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* In locate_grouping_columns(), don't expect an exact match of Var typmods.Tom Lane2013-08-23
| | | | | | | | | | | | | | | | | | | | | | | It's possible that inlining of SQL functions (or perhaps other changes?) has exposed typmod information not known at parse time. In such cases, Vars generated by query_planner might have valid typmod values while the original grouping columns only have typmod -1. This isn't a semantic problem since the behavior of grouping only depends on type not typmod, but it breaks locate_grouping_columns' use of tlist_member to locate the matching entry in query_planner's result tlist. We can fix this without an excessive amount of new code or complexity by relying on the fact that locate_grouping_columns only gets called when make_subplanTargetList has set need_tlist_eval == false, and that can only happen if all the grouping columns are simple Vars. Therefore we only need to search the sub_tlist for a matching Var, and we can reasonably define a "match" as being a match of the Var identity fields varno/varattno/varlevelsup. The code still Asserts that vartype matches, but ignores vartypmod. Per bug #8393 from Evan Martin. The added regression test case is basically the same as his example. This has been broken for a very long time, so back-patch to all supported branches.
* Fix hash table size estimation error in choose_hashed_distinct().Tom Lane2013-08-21
| | | | | | | | | | | | | | We should account for the per-group hashtable entry overhead when considering whether to use a hash aggregate to implement DISTINCT. The comparable logic in choose_hashed_grouping() gets this right, but I think I omitted it here in the mistaken belief that there would be no overhead if there were no aggregate functions to be evaluated. This can result in more than 2X underestimate of the hash table size, if the tuples being aggregated aren't very wide. Per report from Tomas Vondra. This bug is of long standing, but per discussion we'll only back-patch into 9.3. Changing the estimation behavior in stable branches seems to carry too much risk of destabilizing plan choices for already-tuned applications.
* Be more wary of unwanted whitespace in pgstat_reset_remove_files().Tom Lane2013-08-19
| | | | | sscanf isn't the easiest thing to use for exact pattern checks ... also, don't use strncmp where strcmp will do.
* Fix removal of files in pgstats directoriesAlvaro Herrera2013-08-19
| | | | | | | | | | | | | | | Instead of deleting all files in stats_temp_directory and the permanent directory on a crash, only remove those files that match the pattern of files we actually write in them, to avoid possibly clobbering existing unrelated contents of the temporary directory. Per complaint from Jeff Janes, and subsequent discussion, starting at message CAMkU=1z9+7RsDODnT4=cDFBRBp8wYQbd_qsLcMtKEf-oFwuOdQ@mail.gmail.com Also, fix a bug in the same routine to avoid removing files from the permanent directory twice (instead of once from that directory and then from the temporary directory), also per report from Jeff Janes, in message CAMkU=1wbk947=-pAosDMX5VC+sQw9W4ttq6RM9rXu=MjNeEQKA@mail.gmail.com
* Rename the "fast_promote" file to just "promote".Heikki Linnakangas2013-08-19
| | | | | | | | | | This keeps the usual trigger file name unchanged from 9.2, avoiding nasty issues if you use a pre-9.3 pg_ctl binary with a 9.3 server or vice versa. The fallback behavior of creating a full checkpoint before starting up is now triggered by a file called "fallback_promote". That can be useful for debugging purposes, but we don't expect any users to have to resort to that and we might want to remove that in the future, which is why the fallback mechanism is undocumented.
* Fix qual-clause-misplacement issues with pulled-up LATERAL subqueries.Tom Lane2013-08-19
| | | | | | | | | | | | | | | | | | | | | | In an example such as SELECT * FROM i LEFT JOIN LATERAL (SELECT * FROM j WHERE i.n = j.n) j ON true; it is safe to pull up the LATERAL subquery into its parent, but we must then treat the "i.n = j.n" clause as a qual clause of the LEFT JOIN. The previous coding in deconstruct_recurse mistakenly labeled the clause as "is_pushed_down", resulting in wrong semantics if the clause were applied at the join node, as per an example submitted awhile ago by Jeremy Evans. To fix, postpone processing of such clauses until we return back up to the appropriate recursion depth in deconstruct_recurse. In addition, tighten the is-safe-to-pull-up checks in is_simple_subquery; we previously missed the possibility that the LATERAL subquery might itself contain an outer join that makes lateral references in lower quals unsafe. A regression test case equivalent to Jeremy's example was already in my commit of yesterday, but was giving the wrong results because of this bug. This patch fixes the expected output for that, and also adds a test case for the second problem.
