== PostgreSQL Weekly News - October 19 2008 ==

== PostgreSQL Weekly News - October 19 2008 ==

Simon Riggs published two revisions of a complete hot-standby
implementation.

The first annual European PGDay www.pgday.org was a success, with
almost 190 people signed up. Bernd Helmle announced that he will be
publishing his WIP patch for updateable views this coming week, and
Zdenek Kotala said he will be making his upgrade-in-place patches
available via git in the same time frame.

Emmanuel Cecchet sent in some instructions on using Eclipse to develop
PostgreSQL.
http://wiki.postgresql.org/wiki/Working_with_Eclipse

== PostgreSQL Product News ==

Archiveopteryx 3.0.2 released.
http://www.archiveopteryx.org/3.0.2

== PostgreSQL Jobs for October ==

http://archives.postgresql.org/pgsql-jobs/2008-10/threads.php

== PostgreSQL Local ==

Dickson Guedes is looking for volunteers to help with a PgMeeting in
Florianópolis. Write to guediz AT gmail DOT com if you want to help.

PostgreSQL has a table at LinuxLive, Olympia, London, UK on 23-25
October, 2008. Write to Dave Page to participate.
dpage AT pgadmin DOT org

There will be a PostgreSQL BoF at Ontario Linux fest October 25.
http://www.onlinux.ca/

== PostgreSQL in the News ==

Planet PostgreSQL: http://www.planetpostgresql.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 david(at)fetter(dot)org, German language
to pwn(at)pgug(dot)de, Italian language to pwn(at)itpug(dot)org(dot)

== Applied Patches ==

Tom Lane committed:

- In pgsql/src/tools/findoidjoins/make_oidjoins_check, fix bogus
comment emitted by make_oidjoins_check, per Greg Stark.

- Update oidjoins test to match CVS HEAD.

- Implement comparison of generic records (composite types), and
invent a pseudo-type record[] to represent arrays of
possibly-anonymous composite types. Since composite datums carry
their own type identification, no extra knowledge is needed at the
array level. The main reason for doing this right now is that it is
necessary to support the general case of detection of cycles in
recursive queries: if you need to compare more than one column to
detect a cycle, you need to compare a ROW() to an array built from
ROW()s, at least if you want to do it as the spec suggests. Add
some documentation and regression tests concerning the cycle
detection issue.

- Eliminate unnecessary array[] decoration in examples of recursive
cycle detection.

- Add docs and regression test about sorting the output of a recursive
query in depth-first search order. Upon close reading of SQL:2008,
it seems that the spec's SEARCH DEPTH FIRST and SEARCH BREADTH FIRST
options do not actually guarantee any particular result order: what
they do is provide a constructed column that the user can then sort
on in the outer query. So this is actually just as much
functionality ...

- In pgsql/src/backend/utils/adt/timestamp.c, fix
EncodeSpecialTimestamp to throw error on unrecognized input, rather
than returning a failure code that none of its callers bothered to
check for.

- Extend the date type to support infinity and -infinity, analogously
to the timestamp types. Turns out this doesn't even reduce the
available range of dates, since the restriction to dates that work
for Julian-date arithmetic is much tighter than the int32 range
anyway. Per a longstanding TODO item.

- Update citext expected output for recent change in error message
location pointers. This is only a whitespace change, which ought to
be ignored by regression testing, but for some reason buildfarm
member spoonbill doesn't like it.

- In pgsql/src/backend/catalog/index.c, add a defense to prevent
storing pseudo-type data into index columns. Formerly, the lack of
any opclasses that could accept such data was enough of a defense,
but now with a "record" opclass we need to check more carefully.
(You can still use that opclass for an index, but you have to store
a named composite type not an anonymous one.)

- In pgsql/src/backend/catalog/heap.c, make the system-attributes loop
in AddNewAttributeTuples depend on lengthof(SysAtt) not
FirstLowInvalidHeapAttributeNumber, for consistency with the other
uses of the SysAtt array, and to make it clearer that it doesn't
walk off the end of that array.

- In pgsql/src/backend/executor/spi.c, fix SPI_getvalue and
SPI_getbinval to range-check the given attribute number according to
the TupleDesc's natts, not the number of physical columns in the
tuple. The previous coding would do the wrong thing in cases where
natts is different from the tuple's column count: either incorrectly
report error when it should just treat the column as null, or
actually crash due to indexing off the end of the TupleDesc's
attribute array. (The second case is probably not possible in
modern PG versions, due to more careful handling of inheritance
cases than we once had. But it's still a clear lack of robustness
here.) The incorrect error indication is ignored by all callers
within the core PG distribution, so this bug has no symptoms visible
within the core code, but it might well be an issue for add-on
packages. So patch all the way back.

