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Commitbbbe825

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Modify processing of DECLARE CURSOR and EXPLAIN so that they can resolve the
types of unspecified parameters when submitted via extended query protocol.This worked in 8.2 but I had broken it during plancache changes. DECLARECURSOR is now treated almost exactly like a plain SELECT through parseanalysis, rewrite, and planning; only just before sending to the executordo we divert it away to ProcessUtility. This requires a special-case checkin a number of places, but practically all of them were already special-casingSELECT INTO, so it's not too ugly. (Maybe it would be a good idea to mergethe two by treating IntoClause as a form of utility statement? Not going toworry about that now, though.) That approach doesn't work for EXPLAIN,however, so for that I punted and used a klugy solution of running parseanalysis an extra time if under extended query protocol.
1 parenta264671 commitbbbe825

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26 files changed

+333
-246
lines changed

26 files changed

+333
-246
lines changed

‎src/backend/commands/copy.c

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.282 2007/04/18 02:28:22 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.283 2007/04/27 22:05:46 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -1015,9 +1015,10 @@ DoCopy(const CopyStmt *stmt, const char *queryString)
10151015

10161016
query= (Query*)linitial(rewritten);
10171017
Assert(query->commandType==CMD_SELECT);
1018+
Assert(query->utilityStmt==NULL);
10181019

10191020
/* Query mustn't use INTO, either */
1020-
if (query->into)
1021+
if (query->intoClause)
10211022
ereport(ERROR,
10221023
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
10231024
errmsg("COPY (SELECT INTO) is not supported")));

‎src/backend/commands/explain.c

Lines changed: 13 additions & 54 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1994-5, Regents of the University of California
88
*
99
* IDENTIFICATION
10-
* $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.161 2007/04/16 01:14:55 tgl Exp $
10+
* $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.162 2007/04/27 22:05:47 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -42,8 +42,8 @@ typedef struct ExplainState
4242
List*rtable;/* range table */
4343
}ExplainState;
4444

45-
staticvoidExplainOneQuery(Query*query,intcursorOptions,
46-
ExplainStmt*stmt,constchar*queryString,
45+
staticvoidExplainOneQuery(Query*query,ExplainStmt*stmt,
46+
constchar*queryString,
4747
ParamListInfoparams,TupOutputState*tstate);
4848
staticdoubleelapsed_time(instr_time*starttime);
4949
staticvoidexplain_outNode(StringInfostr,
@@ -102,8 +102,8 @@ ExplainQuery(ExplainStmt *stmt, const char *queryString,
102102
/* Explain every plan */
103103
foreach(l,rewritten)
104104
{
105-
ExplainOneQuery((Query*)lfirst(l),0,
106-
stmt,queryString,params,tstate);
105+
ExplainOneQuery((Query*)lfirst(l),stmt,
106+
queryString,params,tstate);
107107
/* put a blank line between plans */
108108
if (lnext(l)!=NULL)
109109
do_text_output_oneline(tstate,"");
@@ -134,8 +134,7 @@ ExplainResultDesc(ExplainStmt *stmt)
134134
* print out the execution plan for one Query
135135
*/
136136
staticvoid
137-
ExplainOneQuery(Query*query,intcursorOptions,
138-
ExplainStmt*stmt,constchar*queryString,
137+
ExplainOneQuery(Query*query,ExplainStmt*stmt,constchar*queryString,
139138
ParamListInfoparams,TupOutputState*tstate)
140139
{
141140
PlannedStmt*plan;
@@ -150,7 +149,7 @@ ExplainOneQuery(Query *query, int cursorOptions,
150149
}
151150

152151
/* plan the query */
153-
plan=planner(query,cursorOptions,params);
152+
plan=planner(query,0,params);
154153

155154
/*
156155
* Update snapshot command ID to ensure this query sees results of any
@@ -187,52 +186,7 @@ ExplainOneUtility(Node *utilityStmt, ExplainStmt *stmt,
187186
if (utilityStmt==NULL)
188187
return;
189188

