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Clean up and simplify code in a couple of set-returning functions 

The following set-returning functions have their logic simplified, to be
more consistent with other in-core areas:
- pg_prepared_statement()'s tuple descriptor is now created with
get_call_result_type() instead of being created from scratch, saving
from some duplication with pg_proc.dat.
- show_all_file_settings(), similarly, now uses get_call_result_type()
to build its tuple descriptor instead of creating it from scratch.
- pg_options_to_table() made use of a static routine called only once.
This commit removes this internal routine to make the function easier to
follow.
- pg_config() was using a unique logic style, doing checks on the tuple
descriptor passed down in expectedDesc, but it has no need to do so.
This switches the function to use a tuplestore with a tuple descriptor
retrieved from get_call_result_type(), instead.

This simplifies an upcoming patch aimed at refactoring the way
tuplestores are created and checked in set-returning functions, this
change making sense as its own independent cleanup by shaving some
code.

Author: Melanie Plageman, Michael Paquier
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/CAAKRu_azyd1Z3W_r7Ou4sorTjRCs+PxeHw1CWJeXKofkE6TuZg@mail.gmail.com
This commit is contained in:
Michael Paquier 2022-02-24 16:11:34 +09:00
parent 04e706d423
commit fcc28178c6
5 changed files with 50 additions and 130 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
src/backend/commands/prepare.c
View File

@ -22,6 +22,7 @@
#include "catalog/pg_type.h"
#include "commands/createas.h"
#include "commands/prepare.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/analyze.h"
@ -716,30 +717,13 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/* need to build tuplestore in query context */
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/*
* build tupdesc for result tuples. This must match the definition of the
* pg_prepared_statements view in system_views.sql
*/
tupdesc = CreateTemplateTupleDesc(7);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "prepare_time",
TIMESTAMPTZOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "parameter_types",
REGTYPEARRAYOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "from_sql",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "generic_plans",
INT8OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 7, "custom_plans",
INT8OID, -1, 0);
/*
* We put all the tuples into a tuplestore in one scan of the hashtable.
* This avoids any issue of the hashtable possibly changing between calls.
@ -747,6 +731,9 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
tupstore =
tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random,
false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
/* generate junk in short-term context */
MemoryContextSwitchTo(oldcontext);
@ -778,10 +765,6 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
}
}
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
return (Datum) 0;
}

37
src/backend/foreign/foreign.c
View File

@ -499,17 +499,19 @@ IsImportableForeignTable(const char *tablename,
/*
* deflist_to_tuplestore - Helper function to convert DefElem list to
* tuplestore usable in SRF.
* pg_options_to_table - Convert options array to name/value table
*
* This is useful to provide details for information_schema and pg_dump.
*/
static void
deflist_to_tuplestore(ReturnSetInfo *rsinfo, List *options)
Datum
pg_options_to_table(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
ListCell *cell;
List *options;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
Datum values[2];
bool nulls[2];
MemoryContext per_query_ctx;
MemoryContext oldcontext;
@ -524,6 +526,9 @@ deflist_to_tuplestore(ReturnSetInfo *rsinfo, List *options)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
options = untransformRelOptions(array);
rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
@ -536,9 +541,13 @@ deflist_to_tuplestore(ReturnSetInfo *rsinfo, List *options)
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
foreach(cell, options)
{
DefElem *def = lfirst(cell);
Datum values[2];
bool nulls[2];
values[0] = CStringGetTextDatum(def->defname);
nulls[0] = false;
@ -555,22 +564,6 @@ deflist_to_tuplestore(ReturnSetInfo *rsinfo, List *options)
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
MemoryContextSwitchTo(oldcontext);
}
/*
* Convert options array to name/value table. Useful for information
* schema and pg_dump.
*/
Datum
pg_options_to_table(PG_FUNCTION_ARGS)
{
Datum array = PG_GETARG_DATUM(0);
deflist_to_tuplestore((ReturnSetInfo *) fcinfo->resultinfo,
untransformRelOptions(array));
return (Datum) 0;
}

