since these seem to happen after all in corrupted indexes. Make sure we
supply the index name in all cases, and provide relevant block numbers where
available. Also consistently identify the index name as such.
Back-patch to 8.2, in hopes that this might help Mason Hale figure out his
problem.
it failed for splits of non-leaf pages because in such pages the first
data key on a page is suppressed, and so we can't just copy the first
key from the right page to reconstitute the left page's high key.
Problem found by Koichi Suzuki, patch by Heikki.
columns, and the new version can be stored on the same heap page, we no longer
generate extra index entries for the new version. Instead, index searches
follow the HOT-chain links to ensure they find the correct tuple version.
In addition, this patch introduces the ability to "prune" dead tuples on a
per-page basis, without having to do a complete VACUUM pass to recover space.
VACUUM is still needed to clean up dead index entries, however.
Pavan Deolasee, with help from a bunch of other people.
than two independent bits (one of which was never used in heap pages anyway,
or at least hadn't been in a very long time). This gives us flexibility to
add the HOT notions of redirected and dead item pointers without requiring
anything so klugy as magic values of lp_off and lp_len. The state values
are chosen so that for the states currently in use (pre-HOT) there is no
change in the physical representation.
WAL records that shows whether it is safe to remove full-page images
(ie, whether or not an on-line backup was in progress when the WAL entry
was made). Also make provision for an XLOG_NOOP record type that can be
used to fill in the extra space when decompressing the data for restore.
This is the portion of Koichi Suzuki's "full page writes" patch that
has to go into the core database. The remainder of that work is two
external compression and decompression programs, which for the time being
will undergo separate development on pgfoundry. Per discussion.
Also, twiddle the handling of BTREE_SPLIT records to ensure it'll be
possible to compress them (the previous coding caused essential info
to be omitted). The other commonly-used record types seem OK already,
with the possible exception of GIN and GIST WAL records, which I don't
understand well enough to opine on.
(original code *always* created a full-page image for the left page, thus
leaving the intended savings unrealized), avoid risk of not having enough room
on the page during xlog restore, squeeze out another couple bytes in the xlog
record, clean up neglected comments.
pointer" in every Snapshot struct. This allows removal of the case-by-case
tests in HeapTupleSatisfiesVisibility, which should make it a bit faster
(I didn't try any performance tests though). More importantly, we are no
longer violating portable C practices by assuming that small integers are
distinct from all pointer values, and HeapTupleSatisfiesDirty no longer
has a non-reentrant API involving side-effects on a global variable.
There were a couple of places calling HeapTupleSatisfiesXXX routines
directly rather than through the HeapTupleSatisfiesVisibility macro.
Since these places had to be changed anyway, I chose to make them go
through the macro for uniformity.
Along the way I renamed HeapTupleSatisfiesSnapshot to HeapTupleSatisfiesMVCC
to emphasize that it's only used with MVCC-type snapshots. I was sorely
tempted to rename HeapTupleSatisfiesVisibility to HeapTupleSatisfiesSnapshot,
but forebore for the moment to avoid confusion and reduce the likelihood that
this patch breaks some of the pending patches. Might want to reconsider
doing that later.
I refactored findsplitloc and checksplitloc so that the division of
labor is more clear IMO. I pushed all the space calculation inside the
loop to checksplitloc.
I also fixed the off by 4 in free space calculation caused by
PageGetFreeSpace subtracting sizeof(ItemIdData), even though it was
harmless, because it was distracting and I felt it might come back to
bite us in the future if we change the page layout or alignments.
There's now a new function PageGetExactFreeSpace that doesn't do the
subtraction.
findsplitloc now tries the "just the new item to right page" split as
well. If people don't like the refactoring, I can write a patch to just
add that.
Heikki Linnakangas
> Currently, an index split writes all the data on the split page to
> WAL. That's a lot of WAL traffic. The tuples that are copied to the
> right page need to be WAL logged, but the tuples that stay on the
> original page don't.
Heikki Linnakangas
exactly at the point where we need to insert a new item, the calculation used
the wrong size for the "high key" of the new left page. This could lead to
choosing an unworkable split, resulting in "PANIC: failed to add item to the
left sibling" (or "right sibling") failure. Although this bug has been there
a long time, it's very difficult to trigger a failure before 8.2, since there
was generally a lot of free space on both sides of a chosen split. In 8.2,
where the user-selected fill factor determines how much free space the code
tries to leave, an unworkable split is much more likely. Report by Joe
Conway, diagnosis and fix by Heikki Linnakangas.
deletion code to avoid the case where an upper-level btree page remains "half
dead" for a significant period of time, and to block insertions into a key
range that is in process of being re-assigned to the right sibling of the
deleted page's parent. This prevents the scenario reported by Ed L. wherein
index keys could become out-of-order in the grandparent index level.
