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Clean up the mess around EXPLAIN and materialized views.
Revert the matview-related changes in explain.c's API, as per recent complaint from Robert Haas. The reason for these appears to have been principally some ill-considered choices around having intorel_startup do what ought to be parse-time checking, plus a poor arrangement for passing it the view parsetree it needs to store into pg_rewrite when creating a materialized view. Do the latter by having parse analysis stick a copy into the IntoClause, instead of doing it at runtime. (On the whole, I seriously question the choice to represent CREATE MATERIALIZED VIEW as a variant of SELECT INTO/CREATE TABLE AS, because that means injecting even more complexity into what was already a horrid legacy kluge. However, I didn't go so far as to rethink that choice ... yet.) I also moved several error checks into matview parse analysis, and made the check for external Params in a matview more accurate. In passing, clean things up a bit more around interpretOidsOption(), and fix things so that we can use that to force no-oids for views, sequences, etc, thereby eliminating the need to cons up "oids = false" options when creating them. catversion bump due to change in IntoClause. (I wonder though if we really need readfuncs/outfuncs support for IntoClause anymore.)
1 parent 5003f94 commit 0b33790

26 files changed

+230
-226
lines changed

‎src/backend/commands/createas.c

Lines changed: 43 additions & 99 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,14 @@
11
/*-------------------------------------------------------------------------
22
*
33
* createas.c
4-
* Execution of CREATE TABLE ... AS, a/k/a SELECT INTO
4+
* Execution of CREATE TABLE ... AS, a/k/a SELECT INTO.
55
* Since CREATE MATERIALIZED VIEW shares syntax and most behaviors,
6-
* implement that here, too.
6+
* we implement that here, too.
77
*
88
* We implement this by diverting the query's normal output to a
99
* specialized DestReceiver type.
1010
*
11-
* Formerly, this command was implemented as a variant of SELECT, which led
11+
* Formerly, CTAS was implemented as a variant of SELECT, which led
1212
* to assorted legacy behaviors that we still try to preserve, notably that
1313
* we must return a tuples-processed count in the completionTag.
1414
*
@@ -33,7 +33,6 @@
3333
#include "commands/prepare.h"
3434
#include "commands/tablecmds.h"
3535
#include "commands/view.h"
36-
#include "parser/analyze.h"
3736
#include "parser/parse_clause.h"
3837
#include "rewrite/rewriteHandler.h"
3938
#include "storage/smgr.h"
@@ -48,7 +47,6 @@ typedef struct
4847
{
4948
DestReceiver pub; /* publicly-known function pointers */
5049
IntoClause *into; /* target relation specification */
51-
Query *viewParse; /* the query which defines/populates data */
5250
/* These fields are filled by intorel_startup: */
5351
Relation rel; /* relation to write to */
5452
CommandId output_cid; /* cmin to insert in output tuples */
@@ -62,62 +60,6 @@ static void intorel_shutdown(DestReceiver *self);
6260
static void intorel_destroy(DestReceiver *self);
6361

