maintained for each cache entry. A cache entry will not be freed until
the matching ReleaseSysCache call has been executed. This eliminates
worries about cache entries getting dropped while still in use. See
my posting to pg-hackers of even date for more info.
(WAL logging for this is not done yet, however.) Clean up a number of really
crufty things that are no longer needed now that DROP behaves nicely. Make
temp table mapper do the right things when drop or rename affecting a temp
table is rolled back. Also, remove "relation modified while in use" error
check, in favor of locking tables at first reference and holding that lock
throughout the statement.
pass-by-ref data types --- eg, an index on lower(textfield) --- no longer
leak memory during index creation or update. Clean up a lot of redundant
code ... did you know that copy, vacuum, truncate, reindex, extend index,
and bootstrap each basically duplicated the main executor's logic for
extracting information about an index and preparing index entries?
Functional indexes should be a little faster now too, due to removal
of repeated function lookups.
CREATE INDEX 'opt_type' clause is deimplemented by these changes,
but I haven't removed it from the parser yet (need to merge with
Thomas' latest change set first).
Don't go through pg_exec_query_dest(), but directly to the execution
routines. Also, extend parameter lists so that there's no need to
change the global setting of allowSystemTableMods, a hack that was
certain to cause trouble in the event of any error.
passing the index-is-unique flag to index build routines (duh! ...
why wasn't it done this way to begin with?). Aside from eliminating
an eyesore, this should save a few milliseconds in btree index creation
because a full scan of pg_index is not needed any more.
indexes, apparently, nor on functional indexes with more than one input
column (force of natts = 1 was in the wrong branch of IF statement).
Coredumped if source relation contained any uncommitted tuples, due to
failure to test for success return from heap_fetch. Fetched tuple
was passed directly to heap_insert, which clobbers the TID and commit
status in the tuple header it's given, which meant that the source
relation's tuples all got trashed as the copy proceeded. Abort partway
through, and you're left with a lot of missing tuples.
I wonder what else is lurking here ...
Make all system indexes unique.
Make all cache loads use system indexes.
Rename *rel to *relid in inheritance tables.
Rename cache names to be clearer.
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.
a field was labelled as a primary key, the system automatically
created a unique index on the field. This patch extends it so
that the index has the indisprimary field set. You can pull a list
of primary keys with the followiing select.
SELECT pg_class.relname, pg_attribute.attname
FROM pg_class, pg_attribute, pg_index
WHERE pg_class.oid = pg_attribute.attrelid AND
pg_class.oid = pg_index.indrelid AND
pg_index.indkey[0] = pg_attribute.attnum AND
pg_index.indisunique = 't';
There is nothing in this patch that modifies the template database to
set the indisprimary attribute for system tables. Should they be
changed or should we only be concerned with user tables?
D'Arcy
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;
Tom Lane