ReadBuffer_Resync() and BufferAlloc_Resync() were not materially different
from plain ReadBuffer() and BufferAlloc(), so just use the latter directly.

In the passing, also:
* rename BufferAlloc_Internal to BufferAlloc_common, like it's called in
  newer upstream versions.
* revert some spurious whitespace and comment differences vs. upstream.

back-stamped for this.

from Magnus that MSVC complains about this.

partitions, as per discussion.  Passes functionality checks, but
I don't have any performance data yet.

misleadingly-named WriteBuffer routine, and instead require routines that
change buffer pages to call MarkBufferDirty (which does exactly what it says).
We also require that they do so before calling XLogInsert; this takes care of
the synchronization requirement documented in SyncOneBuffer.  Note that
because bufmgr takes the buffer content lock (in shared mode) while writing
out any buffer, it doesn't matter whether MarkBufferDirty is executed before
the buffer content change is complete, so long as the content change is
completed before releasing exclusive lock on the buffer.  So it's OK to set
the dirtybit before we fill in the LSN.
This eliminates the former kluge of needing to set the dirtybit in LockBuffer.
Aside from making the code more transparent, we can also add some new
debugging assertions, in particular that the caller of MarkBufferDirty must
hold the buffer content lock, not merely a pin.

in favor of having just one set of macros that don't do HOLD/RESUME_INTERRUPTS
(hence, these correspond to the old SpinLockAcquire_NoHoldoff case).
Given our coding rules for spinlock use, there is no reason to allow
CHECK_FOR_INTERRUPTS to be done while holding a spinlock, and also there
is no situation where ImmediateInterruptOK will be true while holding a
spinlock.  Therefore doing HOLD/RESUME_INTERRUPTS while taking/releasing a
spinlock is just a waste of cycles.  Qingqing Zhou and Tom Lane.

comment line where output as too long, and update typedefs for /lib
directory.  Also fix case where identifiers were used as variable names
in the backend, but as typedefs in ecpg (favor the backend for
indenting).

Backpatch to 8.1.X.

that was added to localbuf.c in 8.1; therefore, applying it to a temp table
left corrupt lookup state in memory.  The only case where this had a
significant chance of causing problems was an ON COMMIT DELETE ROWS temp
table; the other possible paths left bogus state that was unlikely to
be used again.  Per report from Csaba Nagy.

pointers, to ensure that compilers won't rearrange accesses to occur
while we're not holding the buffer header spinlock.  It's probably
not necessary to mark volatile in every single place in bufmgr.c,
but better safe than sorry.  Per trouble report from Kevin Grittner.

to 'Size' (that is, size_t), and install overflow detection checks in it.
This allows us to remove the former arbitrary restrictions on NBuffers
etc.  It won't make any difference in a 32-bit machine, but in a 64-bit
machine you could theoretically have terabytes of shared buffers.
(How efficiently we could manage 'em remains to be seen.)  Similarly,
num_temp_buffers, work_mem, and maintenance_work_mem can be set above
2Gb on a 64-bit machine.  Original patch from Koichi Suzuki, additional
work by moi.

communication structure, and make it its own module with its own lock.
This should reduce contention at least a little, and it definitely makes
the code seem cleaner.  Per my recent proposal.

the freelist, plus per-buffer spinlocks that protect access to individual
shared buffer headers.  This requires abandoning a global freelist (since
the freelist is a global contention point), which shoots down ARC and 2Q
as well as plain LRU management.  Adopt a clock sweep algorithm instead.
Preliminary results show substantial improvement in multi-backend situations.

This refactoring does not change any algorithms or data structures, just
remove visibility of the ARC datastructures from other source files.

Tag appropriate files for rc3

Also performed an initial run through of upgrading our Copyright date to
extend to 2005 ... first run here was very simple ... change everything
where: grep 1996-2004 && the word 'Copyright' ... scanned through the
generated list with 'less' first, and after, to make sure that I only
picked up the right entries ...

(if any) currently waited for by LockBufferForCleanup(), which is all
that we were using it for anymore.  Saves some space and eliminates
proportional-to-NBuffers slowdown in UnlockBuffers().

There are various things left to do: contrib dbsize and oid2name modules
need work, and so does the documentation.  Also someone should think about
COMMENT ON TABLESPACE and maybe RENAME TABLESPACE.  Also initlocation is
dead, it just doesn't know it yet.

Gavin Sherry and Tom Lane.

of whether we have successfully read data into a buffer; this makes the
error behavior a bit more transparent (IMHO anyway), and also makes it
work correctly for local buffers which don't use Start/TerminateBufferIO.
Collapse three separate functions for writing a shared buffer into one.
This overlaps a bit with cleanups that Neil proposed awhile back, but
seems not to have committed yet.

of VACUUM cases so that VACUUM requests don't affect the ARC state at all,
avoid corner case where BufferSync would uselessly rewrite a buffer that
no longer contains the page that was to be flushed.  Make some minor
other cleanups in and around the bufmgr as well, such as moving PinBuffer
and UnpinBuffer into bufmgr.c where they really belong.

for already empty buffers because their buffer tag was not cleard out
when the buffers have been invalidated before.

Also removed the misnamed BM_FREE bufhdr flag and replaced the checks,
which effectively ask if the buffer is unpinned, with checks against the
refcount field.

Jan

ARC buffer replacement strategy.

Jan

some concurrent changes Jan was making to the bufmgr. Here's an
updated version of the patch -- it should apply cleanly to CVS
HEAD and passes the regression tests.

This patch makes the following changes:

     - remove the UnlockAndReleaseBuffer() and UnlockAndWriteBuffer()
       macros, and replace uses of them with calls to the appropriate
       functions.

     - remove a bunch of #ifdef BMTRACE code: it is ugly & broken
       (i.e. it doesn't compile)

     - make BufferReplace() return a bool, not an int

     - cleanup some logic in bufmgr.c; should be functionality
       equivalent to the previous code, just cleaner now

     - remove the BM_PRIVATE flag as it is unused

     - improve a few comments, etc.

make sure the $Id tags are converted to $PostgreSQL as well ...

I added a couple more Assertions while tracking down the exact
cause of the former bug.

All 93 regression tests pass now.

Jan

Jan

algorithm adopted for PostgreSQL.

Jan

The local buffer manager is no longer used for newly-created relations
(unless they are TEMP); a new non-TEMP relation goes through the shared
bufmgr and thus will participate normally in checkpoints.  But TEMP relations
use the local buffer manager throughout their lifespan.  Also, operations
in TEMP relations are not logged in WAL, thus improving performance.
Since it's no longer necessary to fsync relations as they move out of the
local buffers into shared buffers, quite a lot of smgr.c/md.c/fd.c code
is no longer needed and has been removed: there's no concept of a dirty
relation anymore in md.c/fd.c, and we never fsync anything but WAL.
Still TODO: improve local buffer management algorithms so that it would
be reasonable to increase NLocBuffer.

>I'd vote for changing WriteBuffer to
>return void, and have it elog() on bad argument.

Manfred Koizar

  SharedBufferChanged
  BufferRelidLastDirtied
  BufferTagLastDirtied
  BufferDirtiedByMe

Manfred Koizar

initdb/regression tests pass.

spacing.  Also adds space for one-line comments.

tests pass.