Commit Graph

26060 Commits

Author SHA1 Message Date
Peter Eisentraut 1e95bbc870 Fix SHLIB_PREREQS use in contrib, allowing PGXS builds
dblink and postgres_fdw use SHLIB_PREREQS = submake-libpq to build libpq
first.  This doesn't work in a PGXS build, because there is no libpq to
build.  So just omit setting SHLIB_PREREQS in this case.

Note that PGXS users can still use SHLIB_PREREQS (although it is not
documented).  The problem here is only that contrib modules can be built
in-tree or using PGXS, and the prerequisite is only applicable in the
former case.

Commit 6697aa2bc2 previously attempted to
address this by creating a somewhat fake submake-libpq target in
Makefile.global.  That was not the right fix, and it was also done in a
nonportable way, so revert that.
2014-12-04 07:58:12 -05:00
Peter Eisentraut e86507d770 Move PG_AUTOCONF_FILENAME definition
Since this is not something that a user should change,
pg_config_manual.h was an inappropriate place for it.

In initdb.c, remove the use of the macro, because utils/guc.h can't be
included by non-backend code.  But we hardcode all the other
configuration file names there, so this isn't a disaster.
2014-12-03 19:54:01 -05:00
Alvaro Herrera 73c986adde Keep track of transaction commit timestamps
Transactions can now set their commit timestamp directly as they commit,
or an external transaction commit timestamp can be fed from an outside
system using the new function TransactionTreeSetCommitTsData().  This
data is crash-safe, and truncated at Xid freeze point, same as pg_clog.

This module is disabled by default because it causes a performance hit,
but can be enabled in postgresql.conf requiring only a server restart.

A new test in src/test/modules is included.

Catalog version bumped due to the new subdirectory within PGDATA and a
couple of new SQL functions.

Authors: Álvaro Herrera and Petr Jelínek

Reviewed to varying degrees by Michael Paquier, Andres Freund, Robert
Haas, Amit Kapila, Fujii Masao, Jaime Casanova, Simon Riggs, Steven
Singer, Peter Eisentraut
2014-12-03 11:53:02 -03:00
Alvaro Herrera 6597ec9be6 Fix typos 2014-12-03 11:52:15 -03:00
Peter Eisentraut bc2f43eaa4 Fix whitespace 2014-12-02 23:45:03 -05:00
Alvaro Herrera da34731bd3 Install kludges to fix check-world for src/test/modules
check-world failed in a completely clean tree, because src/test/modules
fail to build unless errcodes.h is generated first.  To fix this,
install a dependency in src/test/modules' Makefile so that the necessary
file is generated.  Even with this, running "make check" within
individual module subdirs will still fail because the dependency is not
considered there, but this case is less interesting and would be messier
to fix.

check-world still failed with the above fix in place, this time because
dummy_seclabel used LOAD to load the dynamic library, which doesn't work
because the @libdir@ (expanded by the makefile) is expanded to the final
install path, not the temporary installation directory used by make
check.  To fix, tweak things so that CREATE EXTENSION can be used
instead, which solves the problem because the library path is expanded
by the backend, which is aware of the true libdir.
2014-12-02 23:43:53 -03:00
Tom Lane 475aedd1ef Improve error messages for malformed array input strings.
Make the error messages issued by array_in() uniformly follow the style
	ERROR: malformed array literal: "actual input string"
	DETAIL: specific complaint here
and rewrite many of the specific complaints to be clearer.

The immediate motivation for doing this is a complaint from Josh Berkus
that json_to_record() produced an unintelligible error message when
dealing with an array item, because it tries to feed the JSON-format
array value to array_in().  Really it ought to be smart enough to
perform JSON-to-Postgres array conversion, but that's a future feature
not a bug fix.  In the meantime, this change is something we agreed
we could back-patch into 9.4, and it should help de-confuse things a bit.
2014-12-02 18:23:27 -05:00
Andres Freund 0fd38e1370 Don't skip SQL backends in logical decoding for visibility computation.
The logical decoding patchset introduced PROC_IN_LOGICAL_DECODING flag
PGXACT flag, that allows such backends to be skipped when computing
the xmin horizon/snapshots. That's fine and sensible for walsenders
streaming out logical changes, but not at all fine for SQL backends
doing logical decoding. If the latter set that flag any change they
have performed outside of logical decoding will not be regarded as
visible - which e.g. can lead to that change being vacuumed away.

Note that not setting the flag for SQL backends isn't particularly
bothersome - the SQL backend doesn't do streaming, so it only runs for
a limited amount of time.

Per buildfarm member 'tick' and Alvaro.

Backpatch to 9.4, where logical decoding was introduced.
2014-12-02 23:47:08 +01:00
Tom Lane 75ef435218 Fix JSON aggregates to work properly when final function is re-executed.
Davide S. reported that json_agg() sometimes produced multiple trailing
right brackets.  This turns out to be because json_agg_finalfn() attaches
the final right bracket, and was doing so by modifying the aggregate state
in-place.  That's verboten, though unfortunately it seems there's no way
for nodeAgg.c to check for such mistakes.

Fix that back to 9.3 where the broken code was introduced.  In 9.4 and
HEAD, likewise fix json_object_agg(), which had copied the erroneous logic.
Make some cosmetic cleanups as well.
2014-12-02 15:02:37 -05:00
Tom Lane 1511521a36 Minor cleanup of function declarations for BRIN.
Get rid of PG_FUNCTION_INFO_V1() macros, which are quite inappropriate
for built-in functions (possibly leftovers from testing as a loadable
module?).  Also, fix gratuitous inconsistency between SQL-level and
C-level names of the minmax support functions.
2014-12-02 14:07:54 -05:00
Alvaro Herrera 3325624377 dummy_seclabel: add sql/, expected/, and .gitignores
Michael Paquier
2014-12-02 11:14:56 -03:00
Tom Lane 0927bf8060 Guard against bad "dscale" values in numeric_recv().
We were not checking to see if the supplied dscale was valid for the given
digit array when receiving binary-format numeric values.  While dscale can
validly be more than the number of nonzero fractional digits, it shouldn't
be less; that case causes fractional digits to be hidden on display even
though they're there and participate in arithmetic.

Bug #12053 from Tommaso Sala indicates that there's at least one broken
client library out there that sometimes supplies an incorrect dscale value,
leading to strange behavior.  This suggests that simply throwing an error
might not be the best response; it would lead to failures in applications
that might seem to be working fine today.  What seems the least risky fix
is to truncate away any digits that would be hidden by dscale.  This
preserves the existing behavior in terms of what will be printed for the
transmitted value, while preventing subsequent arithmetic from producing
results inconsistent with that.

