takes two parameters, an OID x and an integer y, and returns "true" with
probability 1/y (the OID argument is ignored). This can be useful -- for
example, it can be used to select a random sampling of the rows in a
table (which is what the "random" regression test uses it for).
This patch removes that function, because it was old and messy. The old
function had the following problems:
- it was undocumented
- it was poorly named
- it was designed to workaround an optimizer bug that no longer exists
(the OID argument is to ensure that the optimizer won't optimize away
calls to the function; AFAIK marking the function as 'volatile' suffices
nowadays)
- it used a different random-number generation technique than the other
PSRNG-related functions in the backend do (it called random() like they
do, but it had its own logic for setting a set and deciding when to
reseed the RNG).
Ok, this patch removes oidrand(), oidsrand(), and userfntest(), and
improves the SGML docs a little bit (un-commenting the setseed()
documentation).
Neil Conway
expression accepted by the regex operators, per discussion yesterday.
Along the way, reduce deadlock_timeout from PGC_POSTMASTER to PGC_SIGHUP
category. It is probably best to insist that all backends share the same
setting, but that doesn't mean it has to be frozen at startup.
startup, not in the parser; this allows ALTER DOMAIN to work correctly
with domain constraint operations stored in rules. Rod Taylor;
code review by Tom Lane.
value of MAX_TIME_PRECISION in floating-point-timestamp-storage case
from 13 to 10, which is as much as time_out is actually willing to print.
(The alternative of increasing the number of digits we are willing to
print looks risky; we might find ourselves printing roundoff garbage.)
passed to join selectivity estimators. Make use of this in eqjoinsel
to derive non-bogus selectivity for IN clauses. Further tweaking of
cost estimation for IN.
initdb forced because of pg_proc.h changes.
There are two implementation techniques: the executor understands a new
JOIN_IN jointype, which emits at most one matching row per left-hand row,
or the result of the IN's sub-select can be fed through a DISTINCT filter
and then joined as an ordinary relation.
Along the way, some minor code cleanup in the optimizer; notably, break
out most of the jointree-rearrangement preprocessing in planner.c and
put it in a new file prep/prepjointree.c.
datetime token tables. Even more embarrassing, the regression tests
revealed some of the problems --- but evidently the bogus output wasn't
questioned. Add code to postmaster startup to directly check the tables
for correct ordering, in hopes of not being embarrassed like this again.
containing a volatile function), rather than only on 'Var = Var' clauses
as before. This makes it practical to do flatten_join_alias_vars at the
start of planning, which in turn eliminates a bunch of klugery inside the
planner to deal with alias vars. As a free side effect, we now detect
implied equality of non-Var expressions; for example in
SELECT ... WHERE a.x = b.y and b.y = 42
we will deduce a.x = 42 and use that as a restriction qual on a. Also,
we can remove the restriction introduced 12/5/02 to prevent pullup of
subqueries whose targetlists contain sublinks.
Still TODO: make statistical estimation routines in selfuncs.c and costsize.c
smarter about expressions that are more complex than plain Vars. The need
for this is considerably greater now that we have to be able to estimate
the suitability of merge and hash join techniques on such expressions.
practice of evaluating MemSet's arguments multiple times, except for
the special case of newNode(), where we can assume the argument is
a constant sizeof() operator.
Also, add GetMemoryChunkContext() to mcxt.c's API, in preparation for
fixing recent GEQO breakage.
given any malloc block until something is first allocated in it; but
thereafter, MemoryContextReset won't release that first malloc block.
This preserves the quick-reset property of the original policy, without
forcing 8K to be allocated to every context whether any of it is ever
used or not. Also, remove some more no-longer-needed explicit freeing
during ExecEndPlan.
execution state trees, and ExecEvalExpr takes an expression state tree
not an expression plan tree. The plan tree is now read-only as far as
the executor is concerned. Next step is to begin actually exploiting
this property.
documentation and regression test mods. It seemed small and unobtrusive enough
to not require a specific proposal on the hackers list -- but if not, let me
know and I'll make a pitch. Otherwise, if there are no objections please apply.
Joe Conway
to plan nodes, not vice-versa. All executor state nodes now inherit from
struct PlanState. Copying of plan trees has been simplified by not
storing a list of SubPlans in Plan nodes (eliminating duplicate links).
The executor still needs such a list, but it can build it during
ExecutorStart since it has to scan the plan tree anyway.
No initdb forced since no stored-on-disk structures changed, but you
will need a full recompile because of node-numbering changes.
('SELECT expression') inline, like macros, during the constant-folding
phase of planning. The actual expansion is not difficult, but checking
that we're not changing the semantics of the call turns out to be more
subtle than one might think; in particular must pay attention to
permissions issues, strictness, and volatility.
-hackers a couple days ago.
Notes/caveats:
- added regression tests for the new functionality, all
regression tests pass on my machine
- added pg_dump support
- updated PL/PgSQL to support per-statement triggers; didn't
look at the other procedural languages.
