and anti joins. To do this, pass the SpecialJoinInfo struct for the current
join as an additional optional argument to operator join selectivity
estimation functions. This allows the estimator to tell not only what kind
of join is being formed, but which variable is on which side of the join;
a requirement long recognized but not dealt with till now. This also leaves
the door open for future improvements in the estimators, such as accounting
for the null-insertion effects of lower outer joins. I didn't do anything
about that in the current patch but the information is in principle deducible
from what's passed.
The patch also clarifies the definition of join selectivity for semi/anti
joins: it's the fraction of the left input that has (at least one) match
in the right input. This allows getting rid of some very fuzzy thinking
that I had committed in the original 7.4-era IN-optimization patch.
There's probably room to estimate this better than the present patch does,
but at least we know what to estimate.
Since I had to touch CREATE OPERATOR anyway to allow a variant signature
for join estimator functions, I took the opportunity to add a couple of
additional checks that were missing, per my recent message to -hackers:
* Check that estimator functions return float8;
* Require execute permission at the time of CREATE OPERATOR on the
operator's function as well as the estimator functions;
* Require ownership of any pre-existing operator that's modified by
the command.
I also moved the lookup of the functions out of OperatorCreate() and
into operatorcmds.c, since that seemed more consistent with most of
the other catalog object creation processes, eg CREATE TYPE.
the old JOIN_IN code, but antijoins are new functionality.) Teach the planner
to convert appropriate EXISTS and NOT EXISTS subqueries into semi and anti
joins respectively. Also, LEFT JOINs with suitable upper-level IS NULL
filters are recognized as being anti joins. Unify the InClauseInfo and
OuterJoinInfo infrastructure into "SpecialJoinInfo". With that change,
it becomes possible to associate a SpecialJoinInfo with every join attempt,
which permits some cleanup of join selectivity estimation. That needs to be
taken much further than this patch does, but the next step is to change the
API for oprjoin selectivity functions, which seems like material for a
separate patch. So for the moment the output size estimates for semi and
especially anti joins are quite bogus.
as per my recent proposal:
1. Fold SortClause and GroupClause into a single node type SortGroupClause.
We were already relying on them to be struct-equivalent, so using two node
tags wasn't accomplishing much except to get in the way of comparing items
with equal().
2. Add an "eqop" field to SortGroupClause to carry the associated equality
operator. This is cheap for the parser to get at the same time it's looking
up the sort operator, and storing it eliminates the need for repeated
not-so-cheap lookups during planning. In future this will also let us
represent GROUP/DISTINCT operations on datatypes that have hash opclasses
but no btree opclasses (ie, they have equality but no natural sort order).
The previous representation simply didn't work for that, since its only
indicator of comparison semantics was a sort operator.
3. Add a hasDistinctOn boolean to struct Query to explicitly record whether
the distinctClause came from DISTINCT or DISTINCT ON. This allows removing
some complicated and not 100% bulletproof code that attempted to figure
that out from the distinctClause alone.
This patch doesn't in itself create any new capability, but it's necessary
infrastructure for future attempts to use hash-based grouping for DISTINCT
and UNION/INTERSECT/EXCEPT.
with system catalog lookups, as was foreseen to be necessary almost since
their creation. Instead put the information into two new pg_type columns,
typcategory and typispreferred. Add support for setting these when
creating a user-defined base type.
The category column is just a "char" (i.e. a poor man's enum), allowing
a crude form of user extensibility of the category list: just use an
otherwise-unused character. This seems sufficient for foreseen uses,
but we could upgrade to having an actual category catalog someday, if
there proves to be a huge demand for custom type categories.
In this patch I have attempted to hew exactly to the behavior of the
previous hardwired logic, except for introducing new type categories for
arrays, composites, and enums. In particular the default preferred state
for user-defined types remains TRUE. That seems worth revisiting, but it
should be done as a separate patch from introducing the infrastructure.
Likewise, any adjustment of the standard set of categories should be done
separately.
default_reloptions(). The previous coding was really a bug because pg_atoi()
will always throw elog on bad input data, whereas default_reloptions is not
supposed to complain about bad input unless its validate parameter is true.
Right now you could only expose the problem by hand-modifying
pg_class.reloptions into an invalid state, so it doesn't seem worth
back-patching; but we should get it right in HEAD because there might be other
situations in future. Noted while studying GIN fast-update patch.
a portal are never NULL, but reliably provide the source text of the query.
It turns out that there was only one place that was really taking a short-cut,
which was the 'EXECUTE' utility statement. That doesn't seem like a
sufficiently critical performance hotspot to justify not offering a guarantee
of validity of the portal source text. Fix it to copy the source text over
from the cached plan. Add Asserts in the places that set up cached plans and
portals to reject null source strings, and simplify a bunch of places that
formerly needed to guard against nulls.
There may be a few places that cons up statements for execution without
having any source text at all; I found one such in ConvertTriggerToFK().
It seems sufficient to inject a phony source string in such a case,
for instance
ProcessUtility((Node *) atstmt,
"(generated ALTER TABLE ADD FOREIGN KEY command)",
NULL, false, None_Receiver, NULL);
We should take a second look at the usage of debug_query_string,
particularly the recently added current_query() SQL function.
ITAGAKI Takahiro and Tom Lane
warnings. Clean up various unneeded cruft that was left behind after
creating those routines. Introduce some convenience functions str_tolower_z
etc to eliminate tedious and error-prone double arguments in formatting.c.