20
src/backend/utils/misc/guc.c
View File

@ -10174,6 +10174,9 @@ show_all_file_settings(PG_FUNCTION_ARGS)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/* Scan the config files using current context as workspace */
conf = ProcessConfigFileInternal(PGC_SIGHUP, false, DEBUG3);
@ -10181,23 +10184,6 @@ show_all_file_settings(PG_FUNCTION_ARGS)
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/* Build a tuple descriptor for our result type */
tupdesc = CreateTemplateTupleDesc(NUM_PG_FILE_SETTINGS_ATTS);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "sourcefile",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "sourceline",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "seqno",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "name",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "setting",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "applied",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 7, "error",
TEXTOID, -1, 0);
/* Build a tuplestore to return our results in */
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;

69
src/backend/utils/misc/pg_config.c
View File

@ -26,14 +26,10 @@ pg_config(PG_FUNCTION_ARGS)
{
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
Tuplestorestate *tupstore;
HeapTuple tuple;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
ConfigData *configdata;
size_t configdata_len;
char *values[2];
int i = 0;
/* check to see if caller supports us returning a tuplestore */
@ -41,65 +37,38 @@ pg_config(PG_FUNCTION_ARGS)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize) ||
rsinfo->expectedDesc == NULL)
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/* get the requested return tuple description */
tupdesc = CreateTupleDescCopy(rsinfo->expectedDesc);
/* Build tuplestore to hold the result rows */
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
/*
* Check to make sure we have a reasonable tuple descriptor
*/
if (tupdesc->natts != 2 ||
TupleDescAttr(tupdesc, 0)->atttypid != TEXTOID ||
TupleDescAttr(tupdesc, 1)->atttypid != TEXTOID)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("query-specified return tuple and "
"function return type are not compatible")));
/* OK to use it */
attinmeta = TupleDescGetAttInMetadata(tupdesc);
/* let the caller know we're sending back a tuplestore */
rsinfo->returnMode = SFRM_Materialize;
/* initialize our tuplestore */
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
configdata = get_configdata(my_exec_path, &configdata_len);
for (i = 0; i < configdata_len; i++)
{
values[0] = configdata[i].name;
values[1] = configdata[i].setting;
Datum values[2];
bool nulls[2];
tuple = BuildTupleFromCStrings(attinmeta, values);
tuplestore_puttuple(tupstore, tuple);
memset(values, 0, sizeof(values));
memset(nulls, 0, sizeof(nulls));
values[0] = CStringGetTextDatum(configdata[i].name);
values[1] = CStringGetTextDatum(configdata[i].setting);
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
/*
* no longer need the tuple descriptor reference created by
* TupleDescGetAttInMetadata()
*/
ReleaseTupleDesc(tupdesc);
rsinfo->setResult = tupstore;
/*
* SFRM_Materialize mode expects us to return a NULL Datum. The actual
* tuples are in our tuplestore and passed back through rsinfo->setResult.
* rsinfo->setDesc is set to the tuple description that we actually used
* to build our tuples with, so the caller can verify we did what it was
* expecting.
*/
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
return (Datum) 0;
}

23
src/backend/utils/mmgr/portalmem.c
View File

@ -21,6 +21,7 @@
#include "access/xact.h"
#include "catalog/pg_type.h"
#include "commands/portalcmds.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "storage/ipc.h"
#include "utils/builtins.h"
@ -1152,23 +1153,8 @@ pg_cursor(PG_FUNCTION_ARGS)
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
/*
* build tupdesc for result tuples. This must match the definition of the
* pg_cursors view in system_views.sql
*/
tupdesc = CreateTemplateTupleDesc(6);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "is_holdable",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "is_binary",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "is_scrollable",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "creation_time",
TIMESTAMPTZOID, -1, 0);
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/*
* We put all the tuples into a tuplestore in one scan of the hashtable.
@ -1177,6 +1163,9 @@ pg_cursor(PG_FUNCTION_ARGS)
tupstore =
tuplestore_begin_heap(rsinfo->allowedModes & SFRM_Materialize_Random,
false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
/* generate junk in short-term context */
MemoryContextSwitchTo(oldcontext);