Since this is a moderately invasive fix, I'm applying it only to HEAD.
The bug exists back to 7.4, but the back branches will get a different patch.
When we are about to split an index page to do an insertion, first look
to see if any entries marked LP_DELETE exist on the page, and if so remove
them to try to make enough space for the desired insert. This should reduce
index bloat in heavily-updated tables, although of course you still need
VACUUM eventually to clean up the heap.
Junji Teramoto
it can handle small fillfactors for ordinary-sized index entries without
failing on large ones; fix nbtinsert.c to distinguish leaf and nonleaf
pages; change the minimum fillfactor to 10% for all index types.
discussion (including making def_arg allow reserved words), add missed
opt_definition for UNIQUE case. Put the reloptions support code in a less
random place (I chose to make a new file access/common/reloptions.c).
Eliminate header inclusion creep. Make the index options functions safely
user-callable (seems like client apps might like to be able to test validity
of options before trying to make an index). Reduce overhead for normal case
with no options by allowing rd_options to be NULL. Fix some unmaintainably
klugy code, including getting rid of Natts_pg_class_fixed at long last.
Some stylistic cleanup too, and pay attention to keeping comments in sync
with code.
Documentation still needs work, though I did fix the omissions in
catalogs.sgml and indexam.sgml.
into a single mostly-physical-order scan of the index. This requires some
ticklish interlocking considerations, but should create no material
performance impact on normal index operations (at least given the
already-committed changes to make scans work a page at a time). VACUUM
itself should get significantly faster in any index that's degenerated to a
very nonlinear page order. Also, we save one pass over the index entirely,
except in the case where there were no deletions to do and so only one pass
happened anyway.
Original patch by Heikki Linnakangas, rework by Tom Lane.
thereby saving a visit to the metapage in most index searches/updates.
This wouldn't actually save any I/O (since in the old regime the metapage
generally stayed in cache anyway), but it does provide a useful decrease
in bufmgr traffic in high-contention scenarios. Per my recent proposal.
upper-level insertion completes a previously-seen split, we cannot simply grab
the downlink block number out of the buffer, because the buffer could contain
a later state of the page --- or perhaps the page doesn't even exist at all
any more, due to relation truncation. These possibilities have been masked up
to now because the use of full_page_writes effectively ensured that no xlog
replay routine ever actually saw a page state newer than its own change.
Since we're deprecating full_page_writes in 8.1.*, there's no need to fix this
in existing release branches, but we need a fix in HEAD if we want to have any
hope of re-allowing full_page_writes. Accordingly, adjust the contents of
btree WAL records so that we can always get the downlink block number from the
WAL record rather than having to depend on buffer contents. Per report from
Kevin Grittner and Peter Brant.
Improve a few comments in related code while at it.
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.
just refer to btree index entries as plain IndexTuples, which is what
they have been for a very long time. This is mostly just an exercise
in removing extraneous notation, but it does save a palloc/pfree cycle
per index insertion.
are two basically different kinds of scankeys, and we ought to try harder
to indicate which is used in each place in the code. I've chosen the names
"search scankey" and "insertion scankey", though you could make about
as good an argument for "operator scankey" and "comparison function
scankey".
rather than "return expr;" -- the latter style is used in most of the
tree. I kept the parentheses when they were necessary or useful because
the return expression was complex.
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.
on every index page they read; in particular to catch the case of an
all-zero page, which PageHeaderIsValid allows to pass. It turns out
hash already had this idea, but it was just Assert()ing things rather
than doing a straight error check, and the Asserts were partially
redundant with PageHeaderIsValid anyway. Per recent failure example
from Jim Nasby. (gist still needs the same treatment.)
the wrong buffer dirty when trying to kill a dead index entry that's on
a page after the one it started on. No risk of data corruption, just
inefficiency, but still a bug.
up have the standard layout with unused space between pd_lower and pd_upper.
When this is set, XLogInsert will omit the unused space without bothering
to scan it to see if it's zero. That saves time in XLogInsert, and also
allows reversion of my earlier patch to make PageRepairFragmentation et al
explicitly re-zero freed space. Per suggestion by Heikki Linnakangas.
convention for isnull flags. Also, remove the useless InsertIndexResult
return struct from index AM aminsert calls --- there is no reason for
the caller to know where in the index the tuple was inserted, and we
were wasting a palloc cycle per insert to deliver this uninteresting
value (plus nontrivial complexity in some AMs).
I forced initdb because of the change in the signature of the aminsert
routines, even though nothing really looks at those pg_proc entries...