In passing, throw a specific error for the case of dscale being outside
the range that will fit into a numeric's header.  Before you got "value
overflows numeric format", which is a bit misleading.

Back-patch to all supported branches.
2014-12-01 15:25:02 -05:00
Alvaro Herrera df761e3cf7 Move security_label test
Rather than have the core security_label regression test depend on the
dummy_seclabel module, have that part of the test be executed by
dummy_seclabel itself directly.  This simplifies the testing rig a bit;
in particular it should silence the problems from the MSVC buildfarm
phylum, which haven't yet gotten taught how to install src/test/modules.
2014-12-01 16:12:43 -03:00
Andrew Dunstan e09996ff8d Fix hstore_to_json_loose's detection of valid JSON number values.
We expose a function IsValidJsonNumber that internally calls the lexer
for json numbers. That allows us to use the same test everywhere,
instead of inventing a broken test for hstore conversions. The new
function is also used in datum_to_json, replacing the code that is now
moved to the new function.

Backpatch to 9.3 where hstore_to_json_loose was introduced.
2014-12-01 11:28:45 -05:00
Heikki Linnakangas 4e86f1b16d Put SSL_pending() call behind the new internal SSL API.
It seems likely that any SSL implementation will need a similar call, not
just OpenSSL.
2014-12-01 17:45:04 +02:00
Tom Lane 866737c923 Add a #define for the inet overlaps operator.
Extracted from pending inet selectivity patch.  The rest of it isn't
quite ready to commit, but we might as well push this part so the patch
doesn't have to track the moving target of pg_operator.h.
2014-11-30 19:43:43 -05:00
Tom Lane 1adbb347ec Fix minor bugs in commit 30bf4689a9 et al.
Coverity complained that the "else" added to fillPGconn() was unreachable,
which it was.  Remove the dead code.  In passing, rearrange the tests so as
not to bother trying to fetch values for options that can't be assigned.

Pre-9.3 did not have that issue, but it did have a "return" that should be
"goto oom_error" to ensure that a suitable error message gets filled in.
2014-11-30 12:20:44 -05:00
Alvaro Herrera 22dfd116a1 Move test modules from contrib to src/test/modules
This is advance preparation for introducing even more test modules; the
easy solution is to add them to contrib, but that's bloated enough that
it seems a good time to think of something different.

Moved modules are dummy_seclabel, test_shm_mq, test_parser and
worker_spi.

(test_decoding was also a candidate, but there was too much opposition
to moving that one.  We can always reconsider later.)
2014-11-29 23:55:00 -03:00
Noah Misch 64f86fb11e Reimplement 9f80f4835a with PQconninfo().
Apart from ignoring "hostaddr" set to the empty string, this behaves
identically to its predecessor.  Back-patch to 9.4, where the original
commit first appeared.

Reviewed by Fujii Masao.
2014-11-29 12:31:43 -05:00
Noah Misch 2cda889984 Revert "Add libpq function PQhostaddr()."
This reverts commit 9f80f4835a.  The
function returned the raw value of a connection parameter, a task served
by PQconninfo().  The next commit will reimplement the psql \conninfo
change that way.  Back-patch to 9.4, where that commit first appeared.
2014-11-29 12:31:21 -05:00
Alvaro Herrera 816e10d800 Fix BRIN operator family definitions
The original definitions were leaving no room for cross-type operators,
so queries that compared a column of one type against something of a
different type were not taking advantage of the index.  Fix by making
the opfamilies more like the ones for Btree, and include a few
cross-type operator classes.

Catalog version bumped.

Per complaints from Hubert Lubaczewski, Mark Wong, Heikki Linnakangas.
2014-11-28 18:09:19 -03:00
Alvaro Herrera ae04bf5027 Update transaction README for persistent multixacts
Multixacts are now maintained during recovery, but the README didn't get
the memo.  Backpatch to 9.3, where the divergence was introduced.
2014-11-28 18:06:18 -03:00
Tom Lane d25367ec4f Add bms_get_singleton_member(), and use it where appropriate.
This patch adds a function that replaces a bms_membership() test followed
by a bms_singleton_member() call, performing both the test and the
extraction of a singleton set's member in one scan of the bitmapset.
The performance advantage over the old way is probably minimal in current
usage, but it seems worthwhile on notational grounds anyway.

David Rowley
2014-11-28 14:16:24 -05:00
Tom Lane f4e031c662 Add bms_next_member(), and use it where appropriate.
This patch adds a way of iterating through the members of a bitmapset
nondestructively, unlike the old way with bms_first_member().  While
bms_next_member() is very slightly slower than bms_first_member()
(at least for typical-size bitmapsets), eliminating the need to palloc
and pfree a temporary copy of the target bitmapset is a significant win.
So this method should be preferred in all cases where a temporary copy
would be necessary.

Tom Lane, with suggestions from Dean Rasheed and David Rowley
2014-11-28 13:37:25 -05:00
Tom Lane 96d66bcfc6 Improve performance of OverrideSearchPathMatchesCurrent().
This function was initially coded on the assumption that it would not be
performance-critical, but that turns out to be wrong in workloads that
are heavily dependent on the speed of plpgsql functions.  Speed it up by
hard-coding the comparison rules, thereby avoiding palloc/pfree traffic
from creating and immediately freeing an OverrideSearchPath object.
Per report from Scott Marlowe.
2014-11-28 12:37:27 -05:00
Tom Lane e384ed6cde Improve typcache: cache negative lookup results, add invalidation logic.
Previously, if the typcache had for example tried and failed to find a hash
opclass for a given data type, it would nonetheless repeat the unsuccessful
catalog lookup each time it was asked again.  This can lead to a
significant amount of useless bufmgr traffic, as in a recent report from
Scott Marlowe.  Like the catalog caches, typcache should be able to cache
negative results.  This patch arranges that by making use of separate flag
bits to remember whether a particular item has been looked up, rather than
treating a zero OID as an indicator that no lookup has been done.

Also, install a credible invalidation mechanism, namely watching for inval
events in pg_opclass.  The sole advantage of the lack of negative caching
was that the code would cope if operators or opclasses got added for a type
mid-session; to preserve that behavior we have to be able to invalidate
stale lookup results.  Updates in pg_opclass should be pretty rare in
production systems, so it seems sufficient to just invalidate all the
dependent data whenever one happens.

