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postgres/src/backend/executor/execSRF.c
Andres Freund 578b229718 Remove WITH OIDS support, change oid catalog column visibility. 
Previously tables declared WITH OIDS, including a significant fraction
of the catalog tables, stored the oid column not as a normal column,
but as part of the tuple header.

This special column was not shown by default, which was somewhat odd,
as it's often (consider e.g. pg_class.oid) one of the more important
parts of a row.  Neither pg_dump nor COPY included the contents of the
oid column by default.

The fact that the oid column was not an ordinary column necessitated a
significant amount of special case code to support oid columns. That
already was painful for the existing, but upcoming work aiming to make
table storage pluggable, would have required expanding and duplicating
that "specialness" significantly.

WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0).
Remove it.

Removing includes:
- CREATE TABLE and ALTER TABLE syntax for declaring the table to be
  WITH OIDS has been removed (WITH (oids[ = true]) will error out)
- pg_dump does not support dumping tables declared WITH OIDS and will
  issue a warning when dumping one (and ignore the oid column).
- restoring an pg_dump archive with pg_restore will warn when
  restoring a table with oid contents (and ignore the oid column)
- COPY will refuse to load binary dump that includes oids.
- pg_upgrade will error out when encountering tables declared WITH
  OIDS, they have to be altered to remove the oid column first.
- Functionality to access the oid of the last inserted row (like
  plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed.

The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false)
for CREATE TABLE) is still supported. While that requires a bit of
support code, it seems unnecessary to break applications / dumps that
do not use oids, and are explicit about not using them.

The biggest user of WITH OID columns was postgres' catalog. This
commit changes all 'magic' oid columns to be columns that are normally
declared and stored. To reduce unnecessary query breakage all the
newly added columns are still named 'oid', even if a table's column
naming scheme would indicate 'reloid' or such.  This obviously
requires adapting a lot code, mostly replacing oid access via
HeapTupleGetOid() with access to the underlying Form_pg_*->oid column.

The bootstrap process now assigns oids for all oid columns in
genbki.pl that do not have an explicit value (starting at the largest
oid previously used), only oids assigned later by oids will be above
FirstBootstrapObjectId. As the oid column now is a normal column the
special bootstrap syntax for oids has been removed.

Oids are not automatically assigned during insertion anymore, all
backend code explicitly assigns oids with GetNewOidWithIndex(). For
the rare case that insertions into the catalog via SQL are called for
the new pg_nextoid() function can be used (which only works on catalog
tables).

The fact that oid columns on system tables are now normal columns
means that they will be included in the set of columns expanded
by * (i.e. SELECT * FROM pg_class will now include the table's oid,
previously it did not). It'd not technically be hard to hide oid
column by default, but that'd mean confusing behavior would either
have to be carried forward forever, or it'd cause breakage down the
line.

While it's not unlikely that further adjustments are needed, the
scope/invasiveness of the patch makes it worthwhile to get merge this
now. It's painful to maintain externally, too complicated to commit
after the code code freeze, and a dependency of a number of other
patches.

Catversion bump, for obvious reasons.

Author: Andres Freund, with contributions by John Naylor
Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
2018-11-20 16:00:17 -08:00

