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* Remove unnecessary memcpy when reading WAL record fitting on pageMichael Paquier2018-11-19
| | | | | | | | | | | | | When reading a WAL record, its contents are copied into an intermediate buffer. However, doing so is not necessary if the record fits fully into the current page, saving one memcpy for each such record. The allocation handling of the intermediate buffer is also now done only when a record crosses a page boundary, shaving some extra cycles when reading a WAL record. Author: Andrey Lepikhov Reviewed-by: Kyotaro Horiguchi, Heikki Linnakangas Discussion: https://postgr.es/m/c2ea54dd-a1d3-80eb-ddbf-7e6f258e615e@postgrespro.ru
* Avoid using potentially-under-aligned page buffers.Tom Lane2018-09-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's a project policy against using plain "char buf[BLCKSZ]" local or static variables as page buffers; preferred style is to palloc or malloc each buffer to ensure it is MAXALIGN'd. However, that policy's been ignored in an increasing number of places. We've apparently got away with it so far, probably because (a) relatively few people use platforms on which misalignment causes core dumps and/or (b) the variables chance to be sufficiently aligned anyway. But this is not something to rely on. Moreover, even if we don't get a core dump, we might be paying a lot of cycles for misaligned accesses. To fix, invent new union types PGAlignedBlock and PGAlignedXLogBlock that the compiler must allocate with sufficient alignment, and use those in place of plain char arrays. I used these types even for variables where there's no risk of a misaligned access, since ensuring proper alignment should make kernel data transfers faster. I also changed some places where we had been palloc'ing short-lived buffers, for coding style uniformity and to save palloc/pfree overhead. Since this seems to be a live portability hazard (despite the lack of field reports), back-patch to all supported versions. Patch by me; thanks to Michael Paquier for review. Discussion: https://postgr.es/m/1535618100.1286.3.camel@credativ.de
* Flip argument order in XLogSegNoOffsetToRecPtrAlvaro Herrera2018-07-09
| | | | | | | | | Commit fc49e24fa69a added an input argument after the existing output argument. Flip those. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20180708182345.imdgovmkffgtihhk@alvherre.pgsql
* pgindent run prior to branchingAndrew Dunstan2018-06-30
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* Prevent hard failures of standbys caused by recycled WAL segmentsMichael Paquier2018-06-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a standby's WAL receiver stops reading WAL from a WAL stream, it writes data to the current WAL segment without having priorily zero'ed the page currently written to, which can cause the WAL reader to read junk data from a past recycled segment and then it would try to get a record from it. While sanity checks in place provide most of the protection needed, in some rare circumstances, with chances increasing when a record header crosses a page boundary, then the startup process could fail violently on an allocation failure, as follows: FATAL: invalid memory alloc request size XXX This is confusing for the user and also unhelpful as this requires in the worst case a manual restart of the instance, impacting potentially the availability of the cluster, and this also makes WAL data look like it is in a corrupted state. The chances of seeing failures are higher if the connection between the standby and its root node is unstable, causing WAL pages to be written in the middle. A couple of approaches have been discussed, like zero-ing new WAL pages within the WAL receiver itself but this has the disadvantage of impacting performance of any existing instances as this breaks the sequential writes done by the WAL receiver. This commit deals with the problem with a more simple approach, which has no performance impact without reducing the detection of the problem: if a record is found with a length higher than 1GB for backends, then do not try any allocation and report a soft failure which will force the standby to retry reading WAL. It could be possible that the allocation call passes and that an unnecessary amount of memory is allocated, however follow-up checks on records would just fail, making this allocation short-lived anyway. This patch owes a great deal to Tsunakawa Takayuki for reporting the failure first, and then discussing a couple of potential approaches to the problem. Backpatch down to 9.5, which is where palloc_extended has been introduced. Reported-by: Tsunakawa Takayuki Reviewed-by: Tsunakawa Takayuki Author: Michael Paquier Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8B57AD@G01JPEXMBYT05
* Fix scenario where streaming standby gets stuck at a continuation record.Heikki Linnakangas2018-05-05