190-
if (IsA(utilityStmt,DeclareCursorStmt))
191-
{
192-
DeclareCursorStmt*dcstmt= (DeclareCursorStmt*)utilityStmt;
193-
Oid*param_types;
194-
intnum_params;
195-
Query*query;
196-
List*rewritten;
197-
ExplainStmtnewstmt;
198-
199-
/* Convert parameter type data to the form parser wants */
200-
getParamListTypes(params,&param_types,&num_params);
201-
202-
/*
203-
* Run parse analysis and rewrite. Note this also acquires sufficient
204-
* locks on the source table(s).
205-
*
206-
* Because the parser and planner tend to scribble on their input, we
207-
* make a preliminary copy of the source querytree. This prevents
208-
* problems in the case that the DECLARE CURSOR is in a portal or
209-
* plpgsql function and is executed repeatedly. (See also the same
210-
* hack in COPY and PREPARE.) XXX FIXME someday.
211-
*/
212-
rewritten=pg_analyze_and_rewrite((Node*)copyObject(dcstmt->query),
213-
queryString,
214-
param_types,num_params);
215-
216-
/* We don't expect more or less than one result query */
217-
if (list_length(rewritten)!=1|| !IsA(linitial(rewritten),Query))
218-
elog(ERROR,"unexpected rewrite result");
219-
query= (Query*)linitial(rewritten);
220-
if (query->commandType!=CMD_SELECT)
221-
elog(ERROR,"unexpected rewrite result");
222-
223-
/* But we must explicitly disallow DECLARE CURSOR ... SELECT INTO */
224-
if (query->into)
225-
ereport(ERROR,
226-
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
227-
errmsg("DECLARE CURSOR cannot specify INTO")));
228-
229-
/* do not actually execute the underlying query! */
230-
memcpy(&newstmt,stmt,sizeof(ExplainStmt));
231-
newstmt.analyze= false;
232-
ExplainOneQuery(query,dcstmt->options,&newstmt,
233-
queryString,params,tstate);
234-
}
235-
elseif (IsA(utilityStmt,ExecuteStmt))
189+
if (IsA(utilityStmt,ExecuteStmt))
236190
ExplainExecuteQuery((ExecuteStmt*)utilityStmt,stmt,
237191
queryString,params,tstate);
238192
elseif (IsA(utilityStmt,NotifyStmt))
@@ -247,6 +201,11 @@ ExplainOneUtility(Node *utilityStmt, ExplainStmt *stmt,
247201
*given a planned query, execute it if needed, and then print
248202
*EXPLAIN output
249203
*
204+
* Since we ignore any DeclareCursorStmt that might be attached to the query,
205+
* if you say EXPLAIN ANALYZE DECLARE CURSOR then we'll actually run the
206+
* query. This is different from pre-8.3 behavior but seems more useful than
207+
* not running the query. No cursor will be created, however.
208+
*
250209
* This is exported because it's called back from prepare.c in the
251210
* EXPLAIN EXECUTE case
252211
*

‎src/backend/commands/portalcmds.c

Lines changed: 18 additions & 64 deletions
Original file line numberDiff line numberDiff line change
@@ -14,7 +14,7 @@
1414
*
1515
*
1616
* IDENTIFICATION
17-
* $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.64 2007/04/16 01:14:55 tgl Exp $
17+
* $PostgreSQL: pgsql/src/backend/commands/portalcmds.c,v 1.65 2007/04/27 22:05:47 tgl Exp $
1818
*
1919
*-------------------------------------------------------------------------
2020
*/
@@ -26,34 +26,34 @@
2626
#include"access/xact.h"
2727
#include"commands/portalcmds.h"
2828
#include"executor/executor.h"
29-
#include"optimizer/planner.h"
30-
#include"rewrite/rewriteHandler.h"
3129
#include"tcop/pquery.h"
32-
#include"tcop/tcopprot.h"
3330
#include"utils/memutils.h"
3431

3532

3633
/*
3734
* PerformCursorOpen
3835
*Execute SQL DECLARE CURSOR command.
36+
*
37+
* The query has already been through parse analysis, rewriting, and planning.
38+
* When it gets here, it looks like a SELECT PlannedStmt, except that the
39+
* utilityStmt field is set.
3940
*/
4041
void
41-
PerformCursorOpen(DeclareCursorStmt*stmt,ParamListInfoparams,
42+
PerformCursorOpen(PlannedStmt*stmt,ParamListInfoparams,
4243
constchar*queryString,boolisTopLevel)
4344
{
44-
Oid*param_types;
45-
intnum_params;
46-
List*rewritten;
47-
Query*query;
48-
PlannedStmt*plan;
45+
DeclareCursorStmt*cstmt= (DeclareCursorStmt*)stmt->utilityStmt;
4946
Portalportal;
5047
MemoryContextoldContext;
5148

