is still alive. This improves our odds of not getting fooled by an
unrelated process when checking a stale lock file. Other checks already
in place, plus one newly added in checkDataDir(), ensure that we cannot
attempt to usurp the place of a postmaster belonging to a different userid,
so there is no need to error out. Add comments indicating the importance
of these other checks.
grouping_planner() to preprocess_targetlist(), according to a comment
in grouping_planner(). I think the refactoring makes sense, and moves
some extraneous details out of grouping_planner().
and rules alphabetically in the output. This makes it the same as
for indexes and stops the irritating random or reverse ordering it
currently has.
Chris KL
of tuples when passing data up through multiple plan nodes. A slot can now
hold either a normal "physical" HeapTuple, or a "virtual" tuple consisting
of Datum/isnull arrays. Upper plan levels can usually just copy the Datum
arrays, avoiding heap_formtuple() and possible subsequent nocachegetattr()
calls to extract the data again. This work extends Atsushi Ogawa's earlier
patch, which provided the key idea of adding Datum arrays to TupleTableSlots.
(I believe however that something like this was foreseen way back in Berkeley
days --- see the old comment on ExecProject.) A test case involving many
levels of join of fairly wide tables (about 80 columns altogether) showed
about 3x overall speedup, though simple queries will probably not be
helped very much.
I have also duplicated some code in heaptuple.c in order to provide versions
of heap_formtuple and friends that use "bool" arrays to indicate null
attributes, instead of the old convention of "char" arrays containing either
'n' or ' '. This provides a better match to the convention used by
ExecEvalExpr. While I have not made a concerted effort to get rid of uses
of the old routines, I think they should be deprecated and eventually removed.
locale is C.
Backpatch to 8.0.X because some operating systems were throwing errors
for such operations, rather than ignoring the locale when it was C.
a tuple are being accessed via ExecEvalVar and the attcacheoff shortcut
isn't usable (due to nulls and/or varlena columns). To do this, cache
Datums extracted from a tuple in the associated TupleTableSlot.
Also some code cleanup in and around the TupleTable handling.
Atsushi Ogawa with some kibitzing by Tom Lane.
whether or not it is a security definer. Changing a function's strictness
is required by SQL2003, and the other capabilities make sense. Also, allow
an optional RESTRICT noise word to be specified, for SQL conformance.
Some trivial regression tests added and the documentation has been
updated.
database's datallowconn and datfrozenxid to the current transaction ID
instead of copying the source database's values. This is OK because we
assume the source DB contains no normal transaction IDs whatsoever.
This keeps VACUUM from immediately starting to complain about unvacuumed
databases in the situation where we are more than 2 billion transactions
out from the XID stamp of template0. Per discussion with Milen Radev
(although his complaint turned out to be due to something else, but the
problem is real anyway).
can tell whether it is being used as an aggregate or not. This allows
such a function to avoid re-pallocing a pass-by-reference transition
value; normally it would be unsafe for a function to scribble on an input,
but in the aggregate case it's safe to reuse the old transition value.
Make int8inc() do this. This gets a useful improvement in the speed of
COUNT(*), at least on narrow tables (it seems to be swamped by I/O when
the table rows are wide). Per a discussion in early December with
Neil Conway. I also fixed int_aggregate.c to check this, thereby
turning it into something approaching a supportable technique instead
of being a crude hack.
elog if the former has trouble writing its file. Code review for
Magnus' patch to redirect stderr to syslog on Windows (Bruce's version
seems right, but did some minor prettification).
Backpatch both changes to 8.0 branch.
Document use of macros for pg_printf functions.
Bump major versions of all interfaces to handle movement of get_progname
from libpq to libpgport in 8.0, and probably other libpgport changes in 8.1.
