In nearly all cases, the caller already knows the correct collation, and
in a number of places, the value the caller has handy is more correct than
the default for the type would be. (In particular, this patch makes it
significantly less likely that eval_const_expressions will result in
changing the exposed collation of an expression.) So an internal lookup
is both expensive and wrong.
Ensure that parameter symbols receive collation from the function's
resolved input collation, and fix inlining to behave properly.
BTW, this commit lays about 90% of the infrastructure needed to support
use of argument names in SQL functions. Parsing of parameters is now
done via the parser-hook infrastructure ... we'd just need to supply
a column-ref hook ...
All expression nodes now have an explicit output-collation field, unless
they are known to only return a noncollatable data type (such as boolean
or record). Also, nodes that can invoke collation-aware functions store
a separate field that is the collation value to pass to the function.
This avoids confusion that arises when a function has collatable inputs
and noncollatable output type, or vice versa.
Also, replace the parser's on-the-fly collation assignment method with
a post-pass over the completed expression tree. This allows us to use
a more complex (and hopefully more nearly spec-compliant) assignment
rule without paying for it in extra storage in every expression node.
Fix assorted bugs in the planner's handling of collations by making
collation one of the defining properties of an EquivalenceClass and
by converting CollateExprs into discardable RelabelType nodes during
expression preprocessing.
With this patch, portals, SQL functions, and SPI all agree that there
should be only a CommandCounterIncrement between the queries that are
generated from a single SQL command by rule expansion. Fetching a whole
new snapshot now happens only between original queries. This is equivalent
to the existing behavior of EXPLAIN ANALYZE, and it was judged to be the
best choice since it eliminates one source of concurrency hazards for
rules. The patch should also make things marginally faster by reducing the
number of snapshot push/pop operations.
The patch removes pg_parse_and_rewrite(), which is no longer used anywhere.
There was considerable discussion about more aggressive refactoring of the
query-processing functions exported by postgres.c, but for the moment
nothing more has been done there.
I also took the opportunity to refactor snapmgr.c's API slightly: the
former PushUpdatedSnapshot() has been split into two functions.
Marko Tiikkaja, reviewed by Steve Singer and Tom Lane
The originally committed patch for modifying CTEs didn't interact well
with EXPLAIN, as noted by myself, and also had corner-case problems with
triggers, as noted by Dean Rasheed. Those problems show it is really not
practical for ExecutorEnd to call any user-defined code; so split the
cleanup duties out into a new function ExecutorFinish, which must be called
between the last ExecutorRun call and ExecutorEnd. Some Asserts have been
added to these functions to help verify correct usage.
It is no longer necessary for callers of the executor to call
AfterTriggerBeginQuery/AfterTriggerEndQuery for themselves, as this is now
done by ExecutorStart/ExecutorFinish respectively. If you really need to
suppress that and do it for yourself, pass EXEC_FLAG_SKIP_TRIGGERS to
ExecutorStart.
Also, refactor portal commit processing to allow for the possibility that
PortalDrop will invoke user-defined code. I think this is not actually
necessary just yet, since the portal-execution-strategy logic forces any
non-pure-SELECT query to be run to completion before we will consider
committing. But it seems like good future-proofing.
There were corner cases in which the planner would attempt to inline such
a function, which would result in a failure at runtime due to loss of
information about exactly what the result record type is. Fix by disabling
inlining when the function's recorded result type is RECORD. There might
be some sub-cases where inlining could still be allowed, but this is a
simple and backpatchable fix, so leave refinements for another day.
Per bug #5777 from Nate Carson.
Back-patch to all supported branches. 8.1 happens to avoid a core-dump
here, but it still does the wrong thing.
catalog entries via SearchSysCache and related operations. Although, at the
time that these callbacks are called by elog.c, we have not officially aborted
the current transaction, it still seems rather risky to initiate any new
catalog fetches. In all these cases the needed information is readily
available in the caller and so it's just a matter of a bit of extra notation
to pass it to the callback.
Per crash report from Dennis Koegel. I've concluded that the real fix for
his problem is to clear the error context stack at entry to proc_exit, but
it still seems like a good idea to make the callbacks a bit less fragile
for other cases.