* Fix pg_upgrade failure from servers older than 9.3Alvaro Herrera2013-08-19
| | | | | | | | | | | | | | When upgrading from servers of versions 9.2 and older, and MultiXactIds have been used in the old server beyond the first page (that is, 2048 multis or more in the default 8kB-page build), pg_upgrade would set the next multixact offset to use beyond what has been allocated in the new cluster. This would cause a failure the first time the new cluster needs to use this value, because the pg_multixact/offsets/ file wouldn't exist or wouldn't be large enough. To fix, ensure that the transient server instances launched by pg_upgrade extend the file as necessary. Per report from Jesse Denardo in CANiVXAj4c88YqipsyFQPboqMudnjcNTdB3pqe8ReXqAFQ=HXyA@mail.gmail.com
* Translation updatesPeter Eisentraut2013-08-18
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* Remove relcache entry invalidation in REFRESH MATERIALIZED VIEW.Kevin Grittner2013-08-18
| | | | | | | | This was added as part of the attempt to support unlogged matviews along with a populated status. It got missed when unlogged support was removed pre-commit. Noticed by Noah Misch. Back-patched to 9.3 branch.
* Fix thinko in comment.Tom Lane2013-08-17
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* Fix planner problems with LATERAL references in PlaceHolderVars.Tom Lane2013-08-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The planner largely failed to consider the possibility that a PlaceHolderVar's expression might contain a lateral reference to a Var coming from somewhere outside the PHV's syntactic scope. We had a previous report of a problem in this area, which I tried to fix in a quick-hack way in commit 4da6439bd8553059766011e2a42c6e39df08717f, but Antonin Houska pointed out that there were still some problems, and investigation turned up other issues. This patch largely reverts that commit in favor of a more thoroughly thought-through solution. The new theory is that a PHV's ph_eval_at level cannot be higher than its original syntactic level. If it contains lateral references, those don't change the ph_eval_at level, but rather they create a lateral-reference requirement for the ph_eval_at join relation. The code in joinpath.c needs to handle that. Another issue is that createplan.c wasn't handling nested PlaceHolderVars properly. In passing, push knowledge of lateral-reference checks for join clauses into join_clause_is_movable_to. This is mainly so that FDWs don't need to deal with it. This patch doesn't fix the original join-qual-placement problem reported by Jeremy Evans (and indeed, one of the new regression test cases shows the wrong answer because of that). But the PlaceHolderVar problems need to be fixed before that issue can be addressed, so committing this separately seems reasonable.
* Move more bgworker code to bgworker.c; also, some renaming.Robert Haas2013-08-16
| | | | | | | Per discussion on pgsql-hackers. Michael Paquier, slightly modified by me. Original suggestion from Amit Kapila.
* Fix typo in comment.Heikki Linnakangas2013-08-16
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* Don't allow ALTER MATERIALIZED VIEW ADD UNIQUE.Kevin Grittner2013-08-15
| | | | | | | Was accidentally allowed, but not documented and lacked support for rename or drop once created. Per report from Noah Misch.
* Treat timeline IDs as unsigned in replication parserPeter Eisentraut2013-08-14
| | | | | Timeline IDs are unsigned ints everywhere, except the replication parser treated them as signed ints.
* Improve error message when view is not updatablePeter Eisentraut2013-08-14
| | | | | Avoid using the term "updatable" in confusing ways. Suggest a trigger first, before a rule.
* Remove ph_may_need from PlaceHolderInfo, with attendant simplifications.Tom Lane2013-08-14
| | | | | | | | | | | | | | | | | | | | | The planner logic that attempted to make a preliminary estimate of the ph_needed levels for PlaceHolderVars seems to be completely broken by lateral references. Fortunately, the potential join order optimization that this code supported seems to be of relatively little value in practice; so let's just get rid of it rather than trying to fix it. Getting rid of this allows fairly substantial simplifications in placeholder.c, too, so planning in such cases should be a bit faster. Issue noted while pursuing bugs reported by Jeremy Evans and Antonin Houska, though this doesn't in itself fix either of their reported cases. What this does do is prevent an Assert crash in the kind of query illustrated by the added regression test. (I'm not sure that the plan for that query is stable enough across platforms to be usable as a regression test output ... but we'll soon find out from the buildfarm.) Back-patch to 9.3. The problem case can't arise without LATERAL, so no need to touch older branches.