Adding proper invalidation also means that this code will now react sanely
if an opclass is dropped mid-session.  Arguably, that's a back-patchable
bug fix, but in view of the lack of complaints from the field I'll refrain
from back-patching.  (Probably, in most cases where an opclass is dropped,
the data type itself is dropped soon after, so that this misfeasance has
no bad consequences.)
2014-11-28 12:19:14 -05:00
Fujii Masao 202cbdf782 Add tab-completion for ALTER TABLE ALTER CONSTRAINT in psql.
Back-patch to 9.4 where ALTER TABLE ALTER CONSTRAINT was added.

Michael Paquier, bug reported by Andrey Lizenko.
2014-11-28 21:29:45 +09:00
Heikki Linnakangas afeacd2748 Fix assertion failure at end of PITR.
InitXLogInsert() cannot be called in a critical section, because it
allocates memory. But CreateCheckPoint() did that, when called for the
end-of-recovery checkpoint by the startup process.

In the passing, fix the scratch space allocation in InitXLogInsert to go to
the right memory context. Also update the comment at InitXLOGAccess, which
hasn't been totally accurate since hot standby was introduced (in a hot
standby backend, InitXLOGAccess isn't called at backend startup).

Reported by Michael Paquier
2014-11-28 09:31:53 +02:00
Fujii Masao a5eb85eb62 Make \watch respect the user's \pset null setting.
Previously \watch always ignored the user's \pset null setting.
\pset null setting should be ignored for \d and similar queries.
For those, the code can reasonably have an opinion about what
the presentation should be like, since it knows what SQL query
it's issuing. This argument surely doesn't apply to \watch,
so this commit makes \watch use the user's \pset null setting.

Back-patch to 9.3 where \watch was added.
2014-11-28 02:42:43 +09:00
Fujii Masao e656f5d247 Mark response messages for translation in pg_isready.
Back-patch to 9.3 where pg_isready was added.

Mats Erik Andersson
2014-11-28 02:12:45 +09:00
Stephen Frost 143b39c185 Rename pg_rowsecurity -> pg_policy and other fixes
As pointed out by Robert, we should really have named pg_rowsecurity
pg_policy, as the objects stored in that catalog are policies.  This
patch fixes that and updates the column names to start with 'pol' to
match the new catalog name.

The security consideration for COPY with row level security, also
pointed out by Robert, has also been addressed by remembering and
re-checking the OID of the relation initially referenced during COPY
processing, to make sure it hasn't changed under us by the time we
finish planning out the query which has been built.

Robert and Alvaro also commented on missing OCLASS and OBJECT entries
for POLICY (formerly ROWSECURITY or POLICY, depending) in various
places.  This patch fixes that too, which also happens to add the
ability to COMMENT on policies.

In passing, attempt to improve the consistency of messages, comments,
and documentation as well.  This removes various incarnations of
'row-security', 'row-level security', 'Row-security', etc, in favor
of 'policy', 'row level security' or 'row_security' as appropriate.

Happy Thanksgiving!
2014-11-27 01:15:57 -05:00
Heikki Linnakangas 1812ee5767 Remove dead function prototype
It was added in commit efc16ea5, but never defined.
2014-11-26 11:05:54 +02:00
Robert Haas a6c84c770e Attempt to suppress uninitialized variable warning.
Report by Heikki Linnakangas.
2014-11-25 20:07:07 -05:00
Tom Lane d934a05234 Fix uninitialized-variable warning.
In passing, add an Assert defending the presumption that bytes_left
is positive to start with.  (I'm not exactly convinced that using an
unsigned type was such a bright thing here, but let's at least do
this much.)
2014-11-25 15:17:16 -05:00
Simon Riggs aedccb1f6f action_at_recovery_target recovery config option
action_at_recovery_target = pause | promote | shutdown

Petr Jelinek

Reviewed by Muhammad Asif Naeem, Fujji Masao and
Simon Riggs
2014-11-25 20:13:30 +00:00
Tom Lane bb1b8f694a De-reserve most statement-introducing keywords in plpgsql.
Add a bit of context sensitivity to plpgsql_yylex() so that it can
recognize when the word it is looking at is the first word of a new
statement, and if so whether it is the target of an assignment statement.
When we are at start of statement and it's not an assignment, we can
prefer recognizing unreserved keywords over recognizing variable names,
thereby allowing most statements' initial keywords to be demoted from
reserved to unreserved status.  This is rather useful already (there are
15 such words that get demoted here), and what's more to the point is
that future patches proposing to add new plpgsql statements can avoid
objections about having to add new reserved words.

The keywords BEGIN, DECLARE, FOR, FOREACH, LOOP, WHILE need to remain
reserved because they can be preceded by block labels, and the logic
added here doesn't understand about block labels.  In principle we
could probably fix that, but it would take more than one token of
lookback and the benefit doesn't seem worth extra complexity.

Also note I didn't de-reserve EXECUTE, because it is used in more places
than just statement start.  It's possible it could be de-reserved with
more work, but that would be an independent fix.

In passing, also de-reserve COLLATE and DEFAULT, which shouldn't have
been reserved in the first place since they only need to be recognized
within DECLARE sections.
2014-11-25 15:02:09 -05:00
Tom Lane bac27394a1 Support arrays as input to array_agg() and ARRAY(SELECT ...).
These cases formerly failed with errors about "could not find array type
for data type".  Now they yield arrays of the same element type and one
higher dimension.

The implementation involves creating functions with API similar to the
existing accumArrayResult() family.  I (tgl) also extended the base family
by adding an initArrayResult() function, which allows callers to avoid
special-casing the zero-inputs case if they just want an empty array as
result.  (Not all do, so the previous calling convention remains valid.)
This allowed simplifying some existing code in xml.c and plperl.c.

Ali Akbar, reviewed by Pavel Stehule, significantly modified by me
2014-11-25 12:21:28 -05:00
Stephen Frost 25976710df Add int64 -> int8 mapping to genbki
Per discussion with Tom and Andrew, 64bit integers are no longer a
problem for the catalogs, so go ahead and add the mapping from the C
int64 type to the int8 SQL identification to allow using them.

Patch by Adam Brightwell
2014-11-25 12:12:19 -05:00
Heikki Linnakangas b3fc6727ce Allow using connection URI in primary_conninfo.
The old method of appending options to the connection string didn't work if
the primary_conninfo was a postgres:// style URI, instead of a traditional
connection string. Use PQconnectdbParams instead.

