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2021-07-31Fix corner-case errors and loss of precision in numeric_power().Dean Rasheed
This fixes a couple of related problems that arise when raising numbers to very large powers. Firstly, when raising a negative number to a very large integer power, the result should be well-defined, but the previous code would only cope if the exponent was small enough to go through power_var_int(). Otherwise it would throw an internal error, attempting to take the logarithm of a negative number. Fix this by adding suitable handling to the general case in power_var() to cope with negative bases, checking for integer powers there. Next, when raising a (positive or negative) number whose absolute value is slightly less than 1 to a very large power, the result should approach zero as the power is increased. However, in some cases, for sufficiently large powers, this would lose all precision and return 1 instead of 0. This was due to the way that the local_rscale was being calculated for the final full-precision calculation: local_rscale = rscale + (int) val - ln_dweight + 8 The first two terms on the right hand side are meant to give the number of significant digits required in the result ("val" being the estimated result weight). However, this failed to account for the fact that rscale is clipped to a maximum of NUMERIC_MAX_DISPLAY_SCALE (1000), and the result weight might be less then -1000, causing their sum to be negative, leading to a loss of precision. Fix this by forcing the number of significant digits calculated to be nonnegative. It's OK for it to be zero (when the result weight is less than -1000), since the local_rscale value then includes a few extra digits to ensure an accurate result. Finally, add additional underflow checks to exp_var() and power_var(), so that they consistently return zero for cases like this where the result is indistinguishable from zero. Some paths through this code already returned zero in such cases, but others were throwing overflow errors. Dean Rasheed, reviewed by Yugo Nagata. Discussion: http://postgr.es/m/CAEZATCW6Dvq7+3wN3tt5jLj-FyOcUgT5xNoOqce5=6Su0bCR0w@mail.gmail.com
2021-07-27Set pg_setting.pending_restart when pertinent config lines are removedAlvaro Herrera
This changes the behavior of examining the pg_file_settings view after changing a config option that requires restart. The user needs to know that any change of such options does not take effect until a restart, and this worked correctly if the line is edited without removing it. However, for the case where the line is removed altogether, the flag doesn't get set, because a flag was only set in set_config_option, but that's not called for lines removed. Repair. (Ref.: commits 62d16c7fc561 and a486e35706ea) Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/202107262302.xsfdfc5sb7sh@alvherre.pgsql
2021-07-28Avoid using ambiguous word "non-negative" in error messages.Fujii Masao
The error messages using the word "non-negative" are confusing because it's ambiguous about whether it accepts zero or not. This commit improves those error messages by replacing it with less ambiguous word like "greater than zero" or "greater than or equal to zero". Also this commit added the note about the word "non-negative" to the error message style guide, to help writing the new error messages. When postgres_fdw option fetch_size was set to zero, previously the error message "fetch_size requires a non-negative integer value" was reported. This error message was outright buggy. Therefore back-patch to all supported versions where such buggy error message could be thrown. Reported-by: Hou Zhijie Author: Bharath Rupireddy Reviewed-by: Kyotaro Horiguchi, Fujii Masao Discussion: https://postgr.es/m/OS0PR01MB5716415335A06B489F1B3A8194569@OS0PR01MB5716.jpnprd01.prod.outlook.com
2021-07-13Robustify tuplesort's free_sort_tuple functionDavid Rowley
41469253e went to the trouble of removing a theoretical bug from free_sort_tuple by checking if the tuple was NULL before freeing it. Let's make this a little more robust by also setting the tuple to NULL so that should we be called again we won't end up doing a pfree on the already pfree'd tuple. Per advice from Tom Lane. Discussion: https://postgr.es/m/3188192.1626136953@sss.pgh.pa.us Backpatch-through: 9.6, same as 41469253e
2021-07-13Fix theoretical bug in tuplesortDavid Rowley
This fixes a theoretical bug in tuplesort.c which, if a bounded sort was used in combination with a byval Datum sort (tuplesort_begin_datum), when switching the sort to a bounded heap in make_bounded_heap(), we'd call free_sort_tuple(). The problem was that when sorting Datums of a byval type, the tuple is NULL and free_sort_tuple() would free the memory for it regardless of that. This would result in a crash. Here we fix that simply by adding a check to see if the tuple is NULL before trying to disassociate and free any memory belonging to it. The reason this bug is only theoretical is that nowhere in the current code base do we do tuplesort_set_bound() when performing a Datum sort. However, let's backpatch a fix for this as if any extension uses the code in this way then it's likely to cause problems. Author: Ronan Dunklau Discussion: https://postgr.es/m/CAApHDvpdoqNC5FjDb3KUTSMs5dg6f+XxH4Bg_dVcLi8UYAG3EQ@mail.gmail.com Backpatch-through: 9.6, oldest supported version
2021-07-10Fix numeric_mul() overflow due to too many digits after decimal point.Dean Rasheed
This fixes an overflow error when using the numeric * operator if the result has more than 16383 digits after the decimal point by rounding the result. Overflow errors should only occur if the result has too many digits *before* the decimal point. Discussion: https://postgr.es/m/CAEZATCUmeFWCrq2dNzZpRj5+6LfN85jYiDoqm+ucSXhb9U2TbA@mail.gmail.com
