PostgreSQL Weekly News – September 19 2010

== PostgreSQL Weekly News – September 19 2010 ==

Barring catastrophe, PostgreSQL 9.0.0, now with, among many other new
features, built-in replication, will be out Monday, September 20,
2010. Rejoice!

Early bird registration for JDCon West 2010 is now open.

Surge 2010, the scalability and performance conference will be in
Baltimore, MD, USA on September 30 – October 1st, 2010.

== PostgreSQL Product News ==

Another PostgreSQL Diff Tool 2.0.2, a tool for database diffs, released.

Benetl 3.6, an ETL tool for files using PostgreSQL, released.

phpPgAdmin 5.0-beta1, a web-based administrative tool for PostgreSQL, released.

== PostgreSQL Jobs for September ==

== PostgreSQL Local ==

Surge 2010, the scalability and performance conference will be in
Baltimore, MD, USA on September 30 – October 1st, 2010.

Call for Papers for PGDay.EU 2010 held on December 6-8 in Stuttgart,
Germany is open.

== PostgreSQL in the News ==

Planet PostgreSQL:

PostgreSQL Weekly News is brought to you this week by David Fetter

Submit news and announcements by Sunday at 3:00pm Pacific time.
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== Reviews ==

– Abhijit Menon-Sen reviewed the “Our CLUSTER implementation is
pessimal” patch and found two chunks that did not apply cleanly,
along with some possible bit rot on copy_heap_data().

– KaiGai Kohei reviewed Peter Eisentraut’s patch to extend ALTER TYPE.

– ITAGAKI Takahiro reviewed the SQL/MED(FDW) patch and found some
unused new types, a missing error check, a place to improve an error
message, and some places to improve consistency in type checks

– Tom Lane reviewed Sushant Sinha’s url-part extention for text

– Hitoshi Harada reviewed Pavel Stehule’s WIP patch for median() and
percentile(), and found that it left out changes to contrib, had
some cosmetic coding style issues, has a possible new out-of-memory
condition due to the extra tuplesorts added, contained neither
documentation nor new regression tests, doesn’t work in windowing
function context.
== Applied Patches ==

Heikki Linnakangas committed:

– In pgsql/src/backend/utils/init/postinit.c, process options from the
startup packed in walsender. Only few options make sense for
walsender, but for example application_name and client_encoding do.
We still don’t apply per-role settings from pg_db_role_setting,
because that would require connecting to a database to read the
table. Fujii Masao

– In pgsql/src/include/replication/walreceiver.h, remove prototype for
non-existent function from walreceiver.h. Tidy up by separating
prototypes for functions in walreceiver.c and walreceiverfuncs.c
with comments.

– In pgsql/src/backend/port/unix_latch.c, add a comment noting that
the owner_pid test in OwnLatch is just a sanity check, per request
by Jeff Davis.

– In pgsql/src/bin/pg_ctl/pg_ctl.c, don’t warn about an in-progress
online backup, when we’re recovering from an online backup instead
of performing one. pg_ctl can detect that by checking if
recovery.conf exists. Backup label file is renamed away early in
recovery, so the window where backup label exists during recovery is
normally very small, but you can run into it e.g if restore_command
is set incorrectly and the startup process never finds even the
first WAL segment containing the checkpoint record to start recovery
from. Fujii Masao with comments by me.

– In pgsql/src/backend/replication/walsender.c, oops, the timeout
argument to WaitLatchOrSocket is in microseconds, not milliseconds.

– In pgsql/src/backend/replication/walsender.c, don’t call OwnLatch
while holding a spinlock. OwnLatch can elog() under some “can’t
happen” scenarios, and spinlocks should only be held for a few
instructions anyway. As pointed out by Fujii Masao.

– Simplify Windows implementation of latches. There’s no need to keep
a dynamic pool of event handles, we can permanently assign one for
each shared latch. Thanks to that, we no longer need a separate
shared memory block for latches, and we don’t need to know in
advance how many shared latches there is, so you no longer need to
remember to update NumSharedLatches when you introduce a new latch
to the system.

– Use a latch to make startup process wake up and replay immediately
when new WAL arrives via streaming replication. This reduces the
latency, and also allows us to use a longer polling interval, which
is good for energy efficiency. We still need to poll to check for
the appearance of a trigger file, but the interval is now 5 seconds
(instead of 100ms), like when waiting for a new WAL segment to
appear in WAL archive.

– In pgsql/src/backend/access/transam/xlog.c, fix two typos in
comments, spotted by Fujii Masao and Thom Brown.

Robert Haas committed:

– In pgsql/doc/src/sgml/catalogs.sgml, elaborate on what gets stored
in pg_authid.rolpasswd. Also, add cross-reference from
pg_shadow.passwd to pg_authid.rolpasswd and fix a bit of markup I
muffed in my previous commit. Per discussion with Josh Kupershmidt.

– In pgsql/src/backend/commands/comment.c, remove duplicated code left
behind by my recent refactoring of comment.c. These checks are also
present in objectaddress.c, so there’s no need to recheck here.

– In pgsql/doc/src/sgml/catalogs.sgml, move pg_db_role_setting docs to
correct place in alphabetical order.