(Currently there seems no need to export the latter, but maybe reconsider
this later.)
corresponding struct definitions. This allows other headers to avoid including
certain highly-loaded headers such as rel.h and relscan.h, instead using just
relcache.h, heapam.h or genam.h, which are more lightweight and thus cause less
unnecessary dependencies.
int2-and-int8 implementations of the basic arithmetic operators +, -, *, /.
This doesn't really add any new functionality, but it avoids "operator is not
unique" failures that formerly occurred in these cases because the parser
couldn't decide whether to promote the int2 to int4 or int8. We could
alternatively have removed the existing cross-type operators, but
experimentation shows that the cost of an additional type coercion expression
node is noticeable compared to such cheap operators; so let's not give up any
performance here. On the other hand, I removed the int2-and-int4 modulo (%)
operators since they didn't seem as important from a performance standpoint.
Per a complaint last January from ykhuang.
the associated datatype as their equality member. This means that these
opclasses can now support plain equality comparisons along with LIKE tests,
thus avoiding the need for an extra index in some applications. This
optimization was not possible when the pattern opclasses were first introduced,
because we didn't insist that text equality meant bitwise equality; but we
do now, so there is no semantic difference between regular and pattern
equality operators.
I removed the name_pattern_ops opclass altogether, since it's really useless:
name's regular comparisons are just strcmp() and are unlikely to become
something different. Instead teach indxpath.c that btree name_ops can be
used for LIKE whether or not the locale is C. This might lead to a useful
speedup in LIKE queries on the system catalogs in non-C locales.
The ~=~ and ~<>~ operators are gone altogether. (It would have been nice to
keep them for backward compatibility's sake, but since the pg_amop structure
doesn't allow multiple equality operators per opclass, there's no way.)
A not-immediately-obvious incompatibility is that the sort order within
bpchar_pattern_ops indexes changes --- it had been identical to plain
strcmp, but is now trailing-blank-insensitive. This will impact
in-place upgrades, if those ever happen.
Per discussions a couple months ago.
There are two ways to track a snapshot: there's the "registered" list, which
is used for arbitrary long-lived snapshots; and there's the "active stack",
which is used for the snapshot that is considered "active" at any time.
This also allows users of snapshots to stop worrying about snapshot memory
allocation and freeing, and about using PG_TRY blocks around ActiveSnapshot
assignment. This is all done automatically now.
As a consequence, this allows us to reset MyProc->xmin when there are no
more snapshots registered in the current backend, reducing the impact that
long-running transactions have on VACUUM.
unnecessary #include lines in it. Also, move some tuple routine prototypes and
macros to htup.h, which allows removal of heapam.h inclusion from some .c
files.
For this to work, a new header file access/sysattr.h needed to be created,
initially containing attribute numbers of system columns, for pg_dump usage.
While at it, make contrib ltree, intarray and hstore header files more
consistent with our header style.
to avoid the pain of manually renumbering them anytime we insert another
name in alphabetical order. An excellent idea from Alex Hunsaker and
NikhilS' inherited-constraints patch --- whether or not the rest of that
gets in, this should. Dunno why we never thought of it before.
where Datum is 8 bytes wide. Since this will break old-style C functions
(those still using version 0 calling convention) that have arguments or
results of these types, provide a configure option to disable it and retain
the old pass-by-reference behavior. Likewise, provide a configure option
to disable the recently-committed float4 pass-by-value change.
Zoltan Boszormenyi, plus configurability stuff by me.
of each plan node, instead of its former behavior of dumping the internal
representation of the plan tree. The latter display is still available for
those who really want it (see debug_print_plan), but uses for it are certainly
few and and far between. Per discussion.
This patch also removes the explain_pretty_print GUC, which is obsoleted
by the change.
corrupted. (Neither is very important if SIGTERM is used to shut down the
whole database cluster together, but there's a problem if someone tries to
SIGTERM individual backends.) To do this, introduce new infrastructure
macros PG_ENSURE_ERROR_CLEANUP/PG_END_ENSURE_ERROR_CLEANUP that take care
of transiently pushing an on_shmem_exit cleanup hook. Also use this method
for createdb cleanup --- that wasn't a shared-memory-corruption problem,
but SIGTERM abort of createdb could leave orphaned files lying around.
Backpatch as far as 8.2. The shmem corruption cases don't exist in 8.1,
and the createdb usage doesn't seem important enough to risk backpatching
further.
no particular need to do get_op_opfamily_properties() while building an
indexscan plan. Postpone that lookup until executor start. This simplifies
createplan.c a lot more than it complicates nodeIndexscan.c, and makes things
more uniform since we already had to do it that way for RowCompare
expressions. Should be a bit faster too, at least for plans that aren't
re-used many times, since we avoid palloc'ing and perhaps copying the
intermediate list data structure.
indexscan always occurs in one call, and the results are returned in a
TIDBitmap instead of a limited-size array of TIDs. This should improve
speed a little by reducing AM entry/exit overhead, and it is necessary
infrastructure if we are ever to support bitmap indexes.
In an only slightly related change, add support for TIDBitmaps to preserve
(somewhat lossily) the knowledge that particular TIDs reported by an index
need to have their quals rechecked when the heap is visited. This facility
is not really used yet; we'll need to extend the forced-recheck feature to
plain indexscans before it's useful, and that hasn't been coded yet.
The intent is to use it to clean up 8.3's horrid @@@ kluge for text search
with weighted queries. There might be other uses in future, but that one
alone is sufficient reason.