Backpatch to 8.4. We could go further back, but the patch doesn't apply
cleanly. In the absence of proof that this fixes something and isn't just
paranoia, I'm not going to expend the effort.
The purpose of this change is to eliminate the need for every caller
of SearchSysCache, SearchSysCacheCopy, SearchSysCacheExists,
GetSysCacheOid, and SearchSysCacheList to know the maximum number
of allowable keys for a syscache entry (currently 4). This will
make it far easier to increase the maximum number of keys in a
future release should we choose to do so, and it makes the code
shorter, too.
Design and review by Tom Lane.
PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.
Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.
Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.
This patch also removes buffer-usage statistics from the track_counts
output, since this (or the global server statistics) is deemed to be a better
interface to this information.
Itagaki Takahiro, reviewed by Euler Taveira de Oliveira.
we have to cope with the possibility that the declared result rowtype contains
dropped columns. This fails in 8.4, as per bug #5240.
While at it, be more paranoid about inserting binary coercions when inlining.
The pre-8.4 code did not really need to worry about that because it could not
inline at all in any case where an added coercion could change the behavior
of the function's statement. However, when inlining a SRF we allow sorting,
grouping, and set-ops such as UNION. In these cases, modifying one of the
targetlist entries that the sort/group/setop depends on could conceivably
change the behavior of the function's statement --- so don't inline when
such a case applies.
As proof of concept, modify plpgsql to use the hooks. plpgsql is still
inserting $n symbols textually, but the "back end" of the parsing process now
goes through the ParamRef hook instead of using a fixed parameter-type array,
and then execution only fetches actually-referenced parameters, using a hook
added to ParamListInfo.
Although there's a lot left to be done in plpgsql, this already cures the
"if (TG_OP = 'INSERT' and NEW.foo ...)" problem, as illustrated by the
changed regression test.
function returning setof record. This used to work, more or less
accidentally, but I had broken it while extending the code to allow
materialize-mode functions to be called in select lists. Add a regression
test case so it doesn't get broken again. Per gripe from Greg Davidson.
mode while callers hold pointers to in-memory tuples. I reported this for
the case of nodeWindowAgg's primary scan tuple, but inspection of the code
shows that all of the calls in nodeWindowAgg and nodeCtescan are at risk.
For the moment, fix it with a rather brute-force approach of copying
whenever one of the at-risk callers requests a tuple. Later we might
think of some sort of reference-count approach to reduce tuple copying.
practically free given prior 8.4 changes in plancache and portal management,
and it makes it a lot easier for ExecutorStart/Run/End hooks to get at the
query text. Extracted from Itagaki Takahiro's pg_stat_statements patch,
with minor editorialization.
that a Portal is a useful and sufficient additional argument for
CreateDestReceiver --- it just isn't, in most cases. Instead formalize
the approach of passing any needed parameters to the receiver separately.
One unexpected benefit of this change is that we can declare typedef Portal
in a less surprising location.
This patch is just code rearrangement and doesn't change any functionality.
I'll tackle the HOLD-cursor-vs-toast problem in a follow-on patch.
DestReceiver created during postquel_start needs to be destroyed during
postquel_end. In a moment of brain fade I had assumed this would be taken
care of by FreeQueryDesc, but it's not (and shouldn't be).
it just return void instead of sometimes returning a TupleTableSlot. SQL
functions don't need that anymore, and noplace else does either. Eliminating
the return value also means one less hassle for the ExecutorRun hook functions
that will be supported beginning in 8.4.
RETURNING clause, not just a SELECT as formerly.
A side effect of this patch is that when a set-returning SQL function is used
in a FROM clause, performance is improved because the output is collected into
a tuplestore within the function, rather than using the less efficient
value-per-call mechanism.
into nodes/nodeFuncs, so as to reduce wanton cross-subsystem #includes inside
the backend. There's probably more that should be done along this line,
but this is a start anyway.
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.
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
are declared to return set, and consist of just a single SELECT. We
can replace the FROM-item with a sub-SELECT and then optimize much as
if we were dealing with a view. Patch from Richard Rowell, cleaned up
by me.
few lines in sql_exec_error_callback() by using the function source string
field that the patch added to SQL function cache entries. This doesn't work
because the fn_extra field isn't filled in yet during init_sql_fcache().