6462

65-
/*
66-
* Common setup needed by both normal execution and EXPLAIN ANALYZE.
67-
*/
68-
Query *
69-
SetupForCreateTableAs(Query *query, IntoClause *into, const char *queryString,
70-
ParamListInfo params, DestReceiver *dest)
71-
{
72-
List *rewritten;
73-
Query *viewParse = NULL;
74-
75-
Assert(query->commandType == CMD_SELECT);
76-
77-
if (into->relkind == RELKIND_MATVIEW)
78-
viewParse = (Query *) parse_analyze((Node *) copyObject(query),
79-
queryString, NULL, 0)->utilityStmt;
80-
81-
/*
82-
* Parse analysis was done already, but we still have to run the rule
83-
* rewriter. We do not do AcquireRewriteLocks: we assume the query either
84-
* came straight from the parser, or suitable locks were acquired by
85-
* plancache.c.
86-
*
87-
* Because the rewriter and planner tend to scribble on the input, we make
88-
* a preliminary copy of the source querytree. This prevents problems in
89-
* the case that CTAS is in a portal or plpgsql function and is executed
90-
* repeatedly. (See also the same hack in EXPLAIN and PREPARE.)
91-
*/
92-
rewritten = QueryRewrite((Query *) copyObject(query));
93-
94-
/* SELECT should never rewrite to more or less than one SELECT query */
95-
if (list_length(rewritten) != 1)
96-
elog(ERROR, "unexpected rewrite result for CREATE TABLE AS SELECT");
97-
query = (Query *) linitial(rewritten);
98-
99-
Assert(query->commandType == CMD_SELECT);
100-
101-
/* Save the query after rewrite but before planning. */
102-
((DR_intorel *) dest)->viewParse = viewParse;
103-
((DR_intorel *) dest)->into = into;
104-
105-
if (into->relkind == RELKIND_MATVIEW)
106-
{
107-
/*
108-
* A materialized view would either need to save parameters for use in
109-
* maintaining or loading the data or prohibit them entirely. The
110-
* latter seems safer and more sane.
111-
*/
112-
if (params != NULL && params->numParams > 0)
113-
ereport(ERROR,
114-
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
115-
errmsg("materialized views may not be defined using bound parameters")));
116-
}
117-
118-
return query;
119-
}
120-
12163
/*
12264
* ExecCreateTableAs -- execute a CREATE TABLE AS command
12365
*/
@@ -128,6 +70,7 @@ ExecCreateTableAs(CreateTableAsStmt *stmt, const char *queryString,
12870
Query *query = (Query *) stmt->query;
12971
IntoClause *into = stmt->into;
13072
DestReceiver *dest;
73+
List *rewritten;
13174
PlannedStmt *plan;
13275
QueryDesc *queryDesc;
13376
ScanDirection dir;
@@ -151,8 +94,26 @@ ExecCreateTableAs(CreateTableAsStmt *stmt, const char *queryString,
15194

15295
return;
15396
}
97+
Assert(query->commandType == CMD_SELECT);
15498

155-
query = SetupForCreateTableAs(query, into, queryString, params, dest);
99+
/*
100+
* Parse analysis was done already, but we still have to run the rule
101+
* rewriter. We do not do AcquireRewriteLocks: we assume the query either
102+
* came straight from the parser, or suitable locks were acquired by
103+
* plancache.c.
104+
*
105+
* Because the rewriter and planner tend to scribble on the input, we make
106+
* a preliminary copy of the source querytree. This prevents problems in
107+
* the case that CTAS is in a portal or plpgsql function and is executed
108+
* repeatedly. (See also the same hack in EXPLAIN and PREPARE.)
109+
*/
110+
rewritten = QueryRewrite((Query *) copyObject(query));
111+
112+
/* SELECT should never rewrite to more or less than one SELECT query */
113+
if (list_length(rewritten) != 1)
114+
elog(ERROR, "unexpected rewrite result for CREATE TABLE AS SELECT");
115+
query = (Query *) linitial(rewritten);
116+
Assert(query->commandType == CMD_SELECT);
156117

157118
/* plan the query */
158119
plan = pg_plan_query(query, 0, params);
@@ -213,20 +174,20 @@ int
213174
GetIntoRelEFlags(IntoClause *intoClause)
214175
{
215176
int flags;
177+
216178
/*
217179
* We need to tell the executor whether it has to produce OIDs or not,
218180
* because it doesn't have enough information to do so itself (since we
219181
* can't build the target relation until after ExecutorStart).
182+
*
183+
* Disallow the OIDS option for materialized views.
220184
*/
221-
if (interpretOidsOption(intoClause->options, intoClause->relkind))
185+
if (interpretOidsOption(intoClause->options,
186+
(intoClause->viewQuery == NULL)))
222187
flags = EXEC_FLAG_WITH_OIDS;
223188
else
224189
flags = EXEC_FLAG_WITHOUT_OIDS;
225190

226-
Assert(intoClause->relkind != RELKIND_MATVIEW ||
227-
(flags & (EXEC_FLAG_WITH_OIDS | EXEC_FLAG_WITHOUT_OIDS)) ==
228-
EXEC_FLAG_WITHOUT_OIDS);
229-
230191
if (intoClause->skipData)
231192
flags |= EXEC_FLAG_WITH_NO_DATA;
232193

@@ -264,6 +225,8 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
264225
{
265226
DR_intorel *myState = (DR_intorel *) self;
266227
IntoClause *into = myState->into;
228+
bool is_matview;
229+
char relkind;
267230
CreateStmt *create;
268231
Oid intoRelationId;
269232
Relation intoRelationDesc;
@@ -275,6 +238,10 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
275238