Heikki Linnakangas, with some adjustments by me.
algorithm. This is a good deal slower than our old roundoff-error-prone
code for long inputs, so we keep the old code for use in the transcendental
functions, where everything is approximate anyway. Also create a
user-accessible function div(numeric, numeric) to provide access to the
exact result of trunc(x/y) --- since the regular numeric / operator will
round off its result, simply computing that expression in SQL doesn't
reliably give the desired answer. This fixes bug #3387 and various related
corner cases, and improves the usefulness of PG for high-precision integer
arithmetic.
snapmgmt.c file for the former. The header files have also been reorganized
in three parts: the most basic snapshot definitions are now in a new file
snapshot.h, and the also new snapmgmt.h keeps the definitions for snapmgmt.c.
tqual.h has been reduced to the bare minimum.
This patch is just a first step towards managing live snapshots within a
transaction; there is no functionality change.
Per my proposal to pgsql-patches on 20080318191940.GB27458@alvh.no-ip.org and
subsequent discussion.
strings. This patch introduces four support functions cstring_to_text,
cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and
two macros CStringGetTextDatum and TextDatumGetCString. A number of
existing macros that provided variants on these themes were removed.
Most of the places that need to make such conversions now require just one
function or macro call, in place of the multiple notational layers that used
to be needed. There are no longer any direct calls of textout or textin,
and we got most of the places that were using handmade conversions via
memcpy (there may be a few still lurking, though).
This commit doesn't make any serious effort to eliminate transient memory
leaks caused by detoasting toasted text objects before they reach
text_to_cstring. We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few
places where it was easy, but much more could be done.
Brendan Jurd and Tom Lane
identical to tuplestore_puttuple(), except it operates on arrays of
Datums + nulls rather than a fully-formed HeapTuple. In several places
that use the tuplestore API, this means we can avoid creating a
HeapTuple altogether, saving a copy.
errdetail except the string goes only to the server log, replacing the normal
errdetail there. This provides a reasonably clean way of dealing with error
details that are too security-sensitive or too bulky to send to the client.
This commit just adds the infrastructure --- actual uses to follow.
except that it returns the string 'NULL', rather than a SQL null, when called
with a null argument. This is often a much more useful behavior for
constructing dynamic queries. Add more discussion to the documentation
about how to use these functions.
Brendan Jurd
a new typedef TimeOffset to represent an intermediate time value. It's
either int64 or double as appropriate, and in most usages will be measured
in microseconds or seconds the same as Timestamp. We don't call it
Timestamp, though, since the value doesn't necessarily represent an absolute
time instant.
Warren Turkal
bucket number, so as to ensure locality of access to the index during the
insertion step. Without this, building an index significantly larger than
available RAM takes a very long time because of thrashing. On the other
hand, sorting is just useless overhead when the index does fit in RAM.
We choose to sort when the initial index size exceeds effective_cache_size.
This is a revised version of work by Tom Raney and Shreya Bhargava.
messages if the calling transaction aborts later on. Collapsing out line
pointer redirects is a done deal as soon as we complete the page update,
so syscache *must* be notified even if the VACUUM FULL as a whole doesn't
complete. To fix, add some functionality to inval.c to allow the pending
inval messages to be sent immediately while heap_page_prune is still
running. The implementation is a bit chintzy: it will only work in the
context of VACUUM FULL. But that's all we need now, and it can always be
extended later if needed. Per my trouble report of a week ago.
variables to it. More need to be converted, but I wanted to get this in
before it conflicts with too much...
Other than just centralising the text-to-int conversion for parameters,
this allows the pg_settings view to contain a list of available options
and allows an error hint to show what values are allowed.
pattern-examination heuristic method to purely histogram-driven selectivity at
histogram size 100, we compute both estimates and use a weighted average.
The weight put on the heuristic estimate decreases linearly with histogram
size, dropping to zero for 100 or more histogram entries.
Likewise in ltreeparentsel(). After a patch by Greg Stark, though I
reorganized the logic a bit to give the caller of histogram_selectivity()
more control.
were discussed last year, but we felt it was too late in the 8.3 cycle to
change the code immediately. Specifically, the patch:
* Reduces the minimum datum size to be considered for compression from
256 to 32 bytes, as suggested by Greg Stark.
* Increases the required compression rate for compressed storage from
20% to 25%, again per Greg's suggestion.
* Replaces force_input_size (size above which compression is forced)
with a maximum size to be considered for compression. It was agreed
that allowing large inputs to escape the minimum-compression-rate
requirement was not bright, and that indeed we'd rather have a knob
that acted in the other direction. I set this value to 1MB for the
moment, but it could use some performance studies to tune it.
* Adds an early-failure path to the compressor as suggested by Jan:
if it's been unable to find even one compressible substring in the
first 1KB (parameterizable), assume we're looking at incompressible
input and give up. (Possibly this logic can be improved, but I'll
commit it as-is for now.)
* Improves the toasting heuristics so that when we have very large
fields with attstorage 'x' or 'e', we will push those out to toast
storage before considering inline compression of shorter fields.
This also responds to a suggestion of Greg's, though my original
proposal for a solution was a bit off base because it didn't fix
the problem for large 'e' fields.