Probably it could be made to work, but it doesn't seem appropriate to contort
the main code paths to make an error-reporting path a tad faster. Per report
from Pavel Stehule.
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.
types of unspecified parameters when submitted via extended query protocol.
This worked in 8.2 but I had broken it during plancache changes. DECLARE
CURSOR is now treated almost exactly like a plain SELECT through parse
analysis, rewrite, and planning; only just before sending to the executor
do we divert it away to ProcessUtility. This requires a special-case check
in a number of places, but practically all of them were already special-casing
SELECT INTO, so it's not too ugly. (Maybe it would be a good idea to merge
the two by treating IntoClause as a form of utility statement? Not going to
worry about that now, though.) That approach doesn't work for EXPLAIN,
however, so for that I punted and used a klugy solution of running parse
analysis an extra time if under extended query protocol.
access to the planner's cursor-related planning options, and provide new
FETCH/MOVE routines that allow access to the full power of those commands.
Small refactoring of planner(), pg_plan_query(), and pg_plan_queries()
APIs to make it convenient to pass the planning options down from SPI.
This is the core-code portion of Pavel Stehule's patch for scrollable
cursor support in plpgsql; I'll review and apply the plpgsql changes
separately.
return void ends with a SELECT, if that SELECT has a single result that is
also of type void. Without this, it's hard to write a void function that
calls another void function. Per gripe from Peter.
Back-patch as far as 8.0.
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.
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.
we should check that the function code returns the claimed result datatype
every time we parse the function for execution. Formerly, for simple
scalar result types we assumed the creation-time check was sufficient, but
this fails if the function selects from a table that's been redefined since
then, and even more obviously fails if check_function_bodies had been OFF.
This is a significant security hole: not only can one trivially crash the
backend, but with appropriate misuse of pass-by-reference datatypes it is
possible to read out arbitrary locations in the server process's memory,
which could allow retrieving database content the user should not be able
to see. Our thanks to Jeff Trout for the initial report.
Security: CVE-2007-0555
rows --- if the surrounding query queued any trigger events between the rows,
the events would be fired at the wrong time, leading to bizarre behavior.
Per report from Merlin Moncure.
This is a simple patch that should solve the problem fully in the back
branches, but in HEAD we also need to consider the possibility of queries
with RETURNING clauses. Will look into a fix for that separately.
that has parameters is always planned afresh for each Bind command,
treating the parameter values as constants in the planner. This removes
the performance penalty formerly often paid for using out-of-line
parameters --- with this definition, the planner can do constant folding,
LIKE optimization, etc. After a suggestion by Andrew@supernews.
merely a matter of fixing the error check, since the underlying Portal
infrastructure already handles it. This in turn allows these statements
to be used in some existing plpgsql and plperl contexts, such as a
plpgsql FOR loop. Also, do some marginal code cleanup in places that
were being sloppy about distinguishing SELECT from SELECT INTO.
not named ones, and replace linear searches of the list with array indexing.
The named-parameter support has been dead code for many years anyway,
and recent profiling suggests that the searching was costing a noticeable
amount of performance for complex queries.
bits indicating which optional capabilities can actually be exercised
at runtime. This will allow Sort and Material nodes, and perhaps later
other nodes, to avoid unnecessary overhead in common cases.
This commit just adds the infrastructure and arranges to pass the correct
flag values down to plan nodes; none of the actual optimizations are here
yet. I'm committing this separately in case anyone wants to measure the
added overhead. (It should be negligible.)
Simon Riggs and Tom Lane
comment line where output as too long, and update typedefs for /lib
directory. Also fix case where identifiers were used as variable names
in the backend, but as typedefs in ecpg (favor the backend for
indenting).