958 lines
27 KiB
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/*-------------------------------------------------------------------------
*
* execSRF.c
* Routines implementing the API for set-returning functions
*
* This file serves nodeFunctionscan.c and nodeProjectSet.c, providing
* common code for calling set-returning functions according to the
* ReturnSetInfo API.
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/executor/execSRF.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/objectaccess.h"
#include "executor/execdebug.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_coerce.h"
#include "pgstat.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/typcache.h"
/* static function decls */
static void init_sexpr(Oid foid, Oid input_collation, Expr *node,
SetExprState *sexpr, PlanState *parent,
MemoryContext sexprCxt, bool allowSRF, bool needDescForSRF);
static void ShutdownSetExpr(Datum arg);
static void ExecEvalFuncArgs(FunctionCallInfo fcinfo,
List *argList, ExprContext *econtext);
static void ExecPrepareTuplestoreResult(SetExprState *sexpr,
ExprContext *econtext,
Tuplestorestate *resultStore,
TupleDesc resultDesc);
static void tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc);
/*
* Prepare function call in FROM (ROWS FROM) for execution.
*
* This is used by nodeFunctionscan.c.
*/
SetExprState *
ExecInitTableFunctionResult(Expr *expr,
ExprContext *econtext, PlanState *parent)
{
SetExprState *state = makeNode(SetExprState);
state->funcReturnsSet = false;
state->expr = expr;
state->func.fn_oid = InvalidOid;
/*
* Normally the passed expression tree will be a FuncExpr, since the
* grammar only allows a function call at the top level of a table
* function reference. However, if the function doesn't return set then
* the planner might have replaced the function call via constant-folding
* or inlining. So if we see any other kind of expression node, execute
* it via the general ExecEvalExpr() code. That code path will not
* support set-returning functions buried in the expression, though.
*/
if (IsA(expr, FuncExpr))
{
FuncExpr *func = (FuncExpr *) expr;
state->funcReturnsSet = func->funcretset;
state->args = ExecInitExprList(func->args, parent);
init_sexpr(func->funcid, func->inputcollid, expr, state, parent,
econtext->ecxt_per_query_memory, func->funcretset, false);
}
else
{
state->elidedFuncState = ExecInitExpr(expr, parent);
}
return state;
}
/*
* ExecMakeTableFunctionResult
*
* Evaluate a table function, producing a materialized result in a Tuplestore
* object.
*
* This is used by nodeFunctionscan.c.
*/
Tuplestorestate *
ExecMakeTableFunctionResult(SetExprState *setexpr,
ExprContext *econtext,
MemoryContext argContext,
TupleDesc expectedDesc,
bool randomAccess)
{
Tuplestorestate *tupstore = NULL;
TupleDesc tupdesc = NULL;
Oid funcrettype;
bool returnsTuple;
bool returnsSet = false;
FunctionCallInfoData fcinfo;
PgStat_FunctionCallUsage fcusage;
ReturnSetInfo rsinfo;
HeapTupleData tmptup;
MemoryContext callerContext;
MemoryContext oldcontext;
bool first_time = true;
callerContext = CurrentMemoryContext;
funcrettype = exprType((Node *) setexpr->expr);
returnsTuple = type_is_rowtype(funcrettype);
/*
* Prepare a resultinfo node for communication. We always do this even if
* not expecting a set result, so that we can pass expectedDesc. In the
* generic-expression case, the expression doesn't actually get to see the
* resultinfo, but set it up anyway because we use some of the fields as
* our own state variables.
*/
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = expectedDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize | SFRM_Materialize_Preferred);
if (randomAccess)
rsinfo.allowedModes |= (int) SFRM_Materialize_Random;
rsinfo.returnMode = SFRM_ValuePerCall;
/* isDone is filled below */
rsinfo.setResult = NULL;
rsinfo.setDesc = NULL;
/*
* Normally the passed expression tree will be a SetExprState, since the
* grammar only allows a function call at the top level of a table
* function reference. However, if the function doesn't return set then
* the planner might have replaced the function call via constant-folding