There was some discussion in the earlier threads of exposing some
of the compression knobs to users, perhaps even on a per-column
basis. I have not done anything about that here. It seems to me
that if we are changing around the parameters, we'd better get some
experience and be sure we are happy with the design before we set
things in stone by providing user-visible knobs.
represented as "char ...[4]" not "int32". Since the length word is never
supposed to be accessed via this struct member anyway, this won't break
any existing code that is following the rules. The advantage is that C
compilers will no longer assume that a pointer to struct varlena is
word-aligned, which prevents incorrect optimizations in TOAST-pointer
access and perhaps other places. gcc doesn't seem to do this (at least
not at -O2), but the problem is demonstrable on some other compilers.
I changed struct inet as well, but didn't bother to touch a lot of other
struct definitions in which it wouldn't make any difference because there
were other fields forcing int alignment anyway. Hopefully none of those
struct definitions are used for accessing unaligned Datums.
data structures and backend internal APIs. This solves problems we've seen
recently with inconsistent layout of pg_control between machines that have
32-bit time_t and those that have already migrated to 64-bit time_t. Also,
we can get out from under the problem that Windows' Unix-API emulation is not
consistent about the width of time_t.
There are a few remaining places where local time_t variables are used to hold
the current or recent result of time(NULL). I didn't bother changing these
since they do not affect any cross-module APIs and surely all platforms will
have 64-bit time_t before overflow becomes an actual risk. time_t should
be avoided for anything visible to extension modules, however.
TimestampTzPlusMilliseconds. An integer argument of more than INT_MAX/1000
milliseconds (ie, about 35 minutes) would provoke a wrong result, resulting
in incorrect enforcement of statement_timestamp values larger than that.
Bug was introduced in my rewrite of 2006-06-20, which fixed some other
overflow risks, but missed this one :-( Per report from Elein.
in whichever context happens to be current during a call of an xml.c function,
use a dedicated context that will not go away until we explicitly delete it
(which we do at transaction end or subtransaction abort). This makes recovery
after an error much simpler --- we don't have to individually delete the data
structures created by libxml. Also, we need to initialize and cleanup libxml
only once per transaction (if there's no error) instead of once per function
call, so it should be a bit faster. We'll need to keep an eye out for
intra-transaction memory leaks, though. Alvaro and Tom.
were reporting ERROR for interactive assignments and LOG for other cases,
some were saying nothing for non-interactive cases, and a few did yet other
things. Make them use a new function GUC_complaint_elevel() to establish
a reasonably uniform policy about how to report. There are still a few
edge cases such as assign_search_path(), but it's much better than before.
Per gripe from Devrim Gunduz and subsequent discussion.
As noted by Alvaro, it'd be better to fold these custom messages into the
standard "invalid parameter value" complaint from guc.c, perhaps as the DETAIL
field. However that will require more redesign than seems prudent for 8.3.
This is a relatively safe, low-impact change that we can afford to risk now.
the two join variables at both ends: not only trailing rows that need not be
scanned because there cannot be a match on the other side, but initial rows
that will be scanned without possibly having a match. This allows a more
realistic estimate of startup cost to be made, per recent pgsql-performance
discussion. In passing, fix a couple of bugs that had crept into
mergejoinscansel: it was not quite up to speed for the task of estimating
descending-order scans, which is a new requirement in 8.3.
constraint status of copied indexes (bug #3774), as well as various other
small bugs such as failure to pstrdup when needed. Allow INCLUDING INDEXES
indexes to be merged with identical declared indexes (perhaps not real useful,
but the code is there and having it not apply to LIKE indexes seems pretty
unorthogonal). Avoid useless work in generateClonedIndexStmt(). Undo some
poorly chosen API changes, and put a couple of routines in modules that seem
to be better places for them.
make_greater_string() try harder to generate a string that's actually greater
than its input string. Before we just assumed that making a string that was
memcmp-greater was enough, but it is easy to generate examples where this is
not so when the locale is not C. Instead, loop until the relevant comparison
function agrees that the generated string is greater than the input.
Unfortunately this is probably not enough to guarantee that the generated
string is greater than all extensions of the input, so we cannot relax the
restriction to C locale for the LIKE/regex index optimization. But it should
at least improve the odds of getting a useful selectivity estimate in
prefix_selectivity(). Per example from Guillaume Smet.
Backpatch to 8.1, mainly because that's what the complainant is using...
it affects. The original coding neglected tablespace entirely (causing
the indexes to move to the database's default tablespace) and for an index
belonging to a UNIQUE or PRIMARY KEY constraint, it would actually try to
assign the parent table's reloptions to the index :-(. Per bug #3672 and
subsequent investigation.
8.0 and 8.1 did not have reloptions, but the tablespace bug is present.
word comes before the weight instead of after. This will allow future
binary-compatible extension of the representation to support compact formats,
as discussed on pgsql-hackers around 2007/06/18. The reason to do it now is
that we've already pretty well broken any chance of simple in-place upgrade
from 8.2 to 8.3, but it's possible that 8.3 to 8.4 (or whenever we get around
to squeezing NUMERIC) could otherwise be data-compatible.
columns, and the new version can be stored on the same heap page, we no longer
generate extra index entries for the new version. Instead, index searches
follow the HOT-chain links to ensure they find the correct tuple version.
In addition, this patch introduces the ability to "prune" dead tuples on a
per-page basis, without having to do a complete VACUUM pass to recover space.
VACUUM is still needed to clean up dead index entries, however.
Pavan Deolasee, with help from a bunch of other people.
database via builtin functions, as recently discussed on -hackers.
chr() now returns a character in the database encoding. For UTF8 encoded databases
the argument is treated as a Unicode code point. For other multi-byte encodings
the argument must designate a strict ascii character, or an error is raised,
as is also the case if the argument is 0.
ascii() is adjusted so that it remains the inverse of chr().