2021-07-09Add missing Int64GetDatum macro in dbsize.cDavid Rowley
I accidentally missed adding this when adjusting 55fe60938 for back patching. This adjustment was made for 9.6 to 13. 14 and master are not affected. Discussion: https://postgr.es/m/CAApHDvp=twCsGAGQG=A=cqOaj4mpknPBW-EZB-sd+5ZS5gCTtA@mail.gmail.com
2021-07-09Fix incorrect return value in pg_size_pretty(bigint)David Rowley
Due to how pg_size_pretty(bigint) was implemented, it's possible that when given a negative number of bytes that the returning value would not match the equivalent positive return value when given the equivalent positive number of bytes. This was due to two separate issues. 1. The function used bit shifting to convert the number of bytes into larger units. The rounding performed by bit shifting is not the same as dividing. For example -3 >> 1 = -2, but -3 / 2 = -1. These two operations are only equivalent with positive numbers. 2. The half_rounded() macro rounded towards positive infinity. This meant that negative numbers rounded towards zero and positive numbers rounded away from zero. Here we fix #1 by dividing the values instead of bit shifting. We fix #2 by adjusting the half_rounded macro always to round away from zero. Additionally, adjust the pg_size_pretty(numeric) function to be more explicit that it's using division rather than bit shifting. A casual observer might have believed bit shifting was used due to a static function being named numeric_shift_right. However, that function was calculating the divisor from the number of bits and performed division. Here we make that more clear. This change is just cosmetic and does not affect the return value of the numeric version of the function. Here we also add a set of regression tests both versions of pg_size_pretty() which test the values directly before and after the function switches to the next unit. This bug was introduced in 8a1fab36a. Prior to that negative values were always displayed in bytes. Author: Dean Rasheed, David Rowley Discussion: https://postgr.es/m/CAEZATCXnNW4HsmZnxhfezR5FuiGgp+mkY4AzcL5eRGO4fuadWg@mail.gmail.com Backpatch-through: 9.6, where the bug was introduced.
2021-07-05Reduce overhead of cache-clobber testing in LookupOpclassInfo().Tom Lane
Commit 03ffc4d6d added logic to bypass all caching behavior in LookupOpclassInfo when CLOBBER_CACHE_ALWAYS is enabled. It doesn't look like I stopped to think much about what that would cost, but recent investigation shows that the cost is enormous: it roughly doubles the time needed for cache-clobber test runs. There does seem to be value in this behavior when trying to test the opclass-cache loading logic itself, but for other purposes the cost is excessive. Hence, let's back off to doing this only when debug_invalidate_system_caches_always is at least 3; or in older branches, when CLOBBER_CACHE_RECURSIVELY is defined. While here, clean up some other minor issues in LookupOpclassInfo. Re-order the code so we aren't left with broken cache entries (leading to later core dumps) in the unlikely case that we suffer OOM while trying to allocate space for a new entry. (That seems to be my oversight in 03ffc4d6d.) Also, in >= v13, stop allocating one array entry too many. That's evidently left over from sloppy reversion in 851b14b0c. Back-patch to all supported branches, mainly to reduce the runtime of cache-clobbering buildfarm animals. Discussion: https://postgr.es/m/1370856.1625428625@sss.pgh.pa.us
2021-06-24Another fix to relmapper race condition.Heikki Linnakangas
In previous commit, I missed that relmap_redo() was also not acquiring the RelationMappingLock. Thanks to Thomas Munro for pointing that out. Backpatch-through: 9.6, like previous commit. Discussion: https://www.postgresql.org/message-id/CA%2BhUKGLev%3DPpOSaL3WRZgOvgk217et%2BbxeJcRr4eR-NttP1F6Q%40mail.gmail.com
2021-06-24Prevent race condition while reading relmapper file.Heikki Linnakangas
Contrary to the comment here, POSIX does not guarantee atomicity of a read(), if another process calls write() concurrently. Or at least Linux does not. Add locking to load_relmap_file() to avoid the race condition. Fixes bug #17064. Thanks to Alexander Lakhin for the report and test case. Backpatch-through: 9.6, all supported versions. Discussion: https://www.postgresql.org/message-id/17064-bb0d7904ef72add3@postgresql.org
2021-06-12Ensure pg_filenode_relation(0, 0) returns NULL.Tom Lane
Previously, a zero value for the relfilenode resulted in a confusing error message about "unexpected duplicate". This function returns NULL for other invalid relfilenode values, so zero should be treated likewise. It's been like this all along, so back-patch to all supported branches. Justin Pryzby Discussion: https://postgr.es/m/20210612023324.GT16435@telsasoft.com
2021-06-01Reject SELECT ... GROUP BY GROUPING SETS (()) FOR UPDATE.Tom Lane
This case should be disallowed, just as FOR UPDATE with a plain GROUP BY is disallowed; FOR UPDATE only makes sense when each row of the query result can be identified with a single table row. However, we missed teaching CheckSelectLocking() to check groupingSets as well as groupClause, so that it would allow degenerate grouping sets. That resulted in a bad plan and a null-pointer dereference in the executor. Looking around for other instances of the same bug, the only one I found was in examine_simple_variable(). That'd just lead to silly estimates, but it should be fixed too. Per private report from Yaoguang Chen. Back-patch to all supported branches.
