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* Allow aggregates to provide estimates of their transition state data size.Tom Lane2013-11-16
| | | | | | | | | | | | | | | | | | | | Formerly the planner had a hard-wired rule of thumb for guessing the amount of space consumed by an aggregate function's transition state data. This estimate is critical to deciding whether it's OK to use hash aggregation, and in many situations the built-in estimate isn't very good. This patch adds a column to pg_aggregate wherein a per-aggregate estimate can be provided, overriding the planner's default, and infrastructure for setting the column via CREATE AGGREGATE. It may be that additional smarts will be required in future, perhaps even a per-aggregate estimation function. But this is already a step forward. This is extracted from a larger patch to improve the performance of numeric and int8 aggregates. I (tgl) thought it was worth reviewing and committing this infrastructure separately. In this commit, all built-in aggregates are given aggtransspace = 0, so no behavior should change. Hadi Moshayedi, reviewed by Pavel Stehule and Tomas Vondra
* Fix incorrect loop counts in tidbitmap.c.Tom Lane2013-11-15
| | | | | | | | | | | | | A couple of places that should have been iterating over WORDS_PER_CHUNK words were iterating over WORDS_PER_PAGE words instead. This thinko accidentally failed to fail, because (at least on common architectures with default BLCKSZ) WORDS_PER_CHUNK is a bit less than WORDS_PER_PAGE, and the extra words being looked at were always zero so nothing happened. Still, it's a bug waiting to happen if anybody ever fools with the parameters affecting TIDBitmap sizes, and it's a small waste of cycles too. So back-patch to all active branches. Etsuro Fujita
* Compute correct em_nullable_relids in get_eclass_for_sort_expr().Tom Lane2013-11-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | Bug #8591 from Claudio Freire demonstrates that get_eclass_for_sort_expr must be able to compute valid em_nullable_relids for any new equivalence class members it creates. I'd worried about this in the commit message for db9f0e1d9a4a0842c814a464cdc9758c3f20b96c, but claimed that it wasn't a problem because multi-member ECs should already exist when it runs. That is transparently wrong, though, because this function is also called by initialize_mergeclause_eclasses, which runs during deconstruct_jointree. The example given in the bug report (which the new regression test item is based upon) fails because the COALESCE() expression is first seen by initialize_mergeclause_eclasses rather than process_equivalence. Fixing this requires passing the appropriate nullable_relids set to get_eclass_for_sort_expr, and it requires new code to compute that set for top-level expressions such as ORDER BY, GROUP BY, etc. We store the top-level nullable_relids in a new field in PlannerInfo to avoid computing it many times. In the back branches, I've added the new field at the end of the struct to minimize ABI breakage for planner plugins. There doesn't seem to be a good alternative to changing get_eclass_for_sort_expr's API signature, though. There probably aren't any third-party extensions calling that function directly; moreover, if there are, they probably need to think about what to pass for nullable_relids anyway. Back-patch to 9.2, like the previous patch in this area.
* Minor comment corrections for sequence hashtable patch.Tom Lane2013-11-15
| | | | There were enough typos in the comments to annoy me ...
* Fix bogus hash table creation.Heikki Linnakangas2013-11-15
| | | | Andres Freund
* Use a hash table to store current sequence values.Heikki Linnakangas2013-11-15
| | | | | | | This speeds up nextval() and currval(), when you touch a lot of different sequences in the same backend. David Rowley
* Fix relfilenodemap.c's handling of cache invalidations.Robert Haas2013-11-13
| | | | | | | | | | | | | | The old code entered a new hash table entry first, then scanned pg_class to determine what value to fill in, and then populated the entry. This fails to work properly if a cache invalidation happens as a result of opening pg_class. Repair. Along the way, get rid of the idea of blowing away the entire hash table as a method of processing invalidations. Instead, just delete all the entries one by one. This is probably not quite as cheap but it's simpler, and shouldn't happen often. Andres Freund
* Fix bug in GIN posting tree root creation.Heikki Linnakangas2013-11-13
| | | | | | | | | | The root page is filled with as many items as fit, and the rest are inserted using normal insertions. However, I fumbled the variable names, and the code actually memcpy'd all the items on the page, overflowing the buffer. While at it, rename the variable to make the distinction more clear. Reported by Teodor Sigaev. This bug was introduced by my recent refactorings, so no backpatching required.
