recover from elog(ERROR).  Problem was created by introduction of hash seq
search tracking awhile back, and affects all branches that have bgwriter;
in HEAD the disease has snuck into autovacuum and walwriter too.  (Not sure
that the latter two use hash_seq_search at the moment, but surely they might
someday.)  Per report from Sergey Koposov.

dynahash.c.  Sergey Koposov's current open problem shows the possible
usefulness of this, and it doesn't add much code.

(ts_rank_cd). Use palloc'ed array in ranking instead of flag.

Backpatch is needed for contrib version.

Rename synonym.syn.sample and thesaurs.ths.sample to
synonym_sample.syn and thesaurs_sample.ths accordingly to be able to use they
in regression test.

Ispell dictionary uses synthetic simple dictionary files.

It will be mush better to reimplement ts_debug in C (instead of SQL as now),
but it's planned for the future.

* Defined new struct WordEntryPosVector that holds a uint16 length and a
variable size array of WordEntries. This replaces the previous
convention of a variable size uint16 array, with the first element
implying the length. WordEntryPosVector has the same layout in memory,
but is more readable in source code. The POSDATAPTR and POSDATALEN
macros are still used, though it would now be more readable to access
the fields in WordEntryPosVector directly.

* Removed needfree field from DocRepresentation. It was always set to false.

* Miscellaneous other commenting and refactoring

for consistency with other column names such as in pg_stat_database.

transaction, unless rolled back or overridden by a SET clause for the same
variable attached to a surrounding function call.  Per discussion, these
seem the best semantics.  Note that this is an INCOMPATIBLE CHANGE: in 8.0
through 8.2, SET LOCAL's effects disappeared at subtransaction commit
(leading to behavior that made little sense at the SQL level).

I took advantage of the opportunity to rewrite and simplify the GUC variable
save/restore logic a little bit.  The old idea of a "tentative" value is gone;
it was a hangover from before we had a stack.  Also, we no longer need a stack
entry for every nesting level, but only for those in which a variable's value
actually changed.

database-wide editions.

Per report from bitsandbytes88 <at> hotmail.com and subsequent discussion.

vacuum, instead of waiting till commit.

Add tsearch subdirectory is added to Makefile to allow
compile  custom tsearch dictionary as an external module.

In most cases it cause because of unneeded lowercasing of flags.

Per experiment with regression checks with ispell dictionary.

an exclusive lock on the table at this point, which we want to release as soon
as possible.  This is called in the phase of lazy vacuum where we truncate the
empty pages at the end of the table.

An alternative solution would be to lower the vacuum delay settings before
starting the truncating phase, but this doesn't work very well in autovacuum
due to the autobalancing code (which can cause other processes to change our
cost delay settings).  This case could be considered in the balancing code, but
it is simpler this way.

name to PushFunction type definition.

Per suggestion by Tome Lane <tgl@sss.pgh.pa.us>

Apparently it's a bug I introduced when I refactored spell.c to use the
readline function for reading and recoding the input file. I didn't
notice that some calls to STRNCMP used the non-lowercased version of the
input line.

Fix grammatical errors in its description.

and in passing, fix some bogosities dating from the custom_variable_classes
patch.  Fix guc-file.l to correctly check changes in custom_variable_classes
that are attempted concurrently with additions/removals of custom variables,
and don't allow the new setting to be applied in advance of checking it.
Clean up messy and undocumented situation for string variables with NULL
boot_val.  Fix DefineCustomVariable functions to initialize boot_val
correctly.  Prevent find_option from inserting bogus placeholders for custom
variables that are simply inquired about rather than being set.

for pg_regress, via --temp-config option. Pick this up in the make file
via TEMP_CONFIG setting.

ReadNewTransactionId from GetSnapshotData --- with a "latestCompletedXid"
variable that is updated during transaction commit or abort.  Since
latestCompletedXid is written only in places that had to lock ProcArrayLock
exclusively anyway, and is read only in places that had to lock ProcArrayLock
shared anyway, it adds no new locking requirements to the system despite being
cluster-wide.  Moreover, removing ReadNewTransactionId from snapshot
acquisition eliminates the need to take both XidGenLock and ProcArrayLock at
the same time.  Since XidGenLock is sometimes held across I/O this can be a
significant win.  Some preliminary benchmarking suggested that this patch has
no effect on average throughput but can significantly improve the worst-case
transaction times seen in pgbench.  Concept by Florian Pflug, implementation
by Tom Lane.

no need for serialization against snapshot-taking because the xact doesn't
affect anyone else's snapshot anyway.  Per discussion.  Also, move various
info about the interlocking of transactions and snapshots out of code comments
and into a hopefully-more-cohesive discussion in access/transam/README.

