When drawing up a very simple "text-drawing" of how the negotiation is done,
I realised I had done this last part (fallback) in a very stupid way. Patch
#4 fixes this, and does it in a much better way.
Included is also the simple text-drawing of how the negotiation is done.
//Magnus
with no input rows, per pghackers discussions around 7/22/99. Clean up
a bunch of ugly coding while at it; remove redundant re-lookup of
aggregate info at start of each new GROUP. Arrange to pfree intermediate
values when they are pass-by-ref types, so that aggregates on pass-by-ref
types no longer eat memory. This takes care of a couple of TODO items...
Frankpitt, plus some improvements from yours truly. The simplifier depends
on the proiscachable field of pg_proc to tell it whether a function is
safe to pre-evaluate --- things like nextval() are not, for example.
Update pg_proc.h to contain reasonable cacheability information; as of
6.5.* hardly any functions were marked cacheable. I may have erred too
far in the other direction; see recent mail to pghackers for more info.
This update does not force an initdb, exactly, but you won't see much
benefit from the simplifier until you do one.
* Buffer refcount cleanup (per my "progress report" to pghackers, 9/22).
* Add links to backend PROC structs to sinval's array of per-backend info,
and use these links for routines that need to check the state of all
backends (rather than the slow, complicated search of the ShmemIndex
hashtable that was used before). Add databaseOID to PROC structs.
* Use this to implement an interlock that prevents DESTROY DATABASE of
a database containing running backends. (It's a little tricky to prevent
a concurrently-starting backend from getting in there, since the new
backend is not able to lock anything at the time it tries to look up
its database in pg_database. My solution is to recheck that the DB is
OK at the end of InitPostgres. It may not be a 100% solution, but it's
a lot better than no interlock at all...)
* In ALTER TABLE RENAME, flush buffers for the relation before doing the
rename of the physical files, to ensure we don't get failures later from
mdblindwrt().
* Update TRUNCATE patch so that it actually compiles against current
sources :-(.
You should do "make clean all" after pulling these changes.
now that sequence names are properly quoted for field defaults, mixed
case sequence names are generated. These are properly quoted in the
CREATE SEQUENCE lines, but not in the SELECT nextval lines, as per
below:
CREATE SEQUENCE "Teams_TeamID_seq" start 10 increment 1 maxvalue
2147483647 minvalue 1 cache 1 ;
SELECT nextval ('Teams_TeamID_seq');
This needs to be:
SELECT nextval ('"Teams_TeamID_seq"');
Patch included below.
--
Ross J. Reedstrom, Ph.D., <reedstrm@rice.edu>
additional argument specifying the kind of lock to acquire/release (or
'NoLock' to do no lock processing). Ensure that all relations are locked
with some appropriate lock level before being examined --- this ensures
that relevant shared-inval messages have been processed and should prevent
problems caused by concurrent VACUUM. Fix several bugs having to do with
mismatched increment/decrement of relation ref count and mismatched
heap_open/close (which amounts to the same thing). A bogus ref count on
a relation doesn't matter much *unless* a SI Inval message happens to
arrive at the wrong time, which is probably why we got away with this
sloppiness for so long. Repair missing grab of AccessExclusiveLock in
DROP TABLE, ALTER/RENAME TABLE, etc, as noted by Hiroshi.
Recommend 'make clean all' after pulling this update; I modified the
Relation struct layout slightly.
Will post further discussion to pghackers list shortly.