| | | | | | | | | | | | | | | | | | | | | If a continuation record is split so that its first half has already been removed from the master, and is only present in pg_wal, and there is a recycled WAL segment in the standby server that looks like it would contain the second half, recovery would get stuck. The code in XLogPageRead() incorrectly started streaming at the beginning of the WAL record, even if we had already read the first page. Backpatch to 9.4. In principle, older versions have the same problem, but without replication slots, there was no straightforward mechanism to prevent the master from recycling old WAL that was still needed by standby. Without such a mechanism, I think it's reasonable to assume that there's enough slack in how many old segments are kept around to not run into this, or you have a WAL archive. Reported by Jonathon Nelson. Analysis and patch by Kyotaro HORIGUCHI, with some extra comments by me. Discussion: https://www.postgresql.org/message-id/CACJqAM3xVz0JY1XFDKPP%2BJoJAjoGx%3DGNuOAshEDWCext7BFvCQ%40mail.gmail.com
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Pad XLogReaderState's per-buffer data_bufsz more aggressively.Simon Riggs2017-11-27
| | | | | | | | | | | | Originally, we palloc'd this buffer just barely big enough to hold the largest xlog backup block seen so far. We now MAXALIGN the palloc size. The original coding could result in many repeated palloc cycles, in the worst case where we see a series ofgradually larger xlog records. We ameliorate that similarly to 8735978e7aebfbc499843630131c18d1f7346c79 by imposing a minimum buffer size of BLCKSZ. Discussion: https://postgr.es/m/E1eHa4J-0006hI-Q8@gemulon.postgresql.org
* Pad XLogReaderState's main_data buffer more aggressively.Tom Lane2017-11-26
| | | | | | | | | | | | | | | | | | | | | | | | | Originally, we palloc'd this buffer just barely big enough to hold the largest xlog record seen so far. It turns out that that can result in valgrind complaints, because some compilers will emit code that assumes it can safely fetch padding bytes at the end of a struct, and those padding bytes were unallocated so far as aset.c was concerned. We can fix that by MAXALIGN'ing the palloc request size, ensuring that it is big enough to include any possible padding that might've been omitted from the on-disk record. An additional objection to the original coding is that it could result in many repeated palloc cycles, in the worst case where we see a series of gradually larger xlog records. We can ameliorate that cheaply by imposing a minimum buffer size that's large enough for most xlog records. BLCKSZ/2 was chosen after a bit of discussion. In passing, remove an obsolete comment in struct xl_heap_new_cid that the combocid field is free due to alignment considerations. Perhaps that was true at some point, but it's not now. Back-patch to 9.5 where this code came in. Discussion: https://postgr.es/m/E1eHa4J-0006hI-Q8@gemulon.postgresql.org
* Change TRUE/FALSE to true/falsePeter Eisentraut2017-11-08
| | | | | | | | | | | | | | The lower case spellings are C and C++ standard and are used in most parts of the PostgreSQL sources. The upper case spellings are only used in some files/modules. So standardize on the standard spellings. The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so those are left as is when using those APIs. In code comments, we use the lower-case spelling for the C concepts and keep the upper-case spelling for the SQL concepts. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
* Make WAL segment size configurable at initdb time.Andres Freund2017-09-19
| | | | | | | | | | | | | | | | | | | | | | | For performance reasons a larger segment size than the default 16MB can be useful. A larger segment size has two main benefits: Firstly, in setups using archiving, it makes it easier to write scripts that can keep up with higher amounts of WAL, secondly, the WAL has to be written and synced to disk less frequently. But at the same time large segment size are disadvantageous for smaller databases. So far the segment size had to be configured at compile time, often making it unrealistic to choose one fitting to a particularly load. Therefore change it to a initdb time setting. This includes a breaking changes to the xlogreader.h API, which now requires the current segment size to be configured. For that and similar reasons a number of binaries had to be taught how to recognize the current segment size. Author: Beena Emerson, editorialized by Andres Freund Reviewed-By: Andres Freund, David Steele, Kuntal Ghosh, Michael Paquier, Peter Eisentraut, Robert Hass, Tushar Ahuja Discussion: https://postgr.es/m/CAOG9ApEAcQ--1ieKbhFzXSQPw_YLmepaa4hNdnY5+ZULpt81Mw@mail.gmail.com
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Post-PG 10 beta1 pgindent runBruce Momjian2017-05-17
| | | | perltidy run not included.