276239
Assert(into != NULL); /* else somebody forgot to set it */
277240

241+
/* This code supports both CREATE TABLE AS and CREATE MATERIALIZED VIEW */
242+
is_matview = (into->viewQuery != NULL);
243+
relkind = is_matview ? RELKIND_MATVIEW : RELKIND_RELATION;
244+
278245
/*
279246
* Create the target relation by faking up a CREATE TABLE parsetree and
280247
* passing it to DefineRelation.
@@ -352,38 +319,12 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
352319
if (lc != NULL)
353320
ereport(ERROR,
354321
(errcode(ERRCODE_SYNTAX_ERROR),
355-
errmsg("too many column names are specified")));
356-
357-
/*
358-
* Enforce validations needed for materialized views only.
359-
*/
360-
if (into->relkind == RELKIND_MATVIEW)
361-
{
362-
/*
363-
* Prohibit a data-modifying CTE in the query used to create a
364-
* materialized view. It's not sufficiently clear what the user would
365-
* want to happen if the MV is refreshed or incrementally maintained.
366-
*/
367-
if (myState->viewParse->hasModifyingCTE)
368-
ereport(ERROR,
369-
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
370-
errmsg("materialized views must not use data-modifying statements in WITH")));
371-
372-
/*
373-
* Check whether any temporary database objects are used in the
374-
* creation query. It would be hard to refresh data or incrementally
375-
* maintain it if a source disappeared.
376-
*/
377-
if (isQueryUsingTempRelation(myState->viewParse))
378-
ereport(ERROR,
379-
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
380-
errmsg("materialized views must not use temporary tables or views")));
381-
}
322+
errmsg("too many column names were specified")));
382323

383324
/*
384325
* Actually create the target table
385326
*/
386-
intoRelationId = DefineRelation(create, into->relkind, InvalidOid);
327+
intoRelationId = DefineRelation(create, relkind, InvalidOid);
387328

388329
/*
389330
* If necessary, create a TOAST table for the target table. Note that
@@ -404,9 +345,12 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
404345
AlterTableCreateToastTable(intoRelationId, toast_options);
405346

406347
/* Create the "view" part of a materialized view. */
407-
if (into->relkind == RELKIND_MATVIEW)
348+
if (is_matview)
408349
{
409-
StoreViewQuery(intoRelationId, myState->viewParse, false);
350+
/* StoreViewQuery scribbles on tree, so make a copy */
351+
Query *query = (Query *) copyObject(into->viewQuery);
352+
353+
StoreViewQuery(intoRelationId, query, false);
410354
CommandCounterIncrement();
411355
}
412356

@@ -415,7 +359,7 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
415359
*/
416360
intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
417361

418-
if (into->relkind == RELKIND_MATVIEW && !into->skipData)
362+
if (is_matview && !into->skipData)
419363
/* Make sure the heap looks good even if no rows are written. */
420364
SetMatViewToPopulated(intoRelationDesc);
421365

@@ -428,7 +372,7 @@ intorel_startup(DestReceiver *self, int operation, TupleDesc typeinfo)
428372
rte = makeNode(RangeTblEntry);
429373
rte->rtekind = RTE_RELATION;
430374
rte->relid = intoRelationId;
431-
rte->relkind = into->relkind;
375+
rte->relkind = relkind;
432376
rte->isResultRel = true;
433377
rte->requiredPerms = ACL_INSERT;
434378

‎src/backend/commands/explain.c

Lines changed: 21 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -47,7 +47,7 @@ explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
4747
#define X_NOWHITESPACE 4
4848

4949
static void ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
50-
const char *queryString, DestReceiver *dest, ParamListInfo params);
50+
const char *queryString, ParamListInfo params);
5151
static void report_triggers(ResultRelInfo *rInfo, bool show_relname,
5252
ExplainState *es);
5353
static double elapsed_time(instr_time *starttime);
@@ -219,7 +219,7 @@ ExplainQuery(ExplainStmt *stmt, const char *queryString,
219219
foreach(l, rewritten)
220220
{
221221
ExplainOneQuery((Query *) lfirst(l), NULL, &es,
222-
queryString, None_Receiver, params);
222+
queryString, params);
223223

224224
/* Separate plans with an appropriate separator */
225225
if (lnext(l) != NULL)
@@ -300,8 +300,7 @@ ExplainResultDesc(ExplainStmt *stmt)
300300
*/
301301
static void
302302
ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
303-
const char *queryString, DestReceiver *dest,
304-
ParamListInfo params)
303+
const char *queryString, ParamListInfo params)
305304
{
306305
/* planner will not cope with utility statements */
307306
if (query->commandType == CMD_UTILITY)
@@ -312,7 +311,7 @@ ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
312311

