Both plannable queries and utility commands are now always executed
within Portals, which have been revamped so that they can handle the
load (they used to be good only for single SELECT queries).  Restructure
code to push command-completion-tag selection logic out of postgres.c,
so that it won't have to be duplicated between simple and extended queries.
initdb forced due to addition of a field to Query nodes.

practice of evaluating MemSet's arguments multiple times, except for
the special case of newNode(), where we can assume the argument is
a constant sizeof() operator.
Also, add GetMemoryChunkContext() to mcxt.c's API, in preparation for
fixing recent GEQO breakage.

given any malloc block until something is first allocated in it; but
thereafter, MemoryContextReset won't release that first malloc block.
This preserves the quick-reset property of the original policy, without
forcing 8K to be allocated to every context whether any of it is ever
used or not.  Also, remove some more no-longer-needed explicit freeing
during ExecEndPlan.

to make a reasonable attempt at accounting for palloc overhead, not just
the requested size of each memory chunk.  Since in many scenarios this
will make for a significant reduction in the amount of space acquired,
partially compensate by doubling the default value of SORT_MEM to 1Mb.
Per discussion in pgsql-general around 9-Jun-2002..

initdb/regression tests pass.

tests pass.

elog(ERROR) not an Assert trap, since we've downgraded out-of-memory to
elog(ERROR) not a fatal error.  Also, change the hard boundary from 256Mb
to 1Gb, just so that anyone who's actually got that much memory to spare
can play with TOAST objects approaching a gigabyte.

apply Karel Zak's patch to recycle residual space in an exhausted allocation
block.  (Bet you thought I'd forgot about that, Karel?)

in-chunk leaks, overwrite-next-chunk leaks and overwrite block-freeptr leaks.

A in-chunk leak --- if something overwrite space after wanted (via palloc()
size, but it is still inside chunk. For example

        x = palloc(12);         /* create 16b chunk */
        memset(x, '#', 13);

this leak is in the current source total invisible, because chunk is 16b and
leak is in the "align space".

 For this feature I add data_size to StandardChunk, and all memory which go
from AllocSetAlloc() is marked as 0x7F.

 The MemoryContextCheck() is compiled '#ifdef USE_ASSERT_CHECKING'.

I add this checking to 'tcop/postgres.c' and is active after each backend
query, but it is probably not sufficient, because some MemoryContext exist
only during memory processing --- will good if someone who known where
it is needful (Tom:-) add it for others contexts;
 A problem in the current source is that we have still some malloc()
allocation that is not needful and this allocation is total invisible for
all context routines. For example Dllist in backend (pretty dirty it is in
catcache where values in Dllist are palloc-ed, but list is malloc-ed).
--- and BTW. this Dllist design stand in the way for query cache :-)

 Tom, if you agree I start replace some mallocs.

 BTW. --- Tom, have you idea for across transaction presistent allocation for
          SQL functions? (like regex - now it is via malloc)


 I almost forget. I add one if() to AllocSetAlloc(), for 'size' that are
greater than ALLOC_BIGCHUNK_LIMIT is not needful check AllocSetFreeIndex(),
because 'fidx' is always 'ALLOCSET_NUM_FREELISTS - 1'. It a little brisk up
allocation for very large chunks. Right?

                                                Karel

for details).  It doesn't really do that much yet, since there are no
short-term memory contexts in the executor, but the infrastructure is
in place and long-term contexts are handled reasonably.  A few long-
standing bugs have been fixed, such as 'VACUUM; anything' in a single
query string crashing.  Also, out-of-memory is now considered a
recoverable ERROR, not FATAL.
Eliminate a large amount of crufty, now-dead code in and around
memory management.
Fix problem with holding off SIGTRAP, SIGSEGV, etc in postmaster and
backend startup.

defined then statistics about memory usage of all the global memory
contexts are printed after each commit.

  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc

to all files copyright Regents of Berkeley.  Man, that's a lot of files.

pg_dump and interfaces/odbc still need some work.)

ALLOC_BIGCHUNK_LIMIT are always allocated as separate malloc() blocks,
and are free()d immediately upon pfree().  Also, if such a chunk is enlarged
with repalloc(), translate the operation into a realloc() so as to
minimize memory usage.  Of course, these large chunks still get freed
automatically if the alloc set is reset.
I have set ALLOC_BIGCHUNK_LIMIT at 64K for now, but perhaps another
size would be better?

for Irix.

bigger the more space is used in an allocset.  This reduces the malloc
overhead very substantially on queries that need lots of memory.

configure, instead of having a bunch of crufty platform-specific guesses.

need not be bogus.

Jan

Nakajima. Since he is not subscribing the mailing list, I'm posting
his patches by his request.  According to him, he has successfully
compiled and passed the regression test on Mac SE/30 running
NetBSD/m68k. Also, another person has reported that with the patches
PostgreSQL is working on NetBSD/sun3 too.
--
Tatsuo Ishii

just two macros.

        Ok, I have finally gotten all of the defines for Dec/Alpha and
Linux/Alpha sorted out as Marc asked. There is no longer any need for
'-Dalpha' or '-Dlinuxalpha' in either the Dec/Alpha or the Linux/Alpha
template files (./src/template/{alpha,linuxalpha}). I have replaced every
instance of 'alpha' or '__alpha__' with '__alpha', as that appears to be
the common symbol between C compilers on both operating systems (RH4.2 &
DecUnix 4.0b) for alpha.

From: Ryan Kirkpatrick <rkirkpat@nag.cs.colorado.edu>