* Add WAL consistency checking facility.Robert Haas2017-02-08
| | | | | | | | | | | | | | When the new GUC wal_consistency_checking is set to a non-empty value, it triggers recording of additional full-page images, which are compared on the standby against the results of applying the WAL record (without regard to those full-page images). Allowable differences such as hints are masked out, and the resulting pages are compared; any difference results in a FATAL error on the standby. Kuntal Ghosh, based on earlier patches by Michael Paquier and Heikki Linnakangas. Extensively reviewed and revised by Michael Paquier and by me, with additional reviews and comments from Amit Kapila, Álvaro Herrera, Simon Riggs, and Peter Eisentraut.
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Be more consistent about masking xl_info with ~XLR_INFO_MASK.Tom Lane2016-11-04
| | | | | | | | | | | | Generally, WAL resource managers are only supposed to examine the top 4 bits of a WAL record's xl_info; the rest are reserved for the WAL mechanism itself. A few places were not consistent about doing this with respect to XLOG_CHECKPOINT and XLOG_SWITCH records. There's no bug currently, since no additional bits ever get set in these specific record types, but that might not be true forever. Let's follow the generic coding rule here too. Michael Paquier
* Fix pg_xlogdump so that it handles cross-page XLP_FIRST_IS_CONTRECORD record.Fujii Masao2016-08-29
| | | | | | | | | | | | | | | | | | Previously pg_xlogdump failed to dump the contents of the WAL file if the file starts with the continuation WAL record which spans more than one pages. Since pg_xlogdump assumed that the continuation record always fits on a page, it could not find the valid WAL record to start reading from in that case. This patch changes pg_xlogdump so that it can handle a continuation WAL record which crosses a page boundary and find the valid record to start reading from. Back-patch to 9.3 where pg_xlogdump was introduced. Author: Pavan Deolasee Reviewed-By: Michael Paquier and Craig Ringer Discussion: CABOikdPsPByMiG6J01DKq6om2+BNkxHTPkOyqHM2a4oYwGKsqQ@mail.gmail.com
* pgindent run for 9.6Robert Haas2016-06-09
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* Revert timeline following in replication slotsAlvaro Herrera2016-05-04
| | | | | | | | | This reverts commits f07d18b6e94d, 82c83b337202, 3a3b309041b0, and 24c5f1a103ce. This feature has shown enough immaturity that it was deemed better to rip it out before rushing some more fixes at the last minute. There are discussions on larger changes in this area for the next release.
* Silence compiler warningAlvaro Herrera2016-04-04
| | | | Reported by Peter Eisentraut to occur on 32bit systems
* Enable logical slots to follow timeline switchesAlvaro Herrera2016-03-30
| | | | | | | | | | | | | | | | | | When decoding from a logical slot, it's necessary for xlog reading to be able to read xlog from historical (i.e. not current) timelines; otherwise, decoding fails after failover, because the archives are in the historical timeline. This is required to make "failover logical slots" possible; it currently has no other use, although theoretically it could be used by an extension that creates a slot on a standby and continues to replay from the slot when the standby is promoted. This commit includes a module in src/test/modules with functions to manipulate the slots (which is not otherwise possible in SQL code) in order to enable testing, and a new test in src/test/recovery to ensure that the behavior is as expected. Author: Craig Ringer Reviewed-By: Oleksii Kliukin, Andres Freund, Petr Jelínek
* XLogReader general code cleanupAlvaro Herrera2016-03-30
| | | | | | | | | Some minor tweaks and comment additions, for cleanliness sake and to avoid having the upcoming timeline-following patch be polluted with unrelated cleanup. Extracted from a larger patch by Craig Ringer, reviewed by Andres Freund, with some additions by myself.
* Update copyright for 2016Bruce Momjian2016-01-02
| | | | Backpatch certain files through 9.1
* Fix message punctuation according to style guidePeter Eisentraut2015-10-01
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* Another attempt at fixing memory leak in xlogreader.Heikki Linnakangas2015-07-28
| | | | | | max_block_id is also reset between reading records. Michael Paquier
* Fix memory leak in xlogreader facility.Heikki Linnakangas2015-07-27
| | | | | | | XLogReaderFree failed to free the per-block data buffers, when they happened to not be used by the latest read WAL record. Michael Paquier. Backpatch to 9.5, where the per-block buffers were added.