Alex Shulgin
2014-11-25 18:26:05 +02:00
Heikki Linnakangas add1b052e2 Allow "dbname" from connection string to be overridden in PQconnectDBParams
If the "dbname" attribute in PQconnectDBParams contained a connection string
or URI (and expand_dbname = TRUE), the database name from the connection
string could not be overridden by a subsequent "dbname" keyword in the
array. That was not intentional; all other options can be overridden.
Furthermore, any subsequent "dbname" caused the connection string from the
first dbname value to be processed again, overriding any values for the same
options that were given between the connection string and the second dbname
option.

In the passing, clarify in the docs that only the first dbname option in the
array is parsed as a connection string.

Alex Shulgin. Backpatch to all supported versions.
2014-11-25 17:39:44 +02:00
Stephen Frost 81d815dc3e Suppress DROP CASCADE notices in regression tests
In the regression tests, when doing cascaded drops, we need to suppress
the notices from DROP CASCADE or there can be transient regression
failures as the order of drops can depend on the physical row order in
pg_depend.

Report and fix suggestion from Tom.
2014-11-25 10:04:49 -05:00
Heikki Linnakangas 30bf4689a9 Check return value of strdup() in libpq connection option parsing.
An out-of-memory in most of these would lead to strange behavior, like
connecting to a different database than intended, but some would lead to
an outright segfault.

Alex Shulgin and me. Backpatch to all supported versions.
2014-11-25 14:10:16 +02:00
Heikki Linnakangas e453cc2741 Make Port->ssl_in_use available, even when built with !USE_SSL
Code that check the flag no longer need #ifdef's, which is more convenient.
In particular, makes it easier to write extensions that depend on it.

In the passing, modify sslinfo's ssl_is_used function to check ssl_in_use
instead of the OpenSSL specific 'ssl' pointer. It doesn't make any
difference currently, as sslinfo is only compiled when built with OpenSSL,
but seems cleaner anyway.
2014-11-25 09:46:11 +02:00
Robert Haas f5d9698a84 Add infrastructure to save and restore GUC values.
This is further infrastructure for parallelism.

Amit Khandekar, Noah Misch, Robert Haas
2014-11-24 16:37:56 -05:00
Heikki Linnakangas 49b86fb1c9 Add a few paragraphs to B-tree README explaining L&Y algorithm.
This gives an overview of what Lehman & Yao's paper is all about, so that
you can understand the rest of the README without having to read the paper.

Per discussion with Peter Geoghegan and others.
2014-11-24 13:43:33 +02:00
Heikki Linnakangas 0bd624d63b Distinguish XLOG_FPI records generated for hint-bit updates.
Add a new XLOG_FPI_FOR_HINT record type, and use that for full-page images
generated for hint bit updates, when checksums are enabled. The new record
type is replayed exactly the same as XLOG_FPI, but allows them to be tallied
separately e.g. in pg_xlogdump.
2014-11-24 11:09:08 +02:00
Tom Lane e2dc3f5772 Get rid of redundant production in plpgsql grammar.
There may once have been a reason for the intermediate proc_stmts
production in the plpgsql grammar, but it isn't doing anything useful
anymore, so let's collapse it into proc_sect.  Saves some code and
probably a small number of nanoseconds per statement list.

In passing, correctly alphabetize keyword lists to match pl_scanner.c;
note that for "rowtype" vs "row_count", pl_scanner.c must sort on the
basis of the lower-case spelling.

Noted while fooling with a patch to de-reserve more plpgsql keywords.
2014-11-23 15:31:36 -05:00
Andrew Dunstan 02d5ab6a86 Fix memory leaks introduced by commit eca2b9b 2014-11-23 13:47:08 -05:00
Noah Misch b779168ffe Detect PG_PRINTF_ATTRIBUTE automatically.
This eliminates gobs of "unrecognized format function type" warnings
under MinGW compilers predating GCC 4.4.
2014-11-23 09:34:03 -05:00
Tom Lane b62f94c603 Allow simplification of EXISTS() subqueries containing LIMIT.
The locution "EXISTS(SELECT ... LIMIT 1)" seems to be rather common among
people who don't realize that the database already performs optimizations
equivalent to putting LIMIT 1 in the sub-select.  Unfortunately, this was
actually making things worse, because it prevented us from optimizing such
EXISTS clauses into semi or anti joins.  Teach simplify_EXISTS_query() to
suppress constant-positive LIMIT clauses.  That fixes the semi/anti-join
case, and may help marginally even for cases that have to be left as
sub-SELECTs.

Marti Raudsepp, reviewed by David Rowley
2014-11-22 19:12:38 -05:00
Tom Lane 9c58101117 Fix mishandling of system columns in FDW queries.
postgres_fdw would send query conditions involving system columns to the
remote server, even though it makes no effort to ensure that system
columns other than CTID match what the remote side thinks.  tableoid,
in particular, probably won't match and might have some use in queries.
Hence, prevent sending conditions that include non-CTID system columns.

Also, create_foreignscan_plan neglected to check local restriction
conditions while determining whether to set fsSystemCol for a foreign
scan plan node.  This again would bollix the results for queries that
test a foreign table's tableoid.

Back-patch the first fix to 9.3 where postgres_fdw was introduced.
Back-patch the second to 9.2.  The code is probably broken in 9.1 as
well, but the patch doesn't apply cleanly there; given the weak state
of support for FDWs in 9.1, it doesn't seem worth fixing.

Etsuro Fujita, reviewed by Ashutosh Bapat, and somewhat modified by me
2014-11-22 16:01:05 -05:00
Andrew Dunstan eca2b9ba3e Rework echo_hidden for \sf and \ef from commit e4d2817.
PSQLexec's error reporting turns out to be too verbose for this case, so
revert to using PQexec instead with minimal error reporting. Prior to
calling PQexec, we call a function that mimics just the echo_hidden
piece of PSQLexec.
2014-11-22 09:39:01 -05:00
Tom Lane 447770404c Rearrange CustomScan API.
Make it work more like FDW plans do: instead of assuming that there are
expressions in a CustomScan plan node that the core code doesn't know
about, insist that all subexpressions that need planner attention be in
a "custom_exprs" list in the Plan representation.  (Of course, the
custom plugin can break the list apart again at executor initialization.)
This lets us revert the parts of the patch that exposed setrefs.c and
subselect.c processing to the outside world.