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 ...
in all cases when keep_buf = true. This allows ANALYZE's inner loop to
use heap_release_fetch, which saves multiple buffer lookups for the same
page and avoids overestimation of cost by the vacuum cost mechanism.
http://archives.postgresql.org/pgsql-hackers/2004-10/msg00464.php.
This fix is intended to be permanent: it moves the responsibility for
calling SetBufferCommitInfoNeedsSave() into the tqual.c routines,
eliminating the requirement for callers to test whether t_infomask changed.
Also, tighten validity checking on buffer IDs in bufmgr.c --- several
routines were paranoid about out-of-range shared buffer numbers but not
about out-of-range local ones, which seems a tad pointless.
value of 'start' could be past the end of the page, if the page was
split by some concurrent inserting process since we visited it. In
this situation the code could look at bogus entries and possibly find
a match (since after all those entries still contain what they had
before the split). This would lead to 'specified item offset is too large'
followed by 'PANIC: failed to add item to the page', as reported by Joe
Conway for scenarios involving heavy concurrent insertion activity.
recovery more manageable. Also, undo recent change to add FILE_HEADER
and WASTED_SPACE records to XLOG; instead make the XLOG page header
variable-size with extra fields in the first page of an XLOG file.
This should fix the boundary-case bugs observed by Mark Kirkwood.
initdb forced due to change of XLOG representation.
the next are handled by ReleaseAndReadBuffer rather than separate
ReleaseBuffer and ReadBuffer calls. This cuts the number of acquisitions
of the BufMgrLock by a factor of 2 (possibly more, if an indexscan happens
to pull successive rows from the same heap page). Unfortunately this
doesn't seem enough to get us out of the recently discussed context-switch
storm problem, but it's surely worth doing anyway.
pointer type when it is not necessary to do so.
For future reference, casting NULL to a pointer type is only necessary
when (a) invoking a function AND either (b) the function has no prototype
OR (c) the function is a varargs function.
to step more than one entry after descending the search tree to arrive at
the correct place to start the scan. This can improve the behavior
substantially when there are many entries equal to the chosen boundary
value. Per suggestion from Dmitry Tkach, 14-Jul-03.
pghackers proposal of 8-Nov. All the existing cross-type comparison
operators (int2/int4/int8 and float4/float8) have appropriate support.
The original proposal of storing the right-hand-side datatype as part of
the primary key for pg_amop and pg_amproc got modified a bit in the event;
it is easier to store zero as the 'default' case and only store a nonzero
when the operator is actually cross-type. Along the way, remove the
long-since-defunct bigbox_ops operator class.
Remove the 'strategy map' code, which was a large amount of mechanism
that no longer had any use except reverse-mapping from procedure OID to
strategy number. Passing the strategy number to the index AM in the
first place is simpler and faster.
This is a preliminary step in planned support for cross-datatype index
operations. I'm committing it now since the ScanKeyEntryInitialize()
API change touches quite a lot of files, and I want to commit those
changes before the tree drifts under me.
killed items; just skip to the next item immediately. Only check for
key equality when we reach a non-killed item or the end of the index
page. This saves key comparisons when there are lots of killed items,
as for example in a heavily-updated table that's not been vacuumed lately.
Seems to be a win for pgbench anyway.
now knows what to do upon hitting a dead page (in theory anyway, it's
untested...). Add a post-VACUUM-cleanup entry point for index AMs, to
provide a place for dead-page scavenging to happen.
Also, fix oversight that broke btpo_prev links in temporary indexes.
initdb forced due to additions in pg_am.
support btree compaction, as per proposal of a few days ago. btree index
pages no longer store parent links, instead they have a level indicator
(counting up from zero for leaf pages). The FixBTree recovery logic is
removed, and replaced by code that detects missing parent-level insertions
during WAL replay. Also, generate appropriate WAL entries when updating
btree metapage and when building a btree index from scratch. I believe
btree indexes are now completely WAL-legal for the first time.
initdb forced due to index and WAL changes.
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.
all places, where pd_linp is accessed. Also introduce new macros
SizeOfPageHeaderData and BTMaxItemSize. This is just source code
cosmetic, no behaviour changed.
Manfred Koizar
transaction, so as to avoid returning them out of the index AM. Saves
repeated heap_fetch operations on frequently-updated rows. Also detect
queries on unique keys (equality to all columns of a unique index), and
don't bother continuing scan once we have found first match.
Killing is implemented in the btree and hash AMs, but not yet in rtree
or gist, because there isn't an equally convenient place to do it in
those AMs (the outer amgetnext routine can't do it without re-pinning
the index page).