The two argument form of convert() is gone, and the three argument form now
takes a bytea first argument and returns a bytea. To cover this loss three new
functions are introduced:
. convert_from(bytea, name) returns text - converts the first argument from the
named encoding to the database encoding
. convert_to(text, name) returns bytea - converts the first argument from the
database encoding to the named encoding
. length(bytea, name) returns int - gives the length of the first argument in
characters in the named encoding
transaction, unless rolled back or overridden by a SET clause for the same
variable attached to a surrounding function call. Per discussion, these
seem the best semantics. Note that this is an INCOMPATIBLE CHANGE: in 8.0
through 8.2, SET LOCAL's effects disappeared at subtransaction commit
(leading to behavior that made little sense at the SQL level).
I took advantage of the opportunity to rewrite and simplify the GUC variable
save/restore logic a little bit. The old idea of a "tentative" value is gone;
it was a hangover from before we had a stack. Also, we no longer need a stack
entry for every nesting level, but only for those in which a variable's value
actually changed.
and in passing, fix some bogosities dating from the custom_variable_classes
patch. Fix guc-file.l to correctly check changes in custom_variable_classes
that are attempted concurrently with additions/removals of custom variables,
and don't allow the new setting to be applied in advance of checking it.
Clean up messy and undocumented situation for string variables with NULL
boot_val. Fix DefineCustomVariable functions to initialize boot_val
correctly. Prevent find_option from inserting bogus placeholders for custom
variables that are simply inquired about rather than being set.
(Actually, it works as a plain statement too, but I didn't document that
because it seems a bit useless.) Unify VariableResetStmt with
VariableSetStmt, and clean up some ancient cruft in the representation of
same.
There are still some loose ends: I didn't do anything about the SET FROM
CURRENT idea yet, and it's not real clear whether we are happy with the
interaction of SET LOCAL with function-local settings. The documentation
is a bit spartan, too.
the number of rows likely to be produced by a query such as
SELECT * FROM t1 LEFT JOIN t2 USING (key) WHERE t2.key IS NULL;
What this is doing is selecting for t1 rows with no match in t2, and thus
it may produce a significant number of rows even if the t2.key table column
contains no nulls at all. 8.2 thinks the table column's null fraction is
relevant and thus may estimate no rows out, which results in terrible plans
if there are more joins above this one. A proper fix for this will involve
passing much more information about the context of a clause to the selectivity
estimator functions than we ever have. There's no time left to write such a
patch for 8.3, and it wouldn't be back-patchable into 8.2 anyway. Instead,
put in an ad-hoc test to defeat the normal table-stats-based estimation when
an IS NULL test is evaluated at an outer join, and just use a constant
estimate instead --- I went with 0.5 for lack of a better idea. This won't
catch every case but it will catch the typical ways of writing such queries,
and it seems unlikely to make things worse for other queries.
days that was obsolete the moment we had IN (SELECT ...) capability.
It's arguably a security hole since it applied no permissions check to
the table it searched, and since it was never documented anywhere,
removing it seems more appropriate than fixing it.
Oleg Bartunov and Teodor Sigaev, but I did a lot of editorializing,
so anything that's broken is probably my fault.
Documentation is nonexistent as yet, but let's land the patch so we can
get some portability testing done.
that still thought they could set HEAP_XMAX_COMMITTED immediately after
seeing the other transaction commit. Make them use the same logic as
tqual.c does to determine if the hint bit can be set yet.
unwarranted liberties with int8 vs float8 values for these types.
Specifically, be sure to apply either hashint8 or hashfloat8 depending
on HAVE_INT64_TIMESTAMP. Per my gripe of even date.
an array of strings rather than an array of integers, and allow any simple
constant or identifier to be used in typmods; for example
create table foo (f1 widget(42,'23skidoo',point));
Of course the typmodin function has still got to pack this info into a
non-negative int32 for storage, but it's still a useful improvement in
flexibility, especially considering that you can do nearly anything if you
are willing to keep the info in a side table. We can get away with this
change since we have not yet released a version providing user-definable
typmods. Per discussion.
were accepted by prior Postgres releases. This takes care of the loose end
left by the preceding patch to downgrade implicit casts-to-text. To avoid
breaking desirable behavior for array concatenation, introduce a new
polymorphic pseudo-type "anynonarray" --- the added concatenation operators
are actually text || anynonarray and anynonarray || text.
from the other string-category types; this eliminates a lot of surprising
interpretations that the parser could formerly make when there was no directly
applicable operator.
Create a general mechanism that supports casts to and from the standard string
types (text,varchar,bpchar) for *every* datatype, by invoking the datatype's
I/O functions. These new casts are assignment-only in the to-string direction,
explicit-only in the other, and therefore should create no surprising behavior.
Remove a bunch of thereby-obsoleted datatype-specific casting functions.
The "general mechanism" is a new expression node type CoerceViaIO that can
actually convert between *any* two datatypes if their external text
representations are compatible. This is more general than needed for the
immediate feature, but might be useful in plpgsql or other places in future.
This commit does nothing about the issue that applying the concatenation
operator || to non-text types will now fail, often with strange error messages
due to misinterpreting the operator as array concatenation. Since it often
(not always) worked before, we should either make it succeed or at least give
a more user-friendly error; but details are still under debate.
Peter Eisentraut and Tom Lane
a session regardless of the existence of cached plans. The plancache
only needs to be invalidated so that rules affected by the new setting
will be reflected in the new query plans.