313312
/* if an advisor plugin is present, let it manage things */
314313
if (ExplainOneQuery_hook)
315-
(*ExplainOneQuery_hook) (query, into, es, queryString, dest, params);
314+
(*ExplainOneQuery_hook) (query, into, es, queryString, params);
316315
else
317316
{
318317
PlannedStmt *plan;
@@ -321,7 +320,7 @@ ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
321320
plan = pg_plan_query(query, 0, params);
322321

323322
/* run it (if needed) and produce output */
324-
ExplainOnePlan(plan, into, es, queryString, dest, params);
323+
ExplainOnePlan(plan, into, es, queryString, params);
325324
}
326325
}
327326

@@ -345,23 +344,19 @@ ExplainOneUtility(Node *utilityStmt, IntoClause *into, ExplainState *es,
345344

346345
if (IsA(utilityStmt, CreateTableAsStmt))
347346
{
348-
DestReceiver *dest;
349-
350347
/*
351348
* We have to rewrite the contained SELECT and then pass it back to
352349
* ExplainOneQuery. It's probably not really necessary to copy the
353350
* contained parsetree another time, but let's be safe.
354351
*/
355352
CreateTableAsStmt *ctas = (CreateTableAsStmt *) utilityStmt;
356-
Query *query = (Query *) ctas->query;
357-
358-
dest = CreateIntoRelDestReceiver(into);
353+
List *rewritten;
359354

360355
Assert(IsA(ctas->query, Query));
361-
362-
query = SetupForCreateTableAs(query, ctas->into, queryString, params, dest);
363-
364-
ExplainOneQuery(query, ctas->into, es, queryString, dest, params);
356+
rewritten = QueryRewrite((Query *) copyObject(ctas->query));
357+
Assert(list_length(rewritten) == 1);
358+
ExplainOneQuery((Query *) linitial(rewritten), ctas->into, es,
359+
queryString, params);
365360
}
366361
else if (IsA(utilityStmt, ExecuteStmt))
367362
ExplainExecuteQuery((ExecuteStmt *) utilityStmt, into, es,
@@ -402,8 +397,9 @@ ExplainOneUtility(Node *utilityStmt, IntoClause *into, ExplainState *es,
402397
*/
403398
void
404399
ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
405-
const char *queryString, DestReceiver *dest, ParamListInfo params)
400+
const char *queryString, ParamListInfo params)
406401
{
402+
DestReceiver *dest;
407403
QueryDesc *queryDesc;
408404
instr_time starttime;
409405
double totaltime = 0;
@@ -427,6 +423,15 @@ ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
427423
PushCopiedSnapshot(GetActiveSnapshot());
428424
UpdateActiveSnapshotCommandId();
429425

426+
/*
427+
* Normally we discard the query's output, but if explaining CREATE TABLE
428+
* AS, we'd better use the appropriate tuple receiver.
429+
*/
430+
if (into)
431+
dest = CreateIntoRelDestReceiver(into);
432+
else
433+
dest = None_Receiver;
434+
430435
/* Create a QueryDesc for the query */
431436
queryDesc = CreateQueryDesc(plannedstmt, queryString,
432437
GetActiveSnapshot(), InvalidSnapshot,

‎src/backend/commands/prepare.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -665,7 +665,7 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
665665
PlannedStmt *pstmt = (PlannedStmt *) lfirst(p);
666666

667667
if (IsA(pstmt, PlannedStmt))
668-
ExplainOnePlan(pstmt, into, es, query_string, None_Receiver, paramLI);
668+
ExplainOnePlan(pstmt, into, es, query_string, paramLI);
669669
else
670670
ExplainOneUtility((Node *) pstmt, into, es, query_string, paramLI);
671671

‎src/backend/commands/sequence.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -210,7 +210,7 @@ DefineSequence(CreateSeqStmt *seq)
210210
stmt->relation = seq->sequence;
211211
stmt->inhRelations = NIL;
212212
stmt->constraints = NIL;
213-
stmt->options = list_make1(defWithOids(false));
213+
stmt->options = NIL;
214214
stmt->oncommit = ONCOMMIT_NOOP;
215215
stmt->tablespacename = NULL;
216216
stmt->if_not_exists = false;

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