* Remove Assert that matview is not in system schema from REFRESH.Kevin Grittner2013-08-14
| | | | | | | | We don't want to prevent an extension which creates a matview from being installed in pg_catalog. Issue was raised by Hitoshi Harada. Backpatched to 9.3.
* Emit a log message if output is about to be redirected away from stderr.Tom Lane2013-08-13
| | | | | | | | | | | | | | | | | | | We've seen multiple cases of people looking at the postmaster's original stderr output to try to diagnose problems, not realizing/remembering that their logging configuration is set up to send log messages somewhere else. This seems particularly likely to happen in prepackaged distributions, since many packagers patch the code to change the factory-standard logging configuration to something more in line with their platform conventions. In hopes of reducing confusion, emit a LOG message about this at the point in startup where we are about to switch log output away from the original stderr, providing a pointer to where to look instead. This message will appear as the last thing in the original stderr output. (We might later also try to emit such link messages when logging parameters are changed on-the-fly; but that case seems to be both noticeably harder to do nicely, and much less frequently a problem in practice.) Per discussion, back-patch to 9.3 but not further.
* Message punctuation and pluralization fixesPeter Eisentraut2013-08-09
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* Message style improvementsPeter Eisentraut2013-08-07
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* Fix assertion failure by an immediate shutdown.Fujii Masao2013-08-08
| | | | | | | | | | | | In PM_WAIT_DEAD_END state, checkpointer process must be dead already. But an immediate shutdown could make postmaster's state machine transition to PM_WAIT_DEAD_END state even if checkpointer process is still running, and which caused assertion failure. This bug was introduced in commit 457d6cf049c57cabe9b46ea13f26138040a214ec. This patch ensures that postmaster's state machine doesn't transition to PM_WAIT_DEAD_END state in an immediate shutdown while checkpointer process is running.
* Simplify query_planner's API by having it return the top-level RelOptInfo.Tom Lane2013-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | Formerly, query_planner returned one or possibly two Paths for the topmost join relation, so that grouping_planner didn't see the join RelOptInfo (at least not directly; it didn't have any hesitation about examining cheapest_path->parent, though). However, correct selection of the Paths involved a significant amount of coupling between query_planner and grouping_planner, a problem which has gotten worse over time. It seems best to give up on this API choice and instead return the topmost RelOptInfo explicitly. Then grouping_planner can pull out the Paths it wants from the rel's path list. In this way we can remove all knowledge of grouping behaviors from query_planner. The only real benefit of the old way is that in the case of an empty FROM clause, we never made any RelOptInfos at all, just a Path. Now we have to gin up a dummy RelOptInfo to represent the empty FROM clause. That's not a very big deal though. While at it, simplify query_planner's API a bit more by having the caller set up root->tuple_fraction and root->limit_tuples, rather than passing those values as separate parameters. Since query_planner no longer does anything with either value, requiring it to fill the PlannerInfo fields seemed pretty arbitrary. This patch just rearranges code; it doesn't (intentionally) change any behaviors. Followup patches will do more interesting things.
* Various cleanups for REFRESH MATERIALIZED VIEW CONCURRENTLY.Kevin Grittner2013-08-05
| | | | | | | | | | | | | | | | | | | | | | | Open and lock each index before checking definition in RMVC. The ExclusiveLock on the related table is not viewed as sufficient to ensure that no changes are made to the index definition, and invalidation messages from other backends might have been missed. Additionally, use RelationGetIndexExpressions() and check for NIL rather than doing our own loop. Protect against redefinition of tid and rowvar operators in RMVC. While working on this, noticed that the fixes for bugs found during the CF made the UPDATE statement useless, since no rows could qualify for that treatment any more. Ripping out code to support the UPDATE statement simplified the operator cleanups. Change slightly confusing local field name. Use meaningful alias names on queries in refresh_by_match_merge(). Per concerns of raised by Andres Freund and comments and suggestions from Noah Misch. Some additional issues remain, which will be addressed separately.