Also revert the GetSpecialCustomVar stuff in ruleutils.c; that concept
may work in future, but it's far from fully baked right now.
2014-11-21 18:21:46 -05:00
Tom Lane c2ea2285e9 Simplify API for initially hooking custom-path providers into the planner.
Instead of register_custom_path_provider and a CreateCustomScanPath
callback, let's just provide a standard function hook in set_rel_pathlist.
This is more flexible than what was previously committed, is more like the
usual conventions for planner hooks, and requires less support code in the
core.  We had discussed this design (including centralizing the
set_cheapest() calls) back in March or so, so I'm not sure why it wasn't
done like this already.
2014-11-21 14:05:46 -05:00
Andrew Dunstan 4077fb4d1d Fix an error in psql that overcounted output lines.
This error counted the first line of a cell as "extra". The effect was
to cause far too frequent invocation of the pager. In most cases this
can be worked around (for example, by using the "less" pager with the -F
flag), so don't backpatch.
2014-11-21 12:37:09 -05:00
Andrew Dunstan e4d28175a1 Make psql's \sf and \ef honor ECHO_HIDDEN.
These commands were calling the database direct rather than  calling
PSQLexec like other slash commands that needed database data.

The code is also changed not to pass the connection as a parameter to
the helper functions. It's available in a global variable, and that's
what PSQLexec uses.
2014-11-21 12:14:05 -05:00
Heikki Linnakangas 622983ea69 No need to call XLogEnsureRecordSpace when the relation is unlogged.
Amit Kapila
2014-11-21 15:13:15 +02:00
Heikki Linnakangas b10a97b819 Add a comment to regress.c explaining what it contains.
Ian Barwick
2014-11-21 15:07:29 +02:00
Heikki Linnakangas 8f5dcb56cb Fix bogus comments in XLogRecordAssemble
Pointed out by Michael Paquier
2014-11-21 12:15:27 +02:00
Tom Lane adbfab119b Remove dead code supporting mark/restore in SeqScan, TidScan, ValuesScan.
There seems no prospect that any of this will ever be useful, and indeed
it's questionable whether some of it would work if it ever got called;
it's certainly not been exercised in a very long time, if ever. So let's
get rid of it, and make the comments about mark/restore in execAmi.c less
wishy-washy.

The mark/restore support for Result nodes is also currently dead code,
but that's due to planner limitations not because it's impossible that
it could be useful.  So I left it in.
2014-11-20 20:20:54 -05:00
Tom Lane a34fa8ee7c Initial code review for CustomScan patch.
Get rid of the pernicious entanglement between planner and executor headers
introduced by commit 0b03e5951b.

Also, rearrange the CustomFoo struct/typedef definitions so that all the
typedef names are seen as used by the compiler.  Without this pgindent
will mess things up a bit, which is not so important perhaps, but it also
removes a bizarre discrepancy between the declaration arrangement used for
CustomExecMethods and that used for CustomScanMethods and
CustomPathMethods.

Clean up the commentary around ExecSupportsMarkRestore to reflect the
rather large change in its API.

Const-ify register_custom_path_provider's argument.  This necessitates
casting away const in the function, but that seems better than forcing
callers of the function to do so (or else not const-ify their method
pointer structs, which was sort of the whole point).

De-export fix_expr_common.  I don't like the exporting of fix_scan_expr
or replace_nestloop_params either, but this one surely has got little
excuse.
2014-11-20 18:36:07 -05:00
Tom Lane 081a6048cf Fix another oversight in CustomScan patch.
execCurrent.c's search_plan_tree() must recognize a CustomScan on the
target relation.  This would only be helpful for custom providers that
support CurrentOfExpr quals, which is probably a bit far-fetched, but
it's not impossible I think.  But even without assuming that, we need
to recognize a scanned-relation match so that we will properly throw
error if the desired relation is being scanned with both a CustomScan
and a regular scan (ie, self-join).

Also recognize ForeignScanState for similar reasons.  Supporting WHERE
CURRENT OF on a foreign table is probably even more far-fetched than
it is for custom scans, but I think in principle you could do it with
postgres_fdw (or another FDW that supports the ctid column).  This
would be a back-patchable bug fix if existing FDWs handled CurrentOfExpr,
but I doubt any do so I won't bother back-patching.
2014-11-20 15:56:39 -05:00
Tom Lane 03e574af5f Fix another oversight in CustomScan patch.
disuse_physical_tlist() must work for all plan types handled by
create_scan_plan().
2014-11-20 14:49:02 -05:00
Tom Lane c5111ea9ca Remove no-longer-needed phony typedefs in genbki.h.
Now that we have a policy of hiding varlena catalog fields behind
"#ifdef CATALOG_VARLEN", there is no need for their type names to be
acceptable to the C compiler.  And experimentation shows that it does
not matter to pgindent either.  (If it did, we'd have problems anyway,
since these typedefs are unreferenced so far as the C compiler is
concerned, and find_typedef fails to identify such typedefs.)

Hence, remove the phony typedefs that genbki.h provided to make
some varlena field definitions compilable.

In passing, rearrange #define's into what seemed a more logical order.
2014-11-20 13:16:14 -05:00
Tom Lane f9e0255c6f Add missing case for CustomScan.
Per KaiGai Kohei.

In passing improve formatting of some code added in commit 30d7ae3c,
because otherwise pgindent will make a mess of it.
2014-11-20 12:32:34 -05:00
Heikki Linnakangas f464042161 Silence compiler warning about variable being used uninitialized.
It's a false positive - the variable is only used when 'onleft' is true,
and it is initialized in that case. But the compiler doesn't necessarily
see that.
2014-11-20 19:17:19 +02:00
Heikki Linnakangas 2c03216d83 Revamp the WAL record format.
Each WAL record now carries information about the modified relation and
block(s) in a standardized format. That makes it easier to write tools that
need that information, like pg_rewind, prefetching the blocks to speed up
recovery, etc.

There's a whole new API for building WAL records, replacing the XLogRecData
chains used previously. The new API consists of XLogRegister* functions,
which are called for each buffer and chunk of data that is added to the
record. The new API also gives more control over when a full-page image is
written, by passing flags to the XLogRegisterBuffer function.

This also simplifies the XLogReadBufferForRedo() calls. The function can dig
the relation and block number from the WAL record, so they no longer need to
be passed as arguments.

