and possibly for other cases too:
DO NOT cache status of transaction in unknown state
(i.e. non-committed and non-aborted ones)
Example:
T1 reads row updated/inserted by running T2 and cache T2 status.
T2 commits.
Now T1 reads a row updated by T2 and with HEAP_XMAX_COMMITTED
in t_infomask (so cached T2 status is not changed).
Now T1 EvalPlanQual gets updated row version without HEAP_XMIN_COMMITTED
-> TransactionIdDidCommit(t_xmin) and TransactionIdDidAbort(t_xmin)
return FALSE and T2 decides that t_xmin is not committed and gets
ERROR above.
It's too late to find more smart way to handle such cases and so
I just changed xact status caching and got rid TransactionIdFlushCache()
from code.
Changed: transam.c, xact.c, lmgr.c and transam.h - last three
just because of TransactionIdFlushCache() is removed.
2. heapam.c:
T1 marked a row for update. T2 waits for T1 commit/abort.
T1 commits. T3 updates the row before T2 locks row page.
Now T2 sees that new row t_xmax is different from xact id (T1)
T2 was waiting for. Old code did Assert here. New one goes to
HeapTupleSatisfiesUpdate. Obvious changes too.
3. Added Assert to vacuum.c
4. bufmgr.c: break
Assert(buf->r_locks == 0 && !buf->ri_lock)
into two Asserts.
BT_READ/BT_WRITE are BUFFER_LOCK_SHARE/BUFFER_LOCK_EXCLUSIVE now.
Also get rid of #define BT_VERSION_1 - we use version 1 as default
for near two years now.
2. Much faster btree tuples deletion in the case when first on page
index tuple is deleted (no movement to the left page(s)).
3. Remember blkno of new root page in BTPageOpaque of
left/right siblings when root page is splitted.
so that fetching an attribute value needs only one SearchSysCacheTuple call
instead of two redundant searches. This speeds up a large SELECT by about
ten percent, and probably will help GROUP BY and SELECT DISTINCT too.
no longer returns buffer pointer, can be gotten from scan;
descriptor; bootstrap can create multi-key indexes;
pg_procname index now is multi-key index; oidint2, oidint4, oidname
are gone (must be removed from regression tests); use System Cache
rather than sequential scan in many places; heap_modifytuple no
longer takes buffer parameter; remove unused buffer parameter in
a few other functions; oid8 is not index-able; remove some use of
single-character variable names; cleanup Buffer variables usage
and scan descriptor looping; cleaned up allocation and freeing of
tuples; 18k lines of diff;
1. Remove the char2, char4, char8 and char16 types from postgresql
2. Change references of char16 to name in the regression tests.
3. Rename the char16.sql regression test to name.sql. 4. Modify
the regression test scripts and outputs to match up.
Might require new regression.{SYSTEM} files...
Darren King
The following patches will allow postgreSQL 6.3 to compile and run on a
UNIXWARE 2.1.2 system with the native C compiler with the following library
change:
The alloca function must be copied from the libucb.a archive and added
to the libgen.a archive.
Also, the GNU flex program is needed to successfully build postgreSQL.