* Move variable closer to where it is usedPeter Eisentraut2013-11-13
| | | | | | | This avoids an unused variable warning on Windows when building without asserts From: David Rowley <dgrowleyml@gmail.com>
* Fix failure with whole-row reference to a subquery.Tom Lane2013-11-11
| | | | | | Simple oversight in commit 1cb108efb0e60d87e4adec38e7636b6e8efbeb57 --- recursively examining a subquery output column is only sane if the original Var refers to a single output column. Found by Kevin Grittner.
* Fix ruleutils pretty-printing to not generate trailing whitespace.Tom Lane2013-11-11
| | | | | | | | | | | | | | | | | | | | The pretty-printing logic in ruleutils.c operates by inserting a newline and some indentation whitespace into strings that are already valid SQL. This naturally results in leaving some trailing whitespace before the newline in many cases; which can be annoying when processing the output with other tools, as complained of by Joe Abbate. We can fix that in a pretty localized fashion by deleting any trailing whitespace before we append a pretty-printing newline. In addition, we have to modify the code inserted by commit 2f582f76b1945929ff07116cd4639747ce9bb8a1 so that we also delete trailing whitespace when transposing items from temporary buffers into the main result string, when a temporary item starts with a newline. This results in rather voluminous changes to the regression test results, but it's easily verified that they are only removal of trailing whitespace. Back-patch to 9.3, because the aforementioned commit resulted in many more cases of trailing whitespace than had occurred in earlier branches.
* Re-allow duplicate aliases within aliased JOINs.Tom Lane2013-11-11
| | | | | | | | | | | | | | Although the SQL spec forbids duplicate table aliases, historically we've allowed queries like SELECT ... FROM tab1 x CROSS JOIN (tab2 x CROSS JOIN tab3 y) z on the grounds that the aliased join (z) hides the aliases within it, therefore there is no conflict between the two RTEs named "x". The LATERAL patch broke this, on the misguided basis that "x" could be ambiguous if tab3 were a LATERAL subquery. To avoid breaking existing queries, it's better to allow this situation and complain only if tab3 actually does contain an ambiguous reference. We need only remove the check that was throwing an error, because the column lookup code is already prepared to handle ambiguous references. Per bug #8444.
* Fix whitespace issues found by git diff --check, add gitattributesPeter Eisentraut2013-11-10
| | | | | Set per file type attributes in .gitattributes to fine-tune whitespace checks. With the associated cleanups, the tree is now clean for git
* Fix race condition in GIN posting tree page deletion.Heikki Linnakangas2013-11-08
| | | | | | | | | | | | | | | | | | If a page is deleted, and reused for something else, just as a search is following a rightlink to it from its left sibling, the search would continue scanning whatever the new contents of the page are. That could lead to incorrect query results, or even something more curious if the page is reused for a different kind of a page. To fix, modify the search algorithm to lock the next page before releasing the previous one, and refrain from deleting pages from the leftmost branch of the tree. Add a new Concurrency section to the README, explaining why this works. There is a lot more one could say about concurrency in GIN, but that's for another patch. Backpatch to all supported versions.
* Add the notion of REPLICA IDENTITY for a table.Robert Haas2013-11-08
| | | | | | | Pending patches for logical replication will use this to determine which columns of a tuple ought to be considered as its candidate key. Andres Freund, with minor, mostly cosmetic adjustments by me
* Make contain_volatile_functions/contain_mutable_functions look into SubLinks.Tom Lane2013-11-08
| | | | | | | | | | | | | | | | | | | | This change prevents us from doing inappropriate subquery flattening in cases such as dangerous functions hidden inside a sub-SELECT in the targetlist of another sub-SELECT. That could result in unexpected behavior due to multiple evaluations of a volatile function, as in a recent complaint from Etienne Dube. It's been questionable from the very beginning whether these functions should look into subqueries (as noted in their comments), and this case seems to provide proof that they should. Because the new code only descends into SubLinks, not SubPlans or InitPlans, the change only affects the planner's behavior during prepjointree processing and not later on --- for example, you can still get it to use a volatile function in an indexqual if you wrap the function in (SELECT ...). That's a historical behavior, for sure, but it's reasonable given that the executor's evaluation rules for subplans don't depend on whether there are volatile functions inside them. In any case, we need to constrain the behavioral change as narrowly as we can to make this reasonable to back-patch.