* Make sure float4in/float8in accept all standard spellings of "infinity".Tom Lane2013-08-03
| | | | | | | | | | | | | | | | The C99 and POSIX standards require strtod() to accept all these spellings (case-insensitively): "inf", "+inf", "-inf", "infinity", "+infinity", "-infinity". However, pre-C99 systems might accept only some or none of these, and apparently Windows still doesn't accept "inf". To avoid surprising cross-platform behavioral differences, manually check for each of these spellings if strtod() fails. We were previously handling just "infinity" and "-infinity" that way, but since C99 is most of the world now, it seems likely that applications are expecting all these spellings to work. Per bug #8355 from Basil Peace. It turns out this fix won't actually resolve his problem, because Python isn't being this careful; but that doesn't mean we shouldn't be.
* Fix old visibility bug in HeapTupleSatisfiesDirtyAlvaro Herrera2013-08-02
| | | | | | | | | | | | | | | | | If a tuple is locked but not updated by a concurrent transaction, HeapTupleSatisfiesDirty would return that transaction's Xid in xmax, causing callers to wait on it, when it is not necessary (in fact, if the other transaction had used a multixact instead of a plain Xid to mark the tuple, HeapTupleSatisfiesDirty would have behave differently and *not* returned the Xmax). This bug was introduced in commit 3f7fbf85dc5b42, dated December 1998, so it's almost 15 years old now. However, it's hard to see this misbehave, because before we had NOWAIT the only consequence of this is that transactions would wait for slightly more time than necessary; so it's not surprising that this hasn't been reported yet. Craig Ringer and Andres Freund
* Fix crash in error report of invalid tuple lockAlvaro Herrera2013-08-02
| | | | | | | | | | | | | | My tweak of these error messages in commit c359a1b082 contained the thinko that a query would always have rowMarks set for a query containing a locking clause. Not so: when declaring a cursor, for instance, rowMarks isn't set at the point we're checking, so we'd be dereferencing a NULL pointer. The fix is to pass the lock strength to the function raising the error, instead of trying to reverse-engineer it. The result not only is more robust, but it also seems cleaner overall. Per report from Robert Haas.
* Fix typo in comment.Robert Haas2013-08-02
| | | | Etsuro Fujita
* Improve comments for IncrementalMaintenance DML enabling functions.Kevin Grittner2013-08-01
| | | | | | | Move the static functions after the comment and expand the comment. Per complaint from Andres Freund, although using different comment text.
* Assorted bgworker-related comment fixes.Robert Haas2013-08-01
| | | | Per gripes by Amit Kapila.
* Remove SnapshotNow and HeapTupleSatisfiesNow.Robert Haas2013-08-01
| | | | | | | | We now use MVCC catalog scans, and, per discussion, have eliminated all other remaining uses of SnapshotNow, so that we can now get rid of it. This will break third-party code which is still using it, which is intentional, as we want such code to be updated to do things the new way.
* Allow a context to be passed in for error handlingStephen Frost2013-08-01
| | | | | | | | | | | As pointed out by Tom Lane, we can allow other users of the error handler callbacks to provide their own memory context by adding the context to use to ErrorData and using that instead of explicitly using ErrorContext. This then allows GetErrorContextStack() to be called from inside exception handlers, so modify plpgsql to take advantage of that and add an associated regression test for it.
* Fix mis-indented linesAlvaro Herrera2013-07-31
| | | | Per Coverity
* Fix regexp_matches() handling of zero-length matches.Tom Lane2013-07-31
| | | | | | | | | | | We'd find the same match twice if it was of zero length and not immediately adjacent to the previous match. replace_text_regexp() got similar cases right, so adjust this search logic to match that. Note that even though the regexp_split_to_xxx() functions share this code, they did not display equivalent misbehavior, because the second match would be considered degenerate and ignored. Jeevan Chalke, with some cosmetic changes by me.
* Fix typo in comment.Fujii Masao2013-07-31
| | | | Hitoshi Harada
* Restore REINDEX constraint validation.Noah Misch2013-07-30
| | | | | | | | | Refactoring as part of commit 8ceb24568054232696dddc1166a8563bc78c900a had the unintended effect of making REINDEX TABLE and REINDEX DATABASE no longer validate constraints enforced by the indexes in question; REINDEX INDEX still did so. Indexes marked invalid remained so, and constraint violations arising from data corruption went undetected. Back-patch to 9.0, like the causative commit.