- pgsql/src/port/win32error.c, reduce chatter from _dosmaperr() when
used in FRONTEND code. ITAGAKI Takahiro.

- In pgsql/src/include/nodes/relation.h, improve comments about
RelOptInfo.reltargetlist.

- In pgsql/src/backend/optimizer/path/costsize.c, salvage a little bit
of work from a failed patch: simplify and speed up set_rel_width().
The code had been catering for the possibility of different varnos
in the relation targetlist, but this is impossible for a base
relation (and if it were possible, putting all the widths in the
same RelOptInfo would be wrong anyway).

- Add a new column to pg_am to specify whether an index AM supports
backward scanning; GiST and GIN do not, and it seems like too much
trouble to make them do so. By teaching ExecSupportsBackwardScan()
about this restriction, we ensure that the planner will protect a
scroll cursor from the problem by adding a Materialize node. In
passing, fix another longstanding bug in the same area: backwards
scan of a plan with set-returning functions in the targetlist did
not work either, since the TupFromTlist expansion code pays no
attention to direction (and has no way to run a SRF backwards
anyway). Again the fix is to make ExecSupportsBackwardScan check
this restriction. Also adjust the index AM API specification to
note that mark/restore support is unnecessary if the AM can't
produce ordered output.

- Remove useless mark/restore support in hash index AM, per
discussion. (I'm leaving GiST/GIN cleanup to Teodor.)

- In pgsql/src/backend/catalog/sql_features.txt, fix broken SQL
features data, per buildfarm results.

Heikki Linnakangas committed:

- In pgsql/src/backend/postmaster/bgwriter.c, fix oversight in the
relation forks patch: forgot to copy fork number to fsync requests.
This should fix the installcheck failure of the buildfarm member
"kudu".

Michael Meskes committed:

- In ECPG, fixed parsing of parameters. Added regression test for
this.

Alvaro Herrera committed:

- In pgsql/src/backend/commands/cluster.c, ensure that CLUSTER leaves
the toast table and index with consistent names, by renaming the new
copies after the catalog games.

- In pgsql/src/backend/utils/error/elog.c, refactor some duplicate
code to set up formatted_log_time and formatted_start_time.

Neil Conway committed:

- In pgsql/src/backend/executor/nodeAgg.c, fix a small memory leak in
ExecReScanAgg() in the hashed aggregation case. In the previous
coding, the list of columns that needed to be hashed on was
allocated in the per-query context, but we reallocated every time
the Agg node was rescanned. Since this information doesn't change
over a rescan, just construct the list of columns once during
ExecInitAgg().

Teodor Sigaev committed:

- During repeated rescan of GiST index it's possible that scan key is
NULL but SK_SEARCHNULL is not set. Add checking IS NULL of keys to
set during key initialization. If key is NULL and SK_SEARCHNULL is
not set then nothnig can be satisfied. With assert-enabled
compilation that causes coredump. Bug was introduced in 8.3 by
support of IS NULL index scan.

- In pgsql/src/backend/tsearch/wparser_def.c, fix small bug in
headline generation. Patch from Sushant Sinha.

- Improve headeline generation. Now headline can contain several
fragments a-la Google. Sushant Sinha.

Peter Eisentraut committed:

- In pgsql/src/backend/catalog/sql_features.txt, small correction SQL
feature table.

- Update feature list for SQL:2008.

- In pgsql/doc/src/sgml/ref/truncate.sgml, update compatibility
section of TRUNCATE for SQL:2008 final.

== Rejected Patches (for now) ==

No one was disappointed this week :-)

== Pending Patches ==

KaiGai Kohei sent in another revision of his SE-PostgreSQL patches.

Jim Cox sent in another revision of his patch to add a VERBOSE option
to CLUSTER.

Euler Taveira de Oliveira sent in another revision of his reloptions
patch.

Simon Riggs sent in two revisions of a full-on Hot Standby patch.

Pavel Stehule sent in another WIP revision of his GROUPING SETS patch.

Ian Caulfield and Robert Haas each sent in a patch to implement
array_agg.

Guillaume Lelarge sent in a patch to enable people to change a
database's tablespace.

Jim Nasby sent in a patch to implement array_length().

KaiGai Kohei sent in another set of revisions to his SE-PostgreSQL
patches.