* or inlining. So if we see any other kind of expression node, execute
* it via the general ExecEvalExpr() code; the only difference is that we
* don't get a chance to pass a special ReturnSetInfo to any functions
* buried in the expression.
*/
if (!setexpr->elidedFuncState)
{
/*
* This path is similar to ExecMakeFunctionResultSet.
*/
returnsSet = setexpr->funcReturnsSet;
InitFunctionCallInfoData(fcinfo, &(setexpr->func),
list_length(setexpr->args),
setexpr->fcinfo_data.fncollation,
NULL, (Node *) &rsinfo);
/*
* Evaluate the function's argument list.
*
* We can't do this in the per-tuple context: the argument values
* would disappear when we reset that context in the inner loop. And
* the caller's CurrentMemoryContext is typically a query-lifespan
* context, so we don't want to leak memory there. We require the
* caller to pass a separate memory context that can be used for this,
* and can be reset each time through to avoid bloat.
*/
MemoryContextReset(argContext);
oldcontext = MemoryContextSwitchTo(argContext);
ExecEvalFuncArgs(&fcinfo, setexpr->args, econtext);
MemoryContextSwitchTo(oldcontext);
/*
* If function is strict, and there are any NULL arguments, skip
* calling the function and act like it returned NULL (or an empty
* set, in the returns-set case).
*/
if (setexpr->func.fn_strict)
{
int i;
for (i = 0; i < fcinfo.nargs; i++)
{
if (fcinfo.argnull[i])
goto no_function_result;
}
}
}
else
{
/* Treat setexpr as a generic expression */
InitFunctionCallInfoData(fcinfo, NULL, 0, InvalidOid, NULL, NULL);
}
/*
* Switch to short-lived context for calling the function or expression.
*/
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
/*
* Loop to handle the ValuePerCall protocol (which is also the same
* behavior needed in the generic ExecEvalExpr path).
*/
for (;;)
{
Datum result;
CHECK_FOR_INTERRUPTS();
/*
* reset per-tuple memory context before each call of the function or
* expression. This cleans up any local memory the function may leak
* when called.
*/
ResetExprContext(econtext);
/* Call the function or expression one time */
if (!setexpr->elidedFuncState)
{
pgstat_init_function_usage(&fcinfo, &fcusage);
fcinfo.isnull = false;
rsinfo.isDone = ExprSingleResult;
result = FunctionCallInvoke(&fcinfo);
pgstat_end_function_usage(&fcusage,
rsinfo.isDone != ExprMultipleResult);
}
else
{
result =
ExecEvalExpr(setexpr->elidedFuncState, econtext, &fcinfo.isnull);
rsinfo.isDone = ExprSingleResult;
}
/* Which protocol does function want to use? */
if (rsinfo.returnMode == SFRM_ValuePerCall)
{
/*
* Check for end of result set.
*/
if (rsinfo.isDone == ExprEndResult)
break;
/*
* If first time through, build tuplestore for result. For a
* scalar function result type, also make a suitable tupdesc.
*/
if (first_time)
{
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo.setResult = tupstore;
if (!returnsTuple)
{
tupdesc = CreateTemplateTupleDesc(1);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
"column",
funcrettype,
-1,
0);
rsinfo.setDesc = tupdesc;
}
MemoryContextSwitchTo(oldcontext);
}
/*
* Store current resultset item.
*/
if (returnsTuple)
{
if (!fcinfo.isnull)
{
HeapTupleHeader td = DatumGetHeapTupleHeader(result);
if (tupdesc == NULL)
{
/*
* This is the first non-NULL result from the
* function. Use the type info embedded in the
* rowtype Datum to look up the needed tupdesc. Make
* a copy for the query.
*/
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupdesc = lookup_rowtype_tupdesc_copy(HeapTupleHeaderGetTypeId(td),
HeapTupleHeaderGetTypMod(td));
rsinfo.setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
}
else
{
/*
* Verify all later returned rows have same subtype;
* necessary in case the type is RECORD.
*/
if (HeapTupleHeaderGetTypeId(td) != tupdesc->tdtypeid ||
HeapTupleHeaderGetTypMod(td) != tupdesc->tdtypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("rows returned by function are not all of the same row type")));
}
/*
* tuplestore_puttuple needs a HeapTuple not a bare
* HeapTupleHeader, but it doesn't need all the fields.
*/
tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
tmptup.t_data = td;