2021-05-10Prevent integer overflows in array subscripting calculations.Tom Lane
While we were (mostly) careful about ensuring that the dimensions of arrays aren't large enough to cause integer overflow, the lower bound values were generally not checked. This allows situations where lower_bound + dimension overflows an integer. It seems that that's harmless so far as array reading is concerned, except that array elements with subscripts notionally exceeding INT_MAX are inaccessible. However, it confuses various array-assignment logic, resulting in a potential for memory stomps. Fix by adding checks that array lower bounds aren't large enough to cause lower_bound + dimension to overflow. (Note: this results in disallowing cases where the last subscript position would be exactly INT_MAX. In principle we could probably allow that, but there's a lot of code that computes lower_bound + dimension and would need adjustment. It seems doubtful that it's worth the trouble/risk to allow it.) Somewhat independently of that, array_set_element() was careless about possible overflow when checking the subscript of a fixed-length array, creating a different route to memory stomps. Fix that too. Security: CVE-2021-32027
2021-04-13Fix some inappropriately-disallowed uses of ALTER ROLE/DATABASE SET.Tom Lane
Most GUC check hooks that inspect database state have special checks that prevent them from throwing hard errors for state-dependent issues when source == PGC_S_TEST. This allows, for example, "ALTER DATABASE d SET default_text_search_config = foo" when the "foo" configuration hasn't been created yet. Without this, we have problems during dump/reload or pg_upgrade, because pg_dump has no idea about possible dependencies of GUC values and can't ensure a safe restore ordering. However, check_role() and check_session_authorization() hadn't gotten the memo about that, and would throw hard errors anyway. It's not entirely clear what is the use-case for "ALTER ROLE x SET role = y", but we've now heard two independent complaints about that bollixing an upgrade, so apparently some people are doing it. Hence, fix these two functions to act more like other check hooks with similar needs. (But I did not change their insistence on being inside a transaction, as it's still not apparent that setting either GUC from the configuration file would be wise.) Also fix check_temp_buffers, which had a different form of the disease of making state-dependent checks without any exception for PGC_S_TEST. A cursory survey of other GUC check hooks did not find any more issues of this ilk. (There are a lot of interdependencies among PGC_POSTMASTER and PGC_SIGHUP GUCs, which may be a bad idea, but they're not relevant to the immediate concern because they can't be set via ALTER ROLE/DATABASE.) Per reports from Charlie Hornsby and Nathan Bossart. Back-patch to all supported branches. Discussion: https://postgr.es/m/HE1P189MB0523B31598B0C772C908088DB7709@HE1P189MB0523.EURP189.PROD.OUTLOOK.COM Discussion: https://postgr.es/m/20160711223641.1426.86096@wrigleys.postgresql.org
2021-04-12Fix out-of-bound memory access for interval -> char conversionMichael Paquier
Using Roman numbers (via "RM" or "rm") for a conversion to calculate a number of months has never considered the case of negative numbers, where a conversion could easily cause out-of-bound memory accesses. The conversions in themselves were not completely consistent either, as specifying 12 would result in NULL, but it should mean XII. This commit reworks the conversion calculation to have a more consistent behavior: - If the number of months and years is 0, return NULL. - If the number of months is positive, return the exact month number. - If the number of months is negative, do a backward calculation, with -1 meaning December, -2 November, etc. Reported-by: Theodor Arsenij Larionov-Trichkin Author: Julien Rouhaud Discussion: https://postgr.es/m/16953-f255a18f8c51f1d5@postgresql.org backpatch-through: 9.6
2021-04-09Fix typoMagnus Hagander
Author: Daniel Westermann Backpatch-through: 9.6 Discussion: https://postgr.es/m/GV0P278MB0483A7AA85BAFCC06D90F453D2739@GV0P278MB0483.CHEP278.PROD.OUTLOOK.COM
2021-03-18Don't leak malloc'd strings when a GUC setting is rejected.Tom Lane
Because guc.c prefers to keep all its string values in malloc'd not palloc'd storage, it has to be more careful than usual to avoid leaks. Error exits out of string GUC hook checks failed to clear the proposed value string, and error exits out of ProcessGUCArray() failed to clear the malloc'd results of ParseLongOption(). Found via valgrind testing. This problem is ancient, so back-patch to all supported branches. Discussion: https://postgr.es/m/3816764.1616104288@sss.pgh.pa.us
2021-02-16Fix compiler warning in back branches (9.6, 10).Thomas Munro
Back-patch a tiny bit of commit fbb2e9a0 into 9.6 and 10, to silence an uninitialized variable warning from GCC 10.2. Seen on buildfarm member handfish, and my own development workflow where I like to use -Werror. Discussion: https://postgr.es/m/CA%2BhUKGJRcwvK86Uf5t-FrTekZjqHtpv3u%3D3MuBg8Zw8R933Mqg%40mail.gmail.com
2021-02-15Default to wal_sync_method=fdatasync on FreeBSD.Thomas Munro
