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;
The diff looks so simple and easy. But to find it wasn't fun.
It must have been there for a long time. What happened:
When a tuple in one of some central catalogs was updated, the
referenced relation got flushed, so it would be reopened on
the next access (to reflect new triggers, rules and table
structure changes into the relation cache).
Some data (the tupleDescriptor e.g.) is used in the system
cache too. So when a relation is subject to the system cache,
this must know too that a cached system relation got flushed
because the tupleDesc data gets freed during the flush!
For the GRANT/REVOKE on pg_class it was slightly different.
There is some local data in inval.c that gets initialized on
the first invalidation of a tuple in some central catalogs.
This needs a SysCache lookup in pg_class. But when the first
of all commands is a GRANT on pg_class, exactly the needed
tuple is the one actually invalidated. So I added little code
snippets that the initialization of the local variables in
inval.c will already happen during InitPostgres().