Did some small cleanup on APIs of HeapTupleSatisfies, heap_fetch, and
index_insert to make this a little easier.
o Change all current CVS messages of NOTICE to WARNING. We were going
to do this just before 7.3 beta but it has to be done now, as you will
see below.
o Change current INFO messages that should be controlled by
client_min_messages to NOTICE.
o Force remaining INFO messages, like from EXPLAIN, VACUUM VERBOSE, etc.
to always go to the client.
o Remove INFO from the client_min_messages options and add NOTICE.
Seems we do need three non-ERROR elog levels to handle the various
behaviors we need for these messages.
Regression passed.
now just below FATAL in server_min_messages. Added more text to
highlight ordering difference between it and client_min_messages.
---------------------------------------------------------------------------
REALLYFATAL => PANIC
STOP => PANIC
New INFO level the prints to client by default
New LOG level the prints to server log by default
Cause VACUUM information to print only to the client
NOTICE => INFO where purely information messages are sent
DEBUG => LOG for purely server status messages
DEBUG removed, kept as backward compatible
DEBUG5, DEBUG4, DEBUG3, DEBUG2, DEBUG1 added
DebugLvl removed in favor of new DEBUG[1-5] symbols
New server_min_messages GUC parameter with values:
DEBUG[5-1], INFO, NOTICE, ERROR, LOG, FATAL, PANIC
New client_min_messages GUC parameter with values:
DEBUG[5-1], LOG, INFO, NOTICE, ERROR, FATAL, PANIC
Server startup now logged with LOG instead of DEBUG
Remove debug_level GUC parameter
elog() numbers now start at 10
Add test to print error message if older elog() values are passed to elog()
Bootstrap mode now has a -d that requires an argument, like postmaster
to insert the same key into a supposedly unique index. The bug is of
low probability, and may not explain any of the recent reports of
duplicated rows; but a bug is a bug.
rightmost on its tree level, we split 2/3 to the left and 1/3 to the
new right page, rather than the even split we use elsewhere. The idea
is that when faced with a steadily increasing series of inserted keys
(such as sequence or timestamp values), we'll end up with a btree that's
about 2/3ds full not 1/2 full, which is much closer to the desired
steady-state load for a btree. Per suggestion from Ann Harrison of
IBPhoenix.
per previous discussion on pghackers. Most of the duplicate code in
different AMs' ambuild routines has been moved out to a common routine
in index.c; this means that all index types now do the right things about
inserting recently-dead tuples, etc. (I also removed support for EXTEND
INDEX in the ambuild routines, since that's about to go away anyway, and
it cluttered the code a lot.) The retail indextuple deletion routines have
been replaced by a "bulk delete" routine in which the indexscan is inside
the access method. I haven't pushed this change as far as it should go yet,
but it should allow considerable simplification of the internal bookkeeping
for deletions. Also, add flag columns to pg_am to eliminate various
hardcoded tests on AM OIDs, and remove unused pg_am columns.
Fix rtree and gist index types to not attempt to store NULLs; before this,
gist usually crashed, while rtree managed not to crash but computed wacko
bounding boxes for NULL entries (which might have had something to do with
the performance problems we've heard about occasionally).
Add AtEOXact routines to hash, rtree, and gist, all of which have static
state that needs to be reset after an error. We discovered this need long
ago for btree, but missed the other guys.
Oh, one more thing: concurrent VACUUM is now the default.
and new root page if old root one was splitted but new root page
wasn't created.
New code is protected by FixBTree bool flag setted to FALSE, so
nothing should be affected by this untested approach.
are treated more like 'cancel' interrupts: the signal handler sets a
flag that is examined at well-defined spots, rather than trying to cope
with an interrupt that might happen anywhere. See pghackers discussion
of 1/12/01.
are now critical sections, so as to ensure die() won't interrupt us while
we are munging shared-memory data structures. Avoid insecure intermediate
states in some code that proc_exit will call, like palloc/pfree. Rename
START/END_CRIT_CODE to START/END_CRIT_SECTION, since that seems to be
what people tend to call them anyway, and make them be called with () like
a function call, in hopes of not confusing pg_indent.
I doubt that this is sufficient to make SIGTERM safe anywhere; there's
just too much code that could get invoked during proc_exit().
Context diff this time.
Remove -m486 compile args for FreeBSD-i386, compile -O2 on i386.
Compile with only -O on alpha for codegen safety.
Make the port use the TEST_AND_SET for alpha and i386 on FreeBSD.
Fix a lot of bogus string formats for outputting pointers (cast to int
and %u/%x replaced with no cast and %p), and 'Size'(size_t) are now
cast to 'unsigned long' and output with %lu/
Remove an unused variable.
Alfred Perlstein
Tom Lane
Bruce Momjian
Peter Eisentraut
Neil Conway
Alvaro Herrera
PostgreSQL Daemon
Jan Wieck
Vadim B. Mikheev