* pgindent run for 9.5Bruce Momjian2015-05-23
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* Introduce replication progress tracking infrastructure.Andres Freund2015-04-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When implementing a replication solution ontop of logical decoding, two related problems exist: * How to safely keep track of replication progress * How to change replication behavior, based on the origin of a row; e.g. to avoid loops in bi-directional replication setups The solution to these problems, as implemented here, consist out of three parts: 1) 'replication origins', which identify nodes in a replication setup. 2) 'replication progress tracking', which remembers, for each replication origin, how far replay has progressed in a efficient and crash safe manner. 3) The ability to filter out changes performed on the behest of a replication origin during logical decoding; this allows complex replication topologies. E.g. by filtering all replayed changes out. Most of this could also be implemented in "userspace", e.g. by inserting additional rows contain origin information, but that ends up being much less efficient and more complicated. We don't want to require various replication solutions to reimplement logic for this independently. The infrastructure is intended to be generic enough to be reusable. This infrastructure also replaces the 'nodeid' infrastructure of commit timestamps. It is intended to provide all the former capabilities, except that there's only 2^16 different origins; but now they integrate with logical decoding. Additionally more functionality is accessible via SQL. Since the commit timestamp infrastructure has also been introduced in 9.5 (commit 73c986add) changing the API is not a problem. For now the number of origins for which the replication progress can be tracked simultaneously is determined by the max_replication_slots GUC. That GUC is not a perfect match to configure this, but there doesn't seem to be sufficient reason to introduce a separate new one. Bumps both catversion and wal page magic. Author: Andres Freund, with contributions from Petr Jelinek and Craig Ringer Reviewed-By: Heikki Linnakangas, Petr Jelinek, Robert Haas, Steve Singer Discussion: 20150216002155.GI15326@awork2.anarazel.de, 20140923182422.GA15776@alap3.anarazel.de, 20131114172632.GE7522@alap2.anarazel.de
* Reorganize our CRC source files again.Heikki Linnakangas2015-04-14
| | | | | | | | | | Now that we use CRC-32C in WAL and the control file, the "traditional" and "legacy" CRC-32 variants are not used in any frontend programs anymore. Move the code for those back from src/common to src/backend/utils/hash. Also move the slicing-by-8 implementation (back) to src/port. This is in preparation for next patch that will add another implementation that uses Intel SSE 4.2 instructions to calculate CRC-32C, where available.
* Fix error handling of XLogReaderAllocate in case of OOMFujii Masao2015-04-03
| | | | | | | | | | | Similarly to previous fix 9b8d478, commit 2c03216 has switched XLogReaderAllocate() to use a set of palloc calls instead of malloc, causing any callers of this function to fail with an error instead of receiving a NULL pointer in case of out-of-memory error. Fix this by using palloc_extended with MCXT_ALLOC_NO_OOM that will safely return NULL in case of an OOM. Michael Paquier, slightly modified by me.
* Rework handling of OOM when allocating record buffer in XLOG reader.Fujii Masao2015-04-03
| | | | | | | | | | Commit 2c03216 changed allocate_recordbuf() so that it uses a palloc to allocate the read buffer and fails immediately when an out-of-memory error shows up, even though its callers still expect that NULL is returned in that case. This bug is fixed making allocate_recordbuf() use a palloc_extended with MCXT_ALLOC_NO_OOM flag and return NULL in OOM case. Michael Paquier
* Tweak __attribute__-wrapping macros for better pgindent results.Tom Lane2015-03-26
| | | | | | | | | | | | | | | | | | | | | This improves on commit bbfd7edae5aa5ad5553d3c7e102f2e450d4380d4 by making two simple changes: * pg_attribute_noreturn now takes parentheses, ie pg_attribute_noreturn(). Likewise pg_attribute_unused(), pg_attribute_packed(). This reduces pgindent's tendency to misformat declarations involving them. * attributes are now always attached to function declarations, not definitions. Previously some places were taking creative shortcuts, which were not merely candidates for bad misformatting by pgindent but often were outright wrong anyway. (It does little good to put a noreturn annotation where callers can't see it.) In any case, if we would like to believe that these macros can be used with non-gcc compilers, we should avoid gratuitous variance in usage patterns. I also went through and manually improved the formatting of a lot of declarations, and got rid of excessively repetitive (and now obsolete anyway) comments informing the reader what pg_attribute_printf is for.