Backpatch to 8.1.X.
few palloc's. I also chose to eliminate the restype and restypmod fields
entirely, since they are redundant with information stored in the node's
contained expression; re-examining the expression at need seems simpler
and more reliable than trying to keep restype/restypmod up to date.
initdb forced due to change in contents of stored rules.
change saves a great deal of space in pg_proc and its primary index,
and it eliminates the former requirement that INDEX_MAX_KEYS and
FUNC_MAX_ARGS have the same value. INDEX_MAX_KEYS is still embedded
in the on-disk representation (because it affects index tuple header
size), but FUNC_MAX_ARGS is not. I believe it would now be possible
to increase FUNC_MAX_ARGS at little cost, but haven't experimented yet.
There are still a lot of vestigial references to FUNC_MAX_ARGS, which
I will clean up in a separate pass. However, getting rid of it
altogether would require changing the FunctionCallInfoData struct,
and I'm not sure I want to buy into that.
executing a statement that fires triggers. Formerly this time was
included in "Total runtime" but not otherwise accounted for.
As a side benefit, we avoid re-opening relations when firing non-deferred
AFTER triggers, because the trigger code can re-use the main executor's
ResultRelInfo data structure.
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.
Also performed an initial run through of upgrading our Copyright date to
extend to 2005 ... first run here was very simple ... change everything
where: grep 1996-2004 && the word 'Copyright' ... scanned through the
generated list with 'less' first, and after, to make sure that I only
picked up the right entries ...
columns. The returned tuple needs to have appropriate NULL columns
inserted so that it actually matches the declared rowtype. It seemed
convenient to use a JunkFilter for this, so I made some cleanups and
simplifications in the JunkFilter code to allow it to support this
additional functionality. (That in turn exposed a latent bug in
nodeAppend.c, which is that it was returning a tuple slot whose
descriptor didn't match its data.) Also, move check_sql_fn_retval
out of pg_proc.c and into functions.c, where it seems to more naturally
belong.
mode see a fresh snapshot for each command in the function, rather than
using the latest interactive command's snapshot. Also, suppress fresh
snapshots as well as CommandCounterIncrement inside STABLE and IMMUTABLE
functions, instead using the snapshot taken for the most closely nested
regular query. (This behavior is only sane for read-only functions, so
the patch also enforces that such functions contain only SELECT commands.)
As per my proposal of 6-Sep-2004; I note that I floated essentially the
same proposal on 19-Jun-2002, but that discussion tailed off without any
action. Since 8.0 seems like the right place to be taking possibly
nontrivial backwards compatibility hits, let's get it done now.
rather than when returning to the idle loop. This makes no particular
difference for interactively-issued queries, but it makes a big difference
for queries issued within functions: trigger execution now occurs before
the calling function is allowed to proceed. This responds to numerous
complaints about nonintuitive behavior of foreign key checking, such as
http://archives.postgresql.org/pgsql-bugs/2004-09/msg00020.php, and
appears to be required by the SQL99 spec.
Also take the opportunity to simplify the data structures used for the
pending-trigger list, rename them for more clarity, and squeeze out a
bit of space.
executed. Previously, the DECLARE would succeed but subsequent FETCHes
would fail since the parameter values supplied to DECLARE were not
propagated to the portal created for the cursor.
In support of this, add type Oids to ParamListInfo entries, which seems
like a good idea anyway since code that extracts a value can double-check
that it got the type of value it was expecting.
Oliver Jowett, with minor editorialization by Tom Lane.
until Bind is received, so that actual parameter values are visible to the
planner. Make use of the parameter values for estimation purposes (but
don't fold them into the actual plan). This buys back most of the
potential loss of plan quality that ensues from using out-of-line
parameters instead of putting literal values right into the query text.
This patch creates a notion of constant-folding expressions 'for
estimation purposes only', in which case we can be more aggressive than
the normal eval_const_expressions() logic can be. Right now the only
difference in behavior is inserting bound values for Params, but it will
be interesting to look at other possibilities. One that we've seen
come up repeatedly is reducing now() and related functions to current
values, so that queries like ... WHERE timestampcol > now() - '1 day'
have some chance of being planned effectively.
Oliver Jowett, with some kibitzing from Tom Lane.
In the past, we used a 'Lispy' linked list implementation: a "list" was
merely a pointer to the head node of the list. The problem with that
design is that it makes lappend() and length() linear time. This patch
fixes that problem (and others) by maintaining a count of the list
length and a pointer to the tail node along with each head node pointer.