tuplestore_puttuple(tupstore, &tmptup);
}
else
{
/*
* NULL result from a tuple-returning function; expand it
* to a row of all nulls. We rely on the expectedDesc to
* form such rows. (Note: this would be problematic if
* tuplestore_putvalues saved the tdtypeid/tdtypmod from
* the provided descriptor, since that might not match
* what we get from the function itself. But it doesn't.)
*/
int natts = expectedDesc->natts;
bool *nullflags;
nullflags = (bool *) palloc(natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(tupstore, expectedDesc, NULL, nullflags);
}
}
else
{
/* Scalar-type case: just store the function result */
tuplestore_putvalues(tupstore, tupdesc, &result, &fcinfo.isnull);
}
/*
* Are we done?
*/
if (rsinfo.isDone != ExprMultipleResult)
break;
}
else if (rsinfo.returnMode == SFRM_Materialize)
{
/* check we're on the same page as the function author */
if (!first_time || rsinfo.isDone != ExprSingleResult)
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("table-function protocol for materialize mode was not followed")));
/* Done evaluating the set result */
break;
}
else
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("unrecognized table-function returnMode: %d",
(int) rsinfo.returnMode)));
first_time = false;
}
no_function_result:
/*
* If we got nothing from the function (ie, an empty-set or NULL result),
* we have to create the tuplestore to return, and if it's a
* non-set-returning function then insert a single all-nulls row. As
* above, we depend on the expectedDesc to manufacture the dummy row.
*/
if (rsinfo.setResult == NULL)
{
MemoryContextSwitchTo(econtext->ecxt_per_query_memory);
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo.setResult = tupstore;
if (!returnsSet)
{
int natts = expectedDesc->natts;
bool *nullflags;
MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
nullflags = (bool *) palloc(natts * sizeof(bool));
memset(nullflags, true, natts * sizeof(bool));
tuplestore_putvalues(tupstore, expectedDesc, NULL, nullflags);
}
}
/*
* If function provided a tupdesc, cross-check it. We only really need to
* do this for functions returning RECORD, but might as well do it always.
*/
if (rsinfo.setDesc)
{
tupledesc_match(expectedDesc, rsinfo.setDesc);
/*
* If it is a dynamically-allocated TupleDesc, free it: it is
* typically allocated in a per-query context, so we must avoid
* leaking it across multiple usages.
*/
if (rsinfo.setDesc->tdrefcount == -1)
FreeTupleDesc(rsinfo.setDesc);
}
MemoryContextSwitchTo(callerContext);
/* All done, pass back the tuplestore */
return rsinfo.setResult;
}
/*
* Prepare targetlist SRF function call for execution.
*
* This is used by nodeProjectSet.c.
*/
SetExprState *
ExecInitFunctionResultSet(Expr *expr,
ExprContext *econtext, PlanState *parent)
{
SetExprState *state = makeNode(SetExprState);
state->funcReturnsSet = true;
state->expr = expr;
state->func.fn_oid = InvalidOid;
/*
* Initialize metadata. The expression node could be either a FuncExpr or
* an OpExpr.
*/
if (IsA(expr, FuncExpr))
{
FuncExpr *func = (FuncExpr *) expr;
state->args = ExecInitExprList(func->args, parent);
init_sexpr(func->funcid, func->inputcollid, expr, state, parent,
econtext->ecxt_per_query_memory, true, true);
}
else if (IsA(expr, OpExpr))
{
OpExpr *op = (OpExpr *) expr;
state->args = ExecInitExprList(op->args, parent);
init_sexpr(op->opfuncid, op->inputcollid, expr, state, parent,
econtext->ecxt_per_query_memory, true, true);
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(expr));
/* shouldn't get here unless the selected function returns set */
Assert(state->func.fn_retset);
return state;
}
/*
* ExecMakeFunctionResultSet
*
* Evaluate the arguments to a set-returning function and then call the
* function itself. The argument expressions may not contain set-returning
* functions (the planner is supposed to have separated evaluation for those).
*
* This should be called in a short-lived (per-tuple) context, argContext
* needs to live until all rows have been returned (i.e. *isDone set to
* ExprEndResult or ExprSingleResult).
*
* This is used by nodeProjectSet.c.
*/
Datum
ExecMakeFunctionResultSet(SetExprState *fcache,