Formerly, if such a clause contained no aggregate functions we mistakenly
treated it as equivalent to WHERE. Per spec it must cause the query to
be treated as a grouped query of a single group, the same as appearance
of aggregate functions would do. Also, the HAVING filter must execute
after aggregate function computation even if it itself contains no
aggregate functions.
before we can invoke fork() -- flush stdio buffers, save and restore the
profiling timer on Linux with LINUX_PROFILE, and handle BeOS stuff. This
patch moves that code into a single function, fork_process(), instead of
duplicating it at the various callsites of fork().
This patch doesn't address the EXEC_BACKEND case; there is room for
further cleanup there.
number of palloc calls. This has a salutory impact on plpgsql operations
with record variables (which create and destroy tupdescs constantly)
and probably helps a bit in some other cases too.
Too much space is allocated for tablespace file path, I guess the
directory name used to be "pg_tablespaces" instead of "pg_tblspc" at
some point.
Heikki Linnakangas
on-the-fly, and thereby avoid blowing out memory when the planner has
underestimated the hash table size. Hash join will now obey the
work_mem limit with some faithfulness. Per my recent proposal
(hash aggregate part isn't done yet though).
the freelist, plus per-buffer spinlocks that protect access to individual
shared buffer headers. This requires abandoning a global freelist (since
the freelist is a global contention point), which shoots down ARC and 2Q
as well as plain LRU management. Adopt a clock sweep algorithm instead.
Preliminary results show substantial improvement in multi-backend situations.
of AND and OR clauses. The key point here is that an OR on the
predicate side has to be treated gingerly: we may be able to prove
that the OR is implied even when no one of its components is implied.
For example (x OR y) implies (x OR y OR z) even though no one of x,
y, or z can be individually proven. This code handles both the
example shown recently by Sergey Koshcheyev and the one shown last
October by Dawid Kuroczko.
no held locks. This maintains the invariant that proclocks are present
only for procs that are holding or awaiting a lock; when this is not
true, LockRelease will fail. Per report from Stephen Clouse.
indexscans involving partial indexes. These would always be dominated
by a simple indexscan on such an index, so there's no point in considering
them. Fixes overoptimism in a patch I applied last October.
it was in 7.4, and add some comments explaining why it has to be this way.
I broke it for OR'd index predicates in a fit of code cleanup last summer.
Per example from Sergey Koshcheyev.
in favor of looking at the flat file copy of pg_database during backend
startup. This should finally eliminate the various corner cases in which
backend startup fails unexpectedly because it isn't able to distinguish
live and dead tuples in pg_database. Simplify locking on pg_database
to be similar to the rules used with pg_shadow and pg_group, and eliminate
FlushRelationBuffers operations that were used only to reduce the odds
of failure of GetRawDatabaseInfo.
initdb forced due to addition of a trigger to pg_database.
implement the md5() SQL-level function). The old code did the
following:
1. de-toast the datum
2. convert it to a cstring via textout()
3. get the length of the cstring via strlen()
Since we are treating the datum context as a blob of binary data,
the latter two steps are unnecessary. Once the data has been
detoasted, we can just use it as-is, and derive its length from
the varlena metadata.
This patch improves some run-of-the-mill md5() computations by
just under 10% in my limited tests, and passes the regression tests.
I also noticed that md5_text() wasn't checking the return value
of md5_hash(); encountering OOM at precisely the right moment
could result in returning a random md5 hash. This patch corrects
that. A better fix would be to make md5_hash() only return on
success (and/or allocate via palloc()), but since it's used in
the frontend as well I don't see an easy way to do that.
and parsing work in PL/PgSQL:
- memory management is now done via palloc(). The compiled representation
of each function now has its own memory context. Therefore, the storage
consumed by a function can be reclaimed via MemoryContextDelete().
During compilation, the CurrentMemoryContext is the function's memory
context. This means that a palloc() is sufficient to allocate memory
that will have the same lifetime as the function itself. As a result,
code invoked during compilation should be careful to pfree() temporary
allocations to avoid leaking memory. Since a lot of the code in the
backend is not careful about releasing palloc'ed memory, that means
we should switch into a temporary memory context before invoking
backend functions. A temporary context appropriate for such allocations
is `compile_tmp_cxt'.