FreeBSD 13 gained O_DSYNC, which would normally cause wal_sync_method to choose open_datasync as its default value. That may not be a good choice for all systems, and performs worse than fdatasync in some scenarios. Let's preserve the existing default behavior for now. Like commit 576477e73c4, which did the same for Linux, back-patch to all supported releases. Discussion: https://postgr.es/m/CA%2BhUKGLsAMXBQrCxCXoW-JsUYmdOL8ALYvaX%3DCrHqWxm-nWbGA%40mail.gmail.com
2021-02-12Avoid divide-by-zero in regex_selectivity() with long fixed prefix.Tom Lane
Given a regex pattern with a very long fixed prefix (approaching 500 characters), the result of pow(FIXED_CHAR_SEL, fixed_prefix_len) can underflow to zero. Typically the preceding selectivity calculation would have underflowed as well, so that we compute 0/0 and get NaN. In released branches this leads to an assertion failure later on. That doesn't happen in HEAD, for reasons I've not explored yet, but it's surely still a bug. To fix, just skip the division when the pow() result is zero, so that we'll (most likely) return a zero selectivity estimate. In the edge cases where "sel" didn't yet underflow, perhaps this isn't desirable, but I'm not sure that the case is worth spending a lot of effort on. The results of regex_selectivity_sub() are barely worth the electrons they're written on anyway :-( Per report from Alexander Lakhin. Back-patch to all supported versions. Discussion: https://postgr.es/m/6de0a0c3-ada9-cd0c-3e4e-2fa9964b41e3@gmail.com
2021-01-25Fix broken ruleutils support for function TRANSFORM clauses.Tom Lane
I chanced to notice that this dumped core due to a faulty Assert. To add insult to injury, the output has been misformatted since v11. Obviously we need some regression testing here. Discussion: https://postgr.es/m/d1cc628c-3953-4209-957b-29427acc38c8@www.fastmail.com
2021-01-05Add an explicit cast to double when using fabs().Dean Rasheed
Commit bc43b7c2c0 used fabs() directly on an int variable, which apparently requires an explicit cast on some platforms. Per buildfarm.
2021-01-05Fix numeric_power() when the exponent is INT_MIN.Dean Rasheed
In power_var_int(), the computation of the number of significant digits to use in the computation used log(Abs(exp)), which isn't safe because Abs(exp) returns INT_MIN when exp is INT_MIN. Use fabs() instead of Abs(), so that the exponent is cast to a double before the absolute value is taken. Back-patch to 9.6, where this was introduced (by 7d9a4737c2). Discussion: https://postgr.es/m/CAEZATCVd6pMkz=BrZEgBKyqqJrt2xghr=fNc8+Z=5xC6cgWrWA@mail.gmail.com
2020-12-28Fix inconsistent code with shared invalidations of snapshotsMichael Paquier
The code in charge of processing a single invalidation message has been using since 568d413 the structure for relation mapping messages. This had fortunately no consequence as both locate the database ID at the same location, but it could become a problem in the future if this area of the code changes. Author: Konstantin Knizhnik Discussion: https://postgr.es/m/8044c223-4d3a-2cdb-42bf-29940840ce94@postgrespro.ru Backpatch-through: 9.5
2020-12-25Invalidate acl.c caches when pg_authid changes.Noah Misch
This makes existing sessions reflect "ALTER ROLE ... [NO]INHERIT" as quickly as they have been reflecting "GRANT role_name". Back-patch to 9.5 (all supported versions). Reviewed by Nathan Bossart. Discussion: https://postgr.es/m/20201221095028.GB3777719@rfd.leadboat.com
2020-12-21Remove "invalid concatenation of jsonb objects" error case.Tom Lane
The jsonb || jsonb operator arbitrarily rejected certain combinations of scalar and non-scalar inputs, while being willing to concatenate other combinations. This was of course quite undocumented. Rather than trying to document it, let's just remove the restriction, creating a uniform rule that unless we are handling an object-to-object concatenation, non-array inputs are converted to one-element arrays, resulting in an array-to-array concatenation. (This does not change the behavior for any case that didn't throw an error before.) Per complaint from Joel Jacobson. Back-patch to all supported branches. Discussion: https://postgr.es/m/163099.1608312033@sss.pgh.pa.us
2020-12-18Avoid memcpy() with same source and destination during relmapper init.Tom Lane
A narrow reading of the C standard says that memcpy(x,x,n) is undefined, although it's hard to envision an implementation that would really misbehave. However, analysis tools such as valgrind might whine about this; accordingly, let's band-aid relmapper.c to not do it. See also 5b630501e, d3f4e8a8a, ad7b48ea0, and other similar fixes. Apparently, none of those folk tried valgrinding initdb? This has been like this for long enough that I'm surprised it hasn't been reported before. Back-patch, just in case anybody wants to use a back branch on a platform that complains about this; we back-patched those earlier fixes too. Discussion: https://postgr.es/m/161790.1608310142@sss.pgh.pa.us
2020-11-10Fix and simplify some usages of TimestampDifference().Tom Lane