For the convenience of redo routines, XLogReader now disects each WAL record
after reading it, copying the main data part and the per-block data into
MAXALIGNed buffers. The data chunks are not aligned within the WAL record,
but the redo routines can assume that the pointers returned by XLogRecGet*
functions are. Redo routines are now passed the XLogReaderState, which
contains the record in the already-disected format, instead of the plain
XLogRecord.

The new record format also makes the fixed size XLogRecord header smaller,
by removing the xl_len field. The length of the "main data" portion is now
stored at the end of the WAL record, and there's a separate header after
XLogRecord for it. The alignment padding at the end of XLogRecord is also
removed. This compansates for the fact that the new format would otherwise
be more bulky than the old format.

Reviewed by Andres Freund, Amit Kapila, Michael Paquier, Alvaro Herrera,
Fujii Masao.
2014-11-20 18:46:41 +02:00
Peter Eisentraut 8dc626defe Fix suggested layout for PGXS makefile
Custom rules must come after pgxs inclusion, not before, because any
rule added before pgxs will break the default 'all' target.

Author: Cédric Villemain <cedric@2ndquadrant.fr>
2014-11-19 22:21:54 -05:00
Heikki Linnakangas 88fc719263 Add test cases for indexam operations not currently covered.
That includes VACUUM on GIN, GiST and SP-GiST indexes, and B-tree indexes
large enough to cause page deletions in B-tree. Plus some other special
cases.

After this patch, the regression tests generate all different WAL record
types. Not all branches within the redo functions are covered, but it's a
step forward.
2014-11-19 19:47:43 +02:00
Fujii Masao d5f4df7264 Fix bug in the test of file descriptor of current WAL file in pg_receivexlog.
In pg_receivexlog, in order to check whether the current WAL file is
being opened or not, its file descriptor has to be checked against -1
as an invalid value. But, oops, 7900e94 added the incorrect test
checking the descriptor against 1. This commit fixes that bug.

Back-patch to 9.4 where the bug was added.

Spotted by Magnus Hagander
2014-11-19 19:10:04 +09:00
Fujii Masao f66c20b317 Fix pg_receivexlog --slot so that it doesn't prevent the server shutdown.
When pg_receivexlog --slot is connecting to the server, at the shutdown
of the server, walsender keeps waiting for the last WAL record to be
replicated and flushed in pg_receivexlog. But previously pg_receivexlog
issued sync command only when WAL file was switched. So there was
the case where the last WAL was never flushed and walsender had to
keep waiting infinitely. This caused the server shutdown to get stuck.

pg_recvlogical handles this problem by calling fsync() when it receives
the request of immediate reply from the server. That is, at shutdown,
walsender sends the request, pg_recvlogical receives it, flushes the last
WAL record, and sends the flush location back to the server. Since
walsender can see that the last WAL record is successfully flushed, it can
exit cleanly.

This commit introduces the same logic as pg_recvlogical has,
to pg_receivexlog.

Back-patch to 9.4 where pg_receivexlog was changed so that it can use
the replication slot.

Original patch by Michael Paquier, rewritten by me.
Bug report by Furuya Osamu.
2014-11-19 14:11:12 +09:00
Tom Lane 8d7af8fbe7 Don't require bleeding-edge timezone data in timestamptz regression test.
The regression test cases added in commits b2cbced9e et al depended in part
on the Russian timezone offset changes of Oct 2014.  While this is of no
particular concern for a default Postgres build, it was possible for a
build using --with-system-tzdata to fail the tests if the system tzdata
database wasn't au courant.  Bjorn Munch and Christoph Berg both complained
about this while packaging 9.4rc1, so we probably shouldn't insist on the
system tzdata being up-to-date.  Instead, make an equivalent test using a
zone change that occurred in Venezuela in 2007.  With this patch, the
regression tests should pass using any tzdata set from 2012 or later.
(I can't muster much sympathy for somebody using --with-system-tzdata
on a machine whose system tzdata is more than three years out-of-date.)
2014-11-18 21:36:39 -05:00
Tom Lane 7aa8d9e56c Update comments in find_typedef.
These comments don't seem to have been touched in a long time.  Make them
describe the current implementation rather than what was here last century,
and be a bit more explicit about the unreferenced-typedefs issue.
2014-11-18 15:51:45 -05:00
Tom Lane 8b13e5c6c0 Fix some bogus direct uses of realloc().
pg_dump/parallel.c was using realloc() directly with no error check.
While the odds of an actual failure here seem pretty low, Coverity
complains about it, so fix by using pg_realloc() instead.

While looking for other instances, I noticed a couple of places in
psql that hadn't gotten the memo about the availability of pg_realloc.
These aren't bugs, since they did have error checks, but verbosely
inconsistent code is not a good thing.

Back-patch as far as 9.3.  9.2 did not have pg_dump/parallel.c, nor
did it have pg_realloc available in all frontend code.
2014-11-18 13:28:06 -05:00
Simon Riggs 606c0123d6 Reduce btree scan overhead for < and > strategies
For <, <=, > and >= strategies, mark the first scan key
as already matched if scanning in an appropriate direction.
If index tuple contains no nulls we can skip the first
re-check for each tuple.

Author: Rajeev Rastogi
Reviewer: Haribabu Kommi
Rework of the code and comments by Simon Riggs
2014-11-18 10:24:55 +00:00
Heikki Linnakangas dedae6c211 Remove obsolete debugging option, RTDEBUG.
The r-tree AM that used it was removed back in 2005.

Peter Geoghegan
2014-11-18 09:55:05 +02:00
Simon Riggs be1cc8f46f Add pg_dump --snapshot option
Allows pg_dump to use a snapshot previously defined by a concurrent
session that has either used pg_export_snapshot() or obtained a
snapshot when creating a logical slot. When this option is used with
parallel pg_dump, the snapshot defined by this option is used and no
new snapshot is taken.

Simon Riggs and Michael Paquier
2014-11-17 22:15:07 +00:00
Fujii Masao c4f99d2029 Add --synchronous option to pg_receivexlog, for more reliable WAL writing.
Previously pg_receivexlog flushed WAL data only when WAL file was switched.
Then 3dad73e added -F option to pg_receivexlog so that users could control
how frequently sync commands were issued to WAL files. It also allowed users
to make pg_receivexlog flush WAL data immediately after writing by
specifying 0 in -F option. However feedback messages were not sent back
immediately even after a flush location was updated. So even if WAL data
was flushed in real time, the server could not see that for a while.