A "list" is now a pointer to a structure containing some meta-data
about the list; the head and tail pointers in that structure refer
to ListCell structures that maintain the actual linked list of nodes.
The function names of the list API have also been changed to, I hope,
be more logically consistent. By default, the old function names are
still available; they will be disabled-by-default once the rest of
the tree has been updated to use the new API names.
'SELECT foo()' in a SQL function returning a rowtype, to simply pass
back the results of another function returning the same rowtype.
However, that hasn't actually worked in many years. Now it works again.
results with tuples as ordinary varlena Datums. This commit does not
in itself do much for us, except eliminate the horrid memory leak
associated with evaluation of whole-row variables. However, it lays the
groundwork for allowing composite types as table columns, and perhaps
some other useful features as well. Per my proposal of a few days ago.
pointer type when it is not necessary to do so.
For future reference, casting NULL to a pointer type is only necessary
when (a) invoking a function AND either (b) the function has no prototype
OR (c) the function is a varargs function.
to allow es_snapshot to be set to SnapshotNow rather than a query snapshot.
This solves a bug reported by Wade Klaver, wherein triggers fired as a
result of RI cascade updates could misbehave.
ANYELEMENT. The effect is to postpone typechecking of the function
body until runtime. Documentation is still lacking.
Original patch by Joe Conway, modified to postpone type checking
by Tom Lane.
handle multiple 'formats' for data I/O. Restructure CommandDest and
DestReceiver stuff one more time (it's finally starting to look a bit
clean though). Code now matches latest 3.0 protocol document as far
as message formats go --- but there is no support for binary I/O yet.
DestReceiver pointers instead of just CommandDest values. The DestReceiver
is made at the point where the destination is selected, rather than
deep inside the executor. This cleans up the original kluge implementation
of tstoreReceiver.c, and makes it easy to support retrieving results
from utility statements inside portals. Thus, you can now do fun things
like Bind and Execute a FETCH or EXPLAIN command, and it'll all work
as expected (e.g., you can Describe the portal, or use Execute's count
parameter to suspend the output partway through). Implementation involves
stuffing the utility command's output into a Tuplestore, which would be
kind of annoying for huge output sets, but should be quite acceptable
for typical uses of utility commands.
the column by table OID and column number, if it's a simple column
reference. Along the way, get rid of reskey/reskeyop fields in Resdoms.
Turns out that representation was not convenient for either the planner
or the executor; we can make the planner deliver exactly what the
executor wants with no more effort.
initdb forced due to change in stored rule representation.
a per-query memory context created by CreateExecutorState --- and destroyed
by FreeExecutorState. This provides a final solution to the longstanding
problem of memory leaked by various ExecEndNode calls.
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.
of functions returning domain types, update documentation for typtype,
move get_typtype to lsyscache.c (actually, resurrect the old version),
add defense against creating pseudo-typed table columns, fix some
bogus list-parsing in grammar. Issues remain with respect to alias
handling and type checking; Joe is on those.
types for Table Functions, as previously proposed on HACKERS. Here is a
brief explanation:
1. Creates a new pg_type typtype: 'p' for pseudo type (currently either
'b' for base or 'c' for catalog, i.e. a class).
2. Creates new builtin type of typtype='p' named RECORD. This is the
first of potentially several pseudo types.
3. Modify FROM clause grammer to accept:
SELECT * FROM my_func() AS m(colname1 type1, colname2 type1, ...)
where m is the table alias, colname1, etc are the column names, and
type1, etc are the column types.
4. When typtype == 'p' and the function return type is RECORD, a list
of column defs is required, and when typtype != 'p', it is
disallowed.
5. A check was added to ensure that the tupdesc provide via the parser
and the actual return tupdesc match in number and type of
attributes.
When creating a function you can do:
CREATE FUNCTION foo(text) RETURNS setof RECORD ...
When using it you can do:
SELECT * from foo(sqlstmt) AS (f1 int, f2 text, f3 timestamp)
or
SELECT * from foo(sqlstmt) AS f(f1 int, f2 text, f3 timestamp)
or
SELECT * from foo(sqlstmt) f(f1 int, f2 text, f3 timestamp)
Included in the patches are adjustments to the regression test sql and
expected files, and documentation.
p.s.
