This commit doesn't make much functional change, but it does eliminate some
duplicated code --- for instance, PageIsNew tests are now done inside
XLogReadBuffer rather than by each caller.
The GIST xlog code still needs a lot of love, but I'll worry about that
separately.
passed extend = true whenever we are reading a page we intend to reinitialize
completely, even if we think the page "should exist". This is because it
might indeed not exist, if the relation got truncated sometime after the
current xlog record was made and before the crash we're trying to recover
from. These two thinkos appear to explain both of the old bug reports
discussed here:
http://archives.postgresql.org/pgsql-hackers/2005-05/msg01369.php
when an error occurs during xlog replay. Also, replace the former risky
'write into a fixed-size buffer with no overflow detection' API for XLOG
record description routines; use an expansible StringInfo instead. (The
latter accounts for most of the patch bulk.)
Qingqing Zhou
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.
Instead of a separate CRC on each backup block, include backup blocks
in their parent WAL record's CRC; this is important to ensure that the
backup block really goes with the WAL record, ie there was not a page
tear right at the start of the backup block. Implement a simple form
of compression of backup blocks: drop any run of zeroes starting at
pd_lower, so as not to store the unused 'hole' that commonly exists in
PG heap and index pages. Tweak PageRepairFragmentation and related
routines to ensure they keep the unused space zeroed, so that the above
compression method remains effective. All per recent discussions.
PageIndexTupleDelete() with a single pass of compactification ---
logic mostly lifted from PageRepairFragmentation. I noticed while
profiling that a VACUUM that's cleaning up a whole lot of deleted
tuples would spend as much as a third of its CPU time in
PageIndexTupleDelete; not too surprising considering the loop method
was roughly O(N^2) in the number of tuples involved.
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 ...
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.
shift support code into heapam.c accordingly. This is in service of
soon-to-be-committed ALTER TABLE SET TABLESPACE code that will want to
use this same record type for both heaps and indexes.
Theoretically I should have forced initdb for this, but in practice there
is no change in xlog contents because CVS tip will never really emit this
record type anyhow...
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.
locking conflict against concurrent CHECKPOINT that was discussed a few
weeks ago. Also, if not using WAL archiving (which is always true ATM
but won't be if PITR makes it into this release), there's no need to
WAL-log the index build process; it's sufficient to force-fsync the
completed index before commit. This seems to gain about a factor of 2
in my tests, which is consistent with writing half as much data. I did
not try it with WAL on a separate drive though --- probably the gain would
be a lot less in that scenario.
In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.
The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.
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.
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.
invalid (has the wrong magic number) until the build is entirely
complete. This turns out to cost no additional writes in the normal
case, since we were rewriting the metapage at the end of the process
anyway. In normal scenarios there's no real gain in security, because
a failed index build would roll back the transaction leaving an unused
index file, but for rebuilding shared system indexes this seems to add
some useful protection.
deleting multiple index entries on a single index page. This makes for
a very substantial reduction in the amount of WAL traffic during a
large delete operation.
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.
Tom Lane
Bruce Momjian
PostgreSQL Daemon
Neil Conway