This commit removes -F option from and adds --synchronous to pg_receivexlog.
If --synchronous is specified, like the standby's wal receiver, pg_receivexlog
flushes WAL data as soon as there is WAL data which has not been flushed yet.
Then it sends back the feedback message identifying the latest flush location
to the server. This option is useful to make pg_receivexlog behave as sync
standby by using replication slot, for example.

Original patch by Furuya Osamu, heavily rewritten by me.
Reviewed by Heikki Linnakangas, Alvaro Herrera and Sawada Masahiko.
2014-11-18 02:32:48 +09:00
Tom Lane bc241488b0 Update time zone data files to tzdata release 2014j.
DST law changes in the Turks & Caicos Islands (America/Grand_Turk) and
in Fiji.  New zone Pacific/Bougainville for portions of Papua New Guinea.
Historical changes for Korea and Vietnam.
2014-11-17 12:09:12 -05:00
Heikki Linnakangas c73669c0e0 Fix WAL-logging of B-tree "unlink halfdead page" operation.
There was some confusion on how to record the case that the operation
unlinks the last non-leaf page in the branch being deleted.
_bt_unlink_halfdead_page set the "topdead" field in the WAL record to
the leaf page, but the redo routine assumed that it would be an invalid
block number in that case. This commit fixes _bt_unlink_halfdead_page to
do what the redo routine expected.

This code is new in 9.4, so backpatch there.
2014-11-17 18:45:46 +02:00
Alvaro Herrera 0f9692b40d Fix relpersistence setting in reindex_index
Buildfarm members with CLOBBER_CACHE_ALWAYS advised us that commit
85b506bbfc was mistaken in setting the relpersistence value of the
index directly in the relcache entry, within reindex_index.  The reason
for the failure is that an invalidation message that comes after mucking
with the relcache entry directly, but before writing it to the catalogs,
would cause the entry to become rebuilt in place from catalogs with the
old contents, losing the update.

Fix by passing the correct persistence value to
RelationSetNewRelfilenode instead; this routine also writes the updated
tuple to pg_class, avoiding the problem.  Suggested by Tom Lane.
2014-11-17 11:23:35 -03:00
Peter Eisentraut 7466a1b75f Translation updates 2014-11-16 21:32:51 -05:00
Simon Riggs 0f66d21201 Emit msg re skipping ANALYZE for absent inh tree
When checking a table that has an inheritance tree marked,
if no child tables remain, we skip ANALYZE. This patch emits
a message to show that the action has been skipped.

Author: Etsuro Fujita
Reviewer: Furuya Osamu
2014-11-15 22:49:54 +00:00
Alvaro Herrera 85b506bbfc Get rid of SET LOGGED indexes persistence kludge
This removes ATChangeIndexesPersistence() introduced by f41872d0c1
which was too ugly to live for long.  Instead, the correct persistence
marking is passed all the way down to reindex_index, so that the
transient relation built to contain the index relfilenode can
get marked correctly right from the start.

Author: Fabrízio de Royes Mello
Review and editorialization by Michael Paquier
                                     and Álvaro Herrera
2014-11-15 01:19:49 -03:00
Alvaro Herrera e4d1e26491 Remove unused InhPaths
Allegedly, the last remaining usages of that struct were removed by
0e99be1c.

Author: Peter Geoghegan
2014-11-15 01:19:39 -03:00
Andres Freund 522c85a6a2 Fix initdb --sync-only to also sync tablespaces.
630cd14426 added initdb --sync-only, for use by pg_upgrade, by just
exposing the existing fsync code. That's wrong, because initdb so far
had absolutely no reason to deal with tablespaces.

Fix --sync-only by additionally explicitly syncing each of the
tablespaces.

Backpatch to 9.3 where --sync-only was introduced.

Abhijit Menon-Sen and Andres Freund
2014-11-15 01:19:40 +01:00
Andres Freund 98ec7fd903 Sync unlogged relations to disk after they have been reset.
Unlogged relations are only reset when performing a unclean
restart. That means they have to be synced to disk during clean
shutdowns. During normal processing that's achieved by registering a
buffer's file to be fsynced at the next checkpoint when flushed. But
ResetUnloggedRelations() doesn't go through the buffer manager, so
nothing will force reset relations to disk before the next shutdown
checkpoint.

So just make ResetUnloggedRelations() fsync the newly created main
forks to disk.

Discussion: 20140912112246.GA4984@alap3.anarazel.de

Backpatch to 9.1 where unlogged tables were introduced.

Abhijit Menon-Sen and Andres Freund
2014-11-15 01:19:31 +01:00
Andres Freund d3586fc8aa Ensure unlogged tables are reset even if crash recovery errors out.
Unlogged relations are reset at the end of crash recovery as they're
only synced to disk during a proper shutdown. Unfortunately that and
later steps can fail, e.g. due to running out of space. This reset
was, up to now performed after marking the database as having finished
crash recovery successfully. As out of space errors trigger a crash
restart that could lead to the situation that not all unlogged
relations are reset.

Once that happend usage of unlogged relations could yield errors like
"could not open file "...": No such file or directory". Luckily
clusters that show the problem can be fixed by performing a immediate
shutdown, and starting the database again.

To fix, just call ResetUnloggedRelations(UNLOGGED_RELATION_INIT)
earlier, before marking the database as having successfully recovered.

Discussion: 20140912112246.GA4984@alap3.anarazel.de

Backpatch to 9.1 where unlogged tables were introduced.

Abhijit Menon-Sen and Andres Freund
2014-11-15 01:19:26 +01:00
Stephen Frost 80eacaa3cd Clean up includes from RLS patch
The initial patch for RLS mistakenly included headers associated with
the executor and planner bits in rewrite/rowsecurity.h.  Per policy and
general good sense, executor headers should not be included in planner
headers or vice versa.

The include of execnodes.h was a mistaken holdover from previous
versions, while the include of relation.h was used for Relation's
definition, which should have been coming from utils/relcache.h.  This
patch cleans these issues up, adds comments to the RowSecurityPolicy
struct and the RowSecurityConfigType enum, and changes Relation->rsdesc
to Relation->rd_rsdesc to follow Relation field naming convention.

Additionally, utils/rel.h was including rewrite/rowsecurity.h, which
wasn't a great idea since that was pulling in things not really needed
in utils/rel.h (which gets included in quite a few places).  Instead,
use 'struct RowSecurityDesc' for the rd_rsdesc field and add comments
explaining why.