Jan
tablespace(s) in which to store temp tables and temporary files. This is a
list to allow spreading the load across multiple tablespaces (a random list
element is chosen each time a temp object is to be created). Temp files are
not stored in per-database pgsql_tmp/ directories anymore, but per-tablespace
directories.
Jaime Casanova and Albert Cervera, with review by Bernd Helmle and Tom Lane.
type. Also, add explicit casts between boolean and text/varchar. Both
of these changes are for conformance with SQL:2003.
Update the regression tests, bump the catversion.
"microsecond" and "millisecond" units were not considered valid input
by themselves, which caused inputs like "1 millisecond" to be rejected
erroneously.
Update the docs, add regression tests, and backport to 8.2 and 8.1
and aborted transactions have different effects; also teach it not to assume
that prepared transactions are always committed.
Along the way, simplify the pgstats API by tying counting directly to
Relations; I cannot detect any redeeming social value in having stats
pointers in HeapScanDesc and IndexScanDesc structures. And fix a few
corner cases in which counts might be missed because the relation's
pgstat_info pointer hadn't been set.
is using mark/restore but not rewind or backward-scan capability. Insert a
materialize plan node between a mergejoin and its inner child if the inner
child is a sort that is expected to spill to disk. The materialize shields
the sort from the need to do mark/restore and thereby allows it to perform
its final merge pass on-the-fly; while the materialize itself is normally
cheap since it won't spill to disk unless the number of tuples with equal
key values exceeds work_mem.
Greg Stark, with some kibitzing from Tom Lane.
- Function renamed to "xpath".
- Function is now strict, per discussion.
- Return empty array in case when XPath expression detects nothing
(previously, NULL was returned in such case), per discussion.
- (bugfix) Work with fragments with prologue: select xpath('/a',
'<?xml version="1.0"?><a /><b />'); // now XML datum is always wrapped
with dummy <x>...</x>, XML prologue simply goes away (if any).
- Some cleanup.
Nikolay Samokhvalov
Some code cleanup and documentation work by myself.
and inet_server_addr() fail if the client connected over a "scoped" IPv6
address. In this case getnameinfo() will return a string ending with
a poorly-standardized "%something" zone specifier, which these functions
try to feed to network_in(), which won't take it. So that we don't lose
functionality altogether, suppress the zone specifier before giving the
string to network_in(). Per report from Brian Hirt.
TODO: probably someday the inet type should support scoped IPv6 addresses,
and then this patch should be reverted.
Backpatch to 8.2 ... is it worth going further?
numerics as "oprcanhash", and make the corresponding system catalog
updates. As a result, hash indexes, hashed aggregation, and hash
joins can now be used with the numeric type. Bump the catversion.
The only tricky aspect to doing this is writing a correct hash
function: it's possible for two Numerics to be equal according to
their equality operator, but have different in-memory bit patterns.
To cope with this, the hash function doesn't consider the Numeric's
"scale" or "sign", and explictly skips any leading or trailing
zeros in the Numeric's digit buffer (the current implementation
should suppress any such zeros, but it seems unwise to rely upon
this). See discussion on pgsql-patches for more details.
and for other compilers, insert a dummy exit() call so that they understand
PG_RE_THROW() doesn't return. Insert fflush(stderr) in ExceptionalCondition,
per recent buildfarm evidence that that might not happen automatically on some
platforms. And const-ify ExceptionalCondition's declaration while at it.
need be returned. We keep a heap of the current best N tuples and sift-up
new tuples into it as we scan the input. For M input tuples this means
only about M*log(N) comparisons instead of M*log(M), not to mention a lot
less workspace when N is small --- avoiding spill-to-disk for large M
is actually the most attractive thing about it. Patch includes planner
and executor support for invoking this facility in ORDER BY ... LIMIT
queries. Greg Stark, with some editorialization by moi.
isn't any place to throw the error to. If so, we should treat the error
as FATAL, just as we would have if it'd been thrown outside the PG_TRY
block to begin with.
Although this is clearly a *potential* source of bugs, it is not clear
at the moment whether it is an *actual* source of bugs; there may not
presently be any PG_TRY blocks in code that can be reached with no outer
longjmp catcher. So for the moment I'm going to be conservative and not
back-patch this. The change breaks ABI for users of PG_RE_THROW and hence
might create compatibility problems for loadable modules, so we should not
put it into released branches without proof that it's needed.
from time_t to TimestampTz representation. This provides full gettimeofday()
resolution of the timestamps, which might be useful when attempting to
do point-in-time recovery --- previously it was not possible to specify
the stop point with sub-second resolution. But mostly this is to get
rid of TimestampTz-to-time_t conversion overhead during commit. Per my
proposal of a day or two back.
messages to the stats collector. This avoids the problem that enabling
stats_row_level for autovacuum has a significant overhead for short
read-only transactions, as noted by Arjen van der Meijden. We can avoid
an extra gettimeofday call by piggybacking on the one done for WAL-logging
xact commit or abort (although that doesn't help read-only transactions,
since they don't WAL-log anything).
In my proposal for this, I noted that we could change the WAL log entries
for commit/abort to record full TimestampTz precision, instead of only
time_t as at present. That's not done in this patch, but will be committed
separately.
is in progress on the same hashtable. This seems the least invasive way to
fix the recently-recognized problem that a split could cause the scan to
visit entries twice or (with much lower probability) miss them entirely.
