextend() for {vm,fsm}_extend() is not a good idea in general, as at least one page of the VM/FSM will be read immediately after, always causing a cache miss, requiring us to read content we just wrote. Discussion: https://postgr.es/m/[email protected]
2023-04-04bufmgr: Remove buffer-write-dirty tracepointsAndres Freund
The trace point was using the relfileno / fork / block for the to-be-read-in buffer. Some upcoming work would make that more expensive to provide. We still have buffer-flush-start/done, which can serve most tracing needs that buffer-write-dirty could serve. Discussion: https://postgr.es/m/[email protected]
2023-04-03Rename BufferAccessStrategyData.ring_size to nbuffersDavid Rowley
The new name better reflects what the field is - the size of the buffers[] array. ring_size sounded more like it is in units of bytes. An upcoming commit allows a BufferAccessStrategy of custom sizes, so it seems relevant to improve this beforehand. Author: Melanie Plageman Reviewed-by: David Rowley Discussion: https://postgr.es/m/CAAKRu_YefVbhg4rAxU2frYFdTap61UftH-kUNQZBvAs%2BYK81Zg%40mail.gmail.com
2023-03-31Track shared buffer hits in pg_stat_ioAndres Freund
Among other things, this should make it easier to calculate a useful cache hit ratio by excluding buffer reads via buffer access strategies. As buffer access strategies reuse buffers (and thus evict the prior buffer contents), it is normal to see reads on repeated scans of the same data. Author: Melanie Plageman <[email protected]> Reviewed-by: Bertrand Drouvot <[email protected]> Reviewed-by: Andres Freund <[email protected]> Discussion: https://postgr.es/m/CAAKRu_beMa9Hzih40%3DXPYqhDVz6tsgUGTrhZXRo%3Dunp%2Bszb%3DUA%40mail.gmail.com
2023-03-30pg_stat_wal: Accumulate time as instr_time instead of microsecondsAndres Freund
In instr_time.h it is stated that: * When summing multiple measurements, it's recommended to leave the * running sum in instr_time form (ie, use INSTR_TIME_ADD or * INSTR_TIME_ACCUM_DIFF) and convert to a result format only at the end. The reason for that is that converting to microseconds is not cheap, and can loose precision. Therefore this commit changes 'PendingWalStats' to use 'instr_time' instead of 'PgStat_Counter' while accumulating 'wal_write_time' and 'wal_sync_time'. Author: Nazir Bilal Yavuz <[email protected]> Reviewed-by: Andres Freund <[email protected]> Reviewed-by: Kyotaro Horiguchi <[email protected]> Reviewed-by: Melanie Plageman <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-03-30Fix format code in fd.c debugging infrastructureAndres Freund
These were not sufficiently adjusted in 2d4f1ba6cfc.
2023-03-30bufmgr: Fix undefined behaviour with, unrealistically, large temp_buffersAndres Freund
Quoting Melanie: > Since if buffer is INT_MAX, then the -(buffer + 1) version invokes > undefined behavior while the -buffer - 1 version doesn't. All other places were already using the correct version. I (Andres), copied the code into more places in a patch. Melanie caught it in review, but to prevent more people from copying the bad code, fix it. Even if it is a theoretical issue. We really ought to wrap these accesses in a helper function... As this is a theoretical issue, don't backpatch. Reported-by: Melanie Plageman <[email protected]> Discussion: https://postgr.es/m/CAAKRu_aW2SX_LWtwHgfnqYpBrunMLfE9PD6-ioPpkh92XH0qpg@mail.gmail.com
2023-03-30Fix incorrect format placeholdersPeter Eisentraut
2023-03-29Remove empty function BufmgrCommit().Tom Lane
This function has been a no-op for over a decade. Even if bufmgr regains a need to be called during commit, it seems unlikely that the most appropriate call points would be precisely here, so it's not doing us much good as a placeholder either. Now, removing it probably doesn't save any noticeable number of cycles --- but the main call is inside the commit critical section, and the less work done there the better. Matthias van de Meent Discussion: https://postgr.es/m/CAEze2Wi1=tLKbxZnXzcD+8fYKyKqBtivVakLQC_mYBsP4Y8qVA@mail.gmail.com
2023-03-29Simplify useless 0L constantsPeter Eisentraut
In ancient times, these belonged to arguments or fields that were actually of type long, but now they are not anymore, so this "L" decoration is just confusing. (Some other 0L and other "L" constants remain, where they are actually associated with a long type.)