This potentially solves (or at least improves) the issue of builtin
Table Functions. They can be bootstrapped as returning RECORD, and
we can wrap system views around them with properly specified column
defs. For example:
CREATE VIEW pg_settings AS
SELECT s.name, s.setting
FROM show_all_settings()AS s(name text, setting text);
Then we can also add the UPDATE RULE that I previously posted to
pg_settings, and have pg_settings act like a virtual table, allowing
settings to be queried and set.
Joe Conway
in snapshots, per my proposal of a few days ago. Also, tweak heapam.c
routines (heap_insert, heap_update, heap_delete, heap_mark4update) to
be passed the command ID to use, instead of doing GetCurrentCommandID.
For catalog updates they'll still get passed current command ID, but
for updates generated from the main executor they'll get passed the
command ID saved in the snapshot the query is using. This should fix
some corner cases associated with functions and triggers that advance
current command ID while an outer query is still in progress.
some kibitzing from Tom Lane. Not everything works yet, and there's
no documentation or regression test, but let's commit this so Joe
doesn't need to cope with tracking changes in so many files ...
are now both invoked once per received SQL command (raw parsetree) from
pg_exec_query_string. BeginCommand is actually just an empty routine
at the moment --- all its former operations have been pushed into tuple
receiver setup routines in printtup.c. This makes for a clean distinction
between BeginCommand/EndCommand (once per command) and the tuple receiver
setup/teardown routines (once per ExecutorRun call), whereas the old code
was quite ad hoc. Along the way, clean up the calling conventions for
ExecutorRun a little bit.
report for each received SQL command, regardless of rewriting activity.
Also ensure that this report comes from the 'original' command, not the
last command generated by rewrite; this fixes 7.2 breakage for INSERT
commands that have actions added by rules. Fernando Nasser and Tom Lane.
allocated by plan nodes are not leaked at end of query. This doesn't
really matter for normal queries, but it sure does for queries invoked
repetitively inside SQL functions. Clean up some other grotty code
associated with tupdescs, and fix a few other memory leaks exposed by
tests with simple SQL functions.
maintained for each cache entry. A cache entry will not be freed until
the matching ReleaseSysCache call has been executed. This eliminates
worries about cache entries getting dropped while still in use. See
my posting to pg-hackers of even date for more info.
joins, and clean things up a good deal at the same time. Append plan node
no longer hacks on rangetable at runtime --- instead, all child tables are
given their own RT entries during planning. Concept of multiple target
tables pushed up into execMain, replacing bug-prone implementation within
nodeAppend. Planner now supports generating Append plans for inheritance
sets either at the top of the plan (the old way) or at the bottom. Expanding
at the bottom is appropriate for tables used as sources, since they may
appear inside an outer join; but we must still expand at the top when the
target of an UPDATE or DELETE is an inheritance set, because we actually need
a different targetlist and junkfilter for each target table in that case.
Fortunately a target table can't be inside an outer join... Bizarre mutual
recursion between union_planner and prepunion.c is gone --- in fact,
union_planner doesn't really have much to do with union queries anymore,
so I renamed it grouping_planner.
ExecutorRun. This allows LIMIT to work in a view. Also, LIMIT in a
cursor declaration will behave in a reasonable fashion, whereas before
it was overridden by the FETCH count.
for example, an SQL function can be used in a functional index. (I make
no promises about speed, but it'll work ;-).) Clean up and simplify
handling of functions returning sets.
from Param nodes, per discussion a few days ago on pghackers. Add new
expression node type FieldSelect that implements the functionality where
it's actually needed. Clean up some other unused fields in Func nodes
as well.
NOTE: initdb forced due to change in stored expression trees for rules.
memory contexts. Currently, only leaks in expressions executed as
quals or projections are handled. Clean up some old dead cruft in
executor while at it --- unused fields in state nodes, that sort of thing.
for details). It doesn't really do that much yet, since there are no
short-term memory contexts in the executor, but the infrastructure is
in place and long-term contexts are handled reasonably. A few long-
standing bugs have been fixed, such as 'VACUUM; anything' in a single
query string crashing. Also, out-of-memory is now considered a
recoverable ERROR, not FATAL.
