|| ||David Fetter <david-AT-fetter.org> |
|| ||PostgreSQL Announce <pgsql-announce-AT-postgresql.org> |
|| ||[ANNOUNCE] == PostgreSQL Weekly News - February 19 2012 == |
|| ||Sun, 19 Feb 2012 23:30:59 -0800|
|| ||Article, Thread
== PostgreSQL Weekly News - February 19 2012 ==
== PostgreSQL Product News ==
PostgreSQL Data Sync 12.2, a tool comparing and syncrhonizing
PostgreSQL database contents, released.
Quick Application Suite and Quick Application Builder 3.0 for
== PostgreSQL Jobs for February ==
== PostgreSQL Local ==
PGDay NYC will be held April 2, 2012 at Lighthouse International in
New York City.
PGCon 2012 will be held 17-18 May 2012, in Ottawa at the University of
Ottawa. It will be preceded by two days of tutorials on 15-16 May 2012.
PGDay France will be in Lyon on June 7, 2012.
== PostgreSQL in the News ==
Planet PostgreSQL: http://planet.postgresql.org/
PostgreSQL Weekly News is brought to you this week by David Fetter
Submit news and announcements by Sunday at 3:00pm Pacific time.
Please send English language ones to firstname.lastname@example.org, German language
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== Applied Patches ==
Heikki Linnakangas pushed:
- Silence warning about deprecated assignment to $[ in
check_keywords.pl. Alex Hunsaker
- Fix heap_multi_insert to set t_self field in the caller's tuples.
If tuples were toasted, heap_multi_insert didn't update the ctid on
the original tuples. This caused a failure if there was an after
trigger (including a foreign key), on the table, and a tuple got
toasted. Per off-list report and test case from Ted Phelps
Andrew Dunstan pushed:
- Fix auto-explain JSON output to be valid JSON. Problem reported by
Peter Eisentraut. Backpatched to release 9.0.
- Improve pretty printing of viewdefs. Some line feeds are added to
target lists and from lists to make them more readable. By default
they wrap at 80 columns if possible, but the wrap column is also
selectable - if 0 it wraps after every item. Andrew Dunstan,
reviewed by Hitoshi Harada.
Michael Meskes pushed:
- Do not use the variable name when defining a varchar structure in
ecpg. With a unique counter being added anyway, there is no need
anymore to have the variable name listed, too.
- Make sure all connection paramters are used in call to
- Windows doesn't have strtok_r, so let's use strtok_s instead.
- gcc on Windows does not know about strtok_s.
- In ecpglib rewrote code that used strtok_r to not use library
functions anymore. This way we don't have to worry which compiler on
which OS offers which version of strtok.
Bruce Momjian pushed:
- Improve labeling of pg_test_fsync open_sync test output.
- Change contrib/pg_test_fsync to control tests in terms of seconds
per test, rather than a number of test cycles. Changes -o/cycles
option to -s/seconds.
- Document that the pg_test_fsync defaults allow the program to
complete in about 30 seconds.
- Document random page cost is only 4x seqeuntial, and not 40x.
- Improve fsync documentation by stating that -W _0_ turns of write
- Try to get pg_test_thread to compile on Windows by using a sleeper
- Fix pg_test_fsync Win32 problems reported by the build farm; add
comments about the alarm method used on Win32.
- Have pg_upgrade output 'link' or 'copy' when reporting its status.
Idea from Peter Eisentraut.
Robert Haas pushed:
- Allow LEAKPROOF functions for better performance of security views.
We don't normally allow quals to be pushed down into a view created
with the security_barrier option, but functions without side effects
are an exception: they're OK. This allows much better performance
in common cases, such as when using an equality operator (that might
even be indexable). There is an outstanding issue here with the
CREATE FUNCTION / ALTER FUNCTION syntax: there's no way to use ALTER
FUNCTION to unset the leakproof flag. But I'm committing this as-is
so that it doesn't have to be rebased again; we can fix up the
grammar in a future commit. KaiGai Kohei, with some wordsmithing by
- Fix new create_function_3 regression tests not to rely on tuple
order. Per buildfarm.
- Remove new, intermittently failing regression test. Per buildfarm.
- sepgsql: Reword and fix typo in docs on DML permissions. Per report
from Christoph Berg.
- Make CREATE/ALTER FUNCTION support NOT LEAKPROOF. Because it isn't
good to be able to turn things on, and not off again.
- More regression tests for LEAKPROOF/NOT LEAKPROOF stuff. Along the
way, move create_function_3 into a parallel schedule. KaiGai Kohei
- Speed up in-memory tuplesorting. Per recent work by Peter
Geoghegan, it's significantly faster to tuplesort on a single
sortkey if ApplySortComparator is inlined into quicksort rather
reached via a function pointer. It's also faster in general to have
a version of quicksort which is specialized for sorting SortTuple
objects rather than objects of arbitrary size and type. This
requires a couple of additional copies of the quicksort logic, which
in this patch are generate using a Perl script. There might be some
benefit in adding further specializations here too, but thus far
it's not clear that those gains are worth their weight in code
- sepgsql: Move some code from hooks.c to label.c. This is some
preliminary refactoring related to a pending patch to allow
sepgsql-enable sessions to make dynamic label transitions. But this
commit doesn't involve any functional change: it just puts some bits
of code in more logical places. KaiGai Kohei
- Fix VPATH builds, broken by my recent commit to speed up
tuplesorting. The relevant commit is
- Invent on_exit_nicely for pg_dump. Per recent discussions on
pgsql-hackers regarding parallel pg_dump.