* Add macros wrapping all usage of gcc's __attribute__.Andres Freund2015-03-11
| | | | | | | | | | | | | | | | | | | | Until now __attribute__() was defined to be empty for all compilers but gcc. That's problematic because it prevents using it in other compilers; which is necessary e.g. for atomics portability. It's also just generally dubious to do so in a header as widely included as c.h. Instead add pg_attribute_format_arg, pg_attribute_printf, pg_attribute_noreturn macros which are implemented in the compilers that understand them. Also add pg_attribute_noreturn and pg_attribute_packed, but don't provide fallbacks, since they can affect functionality. This means that external code that, possibly unwittingly, relied on __attribute__ defined to be empty on !gcc compilers may now run into warnings or errors on those compilers. But there shouldn't be many occurances of that and it's hard to work around... Discussion: 54B58BA3.8040302@ohmu.fi Author: Oskari Saarenmaa, with some minor changes by me.
* Add GUC to enable compression of full page images stored in WAL.Fujii Masao2015-03-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When newly-added GUC parameter, wal_compression, is on, the PostgreSQL server compresses a full page image written to WAL when full_page_writes is on or during a base backup. A compressed page image will be decompressed during WAL replay. Turning this parameter on can reduce the WAL volume without increasing the risk of unrecoverable data corruption, but at the cost of some extra CPU spent on the compression during WAL logging and on the decompression during WAL replay. This commit changes the WAL format (so bumping WAL version number) so that the one-byte flag indicating whether a full page image is compressed or not is included in its header information. This means that the commit increases the WAL volume one-byte per a full page image even if WAL compression is not used at all. We can save that one-byte by borrowing one-bit from the existing field like hole_offset in the header and using it as the flag, for example. But which would reduce the code readability and the extensibility of the feature. Per discussion, it's not worth paying those prices to save only one-byte, so we decided to add the one-byte flag to the header. This commit doesn't introduce any new compression algorithm like lz4. Currently a full page image is compressed using the existing PGLZ algorithm. Per discussion, we decided to use it at least in the first version of the feature because there were no performance reports showing that its compression ratio is unacceptably lower than that of other algorithm. Of course, in the future, it's worth considering the support of other compression algorithm for the better compression. Rahila Syed and Michael Paquier, reviewed in various versions by myself, Andres Freund, Robert Haas, Abhijit Menon-Sen and many others.
* Add missing "goto err" statements in xlogreader.c.Fujii Masao2015-03-09
| | | | Spotted by Andres Freund.
* Update copyright for 2015Bruce Momjian2015-01-06
| | | | Backpatch certain files through 9.0
* Remove superflous variable from xlogreader's XLogFindNextRecord().Andres Freund2015-01-04
| | | | | | | Pointed out by Coverity. Since this is mere, and debatable, cosmetics I'm not backpatching this.
* Revamp the WAL record format.Heikki Linnakangas2014-11-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Each WAL record now carries information about the modified relation and block(s) in a standardized format. That makes it easier to write tools that need that information, like pg_rewind, prefetching the blocks to speed up recovery, etc. There's a whole new API for building WAL records, replacing the XLogRecData chains used previously. The new API consists of XLogRegister* functions, which are called for each buffer and chunk of data that is added to the record. The new API also gives more control over when a full-page image is written, by passing flags to the XLogRegisterBuffer function. This also simplifies the XLogReadBufferForRedo() calls. The function can dig the relation and block number from the WAL record, so they no longer need to be passed as arguments. For the convenience of redo routines, XLogReader now disects each WAL record after reading it, copying the main data part and the per-block data into MAXALIGNed buffers. The data chunks are not aligned within the WAL record, but the redo routines can assume that the pointers returned by XLogRecGet* functions are. Redo routines are now passed the XLogReaderState, which contains the record in the already-disected format, instead of the plain XLogRecord. The new record format also makes the fixed size XLogRecord header smaller, by removing the xl_len field. The length of the "main data" portion is now stored at the end of the WAL record, and there's a separate header after XLogRecord for it. The alignment padding at the end of XLogRecord is also removed. This compansates for the fact that the new format would otherwise be more bulky than the old format. Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera, Fujii Masao.