49+
if (cstmt==NULL|| !IsA(cstmt,DeclareCursorStmt))
50+
elog(ERROR,"PerformCursorOpen called for non-cursor query");
51+
5252
/*
5353
* Disallow empty-string cursor name (conflicts with protocol-level
5454
* unnamed portal).
5555
*/
56-
if (!stmt->portalname||stmt->portalname[0]=='\0')
56+
if (!cstmt->portalname||cstmt->portalname[0]=='\0')
5757
ereport(ERROR,
5858
(errcode(ERRCODE_INVALID_CURSOR_NAME),
5959
errmsg("invalid cursor name: must not be empty")));
@@ -63,70 +63,24 @@ PerformCursorOpen(DeclareCursorStmt *stmt, ParamListInfo params,
6363
* been executed inside a transaction block (or else, it would have no
6464
* user-visible effect).
6565
*/
66-
if (!(stmt->options&CURSOR_OPT_HOLD))
66+
if (!(cstmt->options&CURSOR_OPT_HOLD))
6767
RequireTransactionChain(isTopLevel,"DECLARE CURSOR");
6868

69-
/*
70-
* Don't allow both SCROLL and NO SCROLL to be specified
71-
*/
72-
if ((stmt->options&CURSOR_OPT_SCROLL)&&
73-
(stmt->options&CURSOR_OPT_NO_SCROLL))
74-
ereport(ERROR,
75-
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
76-
errmsg("cannot specify both SCROLL and NO SCROLL")));
77-
78-
/* Convert parameter type data to the form parser wants */
79-
getParamListTypes(params,&param_types,&num_params);
80-
81-
/*
82-
* Run parse analysis and rewrite. Note this also acquires sufficient
83-
* locks on the source table(s).
84-
*
85-
* Because the parser and planner tend to scribble on their input, we
86-
* make a preliminary copy of the source querytree. This prevents
87-
* problems in the case that the DECLARE CURSOR is in a portal or plpgsql
88-
* function and is executed repeatedly. (See also the same hack in
89-
* COPY and PREPARE.) XXX FIXME someday.
90-
*/
91-
rewritten=pg_analyze_and_rewrite((Node*)copyObject(stmt->query),
92-
queryString,param_types,num_params);
93-
94-
/* We don't expect more or less than one result query */
95-
if (list_length(rewritten)!=1|| !IsA(linitial(rewritten),Query))
96-
elog(ERROR,"unexpected rewrite result");
97-
query= (Query*)linitial(rewritten);
98-
if (query->commandType!=CMD_SELECT)
99-
elog(ERROR,"unexpected rewrite result");
100-
101-
/* But we must explicitly disallow DECLARE CURSOR ... SELECT INTO */
102-
if (query->into)
103-
ereport(ERROR,
104-
(errcode(ERRCODE_INVALID_CURSOR_DEFINITION),
105-
errmsg("DECLARE CURSOR cannot specify INTO")));
106-
107-
if (query->rowMarks!=NIL)
108-
ereport(ERROR,
109-
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
110-
errmsg("DECLARE CURSOR ... FOR UPDATE/SHARE is not supported"),
111-
errdetail("Cursors must be READ ONLY.")));
112-
113-
/* plan the query */
114-
plan=planner(query,stmt->options,params);
115-
11669
/*
11770
* Create a portal and copy the plan into its memory context.
11871
*/
119-
portal=CreatePortal(stmt->portalname, false, false);
72+
portal=CreatePortal(cstmt->portalname, false, false);
12073

12174
oldContext=MemoryContextSwitchTo(PortalGetHeapMemory(portal));
12275

123-
plan=copyObject(plan);
76+
stmt=copyObject(stmt);
77+
stmt->utilityStmt=NULL;/* make it look like plain SELECT */
12478