Introduce TimestampDifferenceMilliseconds() to simplify callers that would rather have the difference in milliseconds, instead of the select()-oriented seconds-and-microseconds format. This gets rid of at least one integer division per call, and it eliminates some apparently-easy-to-mess-up arithmetic. Two of these call sites were in fact wrong: * pg_prewarm's autoprewarm_main() forgot to multiply the seconds by 1000, thus ending up with a delay 1000X shorter than intended. That doesn't quite make it a busy-wait, but close. * postgres_fdw's pgfdw_get_cleanup_result() thought it needed to compute microseconds not milliseconds, thus ending up with a delay 1000X longer than intended. Somebody along the way had noticed this problem but misdiagnosed the cause, and imposed an ad-hoc 60-second limit rather than fixing the units. This was relatively harmless in context, because we don't care that much about exactly how long this delay is; still, it's wrong. There are a few more callers of TimestampDifference() that don't have a direct need for seconds-and-microseconds, but can't use TimestampDifferenceMilliseconds() either because they do need microsecond precision or because they might possibly deal with intervals long enough to overflow 32-bit milliseconds. It might be worth inventing another API to improve that, but that seems outside the scope of this patch; so those callers are untouched here. Given the fact that we are fixing some bugs, and the likelihood that future patches might want to back-patch code that uses this new API, back-patch to all supported branches. Alexey Kondratov and Tom Lane Discussion: https://postgr.es/m/3b1c053a21c07c1ed5e00be3b2b855ef@postgrespro.ru
2020-10-12Fix memory leak when guc.c decides a setting can't be applied now.Tom Lane
The prohibitValueChange code paths in set_config_option(), which are executed whenever we re-read a PGC_POSTMASTER variable from postgresql.conf, neglected to free anything before exiting. Thus we'd leak the proposed new value of a PGC_STRING variable, as noted by BoChen in bug #16666. For all variable types, if the check hook creates an "extra" chunk, we'd also leak that. These are malloc not palloc chunks, so there is no mechanism for recovering the leaks before process exit. Fortunately, the values are typically not very large, meaning you'd have to go through an awful lot of SIGHUP configuration-reload cycles to make the leakage amount to anything. Still, for a long-lived postmaster process it could potentially be a problem. Oversight in commit 2594cf0e8. Back-patch to all supported branches. Discussion: https://postgr.es/m/16666-2c41a4eec61b03e1@postgresql.org
2020-09-30Fix handling of BC years in to_date/to_timestamp.Tom Lane
Previously, a conversion such as to_date('-44-02-01','YYYY-MM-DD') would result in '0045-02-01 BC', as the code attempted to interpret the negative year as BC, but failed to apply the correction needed for our internal handling of BC years. Fix the off-by-one problem. Also, arrange for the combination of a negative year and an explicit "BC" marker to cancel out and produce AD. This is how the negative-century case works, so it seems sane to do likewise. Continue to read "year 0000" as 1 BC. Oracle would throw an error, but we've accepted that case for a long time so I'm hesitant to change it in a back-patch. Per bug #16419 from Saeed Hubaishan. Back-patch to all supported branches. Dar Alathar-Yemen and Tom Lane Discussion: https://postgr.es/m/16419-d8d9db0a7553f01b@postgresql.org
2020-08-15Move new LOCKTAG_DATABASE_FROZEN_IDS to end of enum LockTagType.Noah Misch
Several PGXN modules reference LockTagType values; renumbering would force a recompile of those modules. Oversight in back-patch of today's commit 566372b3d6435639e4cc4476d79b8505a0297c87. Back-patch to released branches, v12 through 9.5. Reported by Tom Lane. Discussion: https://postgr.es/m/921383.1597523945@sss.pgh.pa.us
2020-08-15Prevent concurrent SimpleLruTruncate() for any given SLRU.Noah Misch
The SimpleLruTruncate() header comment states the new coding rule. To achieve this, add locktype "frozenid" and two LWLocks. This closes a rare opportunity for data loss, which manifested as "apparent wraparound" or "could not access status of transaction" errors. Data loss is more likely in pg_multixact, due to released branches' thin margin between multiStopLimit and multiWrapLimit. If a user's physical replication primary logged ": apparent wraparound" messages, the user should rebuild standbys of that primary regardless of symptoms. At less risk is a cluster having emitted "not accepting commands" errors or "must be vacuumed" warnings at some point. One can test a cluster for this data loss by running VACUUM FREEZE in every database. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20190218073103.GA1434723@rfd.leadboat.com
2020-08-14Fix postmaster's behavior during smart shutdown.Tom Lane
Up to now, upon receipt of a SIGTERM ("smart shutdown" command), the postmaster has immediately killed all "optional" background processes, and subsequently refused to launch new ones while it's waiting for foreground client processes to exit. No doubt this seemed like an OK policy at some point; but it's a pretty bad one now, because it makes for a seriously degraded environment for the remaining clients: * Parallel queries are killed, and new ones fail to launch. (And our parallel-query infrastructure utterly fails to deal with the case in a reasonable way --- it just hangs waiting for workers that are not going to arrive. There is more work needed in that area IMO.) * Autovacuum ceases to function. We can tolerate that for awhile, but if bulk-update queries continue to run in the surviving client sessions, there's eventually going to be a mess. In the worst case the system could reach a forced shutdown to prevent XID wraparound. * The bgwriter and walwriter are also stopped immediately, likely resulting in performance