that return tuples (such as EXPLAIN). Per gripe from Michael Fuhr.
Side effect: fix an old bug that unintentionally disabled backward scans
for all SPI-created cursors.
column with a default expression. In that situation, we need to rewrite
the heap relation. To evaluate the new default expression, we use
ExecEvalExpr(); however, this can allocate memory in the current memory
context, and ATRewriteTable() does not switch out of the active portal's
heap memory context. The end result is a rather large memory leak (on
the order of gigabytes for a reasonably sized table).
This patch changes ATRewriteTable() to switch to the per-tuple memory
context before beginning the per-tuple loop. It also removes an explicit
heap_freetuple() in the loop, since that is no longer needed.
In an unrelated change, I noticed the code was scanning through the
attributes of the new tuple descriptor for each tuple of the old table.
I changed this to use precomputation, which should slightly speed up
the loop.
Thanks to steve@deefs.net for reporting the leak.
there are corner cases involving dropping toasted columns in which the
previous coding would fail, too: the new version of the table might not
have any TOAST table, but we'd still propagate possibly-wide values of
dropped columns forward.
form of CASE (eg, CASE 0 WHEN 1 THEN ...) can be constant-folded as it
was in 7.4. Also, avoid constant-folding result expressions that are
certainly unreachable --- the former coding was a bit cavalier about this
and could generate unexpected results for all-constant CASE expressions.
Add regression test cases. Per report from Vlad Marchenko.
tests. Contributed by Koju Iijima, review from Neil Conway, Gavin Sherry
and Tom Lane.
Also, fix error in description of WITH CHECK OPTION clause in the CREATE
VIEW reference page: it should be "CASCADED", not "CASCADE".
estimate to less than the number of values estimated for any one grouping
Var, as suggested by Manfred. This is intuitively right, and what's
more it puts the plan choices in the subselect regression test back the
way they were before ...
clamp the estimated number of groups to table row count over 10, instead
of table row count; this reflects a heuristic that people probably won't
group over a near-unique set of columns, and the knowledge that we don't
currently have any way to estimate the correlation of the columns better
than guessing. This change creates a trivial plan change in one of the
regression tests.
look at the actual aggregate transition datatypes and the actual overhead
needed by nodeAgg.c, instead of using pessimistic round numbers.
Per a discussion with Michael Tiemann.
command. This is useful because we can allow truncation of tables
referenced by foreign keys, so long as the referencing table is
truncated in the same command.
Alvaro Herrera
to avoid problems when a cursor depends on objects created or changed in
the same subtransaction. We'd like to do better someday, but this seems
the only workable answer for 8.0.1.
(1) Keep a pin on the scan's current buffer and mark buffer. This
avoids the need to do a ReadBuffer() for each tuple produced by the
scan. Since ReadBuffer() is expensive, this is a significant win.
(2) Convert a ReleaseBuffer(); ReadBuffer() pair into
ReleaseAndReadBuffer(). Surely not a huge win, but it saves a lock
acquire/release...
(3) Remove a bunch of duplicated code in rtget.c; make rtnext() handle
both the "initial result" and "subsequent result" cases.
(4) Add support for index tuple killing
(5) Remove rtscancache(): it is dead code, for the same reason that
gistscancache() is dead code (an index scan ought not be invoked with
NoMovementScanDirection).
The end result is about a 10% improvement in rtree index scan perf,
according to contrib/rtree_gist/bench.
got it wrong when the JOIN was in an outer query level. Per example from
Laurie Burrow. Also fix same issue in markTargetListOrigin. I think the
latter is only a latent bug since we currently don't apply markTargetListOrigin
except at the outer level ... but should do it right anyway.
CASE 'a' WHEN 'a' THEN 1 ELSE 2 END. This worked in 7.4 and before
but had been broken due to premature freezing of the type of the test
expression. Per gripe from GÄbor SzÃcs.
so that we can get the size of a shared inval message back down to what it
was in 7.4 (and simplify the logic too). Phase 2 of fixing the
'SMgrRelation hashtable corrupted' problem.
is the minimum required fix. I want to look next at taking advantage of
it by simplifying the message semantics in the shared inval message queue,
but that part can be held over for 8.1 if it turns out too ugly.
releases, a nonzero 'c' argument meant that the input string could be
terminated by either that character or \0. Recent refactoring broke
that, causing the thing to scan for 'c' only. This went undetected
because no part of the main code actually passes nonzero 'c'. However
it broke tsearch2 and possibly other user-written code that assumed
the old definition. Per report from Tom Hebbron.