2023-03-22Fix memory leak and inefficiency in CREATE DATABASE ... STRATEGY WAL_LOGAndres Freund
RelationCopyStorageUsingBuffer() did not free the strategies used to access the source / target relation. They memory was released at the end of the transaction, but when using a template database with a lot of relations, the temporary leak can become big prohibitively big. RelationCopyStorageUsingBuffer() acquired the buffer for the target relation with RBM_NORMAL, therefore requiring a read of a block guaranteed to be zero. Use RBM_ZERO_AND_LOCK instead. Reviewed-by: Robert Haas <[email protected]> Discussion: https://postgr.es/m/[email protected] Backpatch: 15-, where STRATEGY WAL_LOG was introduced
2023-03-17Improve several permission-related error messages.Peter Eisentraut
Mainly move some detail from errmsg to errdetail, remove explicit mention of superuser where appropriate, since that is implied in most permission checks, and make messages more uniform. Author: Nathan Bossart <[email protected]> Discussion: https://www.postgresql.org/message-id/20230316234701.GA903298@nathanxps13
2023-03-09Fix race in SERIALIZABLE READ ONLY.Thomas Munro
Commit bdaabb9b started skipping doomed transactions when building the list of possible conflicts for SERIALIZABLE READ ONLY. That makes sense, because doomed transactions won't commit, but a couple of subtle things broke: 1. If all uncommitted r/w transactions are doomed, a READ ONLY transaction would arbitrarily not benefit from the safe snapshot optimization. It would not be taken immediately, and yet no other transaction would set SXACT_FLAG_RO_SAFE later. 2. In the same circumstances but with DEFERRABLE, GetSafeSnapshot() would correctly exit its wait loop without sleeping and then take the optimization in non-assert builds, but assert builds would fail a sanity check that SXACT_FLAG_RO_SAFE had been set by another transaction. This is similar to the case for PredXact->WritableSxactCount == 0. We should opt out immediately if our possibleUnsafeConflicts list is empty after filtering. The code to maintain the serializable global xmin is moved down below the new opt out site, because otherwise we'd have to reverse its effects before returning. Back-patch to all supported releases. Bug #17368. Reported-by: Alexander Lakhin <[email protected]> Discussion: https://postgr.es/m/17116-d6ca217acc180e30%40postgresql.org Discussion: https://postgr.es/m/20110707212159.GF76634%40csail.mit.edu
2023-03-08Fix corruption due to vacuum_defer_cleanup_age underflowing 64bit xidsAndres Freund
When vacuum_defer_cleanup_age is bigger than the current xid, including the epoch, the subtraction of vacuum_defer_cleanup_age would lead to a wrapped around xid. While that normally is not a problem, the subsequent conversion to a 64bit xid results in a 64bit-xid very far into the future. As that xid is used as a horizon to detect whether rows versions are old enough to be removed, that allows removal of rows that are still visible (i.e. corruption). If vacuum_defer_cleanup_age was never changed from the default, there is no chance of this bug occurring. This bug was introduced in dc7420c2c92. A lesser version of it exists in 12-13, introduced by fb5344c969a, affecting only GiST. The 12-13 version of the issue can, in rare cases, lead to pages in a gist index getting recycled too early, potentially causing index entries to be found multiple times. The fix is fairly simple - don't allow vacuum_defer_cleanup_age to retreat further than FirstNormalTransactionId. Patches to make similar bugs easier to find, by adding asserts to the 64bit xid infrastructure, have been proposed, but are not suitable for backpatching. Currently there are no tests for vacuum_defer_cleanup_age. A patch introducing infrastructure to make writing a test easier has been posted to the list. Reported-by: Michail Nikolaev <[email protected]> Reviewed-by: Matthias van de Meent <[email protected]> Author: Andres Freund <[email protected]> Discussion: https://postgr.es/m/[email protected] Backpatch: 12-, but impact/fix is smaller for 12-13
2023-03-06Fix assert failures in parallel SERIALIZABLE READ ONLY.Thomas Munro
1. Make sure that we don't decrement SxactGlobalXminCount twice when the SXACT_FLAG_RO_SAFE optimization is reached in a parallel query. This could trigger a sanity check failure in assert builds. Non-assert builds recompute the count in SetNewSxactGlobalXmin(), so the problem was hidden, explaining the lack of field reports. Add a new isolation test to exercise that case. 2. Remove an assertion that the DOOMED flag can't be set on a partially released SERIALIZABLEXACT. Instead, ignore the flag (our transaction was already determined to be read-only safe, and DOOMED is in fact set during partial release, and there was already an assertion that it wasn't set sooner). Improve an existing isolation test so that it reaches that case (previously it wasn't quite testing what it was supposed to be testing; see discussion). Back-patch to 12. Bug #17116. Defects in commit 47a338cf. Reported-by: Alexander Lakhin <[email protected]> Discussion: https://postgr.es/m/17116-d6ca217acc180e30%40postgresql.org