* Fix subtly-wrong volatility checking in BeginCopyFrom().Tom Lane2013-11-08
| | | | | | | | | | | | | contain_volatile_functions() is best applied to the output of expression_planner(), not its input, so that insertion of function default arguments and constant-folding have been done. (See comments at CheckMutability, for instance.) It's perhaps unlikely that anyone will notice a difference in practice, but still we should do it properly. In passing, change variable type from Node* to Expr* to reduce the net number of casts needed. Noted while perusing uses of contain_volatile_functions().
* Make LOCK_PRINT & PROCLOCK_PRINT expand to ((void) 0) when not in use.Tom Lane2013-11-07
| | | | | | | This avoids warnings from more-anal-than-average compilers, and might prevent hidden syntax problems in the future. Andres Freund
* Silence benign warnings from clang version 3.0-6ubuntu3.Kevin Grittner2013-11-07
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* Prevent display of dropped columns in row constraint violation messages.Tom Lane2013-11-07
| | | | | | | | | | | | | | | ExecBuildSlotValueDescription() printed "null" for each dropped column in a row being complained of by ExecConstraints(). This has some sanity in terms of the underlying implementation, but is of course pretty surprising to users. To fix, we must pass the target relation's descriptor to ExecBuildSlotValueDescription(), because the slot descriptor it had been using doesn't get labeled with attisdropped markers. Per bug #8408 from Maxim Boguk. Back-patch to 9.2 where the feature of printing row values in NOT NULL and CHECK constraint violation messages was introduced. Michael Paquier and Tom Lane
* Fix generation of MergeAppend plans for optimized min/max on expressions.Tom Lane2013-11-07
| | | | | | | | | | | | | | | | | | | | | | Before jamming a desired targetlist into a plan node, one really ought to make sure the plan node can handle projections, and insert a buffering Result plan node if not. planagg.c forgot to do this, which is a hangover from the days when it only dealt with IndexScan plan types. MergeAppend doesn't project though, not to mention that it gets unhappy if you remove its possibly-resjunk sort columns. The code accidentally failed to fail for cases in which the min/max argument was a simple Var, because the new targetlist would be equivalent to the original "flat" tlist anyway. For any more complex case, it's been broken since 9.1 where we introduced the ability to optimize min/max using MergeAppend, as reported by Raphael Bauduin. Fix by duplicating the logic from grouping_planner that decides whether we need a Result node. In 9.2 and 9.1, this requires back-porting the tlist_same_exprs() function introduced in commit 4387cf956b9eb13aad569634e0c4df081d76e2e3, else we'd uselessly add a Result node in cases that worked before. It's rather tempting to back-patch that whole commit so that we can avoid extra Result nodes in mainline cases too; but I'll refrain, since that code hasn't really seen all that much field testing yet.
* Fix setting of right bound at GIN page split.Heikki Linnakangas2013-11-07
| | | | Broken by my refactoring.
* Add #ifdef guards for some POSIX error symbols that Windows doesn't like.Tom Lane2013-11-06
| | | | | Per buildfarm results. It looks like the older the Windows version, the more errno codes it hasn't got ...
* Be more robust when strerror() doesn't give a useful result.Tom Lane2013-11-06
| | | | | | | | | | | | | | | | | | | | | | | glibc, at least, is capable of returning "???" instead of anything useful if it doesn't like the setting of LC_CTYPE. If this happens, or in the previously-known case of strerror() returning an empty string, try to print the C macro name for the error code ("EACCES" etc). Only if we don't have the error code in our compiled-in list of popular error codes (which covers most though not quite all of what's called out in the POSIX spec) will we fall back to printing a numeric error code. This should simplify debugging. Note that this functionality is currently only provided for %m in backend ereport/elog messages. That may be sufficient, since we don't fool with the locale environment in frontend clients, but it's foreseeable that we might want similar code in libpq for instance. There was some talk of back-patching this, but let's see how the buildfarm likes it first. It seems likely that at least some of the POSIX-defined error code symbols don't exist on all platforms. I don't want to clutter the entire list with #ifdefs, but we may need more than are here now. MauMau, edited by me
* Support default arguments and named-argument notation for window functions.Tom Lane2013-11-06
| | | | | | | | | | | | | | | | | | | | | | These things didn't work because the planner omitted to do the necessary preprocessing of a WindowFunc's argument list. Add the few dozen lines of code needed to handle that. Although this sounds like a feature addition, it's really a bug fix because the default-argument case was likely to crash previously, due to lack of checking of the number of supplied arguments in the built-in window functions. It's not a security issue because there's no way for a non-superuser to create a window function definition with defaults that refers to a built-in C function, but nonetheless people might be annoyed that it crashes rather than producing a useful error message. So back-patch as far as the patch applies easily, which turns out to be 9.2. I'll put a band-aid in earlier versions as a separate patch. (Note that these features still don't work for aggregates, and fixing that case will be harder since we represent aggregate arg lists as target lists not bare expression lists. There's no crash risk though because CREATE AGGREGATE doesn't accept defaults, and we reject named-argument notation when parsing an aggregate call.)