degradation. Hence, let's rearrange things so that the only immediate change in behavior is refusing to let in new normal connections. Once the last normal connection is gone, shut everything down as though we'd received a "fast" shutdown. To implement this, remove the PM_WAIT_BACKUP and PM_WAIT_READONLY states, instead staying in PM_RUN or PM_HOT_STANDBY while normal connections remain. A subsidiary state variable tracks whether or not we're letting in new connections in those states. This also allows having just one copy of the logic for killing child processes in smart and fast shutdown modes. I moved that logic into PostmasterStateMachine() by inventing a new state PM_STOP_BACKENDS. Back-patch to 9.6 where parallel query was added. In principle this'd be a good idea in 9.5 as well, but the risk/reward ratio is not as good there, since lack of autovacuum is not a problem during typical uses of smart shutdown. Per report from Bharath Rupireddy. Patch by me, reviewed by Thomas Munro Discussion: https://postgr.es/m/CALj2ACXAZ5vKxT9P7P89D87i3MDO9bfS+_bjMHgnWJs8uwUOOw@mail.gmail.com
2020-07-31Fix recently-introduced performance problem in ts_headline().Tom Lane
The new hlCover() algorithm that I introduced in commit c9b0c678d turns out to potentially take O(N^2) or worse time on long documents, if there are many occurrences of individual query words but few or no substrings that actually satisfy the query. (One way to hit this behavior is with a "common_word & rare_word" type of query.) This seems unavoidable given the original goal of checking every substring of the document, so we have to back off that idea. Fortunately, it seems unlikely that anyone would really want headlines spanning all of a long document, so we can avoid the worse-than-linear behavior by imposing a maximum length of substring that we'll consider. For now, just hard-wire that maximum length as a multiple of max_words times max_fragments. Perhaps at some point somebody will argue for exposing it as a ts_headline parameter, but I'm hesitant to make such a feature addition in a back-patched bug fix. I also noted that the hlFirstIndex() function I'd added in that commit was unnecessarily stupid: it really only needs to check whether a HeadlineWordEntry's item pointer is null or not. This wouldn't make all that much difference in typical cases with queries having just a few terms, but a cycle shaved is a cycle earned. In addition, add a CHECK_FOR_INTERRUPTS call in TS_execute_recurse. This ensures that hlCover's loop is cancellable if it manages to take a long time, and it may protect some other TS_execute callers as well. Back-patch to 9.6 as the previous commit was. I also chose to add the CHECK_FOR_INTERRUPTS call to 9.5. The old hlCover() algorithm seems to avoid the O(N^2) behavior, at least on the test case I tried, but nonetheless it's not very quick on a long document. Per report from Stephen Frost. Discussion: https://postgr.es/m/20200724160535.GW12375@tamriel.snowman.net
2020-07-29Backpatch tuplesort.c assertion.Peter Geoghegan
Backpatch an assertion (that was originally added to Postgres 12 by commit dd299df8189) that seems broadly useful. The assertion can detect violations of the HOT invariant (i.e. no two index tuples can point to the same heap TID) when CREATE INDEX somehow incorrectly allows that to take place. For example, a IndexBuildHeapScan/heapam_index_build_range_scan bug might result in two tuples that both point to the same heap TID. If these two tuples also happen to be duplicates, the assertion will fail. Discussion: https://postgr.es/m/CAH2-WzmBxu4o=pMsniur+bwHqCGCmV_AOLkuK6BuU7ngA6evqw@mail.gmail.com Backpatch: 9.5-11 only
2020-06-16Fix buffile.c error handling.Thomas Munro
Convert buffile.c error handling to use ereport. This fixes cases where I/O errors were indistinguishable from EOF or not reported. Also remove "%m" from error messages where errno would be bogus. While we're modifying those strings, add block numbers and short read byte counts where appropriate. Back-patch to all supported releases. Reported-by: Amit Khandekar <amitdkhan.pg@gmail.com> Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Ibrar Ahmed <ibrar.ahmad@gmail.com> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGJE04G%3D8TLK0DLypT_27D9dR8F1RQgNp0jK6qR0tZGWOw%40mail.gmail.com
2020-06-11Fix mishandling of NaN counts in numeric_[avg_]combine.Tom Lane
When merging two NumericAggStates, the code missed adding the new state's NaNcount unless its N was also nonzero; since those counts are independent, this is wrong. This would only have visible effect if some partial aggregate scans found only NaNs while earlier ones found only non-NaNs; then we could end up falsely deciding that there were no NaNs and fail to return a NaN final result as expected. That's pretty improbable, so it's no surprise this hasn't been reported from the field. Still, it's a bug. I didn't try to produce a regression test that would show the bug, but I did notice that these functions weren't being reached at all in our regression tests, so I improved the tests to at least exercise them. With these additions, I see pretty complete code coverage on the aggregation-related functions in numeric.c. Back-patch to 9.6 where this code was introduced. (I only added the improved test case as far back as v10, though, since the relevant part of aggregates.sql isn't there at all in 9.6.)
