equality checks it applies, instead of a random dependence on whatever
operators might be named "=". The equality operators will now be selected
from the opfamily of the unique index that the FK constraint depends on to
enforce uniqueness of the referenced columns; therefore they are certain to be
consistent with that index's notion of equality. Among other things this
should fix the problem noted awhile back that pg_dump may fail for foreign-key
constraints on user-defined types when the required operators aren't in the
search path. This also means that the former warning condition about "foreign
key constraint will require costly sequential scans" is gone: if the
comparison condition isn't indexable then we'll reject the constraint
entirely. All per past discussions.
Along the way, make the RI triggers look into pg_constraint for their
information, instead of using pg_trigger.tgargs; and get rid of the always
error-prone fixed-size string buffers in ri_triggers.c in favor of building up
the RI queries in StringInfo buffers.
initdb forced due to columns added to pg_constraint and pg_trigger.
socket is still read-ready, the code was a tight loop, wasting lots of CPU.
We can't do anything to clear the failure, other than wait, but we should give
other processes more chance to finish and release FDs; so insert a small sleep.
Also, avoid bogus "close(-1)" in this case. Per report from Jim Nasby.
that overlap an outer join's min_righthand but aren't fully contained in it,
to support joining within the RHS after having performed an outer join that
can commute with this one. Aside from the direct fix in make_join_rel(),
fix has_join_restriction() and GEQO's desirable_join() to consider this
possibility. Per report from Ian Harding.
currently have any better strategy for this query than re-running the
sub-select over and over; it seems unlikely that doing so 10000 times
is a more useful test than doing it a few dozen times.
entries for the victim database go away sooner rather than later. We already
did the equivalent thing at the per-relation level, not sure why it's not
been done for whole databases. With this change, pgstat_vacuum_tabstat
should usually not find anything to do; though we still need it as a backstop
in case DROPDB or TABPURGE messages get lost under load.
< * Merge xmin/xmax/cmin/cmax back into three header fields
<
< Before subtransactions, there used to be only three fields needed to
< store these four values. This was possible because only the current
< transaction looks at the cmin/cmax values. If the current transaction
< created and expired the row the fields stored where xmin (same as
< xmax), cmin, cmax, and if the transaction was expiring a row from a
< another transaction, the fields stored were xmin (cmin was not
< needed), xmax, and cmax. Such a system worked because a transaction
< could only see rows from another completed transaction. However,
< subtransactions can see rows from outer transactions, and once the
< subtransaction completes, the outer transaction continues, requiring
< the storage of all four fields. With subtransactions, an outer
< transaction can create a row, a subtransaction expire it, and when the
< subtransaction completes, the outer transaction still has to have
< proper visibility of the row's cmin, for example, for cursors.
<
< One possible solution is to create a phantom cid which represents a
< cmin/cmax pair and is stored in local memory. Another idea is to
< store both cmin and cmax only in local memory.
<
> * -Merge xmin/xmax/cmin/cmax back into three header fields
keeping private state in each backend that has inserted and deleted the same
tuple during its current top-level transaction. This is sufficient since
there is no need to be able to determine the cmin/cmax from any other
transaction. This gets us back down to 23-byte headers, removing a penalty
paid in 8.0 to support subtransactions. Patch by Heikki Linnakangas, with
minor revisions by moi, following a design hashed out awhile back on the
pghackers list.