2023-03-02Don't leak descriptors into subprograms.Thomas Munro
Open long-lived data and WAL file descriptors with O_CLOEXEC. This flag was introduced by SUSv4 (POSIX.1-2008), and by now all of our target Unix systems have it. Our open() implementation for Windows already had that behavior, so provide a dummy O_CLOEXEC flag on that platform. For now, callers of open() and the "thin" wrappers in fd.c that deal in raw descriptors need to pass in O_CLOEXEC explicitly if desired. This commit does that for WAL files, and automatically for everything accessed via VFDs including SMgrRelation and BufFile. (With more discussion we might decide to turn it on automatically for the thin open()-wrappers too to avoid risk of missing places that need it, but these are typically used for short-lived descriptors where we don't expect to fork/exec, and it's remotely possible that extensions could be using these APIs and passing descriptors to subprograms deliberately, so that hasn't been done here.) Do the same for sockets and the postmaster pipe with FD_CLOEXEC. (Later commits might use modern interfaces to remove these extra fcntl() calls and more where possible, but we'll need them as a fallback for a couple of systems, so do it that way in this initial commit.) With this change, subprograms executed for archiving, copying etc will no longer have access to the server's descriptors, other than the ones that we decide to pass down. Reviewed-by: Andres Freund <[email protected]> (earlier version) Discussion: https://postgr.es/m/CA%2BhUKGKb6FsAdQWcRL35KJsftv%2B9zXqQbzwkfRf1i0J2e57%2BhQ%40mail.gmail.com
2023-03-02Fix outdated references to guc.cDaniel Gustafsson
Commit 0a20ff54f split out the GUC variables from guc.c into a new file guc_tables.c. This updates comments referencing guc.c regarding variables which are now in guc_tables.c. Reviewed-by: Tom Lane <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-02-27Update types in smgr APIPeter Eisentraut
Change data buffer to void *, from char *, and add const where appropriate. This makes it match the File API (see also 2d4f1ba6cfc2f0a977f1c30bda9848041343e248) and stdio. Discussion: https://www.postgresql.org/message-id/flat/11dda853-bb5b-59ba-a746-e168b1ce4bdb%40enterprisedb.com
2023-02-21Remove obsolete coding for early macOS.Thomas Munro
Commits 04cad8f7 and 0c088568 supported old macOS systems that didn't define O_CLOEXEC or O_DSYNC yet, but those arrived in macOS releases 10.7 and 10.6 (respectively), which themselves reached EOL around a decade ago. We've already made use of other POSIX features that early macOS vintages can't compile (for example commits 623cc673, d2e15083). A later commit will use O_CLOEXEC on POSIX systems so it would be strange to pretend here that it's optional, and we might as well give O_DSYNC the same treatment since the reference is also guarded by a test for a macOS-specific macro, and we know that current Macs have it. Discussion: https://postgr.es/m/CA%2BhUKGKb6FsAdQWcRL35KJsftv%2B9zXqQbzwkfRf1i0J2e57%2BhQ%40mail.gmail.com
2023-02-20Speedup and increase usability of set proc title functionsDavid Rowley
The setting of the process title could be seen on profiles of very fast-to-execute queries. In many locations where we call set_ps_display() we pass along a string constant, the length of which is known during compilation. Here we effectively rename set_ps_display() to set_ps_display_with_len() and then add a static inline function named set_ps_display() which calls strlen() on the given string. This allows the compiler to optimize away the strlen() call when dealing with call sites passing a string constant. We can then also use memcpy() instead of strlcpy() to copy the string into the destination buffer. That's significantly faster than strlcpy's byte-at-a-time way of copying. Here we also take measures to improve some code which was adjusting the process title to add a " waiting" suffix to it. Call sites which require this can now just call set_ps_display_suffix() to add or adjust the suffix and call set_ps_display_remove_suffix() to remove it again. Reviewed-by: Andres Freund Discussion: https://postgr.es/m/CAApHDvocBvvk-0gWNA2Gohe+sv9fMcv+fK_G+siBKJrgDG4O7g@mail.gmail.com
2023-02-10pgstat: Track more detailed relation IO statisticsAndres Freund
Commit 28e626bde00 introduced the infrastructure for tracking more detailed IO statistics. This commit adds the actual collection of the new IO statistics for relations and temporary relations. See aforementioned commit for goals and high-level design. The changes in this commit are fairly straight-forward. The bulk of the change is to passing sufficient information to the callsites of pgstat_count_io_op(). A somewhat unsightly detail is that it currently is hard to find a better place to count fsyncs than in md.c, whereas the other pgstat_count_io_op() calls are in bufmgr.c/localbuf.c. As the number of fsyncs is tied to md.c implementation details, it's not obvious there is a better answer. Author: Melanie Plageman <[email protected]> Reviewed-by: Andres Freund <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-02-09Fix bugs in GetSafeSnapshotBlockingPids(), introduced in 96003717645Andres Freund