Lastly, add an include into access/nbtree/nbtsort.c for
utils/sortsupport.h, which was evidently missed due to the above mess.

Pointed out by Tom in 16970.1415838651@sss.pgh.pa.us; note that the
concerns regarding a similar situation in the custom-path commit still
need to be addressed.
2014-11-14 17:05:17 -05:00
Alvaro Herrera 86cf9a5650 Reduce disk footprint of brin regression test
Per complaint from Tom.

While at it, throw in some extra tests for nulls as well, and make sure
that the set of data we insert on the second round is not identical to
the first one.  Both measures are intended to improve coverage of the
test.

Also uncomment the ON COMMIT DROP clause on the CREATE TEMP TABLE
commands.  This doesn't have any effect for someone examining the
regression database after the tests are done, but it reduces clutter for
those that execute the script directly.
2014-11-14 16:31:48 -03:00
Alvaro Herrera 51f9ea25dc Allow interrupting GetMultiXactIdMembers
This function has a loop which can lead to uninterruptible process
"stalls" (actually infinite loops) when some bugs are triggered.  Avoid
that unpleasant situation by adding a check for interrupts in a place
that shouldn't degrade performance in the normal case.

Backpatch to 9.3.  Older branches have an identical loop here, but the
aforementioned bugs are only a problem starting in 9.3 so there doesn't
seem to be any point in backpatching any further.
2014-11-14 15:14:01 -03:00
Andres Freund 0c5af0a537 Move BufferGetBlockNumber() out of heap_page_is_all_visible()'s inner loop.
In some workloads BufferGetBlockNumber() shows up in profiles due to
the sheer number of calls to it (and because it causes cache
misses). The compiler can't move it out of the loop because it's a
full extern function call...
2014-11-14 17:04:44 +01:00
Andres Freund 6c878edc1d Add valgrind suppression for pg_atomic_init_u64.
pg_atomic_init_u64 (indirectly) uses compare/exchange to guarantee
atomic writes on platforms where compare/exchange is available, but
64bit writes aren't atomic (yes, those exist). That leads to a
harmless read of the initial value of variable.
2014-11-14 16:59:33 +01:00
Peter Eisentraut a15d387c22 Improve logical decoding log messages
suggestions from Robert Haas
2014-11-13 20:44:34 -05:00
Andres Freund 473f162ce1 Adapt valgrind.supp to the XLogInsert() split.
The CRC computation now happens in XLogInsertRecord(), not
XLogInsert() itself anymore.
2014-11-14 00:59:40 +01:00
Tom Lane be09ceb218 Fix pg_dumpall to restore its ability to dump from ancient servers.
Fix breakage induced by commits d8d3d2a4f3
and 463f2625a5fb183b6a8925ccde98bb3889f921d9: pg_dumpall has crashed when
attempting to dump from pre-8.1 servers since then, due to faulty
construction of the query used for dumping roles from older servers.
The query was erroneous as of the earlier commit, but it wasn't exposed
unless you tried to use --binary-upgrade, which you presumably wouldn't
with a pre-8.1 server.  However commit 463f2625a made it fail always.

In HEAD, also fix additional breakage induced in the same query by
commit 491c029dbc, which evidently wasn't
tested against pre-8.1 servers either.

The bug is only latent in 9.1 because 463f2625a hadn't landed yet, but
it seems best to back-patch all branches containing the faulty query.

Gilles Darold
2014-11-13 18:19:26 -05:00
Andres Freund 89fd41b390 Fix and improve cache invalidation logic for logical decoding.
There are basically three situations in which logical decoding needs
to perform cache invalidation. During/After replaying a transaction
with catalog changes, when skipping a uninteresting transaction that
performed catalog changes and when erroring out while replaying a
transaction. Unfortunately these three cases were all done slightly
differently - partially because 8de3e410fa, which greatly simplifies
matters, got committed in the midst of the development of logical
decoding.

The actually problematic case was when logical decoding skipped
transaction commits (and thus processed invalidations). When used via
the SQL interface cache invalidation could access the catalog - bad,
because we didn't set up enough state to allow that correctly. It'd
not be hard to setup sufficient state, but the simpler solution is to
always perform cache invalidation outside a valid transaction.

Also make the different cache invalidation cases look as similar as
possible, to ease code review.

This fixes the assertion failure reported by Antonin Houska in
53EE02D9.7040702@gmail.com. The presented testcase has been expanded
into a regression test.

Backpatch to 9.4, where logical decoding was introduced.
2014-11-13 20:34:31 +01:00
Andres Freund 5a2c184058 Fix xmin/xmax horizon computation during logical decoding initialization.
When building the initial historic catalog snapshot there were
scenarios where snapbuild.c would use incorrect xmin/xmax values when
starting from a xl_running_xacts record. The values used were always a
bit suspect, but happened to be correct in the easy to test
cases. Notably the values used when the the initial snapshot was
computed while no other transactions were running were correct.

This is likely to be the cause of the occasional buildfarm failures on
animals markhor and tick; but it's quite possible to reproduce
problems without CLOBBER_CACHE_ALWAYS.

Backpatch to 9.4, where logical decoding was introduced.
2014-11-13 20:34:30 +01:00
Heikki Linnakangas 81c4508196 Fix race condition between hot standby and restoring a full-page image.
There was a window in RestoreBackupBlock where a page would be zeroed out,
but not yet locked. If a backend pinned and locked the page in that window,
it saw the zeroed page instead of the old page or new page contents, which
could lead to missing rows in a result set, or errors.

To fix, replace RBM_ZERO with RBM_ZERO_AND_LOCK, which atomically pins,
zeroes, and locks the page, if it's not in the buffer cache already.

In stable branches, the old RBM_ZERO constant is renamed to RBM_DO_NOT_USE,
to avoid breaking any 3rd party extensions that might use RBM_ZERO. More
importantly, this avoids renumbering the other enum values, which would
cause even bigger confusion in extensions that use ReadBufferExtended, but
haven't been recompiled.

Backpatch to all supported versions; this has been racy since hot standby
was introduced.
2014-11-13 20:02:37 +02:00
Robert Haas c0828b78e9 Move the guts of our Levenshtein implementation into core.
The hope is that we can use this to produce better diagnostics in
some cases.

Peter Geoghegan, reviewed by Michael Paquier, with some further
changes by me.
2014-11-13 12:33:26 -05:00