- The ability to use palloc() allows us to simply a lot of the code in
the parser. Rather than representing lists of elements via ad hoc
linked lists or arrays, we can use the List type. Rather than doing
malloc followed by memset(0), we can just use palloc0().
- We now check that the user has supplied the right number of parameters
to a RAISE statement. Supplying either too few or too many results in
an error (at runtime).
- PL/PgSQL's parser needs to accept arbitrary SQL statements. Since we
do not want to duplicate the SQL grammar in the PL/PgSQL grammar, this
means we need to be quite lax in what the PL/PgSQL grammar considers
a "SQL statement". This can lead to misleading behavior if there is a
syntax error in the function definition, since we assume a malformed
PL/PgSQL construct is a SQL statement. Furthermore, these errors were
only detected at runtime (when we tried to execute the alleged "SQL
statement" via SPI).
To rectify this, the patch changes the parser to invoke the main SQL
parser when it sees a string it believes to be a SQL expression. This
means that synctically-invalid SQL will be rejected during the
compilation of the PL/PgSQL function. This is only done when compiling
for "validation" purposes (i.e. at CREATE FUNCTION time), so it should
not impose a runtime overhead.
- Fixes for the various buffer overruns I've patched in stable branches
in the past few weeks. I've rewritten code where I thought it was
warranted (unlike the patches applied to older branches, which were
minimally invasive).
- Various other minor changes and cleanups.
- Updates to the regression tests.
+ # Determine if printf supports %1$ argument selection, e.g. %5$ selects
+ # the fifth argument after the printf print string.
+ # This is not in the C99 standard, but in the Single Unix Specification (SUS).
+ # It is used in our langauge translation strings.
Nicolai Tufar with configure changes by Bruce.
during flat-file writing. The only difference is that SnapshotSelf
would consider tuples of the 'current command' within the current
transaction as valid, where SnapshotNow wouldn't. We can eliminate
the need for this with one extra CommandCounterIncrement call before
we start reading the catalogs.
the AMI_OVERRIDE flag. The fact that TransactionLogFetch treats
BootstrapTransactionId as always committed is sufficient to make
bootstrap work, and getting rid of extra tests in heavily used code
paths seems like a win. The files produced by initdb are demonstrably
the same after this change.
file now identifies group members by usesysid not name; this avoids
needing to depend on SearchSysCache which we can't use during startup.
(The old representation was entirely broken anyway, since we did not
regenerate the file following RENAME USER.) It's only a 95% solution
because if the group membership list is big enough to be toasted out
of line, we cannot read it during startup. I think this will do for
the moment, until we have time to implement the planned pg_role
replacement for pg_group.
in GetNewTransactionId(). Since the limit value has to be computed
before we run any real transactions, this requires adding code to database
startup to scan pg_database and determine the oldest datfrozenxid.
This can conveniently be combined with the first stage of an attack on
the problem that the 'flat file' copies of pg_shadow and pg_group are
not properly updated during WAL recovery. The code I've added to
startup resides in a new file src/backend/utils/init/flatfiles.c, and
it is responsible for rewriting the flat files as well as initializing
the XID wraparound limit value. This will eventually allow us to get
rid of GetRawDatabaseInfo too, but we'll need an initdb so we can add
a trigger to pg_database.
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 ...
initially NULL. For 8.0 we changed the main executor to have this
behavior in an UPDATE of an array column, but plpgsql's equivalent case
was overlooked. Per report from Sven Willenberger.
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.
column values in -d mode. Per report from Marty Scholes. This doesn't
completely solve the issue, because we still need multiple copies of the
field value, but at least one copy can be got rid of painlessly ...
Tom Lane
Michael Meskes
Neil Conway
Bruce Momjian
Teodor Sigaev