12579
PortalDefineQuery(portal,
12680
NULL,
12781
queryString,
12882
"SELECT",/* cursor's query is always a SELECT */
129-
list_make1(plan),
83+
list_make1(stmt),
13084
NULL);
13185

13286
/*----------
@@ -150,10 +104,10 @@ PerformCursorOpen(DeclareCursorStmt *stmt, ParamListInfo params,
150104
* based on whether it would require any additional runtime overhead to do
151105
* so.
152106
*/
153-
portal->cursorOptions=stmt->options;
107+
portal->cursorOptions=cstmt->options;
154108
if (!(portal->cursorOptions& (CURSOR_OPT_SCROLL |CURSOR_OPT_NO_SCROLL)))
155109
{
156-
if (ExecSupportsBackwardScan(plan->planTree))
110+
if (ExecSupportsBackwardScan(stmt->planTree))
157111
portal->cursorOptions |=CURSOR_OPT_SCROLL;
158112
else
159113
portal->cursorOptions |=CURSOR_OPT_NO_SCROLL;

‎src/backend/commands/prepare.c

Lines changed: 9 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
* Copyright (c) 2002-2007, PostgreSQL Global Development Group
1111
*
1212
* IDENTIFICATION
13-
* $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.74 2007/04/26 23:24:44 tgl Exp $
13+
* $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.75 2007/04/27 22:05:47 tgl Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -57,7 +57,6 @@ PrepareQuery(PrepareStmt *stmt, const char *queryString)
5757
intnargs;
5858
List*queries;
5959
Query*query;
60-
constchar*commandTag;
6160
List*query_list,
6261
*plan_list;
6362
inti;
@@ -137,22 +136,15 @@ PrepareQuery(PrepareStmt *stmt, const char *queryString)
137136
switch (query->commandType)
138137
{
139138
caseCMD_SELECT:
140-
commandTag="SELECT";
141-
break;
142139
caseCMD_INSERT:
143-
commandTag="INSERT";
144-
break;
145140
caseCMD_UPDATE:
146-
commandTag="UPDATE";
147-
break;
148141
caseCMD_DELETE:
149-
commandTag="DELETE";
142+
/* OK */
150143
break;
151144
default:
152145
ereport(ERROR,
153146
(errcode(ERRCODE_INVALID_PSTATEMENT_DEFINITION),
154147
errmsg("utility statements cannot be prepared")));
155-
commandTag=NULL;/* keep compiler quiet */
156148
break;
157149
}
158150

@@ -168,7 +160,7 @@ PrepareQuery(PrepareStmt *stmt, const char *queryString)
168160
StorePreparedStatement(stmt->name,
169161
stmt->query,
170162
queryString,
171-
commandTag,
163+
CreateCommandTag((Node*)query),
172164
argtypes,
173165
nargs,
174166
0,/* default cursor options */
@@ -244,11 +236,12 @@ ExecuteQuery(ExecuteStmt *stmt, const char *queryString,
244236
errmsg("prepared statement is not a SELECT")));
245237
pstmt= (PlannedStmt*)linitial(plan_list);
246238
if (!IsA(pstmt,PlannedStmt)||
247-
pstmt->commandType!=CMD_SELECT)
239+
pstmt->commandType!=CMD_SELECT||
240+
pstmt->utilityStmt!=NULL)
248241
ereport(ERROR,
249242
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
250243
errmsg("prepared statement is not a SELECT")));
251-
pstmt->into=copyObject(stmt->into);
244+
pstmt->intoClause=copyObject(stmt->into);
252245

253246
MemoryContextSwitchTo(oldContext);
254247

@@ -689,15 +682,16 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, ExplainStmt *stmt,
689682

690683
if (execstmt->into)
691684
{
692-
if (pstmt->commandType!=CMD_SELECT)
685+
if (pstmt->commandType!=CMD_SELECT||
686+
pstmt->utilityStmt!=NULL)
693687
ereport(ERROR,
694688
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
695689
errmsg("prepared statement is not a SELECT")));
696690

697691
/* Copy the stmt so we can modify it */
698692
pstmt=copyObject(pstmt);
699693

700-
pstmt->into=execstmt->into;
694+
pstmt->intoClause=execstmt->into;
701695
}
702696

703697
/*

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