- there's (even) more code duplication in trigger.c than there
was previously. Any suggestions on how to refactor the
ExecXXXTriggers() functions to reuse more code would be
welcome -- I took a brief look at it, but couldn't see an
easy way to do it (there are several subtly-different
versions of the code in question)
- updated the documentation. I also took the liberty of
removing a big chunk of duplicated syntax documentation in
the Programmer's Guide on triggers, and moving that
information to the CREATE TRIGGER reference page.
- I also included some spelling fixes and similar small
cleanups I noticed while making the changes. If you'd like
me to split those into a separate patch, let me know.
Neil Conway
of groups produced by GROUP BY. This improves the accuracy of planning
estimates for grouped subselects, and is needed to check whether a
hashed aggregation plan risks memory overflow.
precision for float4, float8, and geometric types. Set it in pg_dump
so that float data can be dumped/reloaded exactly (at least on platforms
where the float I/O support is properly implemented). Initial patch by
Pedro Ferreira, some additional work by Tom Lane.
now)" item on the open items, and subsequent plpgsql function I sent in,
made me realize it was too hard to get the upper and lower bound of an
array. The attached creates two functions that I think will be very
useful when combined with the ability of plpgsql to return sets.
array_lower(array, dim_num)
- and -
array_upper(array, dim_num)
They return the value (as an int) of the upper and lower bound of the
requested dim in the provided array.
Joe Conway
where it's safe to do database access. Along the way, fix core dump
for 'DEFAULT' parameters to CREATE DATABASE. initdb forced due to
change in pg_proc entry.
Ray Ontko 28-June-02. Also, fix prefix_selectivity for NAME lefthand
variables (it was bogusly assuming binary compatibility), and adjust
make_greater_string() to not call pg_mbcliplen() with invalid multibyte
data (this last per bug report that I can't find at the moment, but it
was in July '02).
specifically ceil(), floor(), and sign(). There may be other functions
that need to be added, but this is a start. I've included some simple
regression tests.
Neil Conway
so that precision of result is always at least as good as you'd get from
float8 arithmetic (ie, always at least 16 digits of accuracy). Per
pg_hackers discussion a few days ago.
the SQL99 standard. (I'm not sure that the character-class features are
quite right, but that can be fixed later.) Document SQL99 and POSIX
regexps as being different features; provide variants of SUBSTRING for
each.
composite types. Add a couple more lsyscache.c routines to support this,
and make use of them in some other places that were doing lookups the
hard way.
ruleutils display is not such a great idea. For arguments of functions
and operators I think we'd better keep the historical behavior of showing
such casts explicitly, to ensure that the function/operator is reparsed
the same way when the rule is reloaded. This also makes the output of
EXPLAIN less obscurantist about exactly what's happening.
to be flexible about assignment casts without introducing ambiguity in
operator/function resolution. Introduce a well-defined promotion hierarchy
for numeric datatypes (int2->int4->int8->numeric->float4->float8).
Change make_const to initially label numeric literals as int4, int8, or
numeric (never float8 anymore).
Explicitly mark Func and RelabelType nodes to indicate whether they came
from a function call, explicit cast, or implicit cast; use this to do
reverse-listing more accurately and without so many heuristics.
Explicit casts to char, varchar, bit, varbit will truncate or pad without
raising an error (the pre-7.2 behavior), while assigning to a column without
any explicit cast will still raise an error for wrong-length data like 7.3.
This more nearly follows the SQL spec than 7.2 behavior (we should be
reporting a 'completion condition' in the explicit-cast cases, but we have
no mechanism for that, so just do silent truncation).
Fix some problems with enforcement of typmod for array elements;
it didn't work at all in 'UPDATE ... SET array[n] = foo', for example.
Provide a generalized array_length_coerce() function to replace the
specialized per-array-type functions that used to be needed (and were
missing for NUMERIC as well as all the datetime types).
Add missing conversions int8<->float4, text<->numeric, oid<->int8.
initdb forced.
> src/backend/optimizer/path/indxpath.c; see the "special indexable
> operators" stuff near the bottom of that file. (It's a bit of a crock
> that this code is hardwired there, and not somehow accessed through a
> system catalog, but it's what we've got at the moment.)
The attached patch re-enables a bytea right hand argument (as compared
to a text right hand argument), and enables index usage, for bytea LIKE
Joe Conway
pointed out by Barry Lind: UPDATE bigintcol = 10000000000 fails because
the constant is initially taken as float8. We really need a better way,
but it's not gonna happen for 7.3.
Also, remove int4reltime() function, which is redundant with the
existing binary-compatibility coercion path from int4 to reltime,
and probably has been unreachable code for a long while.
type for runtime constraint checks, instead of misusing the parse-time
Constraint node for the purpose. Fix some damage introduced into type
coercion logic; in particular ensure that a coerced expression tree will
read out the correct result type when inspected (patch had broken some
RelabelType cases). Enforce domain NOT NULL constraints against columns
that are omitted from an INSERT.