The only field-reported problem caused by this is the "failed to re-find
shared lock object" PANIC in COMMIT PREPARED reported by Michel Dorochevsky,
which was caused by multiply visited entries. However, it seems certain
that mdsync() is vulnerable to missing required fsync's due to missed
entries, and I am fearful that RelationCacheInitializePhase2() might be at
risk as well. Because of that and the generalized hazard presented by this
bug, back-patch all the supported branches.
Along the way, fix pg_prepared_statement() and pg_cursor() to not assume
that the hashtables they are examining will stay static between calls.
This is risky regardless of the newly noted dynahash problem, because
hash_seq_search() has never promised to cope with deletion of table entries
other than the just-returned one. There may be no bug here because the only
supported way to call these functions is via ExecMakeTableFunctionResult()
which will cycle them to completion before doing anything very interesting,
but it seems best to get rid of the assumption. This affects 8.2 and HEAD
only, since those functions weren't there earlier.
a replan. I had originally thought this was not necessary, but the new
SPI facilities create a path whereby queries planned with non-default
options can get into the cache, so it is necessary.
reviewed by Neil Conway. This patch adds the following DDL command
variants: RESET SESSION, RESET TEMP, RESET PLANS, CLOSE ALL, and
DEALLOCATE ALL. RESET SESSION is intended for use by connection
pool software and the like, in order to reset a client session
to something close to its initial state.
Note that while most of these command variants can be executed
inside a transaction block (but are not transaction-aware!),
RESET SESSION cannot. While this is inconsistent, it is intended
to catch programmer mistakes: RESET SESSION in an open transaction
block is probably unintended.
This commit breaks any code that assumes that the mere act of forming a tuple
(without writing it to disk) does not "toast" any fields. While all available
regression tests pass, I'm not totally sure that we've fixed every nook and
cranny, especially in contrib.
Greg Stark with some help from Tom Lane
seen by code inspecting the expression. The best way to do this seems
to be to drop the original representation as a function invocation, and
instead make a special expression node type that represents applying
the element-type coercion function to each array element. In this way
the element function is exposed and will be checked for volatility.
Per report from Guillaume Smet.
A DBA is allowed to create a language in his database if it's marked
"tmpldbacreate" in pg_pltemplate. The factory default is that this is set
for all standard trusted languages, but of course a superuser may adjust
the settings. In service of this, add the long-foreseen owner column to
pg_language; renaming, dropping, and altering owner of a PL now follow
normal ownership rules instead of being superuser-only.
Jeremy Drake, with some editorialization by Tom Lane.
pointer" in every Snapshot struct. This allows removal of the case-by-case
tests in HeapTupleSatisfiesVisibility, which should make it a bit faster
(I didn't try any performance tests though). More importantly, we are no
longer violating portable C practices by assuming that small integers are
distinct from all pointer values, and HeapTupleSatisfiesDirty no longer
has a non-reentrant API involving side-effects on a global variable.
There were a couple of places calling HeapTupleSatisfiesXXX routines
directly rather than through the HeapTupleSatisfiesVisibility macro.
Since these places had to be changed anyway, I chose to make them go
through the macro for uniformity.
Along the way I renamed HeapTupleSatisfiesSnapshot to HeapTupleSatisfiesMVCC
to emphasize that it's only used with MVCC-type snapshots. I was sorely
tempted to rename HeapTupleSatisfiesVisibility to HeapTupleSatisfiesSnapshot,
but forebore for the moment to avoid confusion and reduce the likelihood that
this patch breaks some of the pending patches. Might want to reconsider
doing that later.
search_path that was active when the plan was first made. To do this,
improve namespace.c to support a stack of "override" search path settings
(we must have a stack since nested replan events are entirely possible).
This facility replaces the "special namespace" hack formerly used by
CREATE SCHEMA, and should be able to support per-function search path
settings as well.
and regexp_split_to_table. These functions provide access to the
capture groups resulting from a POSIX regular expression match,
and provide the ability to split a string on a POSIX regular
expression, respectively. Patch from Jeremy Drake; code review by
Neil Conway, additional comments and suggestions from Tom and
Peter E.
This patch bumps the catversion, adds some regression tests,
and updates the docs.
rules to be defined with different, per session controllable, behaviors
for replication purposes.
This will allow replication systems like Slony-I and, as has been stated
on pgsql-hackers, other products to control the firing mechanism of
triggers and rewrite rules without modifying the system catalog directly.
The firing mechanisms are controlled by a new superuser-only GUC
variable, session_replication_role, together with a change to
pg_trigger.tgenabled and a new column pg_rewrite.ev_enabled. Both
columns are a single char data type now (tgenabled was a bool before).
The possible values in these attributes are:
'O' - Trigger/Rule fires when session_replication_role is "origin"
(default) or "local". This is the default behavior.
'D' - Trigger/Rule is disabled and fires never
'A' - Trigger/Rule fires always regardless of the setting of
session_replication_role
'R' - Trigger/Rule fires when session_replication_role is "replica"
The GUC variable can only be changed as long as the system does not have
any cached query plans. This will prevent changing the session role and
accidentally executing stored procedures or functions that have plans
cached that expand to the wrong query set due to differences in the rule
firing semantics.
The SQL syntax for changing a triggers/rules firing semantics is
ALTER TABLE <tabname> <when> TRIGGER|RULE <name>;
<when> ::= ENABLE | ENABLE ALWAYS | ENABLE REPLICA | DISABLE
psql's \d command as well as pg_dump are extended in a backward
compatible fashion.