ExprContext *econtext,
MemoryContext argContext,
bool *isNull,
ExprDoneCond *isDone)
{
List *arguments;
Datum result;
FunctionCallInfo fcinfo;
PgStat_FunctionCallUsage fcusage;
ReturnSetInfo rsinfo;
bool callit;
int i;
restart:
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
/*
* If a previous call of the function returned a set result in the form of
* a tuplestore, continue reading rows from the tuplestore until it's
* empty.
*/
if (fcache->funcResultStore)
{
TupleTableSlot *slot = fcache->funcResultSlot;
MemoryContext oldContext;
bool foundTup;
/*
* Have to make sure tuple in slot lives long enough, otherwise
* clearing the slot could end up trying to free something already
* freed.
*/
oldContext = MemoryContextSwitchTo(slot->tts_mcxt);
foundTup = tuplestore_gettupleslot(fcache->funcResultStore, true, false,
fcache->funcResultSlot);
MemoryContextSwitchTo(oldContext);
if (foundTup)
{
*isDone = ExprMultipleResult;
if (fcache->funcReturnsTuple)
{
/* We must return the whole tuple as a Datum. */
*isNull = false;
return ExecFetchSlotHeapTupleDatum(fcache->funcResultSlot);
}
else
{
/* Extract the first column and return it as a scalar. */
return slot_getattr(fcache->funcResultSlot, 1, isNull);
}
}
/* Exhausted the tuplestore, so clean up */
tuplestore_end(fcache->funcResultStore);
fcache->funcResultStore = NULL;
*isDone = ExprEndResult;
*isNull = true;
return (Datum) 0;
}
/*
* arguments is a list of expressions to evaluate before passing to the
* function manager. We skip the evaluation if it was already done in the
* previous call (ie, we are continuing the evaluation of a set-valued
* function). Otherwise, collect the current argument values into fcinfo.
*
* The arguments have to live in a context that lives at least until all
* rows from this SRF have been returned, otherwise ValuePerCall SRFs
* would reference freed memory after the first returned row.
*/
fcinfo = &fcache->fcinfo_data;
arguments = fcache->args;
if (!fcache->setArgsValid)
{
MemoryContext oldContext = MemoryContextSwitchTo(argContext);
ExecEvalFuncArgs(fcinfo, arguments, econtext);
MemoryContextSwitchTo(oldContext);
}
else
{
/* Reset flag (we may set it again below) */
fcache->setArgsValid = false;
}
/*
* Now call the function, passing the evaluated parameter values.
*/
/* Prepare a resultinfo node for communication. */
fcinfo->resultinfo = (Node *) &rsinfo;
rsinfo.type = T_ReturnSetInfo;
rsinfo.econtext = econtext;
rsinfo.expectedDesc = fcache->funcResultDesc;
rsinfo.allowedModes = (int) (SFRM_ValuePerCall | SFRM_Materialize);
/* note we do not set SFRM_Materialize_Random or _Preferred */
rsinfo.returnMode = SFRM_ValuePerCall;
/* isDone is filled below */
rsinfo.setResult = NULL;
rsinfo.setDesc = NULL;
/*
* If function is strict, and there are any NULL arguments, skip calling
* the function.
*/
callit = true;
if (fcache->func.fn_strict)
{
for (i = 0; i < fcinfo->nargs; i++)
{
if (fcinfo->argnull[i])
{
callit = false;
break;
}
}
}
if (callit)
{
pgstat_init_function_usage(fcinfo, &fcusage);
fcinfo->isnull = false;
rsinfo.isDone = ExprSingleResult;
result = FunctionCallInvoke(fcinfo);
*isNull = fcinfo->isnull;
*isDone = rsinfo.isDone;
pgstat_end_function_usage(&fcusage,
rsinfo.isDone != ExprMultipleResult);
}
else
{
/* for a strict SRF, result for NULL is an empty set */
result = (Datum) 0;
*isNull = true;
*isDone = ExprEndResult;
}
/* Which protocol does function want to use? */
if (rsinfo.returnMode == SFRM_ValuePerCall)
{
if (*isDone != ExprEndResult)
{
/*
* Save the current argument values to re-use on the next call.
*/
if (*isDone == ExprMultipleResult)
{
fcache->setArgsValid = true;
/* Register cleanup callback if we didn't already */
if (!fcache->shutdown_reg)
{
RegisterExprContextCallback(econtext,
ShutdownSetExpr,
PointerGetDatum(fcache));
fcache->shutdown_reg = true;
}
}
}
}
else if (rsinfo.returnMode == SFRM_Materialize)
{
/* check we're on the same page as the function author */
if (rsinfo.isDone != ExprSingleResult)
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("table-function protocol for materialize mode was not followed")));