While removing the use of SHM_QUEUE from predicate.c, in 96003717645, I made two mistakes in GetSafeSnapshotBlockingPids(): - Removed the check for output_size - Previously, when the first loop didn't find a matching proc, sxact would be NULL. But with naive use of dlist_foreach() it ends up as the value of the last iteration. The second issue is the cause of occasional failures in the deadlock-hard and deadlock-soft isolation tests that we have been observing on CI. The issue was very hard to reproduce, as it requires the transactions.sql regression test to run at the same time as the deadlock-{hard,soft} isolation test. I did not find other similar mistakes in 96003717645. Discussion: https://postgr.es/m/[email protected]
2023-02-07Remove useless casts to (void *) in arguments of some system functionsPeter Eisentraut
The affected functions are: bsearch, memcmp, memcpy, memset, memmove, qsort, repalloc Reviewed-by: Corey Huinker <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/fd9adf5d-b1aa-e82f-e4c7-263c30145807%40enterprisedb.com
2023-02-06Remove useless casts to (void *) in hash_search() callsPeter Eisentraut
Some of these appear to be leftovers from when hash_search() took a char * argument (changed in 5999e78fc45dcb91784b64b6e9ae43f4e4f68ca2). Since after this there is some more horizontal space available, do some light reformatting where suitable. Reviewed-by: Corey Huinker <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/fd9adf5d-b1aa-e82f-e4c7-263c30145807%40enterprisedb.com
2023-01-25Avoid type cheats for invalid dsa_handles and dshash_table_handles.Tom Lane
Invent separate macros for "invalid" values of these types, so that we needn't embed knowledge of their representations into calling code. These are all zeroes anyway ATM, so this is not fixing any live bug, but it makes the code cleaner and more future-proof. I (tgl) also chose to move DSM_HANDLE_INVALID into dsm_impl.h, since it seems like it should live beside the typedef for dsm_handle. Hou Zhijie, Nathan Bossart, Kyotaro Horiguchi, Tom Lane Discussion: https://postgr.es/m/OS0PR01MB5716860B1454C34E5B179B6694C99@OS0PR01MB5716.jpnprd01.prod.outlook.com
2023-01-22Track logrep apply workers' last start times to avoid useless waits.Tom Lane
Enforce wal_retrieve_retry_interval on a per-subscription basis, rather than globally, and arrange to skip that delay in case of an intentional worker exit. This probably makes little difference in the field, where apply workers wouldn't be restarted often; but it has a significant impact on the runtime of our logical replication regression tests (even though those tests use artificially-small wal_retrieve_retry_interval settings already). Nathan Bossart, with mostly-cosmetic editorialization by me Discussion: https://postgr.es/m/20221122004119.GA132961@nathanxps13
2023-01-21Zero initialize uses of instr_time about to trigger compiler warningsAndres Freund
These are all not necessary from a correctness POV. However, in the near future instr_time will be simplified to an int64, at which point gcc would otherwise start to warn about the changed places. Reviewed-by: Tom Lane <[email protected]> Discussion: https://postgr.es/m/[email protected]
2023-01-20Add new GUC reserved_connections.Robert Haas
This provides a way to reserve connection slots for non-superusers. The slots reserved via the new GUC are available only to users who have the new predefined role pg_use_reserved_connections. superuser_reserved_connections remains as a final reserve in case reserved_connections has been exhausted. Patch by Nathan Bossart. Reviewed by Tushar Ahuja and by me. Discussion: http://postgr.es/m/20230119194601.GA4105788@nathanxps13
2023-01-20Remove SHM_QUEUEAndres Freund
Prior patches got rid of all the uses of SHM_QUEUE. ilist.h style lists are more widely used and have an easier to use interface. As there are no users left, remove SHM_QUEUE. Reviewed-by: Thomas Munro <[email protected]> (in an older version) Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2023-01-20Use dlists instead of SHM_QUEUE for predicate lockingAndres Freund
Part of a series to remove SHM_QUEUE. ilist.h style lists are more widely used and have an easier to use interface. Reviewed-by: Thomas Munro <[email protected]> (in an older version) Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2023-01-18Use dlists instead of SHM_QUEUE for syncrep queueAndres Freund
Part of a series to remove SHM_QUEUE. ilist.h style lists are more widely used and have an easier to use interface. Reviewed-by: Thomas Munro <[email protected]> (in an older version) Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2023-01-18Use dlist/dclist instead of PROC_QUEUE / SHM_QUEUE for heavyweight locksAndres Freund
Part of a series to remove SHM_QUEUE. ilist.h style lists are more widely used and have an easier to use interface. As PROC_QUEUE is now unused, remove it. Reviewed-by: Thomas Munro <[email protected]> (in an older version) Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]