* Keep heap open until new heap generated in RMV.Kevin Grittner2013-11-06
| | | | | | | | Early close became apparent when invalidation messages were processed in a new location under CLOBBER_CACHE_ALWAYS builds, due to additional locking. Back-patch to 9.3
* Fix missing argument and function prototypes.Heikki Linnakangas2013-11-06
| | | | Not sure how I missed these in previous commit.
* Misc GIN refactoring.Heikki Linnakangas2013-11-06
| | | | | | | | | | | | | | | Merge the isEnoughSpace and placeToPage functions in the b-tree interface into one function that tries to put a tuple on page, and returns false if it doesn't fit. Move createPostingTree function to gindatapage.c, and change its contract so that it can be passed more items than fit on the root page. It's in a better position than the callers to know how many items fit. Move ginMergeItemPointers out of gindatapage.c, into a separate file. These changes make no difference now, but reduce the footprint of Alexander Korotkov's upcoming patch to pack item pointers more tightly.
* Improve the error message given for modifying a window with frame clause.Tom Lane2013-11-05
| | | | | | | | | | | | | | For rather inscrutable reasons, SQL:2008 disallows copying-and-modifying a window definition that has any explicit framing clause. The error message we gave for this only made sense if the referencing window definition itself contains an explicit framing clause, which it might well not. Moreover, in the context of an OVER clause it's not exactly obvious that "OVER (windowname)" implies copy-and-modify while "OVER windowname" does not. This has led to multiple complaints, eg bug #5199 from Iliya Krapchatov. Change to a hopefully more intelligible error message, and in the case where we have just "OVER (windowname)", add a HINT suggesting that omitting the parentheses will fix it. Also improve the related documentation. Back-patch to all supported branches.
* Lock relation used to generate fresh data for RMV.Kevin Grittner2013-11-05
| | | | | | | | The relation should not be accessible to any other process, but it should be locked for consistency. Since this is not known to cause any bug, it will not be back-patch, at least for now. Per report from Andres Freund
* Fix some obsolete information in src/backend/optimizer/README.Tom Lane2013-11-05
| | | | | | Constant quals aren't handled the same way they used to be. Also, add mention of a couple more major steps in grouping_planner. Per complaint a couple months back from Etsuro Fujita.
* Fix breakage of MV column name list usage.Kevin Grittner2013-11-04
| | | | | | Per bug report from Tomonari Katsumata. Back-patch to 9.3.
* Fix format code used to print dsm request sizes.Robert Haas2013-11-04
| | | | Per report from Peter Eisentraut.
* Get rid of more cases of the "must detoast before output function" meme.Tom Lane2013-11-03
| | | | | I missed that json.c was doing this too, because for some bizarre reason it wasn't doing it adjacent to the output function call.
* Prevent memory leaks from accumulating across printtup() calls.Tom Lane2013-11-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Historically, printtup() has assumed that it could prevent memory leakage by pfree'ing the string result of each output function and manually managing detoasting of toasted values. This amounts to assuming that datatype output functions never leak any memory internally; an assumption we've already decided to be bogus elsewhere, for example in COPY OUT. range_out in particular is known to leak multiple kilobytes per call, as noted in bug #8573 from Godfried Vanluffelen. While we could go in and fix that leak, it wouldn't be very notationally convenient, and in any case there have been and undoubtedly will again be other leaks in other output functions. So what seems like the best solution is to run the output functions in a temporary memory context that can be reset after each row, as we're doing in COPY OUT. Some quick experimentation suggests this is actually a tad faster than the retail pfree's anyway. This patch fixes all the variants of printtup, except for debugtup() which is used in standalone mode. It doesn't seem worth worrying about query-lifespan leaks in standalone mode, and fixing that case would be a bit tedious since debugtup() doesn't currently have any startup or shutdown functions. While at it, remove manual detoast management from several other output-function call sites that had copied it from printtup(). This doesn't make a lot of difference right now, but in view of recent discussions about supporting "non-flattened" Datums, we're going to want that code gone eventually anyway. Back-patch to 9.2 where range_out was introduced. We might eventually decide to back-patch this further, but in the absence of known major leaks in older output functions, I'll refrain for now.
