succeeds or not.  Revise rtree page split algorithm to take care about
making a feasible split --- ie, will the incoming tuple actually fit?
Failure to make a feasible split, combined with failure to notice the
failure, account for Jim Stone's recent bug report.  I suspect that
hash and gist indices may have the same type of bug, but at least now
we'll get error messages rather than silent failures if so.  Also clean
up rtree code to use Datum rather than char* where appropriate.

allocated by plan nodes are not leaked at end of query.  This doesn't
really matter for normal queries, but it sure does for queries invoked
repetitively inside SQL functions.  Clean up some other grotty code
associated with tupdescs, and fix a few other memory leaks exposed by
tests with simple SQL functions.

New feature:
   1. Support of variable size keys - new algorithm of insertion to tree
      (GLI - gist layrered insertion). Previous algorithm was implemented
      as described in paper by Joseph M. Hellerstein et.al
      "Generalized Search Trees for Database Systems".  This (old)
      algorithm was not suitable for variable size keys and could be
      not effective ( walking up-down ) in case of multiple levels split
Bug fixed:
   1. fixed bug in gistPageAddItem - key values were written to disk
      uncompressed. This caused failure if decompression function
      does real job.
   2. NULLs handling - we keep NULLs in tree. Right way is to remove them,
      but we don't know how to inform vacuum about index statistics. This is
      just cosmetic warning message (like in case with R-Tree),
      but I'm not sure how to recognize real problem if we remove NULLs
      and suppress this warning as Tom suggested.
   3. various memory leaks

This work was done by Teodor Sigaev (teodor@stack.net) and
Oleg Bartunov (oleg@sai.msu.su).

maintained for each cache entry.  A cache entry will not be freed until
the matching ReleaseSysCache call has been executed.  This eliminates
worries about cache entries getting dropped while still in use.  See
my posting to pg-hackers of even date for more info.

(WAL logging for this is not done yet, however.)  Clean up a number of really
crufty things that are no longer needed now that DROP behaves nicely.  Make
temp table mapper do the right things when drop or rename affecting a temp
table is rolled back.  Also, remove "relation modified while in use" error
check, in favor of locking tables at first reference and holding that lock
throughout the statement.

pass-by-ref data types --- eg, an index on lower(textfield) --- no longer
leak memory during index creation or update.  Clean up a lot of redundant
code ... did you know that copy, vacuum, truncate, reindex, extend index,
and bootstrap each basically duplicated the main executor's logic for
extracting information about an index and preparing index entries?
Functional indexes should be a little faster now too, due to removal
of repeated function lookups.
CREATE INDEX 'opt_type' clause is deimplemented by these changes,
but I haven't removed it from the parser yet (need to merge with
Thomas' latest change set first).

memory contexts.  Currently, only leaks in expressions executed as
quals or projections are handled.  Clean up some old dead cruft in
executor while at it --- unused fields in state nodes, that sort of thing.

    WARNING: This is actually broken - we have self-deadlocks
	         due to concurrent changes in buffer management.
			 Vadim and me are working on it.

Jan

passing the index-is-unique flag to index build routines (duh! ...
why wasn't it done this way to begin with?).  Aside from eliminating
an eyesore, this should save a few milliseconds in btree index creation
because a full scan of pg_index is not needed any more.

--- ie, they're only called for side-effects.  Add a PG_RETURN_VOID()
macro and use it where appropriate.  This probably doesn't change the
machine code by a single bit ... it's just for documentation.

functions that take pass-by-value datatypes.  Should be ready for
port testing ...

fmgr_faddr() in favor of new-style calls.  Lots of cleanup of
sloppy casts to use XXXGetDatum and DatumGetXXX ...

running gcc and HP's cc with warnings cranked way up.  Signed vs unsigned
comparisons, routines declared static and then defined not-static,
that kind of thing.  Tedious, but perhaps useful...

from a constraint condition does not violate the constraint (cf. discussion
on pghackers 12/9/99).  Implemented by adding a parameter to ExecQual,
specifying whether to return TRUE or FALSE when the qual result is
really NULL in three-valued boolean logic.  Currently, ExecRelCheck is
the only caller that asks for TRUE, but if we find any other places that
have the wrong response to NULL, it'll be easy to fix them.

where necessary --- several of them didn't really need it, though.
tqual-checking macros simplified accordingly.

Fewer calls to nameout.

Better use of RelationGetRelationName.

* Buffer refcount cleanup (per my "progress report" to pghackers, 9/22).
* Add links to backend PROC structs to sinval's array of per-backend info,
and use these links for routines that need to check the state of all
backends (rather than the slow, complicated search of the ShmemIndex
hashtable that was used before).  Add databaseOID to PROC structs.
* Use this to implement an interlock that prevents DESTROY DATABASE of
a database containing running backends.  (It's a little tricky to prevent
a concurrently-starting backend from getting in there, since the new
backend is not able to lock anything at the time it tries to look up
its database in pg_database.  My solution is to recheck that the DB is
OK at the end of InitPostgres.  It may not be a 100% solution, but it's
a lot better than no interlock at all...)
* In ALTER TABLE RENAME, flush buffers for the relation before doing the
rename of the physical files, to ensure we don't get failures later from
mdblindwrt().
* Update TRUNCATE patch so that it actually compiles against current
sources :-(.
You should do "make clean all" after pulling these changes.

additional argument specifying the kind of lock to acquire/release (or
'NoLock' to do no lock processing).  Ensure that all relations are locked
with some appropriate lock level before being examined --- this ensures
that relevant shared-inval messages have been processed and should prevent
problems caused by concurrent VACUUM.  Fix several bugs having to do with
mismatched increment/decrement of relation ref count and mismatched
heap_open/close (which amounts to the same thing).  A bogus ref count on
a relation doesn't matter much *unless* a SI Inval message happens to
arrive at the wrong time, which is probably why we got away with this
sloppiness for so long.  Repair missing grab of AccessExclusiveLock in
DROP TABLE, ALTER/RENAME TABLE, etc, as noted by Hiroshi.
Recommend 'make clean all' after pulling this update; I modified the
Relation struct layout slightly.
Will post further discussion to pghackers list shortly.

real affect now.

New code for locking buffer' context.

Initial attempt to clean up the code...

Switch sprintf() to snprintf()
Remove any/all #if 0 -or- #ifdef NOT_USED -or- #ifdef FALSE sections of
	code