* Add SQL Standard WITH ORDINALITY support for UNNEST (and any other SRF)Greg Stark2013-07-29
| | | | | Author: Andrew Gierth, David Fetter Reviewers: Dean Rasheed, Jeevan Chalke, Stephen Frost
* Message style improvementsPeter Eisentraut2013-07-28
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* Prevent leakage of SPI tuple tables during subtransaction abort.Tom Lane2013-07-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | plpgsql often just remembers SPI-result tuple tables in local variables, and has no mechanism for freeing them if an ereport(ERROR) causes an escape out of the execution function whose local variable it is. In the original coding, that wasn't a problem because the tuple table would be cleaned up when the function's SPI context went away during transaction abort. However, once plpgsql grew the ability to trap exceptions, repeated trapping of errors within a function could result in significant intra-function-call memory leakage, as illustrated in bug #8279 from Chad Wagner. We could fix this locally in plpgsql with a bunch of PG_TRY/PG_CATCH coding, but that would be tedious, probably slow, and prone to bugs of omission; moreover it would do nothing for similar risks elsewhere. What seems like a better plan is to make SPI itself responsible for freeing tuple tables at subtransaction abort. This patch attacks the problem that way, keeping a list of live tuple tables within each SPI function context. Currently, such freeing is automatic for tuple tables made within the failed subtransaction. We might later add a SPI call to mark a tuple table as not to be freed this way, allowing callers to opt out; but until someone exhibits a clear use-case for such behavior, it doesn't seem worth bothering. A very useful side-effect of this change is that SPI_freetuptable() can now defend itself against bad calls, such as duplicate free requests; this should make things more robust in many places. (In particular, this reduces the risks involved if a third-party extension contains now-redundant SPI_freetuptable() calls in error cleanup code.) Even though the leakage problem is of long standing, it seems imprudent to back-patch this into stable branches, since it does represent an API semantics change for SPI users. We'll patch this in 9.3, but live with the leakage in older branches.
* Change currtid functions to use an MVCC snapshot, not SnapshotNow.Robert Haas2013-07-25
| | | | | | | | | This has a slight performance cost, but the only known consumers of these functions, known at the SQL level as currtid and currtid2, is pgsql-odbc; whose usage, we hope, is not sufficiently intensive to make this a problem. Per discussion.
* Don't use SnapshotNow in get_actual_variable_range.Robert Haas2013-07-25
| | | | | | | | Instead, use the active snapshot. Per Tom Lane, this function is most interested in knowing the range of tuples our scan will actually see. This is another step towards full removal of SnapshotNow.
* Improvements to GetErrorContextStack()Stephen Frost2013-07-25
| | | | | | | | | | | | | | | As GetErrorContextStack() borrowed setup and tear-down code from other places, it was less than clear that it must only be called as a top-level entry point into the error system and can't be called by an exception handler (unlike the rest of the error system, which is set up to be reentrant-safe). Being called from an exception handler is outside the charter of GetErrorContextStack(), so add a bit more protection against it, improve the comments addressing why we have to set up an errordata stack for this function at all, and add a few more regression tests. Lack of clarity pointed out by Tom Lane; all bugs are mine.
* Add GET DIAGNOSTICS ... PG_CONTEXT in PL/PgSQLStephen Frost2013-07-24
| | | | | | | | | This adds the ability to get the call stack as a string from within a PL/PgSQL function, which can be handy for logging to a table, or to include in a useful message to an end-user. Pavel Stehule, reviewed by Rushabh Lathia and rather heavily whacked around by Stephen Frost.
