work if either of the join relations are empty. The logic is:
(1) if the inner relation's startup cost is less than the outer
relation's startup cost and this is not an outer join, read
a single tuple from the inner relation via ExecHash()
- if NULL, we're done
(2) read a single tuple from the outer relation
- if NULL, we're done
(3) build the hash table on the inner relation
- if hash table is empty and this is not an outer join,
we're done
(4) otherwise, do hash join as usual
The implementation uses the new MultiExecProcNode API, per a
suggestion from Tom: invoking ExecHash() now produces the first
tuple from the Hash node's child node, whereas MultiExecHash()
builds the hash table.
I had to put in a bit of a kludge to get the row count returned
for EXPLAIN ANALYZE to be correct: since ExecHash() is invoked to
return a tuple, and then MultiExecHash() is invoked, we would
return one too many tuples to EXPLAIN ANALYZE. I hacked around
this by just manually detecting this situation and subtracting 1
from the EXPLAIN ANALYZE row count.
> against rc1. It simply checks with GetDatabaseEncoding() if the current
> database is in UTF-8, and if so, sets the UTF-8 flag on the arguments
> that are passed to perl. This means that it isn't necessary to
> utf8::upgrade() every string, as perl has no way of knowing offhand
> that a string is UTF-8 -- but postgres does, because the database
> encoding is specified, so it makes sense to turn the flag on. You
> should also be able to properly manipulate UTF-8 strings now from
> plperl as opposed to plperlu, because otherwise you'd have to use
> encoding 'utf8' which was not allowed. It could also eliminate some
> unexpected bugs if you assume that perl knows the string is unicode.
It
> is enabled only for perl 5.6 and higher, so earlier versions will not
> be affected.
>
> I have been assured by crab that the patch is quite harmless and will
> not break anything. It would be great to see it in 8 final! :-)
David Kamholz
"AT TIME ZONE", and not just the shorlist previously available. For
example:
SELECT CURRENT_TIMESTAMP AT TIME ZONE 'Europe/London';
works fine now. It will also obey whatever DST rules were in effect at
just that date, which the previous implementation did not.
It also supports the AT TIME ZONE on the timetz datatype. The whole
handling of DST is a bit bogus there, so I chose to make it use whatever
DST rules are in effect at the time of executig the query. not sure if
anybody is actuallyi *using* timetz though, it seems pretty
unpredictable just because of this...
Magnus Hagander
>> assuming this sideeffect is removed, though?
>
>I have no problem with the hashtable, only with preloading it with
>everything. What I'd like to see is that the table inherited at fork()
>contains just the data for the default timezone. (At least in the
>normal case where that setting hasn't been changed since postmaster
>start.)
Here's a patch doing this. Changes score_timezone not to use pg_tzset(),
and thus not loading all the zones in the cache. The actual timezone
being picked will be set using set_global_timezone() which in turn calls
pg_tzset() and loads it in the cache.
Magnus Hagander
it is sufficient to track whether a backend holds a lock or not, and
store information about transaction vs. session locks only in the
inside-the-backend LocalLockTable. Since there can now be but one
PROCLOCK per lock per backend, LockCountMyLocks() is no longer needed,
thus eliminating some O(N^2) behavior when a backend holds many locks.
Also simplify the LockAcquire/LockRelease API by passing just a
'sessionLock' boolean instead of a transaction ID. The previous API
was designed with the idea that per-transaction lock holding would be
important for subtransactions, but now that we have subtransactions we
know that this is unwanted. While at it, add an 'isTempObject' parameter
to LockAcquire to indicate whether the lock is being taken on a temp
table. This is not used just yet, but will be needed shortly for
two-phase commit.
part of service principal. If not set, any service principal matching
an entry in the keytab can be used.
NEW KERBEROS MATCHING BEHAVIOR FOR 8.1.
Todd Kover
if geqo_rand() returns exactly 1.0, resulting in failure due to indexing
off the end of the pool array. Also, since this is using inexact float math,
it seems wise to guard against roundoff error producing values slightly
outside the expected range. Per report from bug@zedware.org.
instead of just scalar variables. Add regression tests and update the
documentation. Along the way, remove some redundant error checking
code from exec_stmt_perform().
Original patch from Pavel Stehule, reworked by Neil Conway.
constraint while determining whether the index sort order matches the
query's ORDER BY. This for example allows an index on (x,y) to match
... WHERE x = 42 ORDER BY y;
It only works for btree indexes, but since those are the only ones we
currently have that are ordered at all, that's good enough for now.
Per popular demand.
nonconsecutive columns of a multicolumn index, as per discussion around
mid-May (pghackers thread "Best way to scan on-disk bitmaps"). This
turns out to require only minimal changes in btree, and so far as I can
see none at all in GiST. btcostestimate did need some work, but its
original assumption that index selectivity == heap selectivity was
quite bogus even before this.
mode to only affect the presentation of normal query results, not the
output of psql slash commands. Documentation updated. I also made
some unrelated minor psql cleanup. Per suggestion from Stuart Cooper.
a descriptor that uses the current transaction snapshot, rather than
SnapshotNow as it did before (and still does if INV_WRITE is set).
This means pg_dump will now dump a consistent snapshot of large object
contents, as it never could do before. Also, add a lo_create() function
that is similar to lo_creat() but allows the desired OID of the large
object to be specified. This will simplify pg_restore considerably
(but I'll fix that in a separate commit).
syntax for database connection parameters. It has been inside an
#ifdef NOT_USED block since 2001 or so and is marked as "broken", so
I don't think it is likely to be rehabilitated any time soon.
patch adds missing checks to the call sites of malloc(), strdup(),
PQmakeEmptyPGresult(), pqResultAlloc(), and pqResultStrdup(), and updates
the documentation. Per original report from Volkan Yazici about
PQmakeEmptyPGresult() not checking for malloc() failure.
These contain the SQLSTATE and error message of the current exception,
respectively. They are scope-local variables that are only defined
in exception handlers (so attempting to reference them outside an
exception handler is an error). Update the regression tests and the
documentation.
Also, do some minor related cleanup: export an unpack_sql_state()
function from the backend and use it to unpack a SQLSTATE into a
string, and add a free_var() function to pl_exec.c
Original patch from Pavel Stehule, review by Neil Conway.
history customizable through a variable named HISTFILE, analogous to
psql's already implemented HISTCONTROL and HISTSIZE variables, and
bash's HISTFILE-Variable.
The motivation was to be able to get psql to maintain separate
histories for separate databases. This is now easily achievable
through a line like the following in ~/.psqlrc:
\set HISTFILE ~/.psql_history-:DBNAME
Andreas Seltenreich
to a subquery if the outer query is simple enough that the LIMIT can
be reflected directly to the subquery. This didn't use to be very
interesting, because a subquery that couldn't have been flattened into
the upper query was usually not going to be very responsive to
tuple_fraction anyway. But with new code that allows UNION ALL subqueries
to pay attention to tuple_fraction, this is useful to do. In particular
this lets the optimization occur when the UNION ALL is directly inside
a view.