if (rsinfo.setResult != NULL)
{
/* prepare to return values from the tuplestore */
ExecPrepareTuplestoreResult(fcache, econtext,
rsinfo.setResult,
rsinfo.setDesc);
/* loop back to top to start returning from tuplestore */
goto restart;
}
/* if setResult was left null, treat it as empty set */
*isDone = ExprEndResult;
*isNull = true;
result = (Datum) 0;
}
else
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_SRF_PROTOCOL_VIOLATED),
errmsg("unrecognized table-function returnMode: %d",
(int) rsinfo.returnMode)));
return result;
}
/*
* init_sexpr - initialize a SetExprState node during first use
*/
static void
init_sexpr(Oid foid, Oid input_collation, Expr *node,
SetExprState *sexpr, PlanState *parent,
MemoryContext sexprCxt, bool allowSRF, bool needDescForSRF)
{
AclResult aclresult;
/* Check permission to call function */
aclresult = pg_proc_aclcheck(foid, GetUserId(), ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_FUNCTION, get_func_name(foid));
InvokeFunctionExecuteHook(foid);
/*
* Safety check on nargs. Under normal circumstances this should never
* fail, as parser should check sooner. But possibly it might fail if
* server has been compiled with FUNC_MAX_ARGS smaller than some functions
* declared in pg_proc?
*/
if (list_length(sexpr->args) > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg_plural("cannot pass more than %d argument to a function",
"cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS,
FUNC_MAX_ARGS)));
/* Set up the primary fmgr lookup information */
fmgr_info_cxt(foid, &(sexpr->func), sexprCxt);
fmgr_info_set_expr((Node *) sexpr->expr, &(sexpr->func));
/* Initialize the function call parameter struct as well */
InitFunctionCallInfoData(sexpr->fcinfo_data, &(sexpr->func),
list_length(sexpr->args),
input_collation, NULL, NULL);
/* If function returns set, check if that's allowed by caller */
if (sexpr->func.fn_retset && !allowSRF)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set"),
parent ? executor_errposition(parent->state,
exprLocation((Node *) node)) : 0));
/* Otherwise, caller should have marked the sexpr correctly */
Assert(sexpr->func.fn_retset == sexpr->funcReturnsSet);
/* If function returns set, prepare expected tuple descriptor */
if (sexpr->func.fn_retset && needDescForSRF)
{
TypeFuncClass functypclass;
Oid funcrettype;
TupleDesc tupdesc;
MemoryContext oldcontext;
functypclass = get_expr_result_type(sexpr->func.fn_expr,
&funcrettype,
&tupdesc);
/* Must save tupdesc in sexpr's context */
oldcontext = MemoryContextSwitchTo(sexprCxt);
if (functypclass == TYPEFUNC_COMPOSITE ||
functypclass == TYPEFUNC_COMPOSITE_DOMAIN)
{
/* Composite data type, e.g. a table's row type */
Assert(tupdesc);
/* Must copy it out of typcache for safety */
sexpr->funcResultDesc = CreateTupleDescCopy(tupdesc);
sexpr->funcReturnsTuple = true;
}
else if (functypclass == TYPEFUNC_SCALAR)
{
/* Base data type, i.e. scalar */
tupdesc = CreateTemplateTupleDesc(1);
TupleDescInitEntry(tupdesc,
(AttrNumber) 1,
NULL,
funcrettype,
-1,
0);
sexpr->funcResultDesc = tupdesc;
sexpr->funcReturnsTuple = false;
}
else if (functypclass == TYPEFUNC_RECORD)
{
/* This will work if function doesn't need an expectedDesc */
sexpr->funcResultDesc = NULL;
sexpr->funcReturnsTuple = true;
}
else
{
/* Else, we will fail if function needs an expectedDesc */
sexpr->funcResultDesc = NULL;
}
MemoryContextSwitchTo(oldcontext);
}
else
sexpr->funcResultDesc = NULL;
/* Initialize additional state */
sexpr->funcResultStore = NULL;
sexpr->funcResultSlot = NULL;
sexpr->shutdown_reg = false;
}
/*
* callback function in case a SetExprState needs to be shut down before it
* has been run to completion
*/
static void
ShutdownSetExpr(Datum arg)
{
SetExprState *sexpr = castNode(SetExprState, DatumGetPointer(arg));
/* If we have a slot, make sure it's let go of any tuplestore pointer */
if (sexpr->funcResultSlot)
ExecClearTuple(sexpr->funcResultSlot);
/* Release any open tuplestore */
if (sexpr->funcResultStore)
tuplestore_end(sexpr->funcResultStore);
sexpr->funcResultStore = NULL;
/* Clear any active set-argument state */
sexpr->setArgsValid = false;
/* execUtils will deregister the callback... */