* Improve ilist.h's support for deletion of slist elements during iteration.Tom Lane2013-07-24
| | | | | | | | | | | | | | | | | | Previously one had to use slist_delete(), implying an additional scan of the list, making this infrastructure considerably less efficient than traditional Lists when deletion of element(s) in a long list is needed. Modify the slist_foreach_modify() macro to support deleting the current element in O(1) time, by keeping a "prev" pointer in addition to "cur" and "next". Although this makes iteration with this macro a bit slower, no real harm is done, since in any scenario where you're not going to delete the current list element you might as well just use slist_foreach instead. Improve the comments about when to use each macro. Back-patch to 9.3 so that we'll have consistent semantics in all branches that provide ilist.h. Note this is an ABI break for callers of slist_foreach_modify(). Andres Freund and Tom Lane
* Fix booltestsel() for case where we have NULL stats but not MCV stats.Tom Lane2013-07-24
| | | | | | | | | | | | In a boolean column that contains mostly nulls, ANALYZE might not find enough non-null values to populate the most-common-values stats, but it would still create a pg_statistic entry with stanullfrac set. The logic in booltestsel() for this situation did the wrong thing for "col IS NOT TRUE" and "col IS NOT FALSE" tests, forgetting that null values would satisfy these tests (so that the true selectivity would be close to one, not close to zero). Per bug #8274. Fix by Andrew Gierth, some comment-smithing by me.
* Move strip_implicit_coercions() from optimizer to nodeFuncs.c.Tom Lane2013-07-23
| | | | | | | | Use of this function has spread into the parser and rewriter, so it seems like time to pull it out of the optimizer and put it into the more central nodeFuncs module. This eliminates the need to #include optimizer/clauses.h in most of the calling files, demonstrating that this function was indeed a bit outside the normal code reference patterns.
* Further hacking on ruleutils' new column-alias-assignment code.Tom Lane2013-07-23
| | | | | | | | | | | | | | | | | After further thought about implicit coercions appearing in a joinaliasvars list, I realized that they represent an additional reason why we might need to reference the join output column directly instead of referencing an underlying column. Consider SELECT x FROM t1 LEFT JOIN t2 USING (x) where t1.x is of type date while t2.x is of type timestamptz. The merged output variable is of type timestamptz, but it won't go to null when t2 does, therefore neither t1.x nor t2.x is a valid substitute reference. The code in get_variable() actually gets this case right, since it knows it shouldn't look through a coercion, but we failed to ensure that the unqualified output column name would be globally unique. To fix, modify the code that trawls for a dangerous situation so that it actually scans through an unnamed join's joinaliasvars list to see if there are any non-simple-Var entries.
* Change post-rewriter representation of dropped columns in joinaliasvars.Tom Lane2013-07-23
| | | | | | | | | | | | | | | | | | | | | It's possible to drop a column from an input table of a JOIN clause in a view, if that column is nowhere actually referenced in the view. But it will still be there in the JOIN clause's joinaliasvars list. We used to replace such entries with NULL Const nodes, which is handy for generation of RowExpr expansion of a whole-row reference to the view. The trouble with that is that it can't be distinguished from the situation after subquery pull-up of a constant subquery output expression below the JOIN. Instead, replace such joinaliasvars with null pointers (empty expression trees), which can't be confused with pulled-up expressions. expandRTE() still emits the old convention, though, for convenience of RowExpr generation and to reduce the risk of breaking extension code. In HEAD and 9.3, this patch also fixes a problem with some new code in ruleutils.c that was failing to cope with implicitly-casted joinaliasvars entries, as per recent report from Feike Steenbergen. That oversight was because of an inadequate description of the data structure in parsenodes.h, which I've now corrected. There were some pre-existing oversights of the same ilk elsewhere, which I believe are now all fixed.
* Tweak FOR UPDATE/SHARE error message wording (again)Alvaro Herrera2013-07-23
| | | | | | | | | | | In commit 0ac5ad5134 I changed some error messages from "FOR UPDATE/SHARE" to a rather long gobbledygook which nobody liked. Then, in commit cb9b66d31 I changed them again, but the alternative chosen there was deemed suboptimal by Peter Eisentraut, who in message 1373937980.20441.8.camel@vanquo.pezone.net proposed an alternative involving a dynamically-constructed string based on the actual locking strength specified in the SQL command. This patch implements that suggestion.
* Use InvalidSnapshot, now SnapshotNow, as the default snapshot.Robert Haas2013-07-23
| | | | | | | | | | | | As far as I can determine, there's no code in the core distribution that fails to explicitly set the snapshot of a scan or executor state. If there is any such code, this will probably cause it to seg fault; friendlier suggestions were discussed on pgsql-hackers, but there was no consensus that anything more than this was needed. This is another step towards the hoped-for complete removal of SnapshotNow.