* Move the backup-block logic from XLogInsert to a new file, xloginsert.c.Heikki Linnakangas2014-11-06
| | | | | | | | | | | | xlog.c is huge, this makes it a little bit smaller, which is nice. Functions related to putting together the WAL record are in xloginsert.c, and the lower level stuff for managing WAL buffers and such are in xlog.c. Also move the definition of XLogRecord to a separate header file. This causes churn in the #includes of all the files that write WAL records, and redo routines, but it avoids pulling in xlog.h into most places. Reviewed by Michael Paquier, Alvaro Herrera, Andres Freund and Amit Kapila.
* Switch to CRC-32C in WAL and other places.Heikki Linnakangas2014-11-04
| | | | | | | | | | | | | | | | | | | | | | | The old algorithm was found to not be the usual CRC-32 algorithm, used by Ethernet et al. We were using a non-reflected lookup table with code meant for a reflected lookup table. That's a strange combination that AFAICS does not correspond to any bit-wise CRC calculation, which makes it difficult to reason about its properties. Although it has worked well in practice, seems safer to use a well-known algorithm. Since we're changing the algorithm anyway, we might as well choose a different polynomial. The Castagnoli polynomial has better error-correcting properties than the traditional CRC-32 polynomial, even if we had implemented it correctly. Another reason for picking that is that some new CPUs have hardware support for calculating CRC-32C, but not CRC-32, let alone our strange variant of it. This patch doesn't add any support for such hardware, but a future patch could now do that. The old algorithm is kept around for tsquery and pg_trgm, which use the values in indexes that need to remain compatible so that pg_upgrade works. While we're at it, share the old lookup table for CRC-32 calculation between hstore, ltree and core. They all use the same table, so might as well.
* pgindent run for 9.4Bruce Momjian2014-05-06
| | | | | This includes removing tabs after periods in C comments, which was applied to back branches, so this change should not effect backpatching.
* Update copyright for 2014Bruce Momjian2014-01-07
| | | | | Update all files in head, and files COPYRIGHT and legal.sgml in all back branches.
* Fix typos in comments.Heikki Linnakangas2013-10-24
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* Minor spelling fixesStephen Frost2013-06-01
| | | | | | Fix a few spelling mistakes. Per bug report #8193 from Lajos Veres.
* pgindent run for release 9.3Bruce Momjian2013-05-29
| | | | | This is the first run of the Perl-based pgindent script. Also update pgindent instructions.
* Remove duplicate initialization in XLogReadRecord.Robert Haas2013-04-09
| | | | Per a note from Dickson S. Guedes.
* Use the right timeline when beginning to stream from master.Heikki Linnakangas2013-01-18
| | | | | | | | | | | | | | | | | | | | | The xlogreader refactoring broke the logic to decide which timeline to start streaming from. XLogPageRead() uses the timeline history to check which timeline the requested WAL position falls into. However, after the refactoring, XLogPageRead() is always first called with the first page in the segment, to verify the segment header, and only then with the actual WAL position we're interested in. That first read of the segment's header made XLogPageRead() to always start streaming from the old timeline containing the segment header, not the timeline containing the actual record, if there was a timeline switch within the segment. I thought I fixed this yesterday, but that fix was too narrow and only fixed this for the corner-case that the timeline switch happened in the first page of the segment. To fix this more robustly, pass explicitly the position of the record we're actually interested in to XLogPageRead, and use that to decide which timeline to read from, rather than deduce it from the page and offset. Per report from Fujii Masao.
* When xlogreader asks the callback function to read a page, make sure weHeikki Linnakangas2013-01-17
| | | | | | | | | get a large enough part of the page to include the beginning of the next record we're interested in. The XLogPageRead callback uses the requested length to decide which timeline to stream WAL from, and if the first call is short, and the page contains a timeline switch, we'll repeatedly try to stream that page from the old timeline, and never get across the timeline switch.
* Fix a couple of error-handling bugs in the xlogreader patch.Heikki Linnakangas2013-01-17
| | | | | | | | | | | | XLogReadRecord should reset its state on every error, to make sure it re-reads the page on next call. It was inconsistent in that some errors did that, but some did not. In ReadRecord(), don't give up on an error if we're in standby mode. The loop was set up to retry, but the checks within the loop broke out of the loop on any error. Andres Freund, with some tweaking by me.