sexpr->shutdown_reg = false;
}
/*
* Evaluate arguments for a function.
*/
static void
ExecEvalFuncArgs(FunctionCallInfo fcinfo,
List *argList,
ExprContext *econtext)
{
int i;
ListCell *arg;
i = 0;
foreach(arg, argList)
{
ExprState *argstate = (ExprState *) lfirst(arg);
fcinfo->arg[i] = ExecEvalExpr(argstate,
econtext,
&fcinfo->argnull[i]);
i++;
}
Assert(i == fcinfo->nargs);
}
/*
* ExecPrepareTuplestoreResult
*
* Subroutine for ExecMakeFunctionResultSet: prepare to extract rows from a
* tuplestore function result. We must set up a funcResultSlot (unless
* already done in a previous call cycle) and verify that the function
* returned the expected tuple descriptor.
*/
static void
ExecPrepareTuplestoreResult(SetExprState *sexpr,
ExprContext *econtext,
Tuplestorestate *resultStore,
TupleDesc resultDesc)
{
sexpr->funcResultStore = resultStore;
if (sexpr->funcResultSlot == NULL)
{
/* Create a slot so we can read data out of the tuplestore */
TupleDesc slotDesc;
MemoryContext oldcontext;
oldcontext = MemoryContextSwitchTo(sexpr->func.fn_mcxt);
/*
* If we were not able to determine the result rowtype from context,
* and the function didn't return a tupdesc, we have to fail.
*/
if (sexpr->funcResultDesc)
slotDesc = sexpr->funcResultDesc;
else if (resultDesc)
{
/* don't assume resultDesc is long-lived */
slotDesc = CreateTupleDescCopy(resultDesc);
}
else
{
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning setof record called in "
"context that cannot accept type record")));
slotDesc = NULL; /* keep compiler quiet */
}
sexpr->funcResultSlot = MakeSingleTupleTableSlot(slotDesc,
&TTSOpsMinimalTuple);
MemoryContextSwitchTo(oldcontext);
}
/*
* If function provided a tupdesc, cross-check it. We only really need to
* do this for functions returning RECORD, but might as well do it always.
*/
if (resultDesc)
{
if (sexpr->funcResultDesc)
tupledesc_match(sexpr->funcResultDesc, resultDesc);
/*
* If it is a dynamically-allocated TupleDesc, free it: it is
* typically allocated in a per-query context, so we must avoid
* leaking it across multiple usages.
*/
if (resultDesc->tdrefcount == -1)
FreeTupleDesc(resultDesc);
}
/* Register cleanup callback if we didn't already */
if (!sexpr->shutdown_reg)
{
RegisterExprContextCallback(econtext,
ShutdownSetExpr,
PointerGetDatum(sexpr));
sexpr->shutdown_reg = true;
}
}
/*
* Check that function result tuple type (src_tupdesc) matches or can
* be considered to match what the query expects (dst_tupdesc). If
* they don't match, ereport.
*
* We really only care about number of attributes and data type.
* Also, we can ignore type mismatch on columns that are dropped in the
* destination type, so long as the physical storage matches. This is
* helpful in some cases involving out-of-date cached plans.
*/
static void
tupledesc_match(TupleDesc dst_tupdesc, TupleDesc src_tupdesc)
{
int i;
if (dst_tupdesc->natts != src_tupdesc->natts)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function return row and query-specified return row do not match"),
errdetail_plural("Returned row contains %d attribute, but query expects %d.",
"Returned row contains %d attributes, but query expects %d.",
src_tupdesc->natts,
src_tupdesc->natts, dst_tupdesc->natts)));
for (i = 0; i < dst_tupdesc->natts; i++)
{
Form_pg_attribute dattr = TupleDescAttr(dst_tupdesc, i);
Form_pg_attribute sattr = TupleDescAttr(src_tupdesc, i);
if (IsBinaryCoercible(sattr->atttypid, dattr->atttypid))
continue; /* no worries */
if (!dattr->attisdropped)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function return row and query-specified return row do not match"),
errdetail("Returned type %s at ordinal position %d, but query expects %s.",
format_type_be(sattr->atttypid),
i + 1,
format_type_be(dattr->atttypid))));
if (dattr->attlen != sattr->attlen ||
dattr->attalign != sattr->attalign)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("function return row and query-specified return row do not match"),
errdetail("Physical storage mismatch on dropped attribute at ordinal position %d.",
i + 1)));
}
}
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