Tom Lane committed:

– Fix join-removal logic for pseudoconstant and outerjoin-delayed
quals. In these cases a qual can get marked with the removable rel
in its required_relids, but this is just to schedule its evaluation
correctly, not because it really depends on the rel. We were
assuming that, in effect, we could throw away *all* quals so marked,
which is nonsense. Tighten up the logic to be a little more
paranoid about which quals belong to the outer join being considered
for removal, and arrange for all quals that don’t belong to be
updated so they will still get evaluated correctly. Also fix
another problem that happened to be exposed by this test case, which
was that make_join_rel() was failing to notice some cases where a
constant-false qual could be used to prove a join relation empty.
If it’s a pushed-down constant false, then the relation is empty
even if it’s an outer join, because the qual applies after the outer
join expansion. Per report from Nathan Grange. Back-patch into

– In pgsql/doc/src/sgml/release-9.0.sgml, add a compatibility note
about plpgsql’s treatment of SELECT INTO rec.fld when fld is of
composite type. Per discussion of bug #5644 from Valentine

– Fix two new-in-9.0 bugs in hstore. There was an incorrect Assert in
hstoreValidOldFormat(), which would cause immediate core dumps when
attempting to work with pre-9.0 hstore data, but of course only in
an assert-enabled build. Also, ghstore_decompress() incorrectly
applied DatumGetHStoreP() to a datum that wasn’t actually an hstore,
but rather a ghstore (ie, a gist signature bitstring). That used to
be harmless, but could now result in misbehavior if the hstore
format conversion code happened to trigger. In reality, since
ghstore is not marked toastable (and doesn’t need to be), this
function is useless anyway; we can lobotomize it down to returning
the passed-in pointer. Both bugs found by Andrew Gierth, though
this isn’t exactly his proposed patch.

– In pgsql/doc/src/sgml/plpgsql.sgml, fix bad grammar.

– Stamp 9.0 release notes with expected release date; also some
last-minute copy-editing.

– In pgsql/src/backend/access/transam/README, add some documentation
about how we WAL-log filesystem actions. Per a question from Robert

– In pgsql/src/backend/parser/analyze.c, give a suitable HINT when an
INSERT’s data source is a RowExpr containing the same number of
columns expected by the insert. This suggests that there were extra
parentheses that converted the intended column list into a row
expression. Original patch by Marko Tiikkaja, rather heavily
editorialized by me.

– In pgsql/src/backend/commands/copy.c, make sure we wait for
protocol-level EOF when ending binary COPY IN. The previous coding
just terminated the COPY immediately after seeing the EOF marker (-1
where a row field count is expected). The expected CopyDone or
CopyFail message just got thrown away later, since we weren’t in
COPY mode anymore. This behavior complicated matters for the JDBC
driver, and arguably was the wrong thing in any case since a
CopyFail message after the marker wouldn’t be honored. Note that
there is a behavioral change here: extra data after the EOF marker
was silently ignored before, but now it will cause an error. Hence
not back-patching, although this is arguably a bug. Per report and
patch by Kris Jurka.

– Fix several broken $PostgreSQL$ keywords. Noted while experimenting
with Magnus’s script to remove these.

– In pgsql/src/backend/utils/mb/Unicode/, replace
last remaining $Id$ with $PostgreSQL$.

Peter Eisentraut committed:

– Translation updates for 9.0.0.

Magnus Hagander committed:

– In pgsql/src/backend/postmaster/postmaster.c, treat exit code 128
(ERROR_WAIT_NO_CHILDREN) as non-fatal on Win32, since it can happen
when a process fails to start when the system is under high load.
Per several bug reports and many peoples investigation. Back-patch
to 8.4, which is as far back as the “deadman-switch” for shared
memory access exists.

Marc Fournier committed:

– Tag v9.0.0 … the big day approaches.

Bruce Momjian committed:

– In pgsql/src/backend/access/heap/README.HOT, update HOT README about
when single-page vacuums happen.

== Rejected Patches (for now) ==

No one was disappointed this week 🙂

== Pending Patches ==

Teodor Sigaev sent in another revision of the patches to add
K-Nearest-Neighbor support to GiST indexes.

Heikki Linnakangas sent in two revisions of a patch using the new
latch facility to reduce walreceiver latency.

Hitoshi Harada sent in two revisions of a patch to allow top-level DML

KaiGai Kohei sent in another revision of the security label patch.

Kevin Grittner sent in another revision of the patch to do
serializable snapshot isolation.

Bernd Helmle sent in another revision of the patch to fix a mismatch
between ALTER TABLE … ALTER COLUMN and table inheritance.

Fujii Masao sent in two more revisions of the synchronous replication

ITAGAKI Takahiro sent in a patch, inspired by Joseph Adams’s Google
Summer of Code work, to add JSON. Joseph Adams sent in a patch based
on it.

SAKAMOTO Masahiko sent in three revisions of a patch to add FDW
(foreign data wrapper) support, which is part of SQL/MED (Management
of External Data).

Peter Eisentraut sent in another WIP patch to implement per-column

Fujii Masao sent in a patch to adjust signal handling during recovery.

Fujii Masao sent in two revisions of a patch to add a user-callable
function to trigger failover in replication.

Simon Riggs sent in a WIP patch which uses latches to adjust behavior
of the startup process.

Peter Eisentraut sent in another revision of the patch to extend ALTER
TYPE for composite types.

Fujii Masao sent in a patch to add a new function to libpq which is
used to send an ACK back from walreceiver.

Kevin Grittner sent in another revision of the patch to do
serializable row locks.

Robert Haas sent in a patch to add a pg_opfamily_is_visible()

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