Also, remove a couple of now-obsolete comments about having to force some WAL
to be written to persuade RecordTransactionCommit to do its thing.

>   http://archives.postgresql.org/pgsql-hackers/2007-09/msg00051.php

big misalignement, then it tries to split page basing on distribution
of boxe's centers.

Per report from  Dolafi, Tom <dolafit@janelia.hhmi.org>

 Backpatch is needed, change doesn't affect on-disk storage.

- change the alignment requirement of lexemes in TSVector slightly.
Lexeme strings were always padded to 2-byte aligned length to make sure
that if there's position array (uint16[]) it has the right alignment.
The patch changes that so that the padding is not done when there's no
positions. That makes the storage of tsvectors without positions
slightly more compact.

- added some #include "miscadmin.h" lines I missed in the earlier when I
added calls to check_stack_depth().

- Reimplement the send/recv functions, and added a comment
above them describing the on-wire format. The CRC is now recalculated in
tsquery as well per previous discussion.

- add code to check that the query tree is well-formed. It was indeed
  possible to send malformed queries in binary mode, which produced all
  kinds of strange results.

- make the left-field a uint32. There's no reason to
  arbitrarily limit it to 16-bits, and it won't increase the disk/memory
  footprint either now that QueryOperator and QueryOperand are separate
  structs.

- add check_stack_depth() call to all recursive functions I found.
  Some of them might have a natural limit so that you can't force
  arbitrarily deep recursions, but check_stack_depth() is cheap enough
  that seems best to just stick it into anything that might be a problem.

small editorization by me

- Brake the QueryItem struct into QueryOperator and QueryOperand.
  Type was really the only common field between them. QueryItem still
  exists, and is used in the TSQuery struct as before, but it's now a
  union of the two. Many other changes fell from that, like separation
  of pushval_asis function into pushValue, pushOperator and pushStop.

- Moved some structs that were for internal use only from header files
  to the right .c-files.

- Moved tsvector parser to a new tsvector_parser.c file. Parser code was
  about half of the size of tsvector.c, it's also used from tsquery.c, and
  it has some data structures of its own, so it seems better to separate
  it. Cleaned up the API so that TSVectorParserState is not accessed from
  outside tsvector_parser.c.

- Separated enumerations (#defines, really) used for QueryItem.type
  field and as return codes from gettoken_query. It was just accidental
  code sharing.

- Removed ParseQueryNode struct used internally by makepol and friends.
  push*-functions now construct QueryItems directly.

- Changed int4 variables to just ints for variables like "i" or "array
  size", where the storage-size was not significant.

databases, per gripe from hubert depesz lubaczewski.  Patch from
Simon Riggs.

null::char(3) to a simple Const node.  (It already worked for non-null values,
but not when we skipped evaluation of a strict coercion function.)  This
prevents loss of typmod knowledge in situations such as exhibited in bug
#3598.  Unfortunately there seems no good way to fix that bug in 8.1 and 8.2,
because they simply don't carry a typmod for a plain Const node.

In passing I made all the other callers of makeNullConst supply "real" typmod
values too, though I think it probably doesn't matter anywhere else.

< * Reduce XID consumption of read-only queries
<
<    http://archives.postgresql.org/pgsql-hackers/2007-08/msg00516.php
<
<
> * -Reduce XID consumption of read-only queries

that examine fields that could change under them.  This is just to make
really sure that when we are fetching a value 'only once', that's what
actually happens.  Possibly this is a bug that should be back-patched,
but in the absence of solid evidence that it's needed, I won't bother.

so that different prepared xacts can be told apart in the pg_locks
view.  Per suggestion from Florian.

rows will normally never obtain an XID at all.  We already did things this way
for subtransactions, but this patch extends the concept to top-level
transactions.  In applications where there are lots of short read-only
transactions, this should improve performance noticeably; not so much from
removal of the actual XID-assignments, as from reduction of overhead that's
driven by the rate of XID consumption.  We add a concept of a "virtual
transaction ID" so that active transactions can be uniquely identified even
if they don't have a regular XID.  This is a much lighter-weight concept:
uniqueness of VXIDs is only guaranteed over the short term, and no on-disk
record is made about them.

Florian Pflug, with some editorialization by Tom.

This just provides text values, we're not exposing the underlying Oid representation.
Catalog version bumped.

Random other wordsmithing.