- Refactor pg_dump.c to avoid duplicating returns-one-row check. Any
patches apt to get broken have probably already been broken by the
error-handling cleanups I just did, so we might as well clean this
up at the same time.
- pg_dump: Remove global connection pointer. Parallel pg_dump wants
to have multiple ArchiveHandle objects, and therefore multiple
PGconns, in play at the same time. This should be just about the
end of the refactoring that we need in order to make that workable.
- pg_dump: Miscellaneous tightening based on recent refactorings. Use
exit_horribly() and ExecuteSqlQueryForSingleRow() in various places
where it's equivalent, or nearly equivalent, to the prior coding.
Apart from being more compact, this also makes the error messages
for the wrong-number-of-tuples case more consistent.
Tom Lane pushed:
- Preserve column names in the execution-time tupledesc for a RowExpr.
The hstore and json datatypes both have record-conversion functions
that pay attention to column names in the composite values they're
handed. We used to not worry about inserting correct field names
into tuple descriptors generated at runtime, but given these
examples it seems useful to do so. Observe the nicer-looking
results in the regression tests whose results changed. catversion
bump because there is a subtle change in requirements for stored
rule parsetrees: RowExprs from ROW() constructs now have to include
field names. Andrew Dunstan and Tom Lane
- Run a portal's cleanup hook immediately when pushing it to FAILED
state. This extends the changes of commit
6252c4f9e201f619e5eebda12fa867acd4e4200e so that we run the cleanup
hook earlier for failure cases as well as success cases. As before,
the point is to avoid an assertion failure from an Assert I added in
commit a874fe7b4c890d1fe3455215a83ca777867beadd, which was meant to
check that no user-written code can be called during portal cleanup.
This fixes a case reported by Pavan Deolasee in which the Assert
could be triggered during backend exit (see the new regression test
case), and also prevents the possibility that the cleanup hook is
run after portions of the portal's state have already been recycled.
That doesn't really matter in current usage, but it foreseeably
could matter in the future. Back-patch to 9.1 where the Assert in
question was added.
- Improve statistics estimation to make some use of DISTINCT in
sub-queries. Formerly, we just punted when trying to estimate stats
for variables coming out of sub-queries using DISTINCT, on the
grounds that whatever stats we might have for underlying table
columns would be inapplicable. But if the sub-query has only one
DISTINCT column, we can consider its output variable as being
unique, which is useful information all by itself. The scope of
this improvement is pretty narrow, but it costs nearly nothing, so
we might as well do it. Per discussion with Andres Freund. This
patch differs from the draft I submitted yesterday in updating
various comments about vardata.isunique (to reflect its extended
meaning) and in tweaking the interaction with security_barrier
views. There does not seem to be a reason why we can't use this
sort of knowledge even when the sub-query is such a view.
- Fix longstanding error in contrib/intarray's int & int operator.
The array intersection code would give wrong results if the first
entry of the correct output array would be "1". (I think only this
value could be at risk, since the previous word would always be a
lower-bound entry with that fixed value.) Problem spotted by Julien
Rouhaud, initial patch by Guillaume Lelarge, cosmetic improvements
- Sync regex code with Tcl 8.5.11. Sync our regex code with upstream
changes since last time we did this, which was Tcl 8.5.0 (see commit
df1e965e12cdd48c11057ee6e15346ee2b8b02f5). There are no functional
changes here; the main point is just to lay down a commit-log marker
that somebody has looked at this recently, and to do what we can to
keep the two codebases comparable.
- Update expected/collate.linux.utf8.out for recent plpgsql changes.
This file was missed in commit
- Create the beginnings of internals documentation for the regex code.