2020-06-01Fix use-after-release mistake in currtid() and currtid2() for viewsMichael Paquier
This issue has been present since the introduction of this code as of a3519a2 from 2002, and has been found by buildfarm member prion that uses RELCACHE_FORCE_RELEASE via the tests introduced recently in e786be5. Discussion: https://postgr.es/m/20200601022055.GB4121@paquier.xyz Backpatch-through: 9.5
2020-05-28Add CHECK_FOR_INTERRUPTS() to the repeat() functionJoe Conway
The repeat() function loops for potentially a long time without ever checking for interrupts. This prevents, for example, a query cancel from interrupting until the work is all done. Fix by inserting a CHECK_FOR_INTERRUPTS() into the loop. Backpatch to all supported versions. Discussion: https://www.postgresql.org/message-id/flat/8692553c-7fe8-17d9-cbc1-7cddb758f4c6%40joeconway.com
2020-05-14Fix the MSVC build for versions 2015 and later.Amit Kapila
Visual Studio 2015 and later versions should still be able to do the same as Visual Studio 2012, but the declaration of locale_name is missing in _locale_t, causing the code compilation to fail, hence this falls back instead on to enumerating all system locales by using EnumSystemLocalesEx to find the required locale name.  If the input argument is in Unix-style then we can get ISO Locale name directly by using GetLocaleInfoEx() with LCType as LOCALE_SNAME. In passing, change the documentation references of the now obsolete links. Note that this problem occurs only with NLS enabled builds. Author: Juan José Santamaría Flecha, Davinder Singh and Amit Kapila Reviewed-by: Ranier Vilela and Amit Kapila Backpatch-through: 9.5 Discussion: https://postgr.es/m/CAHzhFSFoJEWezR96um4-rg5W6m2Rj9Ud2CNZvV4NWc9tXV7aXQ@mail.gmail.com
2020-05-07Fix YA text phrase search bug.Tom Lane
checkcondition_str() failed to report multiple matches for a prefix pattern correctly: it would dutifully merge the match positions, but then after exiting that loop, if the last prefix-matching word had had no suitable positions, it would report there were no matches. The upshot would be failing to recognize a match that the query should match. It looks like you need all of these conditions to see the bug: * a phrase search (else we don't ask for match position details) * a prefix search item (else we don't get to this code) * a weight restriction (else checkclass_str won't fail) Noted while investigating a problem report from Pavel Borisov, though this is distinct from the issue he was on about. Back-patch to 9.6 where phrase search was added.
2020-05-01Get rid of trailing semicolons in C macro definitions.Tom Lane
Writing a trailing semicolon in a macro is almost never the right thing, because you almost always want to write a semicolon after each macro call instead. (Even if there was some reason to prefer not to, pgindent would probably make a hash of code formatted that way; so within PG the rule should basically be "don't do it".) Thus, if we have a semi inside the macro, the compiler sees "something;;". Much of the time the extra empty statement is harmless, but it could lead to mysterious syntax errors at call sites. In perhaps an overabundance of neatnik-ism, let's run around and get rid of the excess semicolons whereever possible. The only thing worse than a mysterious syntax error is a mysterious syntax error that only happens in the back branches; therefore, backpatch these changes where relevant, which is most of them because most of these mistakes are old. (The lack of reported problems shows that this is largely a hypothetical issue, but still, it could bite us in some future patch.) John Naylor and Tom Lane Discussion: https://postgr.es/m/CACPNZCs0qWTqJ2QUSGJ07B7uvAvzMb-KbG2q+oo+J3tsWN5cqw@mail.gmail.com
2020-04-27Fix full text search to handle NOT above a phrase search correctly.Tom Lane
Queries such as '!(foo<->bar)' failed to find matching rows when implemented as a GiST or GIN index search. That's because of failing to handle phrase searches as tri-valued when considering a query without any position information for the target tsvector. We can only say that the phrase operator might match, not that it does match; and therefore its NOT also might match. The previous coding incorrectly inverted the approximate phrase result to decide that there was certainly no match. To fix, we need to make TS_phrase_execute return a real ternary result, and then bubble that up accurately in TS_execute. As long as we have to do that anyway, we can simplify the baroque things TS_phrase_execute was doing internally to manage tri-valued searching with only a bool as explicit result. For now, I left the externally-visible result of TS_execute as a plain bool. There do not appear to be any outside callers that need to distinguish a three-way result, given that they passed in a flag saying what to do in the absence of position data. This might need to change someday, but we wouldn't want to back-patch such a change. Although tsginidx.c has its own TS_execute_ternary implementation for use at upper index levels, that sadly managed to get this case wrong as well :-(. Fixing it is a lot easier fortunately. Per bug #16388 from Charles Offenbacher. Back-patch to 9.6 where phrase search was introduced. Discussion: https://postgr.es/m/16388-98cffba38d0b7e6e@postgresql.org
