regular qpqual ('filter condition'), add special-purpose code to
nodeIndexscan.c to recheck them. This ends being almost no net addition
of code, because the removal of planner code balances out the extra
executor code, but it is significantly more efficient when a lossy
operator is involved in an OR indexscan. The old implementation had
to recheck the entire indexqual in such cases.
with index qual clauses in the Path representation. This saves a little
work during createplan and (probably more importantly) allows reuse of
cached selectivity estimates during indexscan planning. Also fix latent
bug: wrong plan would have been generated for a 'special operator' used
in a nestloop-inner-indexscan join qual, because the special operator
would not have gotten into the list of quals to recheck. This bug is
only latent because at present the special-operator code could never
trigger on a join qual, but sooner or later someone will want to do it.
join conditions in which each OR subclause includes a constraint on
the same relation. This implements the other useful side-effect of
conversion to CNF format, without its unpleasant side-effects. As
per pghackers discussion of a few weeks ago.
run the data through cpp, and we know of at least one platform where
unusual cpp behavior breaks the process. So remove the cpp step,
and make consequent simplifications.
teaching the latter to accept either RestrictInfo nodes or bare
clause expressions; and cache the selectivity result in the RestrictInfo
node when possible. This extends the caching behavior of approx_selectivity
to many more contexts, and should reduce duplicate selectivity
calculations.
first time generate an OR indexscan for a two-column index when the WHERE
condition is like 'col1 = foo AND (col2 = bar OR col2 = baz)' --- before,
the OR had to be on the first column of the index or we'd not notice the
possibility of using it. Some progress towards extracting OR indexscans
from subclauses of an OR that references multiple relations, too, although
this code is #ifdef'd out because it needs more work.
fields: now they are valid whenever the clause is a binary opclause,
not only when it is a potential join clause (there is a new boolean
field canjoin to signal the latter condition). This lets us avoid
recomputing the relid sets over and over while examining indexes.
Still more work to do to make this as useful as it could be, because
there are places that could use the info but don't have access to the
RestrictInfo node.
just look for common clauses that can be pulled out of ORs. Per recent
discussion, extracting common clauses seems to be the only really useful
effect of normalization, and if we do it explicitly then we can avoid
cluttering the qual with partially-redundant duplicated expressions, which
was an unpleasant side-effect of the old approach.
call. You'd think this would cause some problems, but because of the
way hash_create is coded, the only side-effect was creation of a useless
memory context for the hashtable.
conditions is overkill; set_union() does the job about as well, and
much more efficiently. Furthermore this avoids assuming that
canonicalize_qual() will check for duplicate clauses at all, which
it may not always do.
showed that for common operator names such as '=', the pallocs done by
this routine occupied a surprisingly large fraction of the total time
for the parser to process an operator.
about whether it is applied before or after eval_const_expressions().
I believe there were some corner cases where the system would fail to
recognize that a partial index is applicable because of the previous
inconsistency. Store normal rather than 'implicit AND' representations
of constraints and index predicates in the catalogs.
initdb forced due to representation change of constraints/predicates.
instruction in the s_lock() wait loop, and use test before test-and-set
in TAS() macro to avoid unnecessary bus traffic. Patch from Manfred
Spraul, reworked a bit by Tom.
special meaning of these terms in pg_hba.conf.
Also changes ugly pg_hba.conf IPv6 netmask of
ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff to ::1/128.
Andrew Dunstan
> > needed, and other people in the past asked about it too.
>
> It is in Oracle, but you aren't exactly on the spot. It should be
>
> IYYY - 4 digits ('2003')
> IYY - 3 digits ('003')
> IY - 2 digits ('03')
> I - 1 digit ('3')
Here is an updated patch that does that.
Kurt Roeckx
Tom Lane
Neil Conway
Peter Eisentraut
Bruce Momjian
Michael Meskes