* Acquire appropriate locks when rewriting during RMV.Kevin Grittner2013-11-02
| | | | | | | | | Since the query has not been freshly parsed when executing REFRESH MATERIALIZED VIEW, locks must be explicitly taken before rewrite. Backpatch to 9.3. Andres Freund
* Fix subquery reference to non-populated MV in CMV.Kevin Grittner2013-11-02
| | | | | | | | | A subquery reference to a matview should be allowed by CREATE MATERIALIZED VIEW WITH NO DATA, just like a direct reference is. Per bug report from Laurent Sartran. Backpatch to 9.3.
* Retry after buffer locking failure during SPGiST index creation.Tom Lane2013-11-02
| | | | | | | | | The original coding thought this case was impossible, but it can happen if the bgwriter or checkpointer processes decide to write out an index page while creation is still proceeding, leading to a bogus "unexpected spgdoinsert() failure" error. Problem reported by Jonathan S. Katz. Teodor Sigaev
* Ensure all files created for a single BufFile have the same resource owner.Tom Lane2013-11-01
| | | | | | | | | | | Callers expect that they only have to set the right resource owner when creating a BufFile, not during subsequent operations on it. While we could insist this be fixed at the caller level, it seems more sensible for the BufFile to take care of it. Without this, some temp files belonging to a BufFile can go away too soon, eg at the end of a subtransaction, leading to errors or crashes. Reported and fixed by Andres Freund. Back-patch to all active branches.
* Remove CTimeZone/HasCTZSet, root and branch.Tom Lane2013-11-01
| | | | | | | | | | | | | | | | | | | | | These variables no longer have any useful purpose, since there's no reason to special-case brute force timezones now that we have a valid session_timezone setting for them. Remove the variables, and remove the SET/SHOW TIME ZONE code that deals with them. The user-visible impact of this is that SHOW TIME ZONE will now show a POSIX-style zone specification, in the form "<+-offset>-+offset", rather than an interval value when a brute-force zone has been set. While perhaps less intuitive, this is a better definition than before because it's actually possible to give that string back to SET TIME ZONE and get the same behavior, unlike what used to happen. We did not previously mention the angle-bracket syntax when describing POSIX timezone specifications; add some documentation so that people can figure out what these strings do. (There's still quite a lot of undocumented functionality there, but anybody who really cares can go read the POSIX spec to find out about it. In practice most people seem to prefer Olsen-style city names anyway.)
* Remove internal uses of CTimeZone/HasCTZSet.Tom Lane2013-11-01
| | | | | | | | | | | | | | | | | | | | | | The only remaining places where we actually look at CTimeZone/HasCTZSet are abstime2tm() and timestamp2tm(). Now that session_timezone is always valid, we can remove these special cases. The caller-visible impact of this is that these functions now always return a valid zone abbreviation if requested, whereas before they'd return a NULL pointer if a brute-force timezone was in use. In the existing code, the only place I can find that changes behavior is to_char(), whose TZ format code will now print something useful rather than nothing for such zones. (In the places where the returned zone abbreviation is passed to EncodeDateTime, the lack of visible change is because we've chosen the abbreviation used for these zones to match what EncodeTimezone would have printed.) It's likely that there is now a fair amount of removable dead code around the call sites, namely anything that's meant to cope with getting a NULL timezone abbreviation, but I've not made an effort to root that out. This could be back-patched if we decide we'd like to fix to_char()'s behavior in the back branches, but there doesn't seem to be much enthusiasm for that at present.