Jan
uses SPI plans, this finally fixes the ancient gotcha that you can't
drop and recreate a temp table used by a plpgsql function.
Along the way, clean up SPI's API a little bit by declaring SPI plan
pointers as "SPIPlanPtr" instead of "void *". This is cosmetic but
helps to forestall simple programming mistakes. (I have changed some
but not all of the callers to match; there are still some "void *"'s
in contrib and the PL's. This is intentional so that we can see if
anyone's compiler complains about it.)
module and teach PREPARE and protocol-level prepared statements to use it.
In service of this, rearrange utility-statement processing so that parse
analysis does not assume table schemas can't change before execution for
utility statements (necessary because we don't attempt to re-acquire locks
for utility statements when reusing a stored plan). This requires some
refactoring of the ProcessUtility API, but it ends up cleaner anyway,
for instance we can get rid of the QueryContext global.
Still to do: fix up SPI and related code to use the plan cache; I'm tempted to
try to make SQL functions use it too. Also, there are at least some aspects
of system state that we want to ensure remain the same during a replan as in
the original processing; search_path certainly ought to behave that way for
instance, and perhaps there are others.
log_min_messages does; and arrange to suppress the duplicative output
that would otherwise result from log_statement and log_duration messages.
Bruce Momjian and Tom Lane.
Get rid of VARATT_SIZE and VARATT_DATA, which were simply redundant with
VARSIZE and VARDATA, and as a consequence almost no code was using the
longer names. Rename the length fields of struct varlena and various
derived structures to catch anyplace that was accessing them directly;
and clean up various places so caught. In itself this patch doesn't
change any behavior at all, but it is necessary infrastructure if we hope
to play any games with the representation of varlena headers.
Greg Stark and Tom Lane
drill down into subplan targetlists to print the referent expression for an
OUTER or INNER var in an upper plan node. Hence, make it do that always, and
banish the old hack of showing "?columnN?" when things got too complicated.
Along the way, fix an EXPLAIN bug I introduced by suppressing subqueries from
execution-time range tables: get_name_for_var_field() assumed it could look at
rte->subquery to find out the real type of a RECORD var. That doesn't work
anymore, but instead we can look at the input plan of the SubqueryScan plan
node.
storing mostly-redundant Query trees in prepared statements, portals, etc.
To replace Query, a new node type called PlannedStmt is inserted by the
planner at the top of a completed plan tree; this carries just the fields of
Query that are still needed at runtime. The statement lists kept in portals
etc. now consist of intermixed PlannedStmt and bare utility-statement nodes
--- no Query. This incidentally allows us to remove some fields from Query
and Plan nodes that shouldn't have been there in the first place.
Still to do: simplify the execution-time range table; at the moment the
range table passed to the executor still contains Query trees for subqueries.
initdb forced due to change of stored rules.
to_timestamp():
- ID for day-of-week
- IDDD for day-of-year
This makes it possible to convert ISO week dates to and from text
fully represented in either week ('IYYY-IW-ID') or day-of-year
('IYYY-IDDD') format.
I have also added an 'isoyear' field for use with extract / date_part.
Brendan Jurd
equality checks it applies, instead of a random dependence on whatever
operators might be named "=". The equality operators will now be selected
from the opfamily of the unique index that the FK constraint depends on to
enforce uniqueness of the referenced columns; therefore they are certain to be
consistent with that index's notion of equality. Among other things this
should fix the problem noted awhile back that pg_dump may fail for foreign-key
constraints on user-defined types when the required operators aren't in the
search path. This also means that the former warning condition about "foreign
key constraint will require costly sequential scans" is gone: if the
comparison condition isn't indexable then we'll reject the constraint
entirely. All per past discussions.
Along the way, make the RI triggers look into pg_constraint for their
information, instead of using pg_trigger.tgargs; and get rid of the always
error-prone fixed-size string buffers in ri_triggers.c in favor of building up
the RI queries in StringInfo buffers.
initdb forced due to columns added to pg_constraint and pg_trigger.
keeping private state in each backend that has inserted and deleted the same
tuple during its current top-level transaction. This is sufficient since
there is no need to be able to determine the cmin/cmax from any other
transaction. This gets us back down to 23-byte headers, removing a penalty
paid in 8.0 to support subtransactions. Patch by Heikki Linnakangas, with
minor revisions by moi, following a design hashed out awhile back on the
pghackers list.
observe the xmloption.
Reorganize the representation of the XML option in the parse tree and the
API to make it easier to manage and understand.
Add regression tests for parsing back XML expressions.
Hashing for aggregation purposes still needs work, so it's not time to
mark any cross-type operators as hashable for general use, but these cases
work if the operators are so marked by hand in the system catalogs.
that defined in RFC 4122. This patch includes the basic implementation,
plus regression tests. Documentation and perhaps some additional
functionality will come later. Catversion bumped.
Patch from Gevik Babakhani; review from Peter, Tom, and myself.
- Add new SQL command SET XML OPTION (also available via regular GUC) to
control the DOCUMENT vs. CONTENT option in implicit parsing and
serialization operations.
- Subtle corrections in the handling of the standalone property in
xmlroot().
- Allow xmlroot() to work on content fragments.
- Subtle corrections in the handling of the version property in
xmlconcat().
- Code refactoring for producing XML declarations.
FAMILY; and add FAMILY option to CREATE OPERATOR CLASS to allow adding a
class to a pre-existing family. Per previous discussion. Man, what a
tedious lot of cutting and pasting ...