Create src/backend/regex/README to hold an implementation overview
of the regex package, and fill it in with some preliminary notes
about the code's DFA/NFA processing and colormap management. Much
more to do there of course. Also, improve some code comments around
the colormap and cvec code. No functional changes except to add one
- Add caching of ctype.h/wctype.h results in regc_locale.c. While
this doesn't save a huge amount of runtime, it still seems worth
doing, especially since I realized that the data copying I did in my
first draft was quite unnecessary. In this version, once we have
the results cached, getting them back for re-use is really very
cheap. Also, remove the hard-wired limitation to not consider
wctype.h results for character codes above 255. It turns out that
we can't push the limit as far up as I'd originally hoped, because
the regex colormap code is not efficient enough to cope very well
with character classes containing many thousand letters, which a
Unicode locale is entirely capable of producing. Still, we can push
it up to U+7FF (which I chose as the limit of 2-byte UTF8
characters), which will at least make Eastern Europeans happy
pending a better solution. Thus, this commit resolves the specific
complaint in bug #6457, but not the more general issue that letters
of non-western alphabets are mostly not recognized as matching
- Fix regex back-references that are directly quantified with *. The
syntax "\n*", that is a backref with a * quantifier directly applied
to it, has never worked correctly in Spencer's library. This has
been an open bug in the Tcl bug tracker since 2005:
The core of the problem is in parseqatom(), which first changes
"\n*" to "\n+|" and then applies repeat() to the NFA representing
the backref atom. repeat() thinks that any arc leading into its
"rp" argument is part of the sub-NFA to be repeated. Unfortunately,
since parseqatom() already created the arc that was intended to
represent the empty bypass around "\n+", this arc gets moved too, so
that it now leads into the state loop created by repeat(). Thus,
what was supposed to be an "empty" bypass gets turned into something
that represents zero or more repetitions of the NFA representing the
backref atom. In the original example, in place of ^([bc])\1*$ we
now have something that acts like ^([bc])(\1+|[bc]*)$ At runtime,
the branch involving the actual backref fails, as it's supposed to,
but then the other branch succeeds anyway. We could no doubt fix
this by some rearrangement of the operations in parseqatom(), but
that code is plenty ugly already, and what's more the whole business
of converting "x*" to "x+|" probably needs to go away to fix another
problem I'll mention in a moment. Instead, this patch suppresses
the *-conversion when the target is a simple backref atom, leaving
the case of m == 0 to be handled at runtime. This makes the patch
in regcomp.c a one-liner, at the cost of having to tweak
cbrdissect() a little. In the event I went a bit further than that
and rewrote cbrdissect() to check all the string-length-related
conditions before it starts comparing characters. It seems a bit
stupid to possibly iterate through many copies of an n-character
backreference, only to fail at the end because the target string's
length isn't a multiple of n --- we could have found that out before
starting. The existing coding could only be a win if integer
division is hugely expensive compared to character comparison, but I
don't know of any modern machine where that might be true. This
does not fix all the problems with quantified back-references. In
particular, the code is still broken for back-references that appear
within a larger expression that is quantified (so that direct
insertion of the quantification limits into the BACKREF node doesn't
apply). I think fixing that will take some major surgery on the NFA
code, specifically introducing an explicit iteration node type
instead of trying to transform iteration into concatenation of
modified regexps. Back-patch to all supported branches. In HEAD,
also add a regression test case for this. (It may seem a bit silly
to create a regression test file for just one test case; but I'm
expecting that we will soon import a whole bunch of regex regression
tests from Tcl, so might as well create the infrastructure now.)
== Rejected Patches (for now) ==
No one was disappointed this week :-)
== Pending Patches ==
Marko Kreen and Kyotaro HORIGUCHI traded patches to create, and use in
dblink, a new tuple storage for libpq.
Etsuro Fujita and Shigeru HANADA traded patches to make a PostgreSQL
Alvaro Herrera sent in another revision of the patch to create a
special lock type for foreign keys.
Heikki Linnakangas sent in two more revisions of a patch to scale xlog
Dimitri Fontaine sent in a patch to fix an issue with DROP EXTENSION.
Chetan Suttraway sent in another revision of the patch to optimize
referential integrity checks.
Jaime Casanova sent in a flock of patches which: adds gin and spgist
support to pgstattuple and makes pgstattuple use a ring buffer when
reading tables or indexes, adds the relation_free_space function to
pgstattuple, and adds a stats_target parameter to the
Dimitri Fontaine sent in four more revisions of the patch to add
Alexander Korotkov sent in two more revision of the patch to make some
speed improvements on inserting and indexing cubes.
Dan Ports sent in a patch to fix a possible incompatibility between
prepared transactions and SSI.
Peter Eisentraut sent in another revision of the patch to control the
location of server-side SSL files via a new GUC.
MauMau sent in a patch to fix a bug in windows debug builds where the
postmaster would always crash.
Simon Riggs sent in three more revisions of the patch to add page
Kevin Grittner sent in another revision of the patch to (re-)run GUC
check hooks on RESET.
Dan Scales sent in a patch implementing a new option for
wal_sync_method intended to improve performance.
Peter Geoghegan sent in another revision of the patch to normalize
Robert Haas sent in another revision of the patch to display
autovacuum accumulated cost.
Robert Haas sent in another revision of the patch to simulate clog
Peter Eisentraut sent in a patch to make pg_regress set the
application name rather than leaving it as psql.
Jan Urbanski sent in a patch to add PL/Python execution contexts.
Jan Urbanski sent in a patch to fix some reference miscounts and
segfaults in PL/Python.
Simon Riggs sent in a patch intended to reduce the frequency of
Pavel Stehule sent in a patch to add tab completion for functions to
Pavel Stehule sent in a patch to add tab completion for CREATE OR
REPLACE FUNCTION in psql.
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