PostgreSQL Weekly News – February 27 2011
== PostgreSQL Weekly News – February 27 2011 ==
Gabriele Bartolini of ITPUG will present a talk on PostgreSQL 9.0 at Codemotion
in Rome on Saturday, March 5th, 2011 at 4:10PM. More information:
== PostgreSQL Product News ==
pgpool-II 3.0.3, a connection pooler and more, released.
pgwatch 1.0beta1, a monitoring tool for PostgreSQL, released.
psycopg2 2.4, a Python connector for PostgreSQL, released.
== PostgreSQL Jobs for February ==
== PostgreSQL Local ==
PostgreSQL Conference East 2011: NYC March 22nd – 25th
Open Database Camp will be on May 7-9, 2011 in Sardinia, Italy
PGCon will be May 19-20, 2011 at the University of Ottawa, preceded by
two days of tutorials on May 17-18.
== PostgreSQL in the News ==
Planet PostgreSQL: http://planet.postgresql.org/
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== Reviews ==
== Applied Patches ==
ITAGAKI Takahiro pushed:
– Add ENCODING option to COPY TO/FROM and file_fdw. File encodings
can be specified separately from client encoding. If not specified,
client encoding is used for backward compatibility. Cases when the
encoding doesn’t match client encoding are slower than matched cases
because we don’t have conversion procs for other encodings.
Performance improvement would be be a future work. Original patch
by Hitoshi Harada, and modified by me.
– Fix pg_server_to_client, that was broken in the previous commit.
– Make the second words lowercase in psql’s d titles for unlogged
– Add tab-completion for CREATE UNLOGGED TABLE in psql, and fix
unexpected completion for DROP TEMP and UNIQUE.
– More psql tab-completion for new commands: ALTER FOREIGN DATA
WRAPPER with HANDLER, ALTER TABLE VALIDATE CONSTRAINT, ALTER TYPE
ADD VALUE, COPY with ENCODING and FORCE NOT NULL, CREATE FOREIGN
DATA WRAPPER with HANDLER, CREATE TRIGGER … INSTEAD OF
Bruce Momjian pushed:
– Update docs about new role privileges reference, per Alvaro Herrera.
– Move information_schema duplicate constraint note to the top of the
information schema documentation because it affects several tables.
– Reword information_schema duplicate constraint warning text.
– Update wording about information schema and name which views
potentially can have duplicates, per request from Tom Lane.
– Document pg_options_to_table() (not previously documented)
– Fix doc patch — pg_options_to_table() returns “setof record”.
– Document that pg_options_to_table() also works for
– Fix markup for pg_options_to_table() to report the return column
names, per suggestion from Andrew Dunstan.
– Be less detailed about reporting shared memory failure by avoiding
the output of actual Postgres parameter _values_ related to shared
memory, and suggesting that these are only possible parameters to
– Document that last vacuum statistics and counts are for non-FULL
Tom Lane pushed:
– Fix dangling-pointer problem in before-row update trigger
processing. ExecUpdate checked for whether ExecBRUpdateTriggers had
returned a new tuple value by seeing if the returned tuple was
pointer-equal to the old one. But the “old one” was in
estate->es_junkFilter’s result slot, which would be scribbled on if
we had done an EvalPlanQual update in response to a concurrent
update of the target tuple; therefore we were comparing a dangling
pointer to a live one. Given the right set of circumstances we
could get a false match, resulting in not forcing the tuple to be
stored in the slot we thought it was stored in. In the case
reported by Maxim Boguk in bug #5798, this led to “cannot extract
system attribute from virtual tuple” failures when trying to do
“RETURNING ctid”. I believe there is a very-low-probability chance
of more serious errors, such as generating incorrect index entries
based on the original rather than the trigger-modified version of
the row. In HEAD, change all of ExecBRInsertTriggers,
ExecIRInsertTriggers, ExecBRUpdateTriggers, and ExecIRUpdateTriggers
so that they continue to have similar APIs. In the back branches I
just changed ExecBRUpdateTriggers, since there is no bug in the
– Remove ExecRemoveJunk(), which is no longer used anywhere. This was
a leftover from the pre-8.1 design of junkfilters. It doesn’t seem
to have any reason to live, since it’s merely a combination of two
easy function calls, and not a well-designed combination at that (it
encourages callers to leak the result tuple).
– Allow binary I/O of type “void”. void_send is useful for the same
reason that void_out doesn’t throw error, namely that someone might
do “select void_returning_func(…)” from a client that prefers to
operate in binary mode. The void_recv function may or may not have
any practical use, but we provide it for symmetry. Radosław Smogura
– Add a relkind field to RangeTblEntry to avoid some syscache lookups.
The recent additions for FDW support required checking
foreign-table-ness in several places in the parse/plan chain. While
it’s not clear whether that would really result in a noticeable
slowdown, it seems best to avoid any performance risk by keeping a
copy of the relation’s relkind in RangeTblEntry. That might have
some other uses later, anyway. Per discussion.
– Support data-modifying commands (INSERT/UPDATE/DELETE) in WITH.