Eliminate a large amount of crufty, now-dead code in and around
memory management.
Fix problem with holding off SIGTRAP, SIGSEGV, etc in postmaster and
backend startup.
key call sites are changed, but most called functions are still oldstyle.
An exception is that the PL managers are updated (so, for example, NULL
handling now behaves as expected in plperl and plpgsql functions).
NOTE initdb is forced due to added column in pg_proc.
would crash, due to premature invocation of SetQuerySnapshot(). Clean
up problems with handling of multiple queries by splitting
pg_parse_and_plan into two routines. The old code would not, for
example, do the right thing with END; SELECT... submitted in one query
string when it had been in transaction abort state, because it'd decide
to skip planning the SELECT before it had executed the END. New
arrangement is simpler and doesn't force caller to plan if only
parse+rewrite is needed.
lists are now plain old garden-variety Lists, allocated with palloc,
rather than specialized expansible-array data allocated with malloc.
This substantially simplifies their handling and eliminates several
sources of memory leakage.
Several basic types of erroneous queries (syntax error, attempt to
insert a duplicate key into a unique index) now demonstrably leak
zero bytes per query.
patch is applied:
Rewrite rules on relation level work fine now.
Event qualifications on insert/update/delete rules work
fine now.
I added the new keyword OLD to reference the CURRENT
tuple. CURRENT will be removed in 6.5.
Update rules can reference NEW and OLD in the rule
qualification and the actions.
Insert/update/delete rules on views can be established to
let them behave like real tables.
For insert/update/delete rules multiple actions are
supported now. The actions can also be surrounded by
parantheses to make psql happy. Multiple actions are
required if update to a view requires updates to multiple
tables.
Regular users are permitted to create/drop rules on
tables they have RULE permissions for
(DefineQueryRewrite() is now able to get around the
access restrictions on pg_rewrite). This enables view
creation for regular users too. This required an extra
boolean parameter to pg_parse_and_plan() that tells to
set skipAcl on all rangetable entries of the resulting
queries. There is a new function
pg_exec_query_acl_override() that could be used by
backend utilities to use this facility.
All rule actions (not only views) inherit the permissions
of the event relations owner. Sample: User A creates
tables T1 and T2, creates rules that log
INSERT/UPDATE/DELETE on T1 in T2 (like in the regression
tests for rules I created) and grants ALL but RULE on T1
to user B. User B can now fully access T1 and the
logging happens in T2. But user B cannot access T2 at
all, only the rule actions can. And due to missing RULE
permissions on T1, user B cannot disable logging.
Rules on the attribute level are disabled (they don't
work properly and since regular users are now permitted
to create rules I decided to disable them).
Rules on select must have exactly one action that is a
select (so select rules must be a view definition).
UPDATE NEW/OLD rules are disabled (still broken, but
triggers can do it).
There are two new system views (pg_rule and pg_view) that
show the definition of the rules or views so the db admin
can see what the users do. They use two new functions
pg_get_ruledef() and pg_get_viewdef() that are builtins.
The functions pg_get_ruledef() and pg_get_viewdef() could
be used to implement rule and view support in pg_dump.
PostgreSQL is now the only database system I know, that
has rewrite rules on the query level. All others (where I
found a rule statement at all) use stored database
procedures or the like (triggers as we call them) for
active rules (as some call them).
Future of the rule system:
The now disabled parts of the rule system (attribute
level, multiple actions on select and update new stuff)
require a complete new rewrite handler from scratch. The
old one is too badly wired up.
After 6.4 I'll start to work on a new rewrite handler,
that fully supports the attribute level rules, multiple
actions on select and update new. This will be available
for 6.5 so we get full rewrite rule capabilities.
Jan
ExecReScan for nodeAgg, nodeHash, nodeHashjoin, nodeNestloop and nodeResult.
Fixed ExecReScan for nodeMaterial.
Get rid of #ifdef INDEXSCAN_PATCH.
Get rid of ExecMarkPos and ExecRestrPos in nodeNestloop.