* Fix some odd behaviors when using a SQL-style simple GMT offset timezone.Tom Lane2013-11-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Formerly, when using a SQL-spec timezone setting with a fixed GMT offset (called a "brute force" timezone in the code), the session_timezone variable was not updated to match the nominal timezone; rather, all code was expected to ignore session_timezone if HasCTZSet was true. This is of course obviously fragile, though a search of the code finds only timeofday() failing to honor the rule. A bigger problem was that DetermineTimeZoneOffset() supposed that if its pg_tz parameter was pointer-equal to session_timezone, then HasCTZSet should override the parameter. This would cause datetime input containing an explicit zone name to be treated as referencing the brute-force zone instead, if the zone name happened to match the session timezone that had prevailed before installing the brute-force zone setting (as reported in bug #8572). The same malady could affect AT TIME ZONE operators. To fix, set up session_timezone so that it matches the brute-force zone specification, which we can do using the POSIX timezone definition syntax "<abbrev>offset", and get rid of the bogus lookaside check in DetermineTimeZoneOffset(). Aside from fixing the erroneous behavior in datetime parsing and AT TIME ZONE, this will cause the timeofday() function to print its result in the user-requested time zone rather than some previously-set zone. It might also affect results in third-party extensions, if there are any that make use of session_timezone without considering HasCTZSet, but in all cases the new behavior should be saner than before. Back-patch to all supported branches.
* Use appendStringInfoString instead of appendStringInfo where possible.Robert Haas2013-10-31
| | | | | | | This shaves a few cycles, and generally seems like good programming practice. David Rowley
* Avoid too-large shift on 32-bit Windows.Robert Haas2013-10-30
| | | | | | | Apparently, shifts greater than or equal to the width of the type are undefined, and can surprisingly produce a non-zero value. Amit Kapila, with a comment by me.
* Prevent using strncpy with src == dest in TupleDescInitEntry.Tom Lane2013-10-28
| | | | | | | | | | | | | | | | | The C and POSIX standards state that strncpy's behavior is undefined when source and destination areas overlap. While it remains dubious whether any implementations really misbehave when the pointers are exactly equal, some platforms are now starting to force the issue by complaining when an undefined call occurs. (In particular OS X 10.9 has been seen to dump core here, though the exact set of circumstances needed to trigger that remain elusive. Similar behavior can be expected to be optional on Linux and other platforms in the near future.) So tweak the code to explicitly do nothing when nothing need be done. Back-patch to all active branches. In HEAD, this also lets us get rid of an exception in valgrind.supp. Per discussion of a report from Matthias Schmitt.
* Modify dynamic shared memory code to use Size rather than uint64.Robert Haas2013-10-28
| | | | This is more consistent with what we do elsewhere.
* Improve documentation about usage of FDW validator functions.Tom Lane2013-10-28
| | | | | | | | SGML documentation, as well as code comments, failed to note that an FDW's validator will be applied to foreign-table options for foreign tables using the FDW. Etsuro Fujita
* Add large object functions catering to SQL callers.Noah Misch2013-10-27
| | | | | | | | With these, one need no longer manipulate large object descriptors and extract numeric constants from header files in order to read and write large object contents from SQL. Pavel Stehule, reviewed by Rushabh Lathia.
* Suppress -0 in the C field of lines computed by line_construct_pts().Tom Lane2013-10-25
| | | | | | | | It's not entirely clear why some PPC machines are generating -0 here, since the underlying computation should be exactly 0 - 0. Perhaps there's some wider-than-nominal-precision calculations happening? Anyway, the best way to avoid platform-dependent results seems to be to explicitly reset -0 to regular zero.
* Use improved vsnprintf calling logic in more places.Tom Lane2013-10-24
| | | | | | | | | | | | | | | | | | | | | | When we are using a C99-compliant vsnprintf implementation (which should be most places, these days) it is worth the trouble to make use of its report of how large the buffer needs to be to succeed. This patch adjusts stringinfo.c and some miscellaneous usages in pg_dump to do that, relying on the logic recently added in libpgcommon's psprintf.c. Since these places want to know the number of bytes written once we succeed, modify the API of pvsnprintf() to report that. There remains near-duplicate logic in pqexpbuffer.c, but since that code is in libpq, psprintf.c's approach of exit()-on-error isn't appropriate for use there. Also note that I didn't bother touching the multitude of places that call (v)snprintf without any attempt to provide a resizable buffer. Release-note-worthy incompatibility: the API of appendStringInfoVA() changed. If there's any third-party code that's calling that directly, it will need tweaking along the same lines as in this patch. David Rowley and Tom Lane