This patch implements data-modifying WITH queries according to the
semantics that the updates all happen with the same command counter
value, and in an unspecified order. Therefore one WITH clause can’t
see the effects of another, nor can the outer query see the effects
other than through the RETURNING values. And attempts to do
conflicting updates will have unpredictable results. We’ll need to
document all that. This commit just fixes the code; documentation
updates are waiting on author. Marko Tiikkaja and Hitoshi Harada
– Fix order of shutdown processing when CTEs contain inter-references.
We need ExecutorEnd to run the ModifyTable nodes to completion in
reverse order of initialization, not forward order. Easily done by
constructing the list back-to-front.
– Refactor the executor’s API to support data-modifying CTEs better.
The originally committed patch for modifying CTEs didn’t interact
well with EXPLAIN, as noted by myself, and also had corner-case
problems with triggers, as noted by Dean Rasheed. Those problems
show it is really not practical for ExecutorEnd to call any
user-defined code; so split the cleanup duties out into a new
function ExecutorFinish, which must be called between the last
ExecutorRun call and ExecutorEnd. Some Asserts have been added to
these functions to help verify correct usage. It is no longer
necessary for callers of the executor to call
AfterTriggerBeginQuery/AfterTriggerEndQuery for themselves, as this
is now done by ExecutorStart/ExecutorFinish respectively. If you
really need to suppress that and do it for yourself, pass
EXEC_FLAG_SKIP_TRIGGERS to ExecutorStart. Also, refactor portal
commit processing to allow for the possibility that PortalDrop will
invoke user-defined code. I think this is not actually necessary
just yet, since the portal-execution-strategy logic forces any
non-pure-SELECT query to be run to completion before we will
consider committing. But it seems like good future-proofing.
– Add documentation for data-modifying statements in WITH clauses.
Marko Tiikkaja, somewhat reworked by Tom Lane.
Robert Haas pushed:
– Fix a couple of unlogged tables goofs. “SELECT … INTO UNLOGGED
tabname” works, but wasn’t documented; CREATE UNLOGGED SEQUENCE and
CREATE UNLOGGED VIEW failed an assertion, instead of throwing a
sensible error. Latter issue reported by Itagaki Takahiro; patch
review by Tom Lane.
– Named restore point improvements. Emit a log message when creating
a named restore point, and improve documentation for
pg_create_restore_point(). Euler Taveira de Oliveira, per
suggestions from Thom Brown, with some additional wordsmithing by
Peter Eisentraut pushed:
– Add PL/Python functions for quoting strings. Add functions
plpy.quote_ident, plpy.quote_literal, plpy.quote_nullable, which
wrap the equivalent SQL functions. To be able to propagate char *
constness properly, make the argument of quote_literal_cstr() const
char *. This also makes it more consistent with quote_identifier().
Jan Urbański, reviewed by Hitoshi Harada, some refinements by Peter
– Table function support for PL/Python. This allows functions with
multiple OUT parameters returning both one or multiple records
(RECORD or SETOF RECORD). Jan Urbański, reviewed by Hitoshi Harada
– Remove remaining expected file for Python 2.2. We don’t have
complete expected coverage for Python 2.2 anyway, so it doesn’t seem
worth keeping this one around that no one appears to be updating
anyway. Visual inspection of the differences ought to be good
enough for those few who care about this obsolete Python version.
– PL/Python explicit subtransactions. Adds a context manager,
obtainable by plpy.subtransaction(), to run a group of statements in
a subtransaction. Jan Urbański, reviewed by Steve Singer,
additional scribbling by me
Alvaro Herrera pushed:
– Fix pageinspect’s heap_page_item to return infomasks as 32 bit
values. HeapTupleHeader’s t_infomask and t_infomask2 are defined as
16-bit unsigned integers, so when the 16th bit was set,
heap_page_item was returning them as negative values, which was
ugly. The change to pageinspect–unpackaged–1.0.sql allows a
module upgraded from 9.0 to be cleanly updated from the previous
– Update pageinspect–1.0.sql to match the upgrade script. Per
comment from Tom Lane
Andrew Dunstan pushed:
– Add a configure check for Python.h if building with python.
Heikki Linnakangas pushed:
– Increase the default for wal_sender_delay from 200ms to 1s. Now
that WAL sender is immediately woken up by transaction commit,
there’s no need to wake up so aggressively.
Magnus Hagander pushed:
– Fix verbose display of REPLICATION role attribute. Josh Kupershmidt
== Rejected Patches (for now) ==
No one was disappointed this week
== Pending Patches ==
Hans-Juergen Schoenig sent in a WIP patch to track cross-column
Kevin Grittner sent in two revisions of a patch to track changes with
Radoslaw Smogura sent in three revisions of a patch to add a binary
in/out for aclitem.
Alexander Korotkov sent in a WIP patch to collect statistics for array
Shigeru HANADA sent in another revision of the postgresql_fdw patch.
Gurjeet Singh sent in a patch to allow the use of paths relative to
that of the current file in psql.
Andrew Tipton sent in a patch to add GiST support for BOX @> POINT
Magnus Hagander sent in another revision of the patch to allow
streaming a base backup.
Fujii Masao sent in another revision of the patch to add replication
Rumko (rumcic AT gmail DOT com) sent in a patch to allow PostgreSQL to
compile on Dragonfly BSD.
Jaime Casanova sent in another revision of the patch to allow for
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