2020-04-07Fix circle_in to accept "(x,y),r" as it's advertised to do.Tom Lane
Our documentation describes four allowed input syntaxes for circles, but the regression tests tried only three ... with predictable consequences. Remarkably, this has been wrong since the circle datatype was added in 1997, but nobody noticed till now. David Zhang, with some help from me Discussion: https://postgr.es/m/332c47fa-d951-7574-b5cc-a8f7f7201202@highgo.ca
2020-04-07Adjust bytea get_bit/set_bit to cope with bytea strings > 256MB.Tom Lane
Since the existing bit number argument can't exceed INT32_MAX, it's not possible for these functions to manipulate bits beyond the first 256MB of a bytea value. However, it'd be good if they could do at least that much, and not fall over entirely for longer bytea values. Adjust the comparisons to be done in int64 arithmetic so that works. Also tweak the error reports to show sane values in case of overflow. Also add some test cases to improve the miserable code coverage of these functions. Apply patch to back branches only; HEAD has a better solution as of commit 26a944cf2. Extracted from a much larger patch by Movead Li Discussion: https://postgr.es/m/20200312115135445367128@highgo.ca
2020-04-06Preserve clustered index after rewrites with ALTER TABLEMichael Paquier
A table rewritten by ALTER TABLE would lose tracking of an index usable for CLUSTER. This setting is tracked by pg_index.indisclustered and is controlled by ALTER TABLE, so some extra work was needed to restore it properly. Note that ALTER TABLE only marks the index that can be used for clustering, and does not do the actual operation. Author: Amit Langote, Justin Pryzby Reviewed-by: Ibrar Ahmed, Michael Paquier Discussion: https://postgr.es/m/20200202161718.GI13621@telsasoft.com Backpatch-through: 9.5
2020-03-28Ensure snapshot is registered within ScanPgRelation().Andres Freund
In 9.4 I added support to use a historical snapshot in ScanPgRelation(), while adding logical decoding. Unfortunately a conflict with the concurrent removal of SnapshotNow was incorrectly resolved, leading to an unregistered snapshot being used. It is not correct to use an unregistered (or non-active) snapshot for anything non-trivial, because catalog invalidations can cause the snapshot to be invalidated. Luckily it seems unlikely to actively cause problems in practice, as ScanPgRelation() requires that we already have a lock on the relation, we only look for a single row, and we don't appear to rely on the result's tid to be correct. It however is clearly wrong and potential negative consequences would likely be hard to find. So it seems worth backpatching the fix, even without a concrete hazard. Discussion: https://postgr.es/m/20200229052459.wzhqnbhrriezg4v2@alap3.anarazel.de Backpatch: 9.5-
2020-03-22Revert "Skip WAL for new relfilenodes, under wal_level=minimal."Noah Misch
This reverts commit cb2fd7eac285b1b0a24eeb2b8ed4456b66c5a09f. Per numerous buildfarm members, it was incompatible with parallel query, and a test case assumed LP64. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20200321224920.GB1763544@rfd.leadboat.com
2020-03-21Skip WAL for new relfilenodes, under wal_level=minimal.Noah Misch
Until now, only selected bulk operations (e.g. COPY) did this. If a given relfilenode received both a WAL-skipping COPY and a WAL-logged operation (e.g. INSERT), recovery could lose tuples from the COPY. See src/backend/access/transam/README section "Skipping WAL for New RelFileNode" for the new coding rules. Maintainers of table access methods should examine that section. To maintain data durability, just before commit, we choose between an fsync of the relfilenode and copying its contents to WAL. A new GUC, wal_skip_threshold, guides that choice. If this change slows a workload that creates small, permanent relfilenodes under wal_level=minimal, try adjusting wal_skip_threshold. Users setting a timeout on COMMIT may need to adjust that timeout, and log_min_duration_statement analysis will reflect time consumption moving to COMMIT from commands like COPY. Internally, this requires a reliable determination of whether RollbackAndReleaseCurrentSubTransaction() would unlink a relation's current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the specification of rd_createSubid such that the field is zero when a new rel has an old rd_node. Make relcache.c retain entries for certain dropped relations until end of transaction. Back-patch to 9.5 (all supported versions). This introduces a new WAL record type, XLOG_GIST_ASSIGN_LSN, without bumping XLOG_PAGE_MAGIC. As always, update standby systems before master systems. This changes sizeof(RelationData) and sizeof(IndexStmt), breaking binary compatibility for affected extensions. (The most recent commit to affect the same class of extensions was 089e4d405d0f3b94c74a2c6a54357a84a681754b.) Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert Haas. Heikki Linnakangas and Michael Paquier implemented earlier designs that materially clarified the problem. Reviewed, in earlier designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane, Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout. Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org