Implement EXPLAIN EXECUTE. By Neil Conway, with some kibitzing from
Tom Lane.
This commit is contained in:
Tom Lane
parent
6adb475f77
commit
c7bceca156
|
|
@ -1,5 +1,5 @@
|
|||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/execute.sgml,v 1.2 2003/01/19 00:13:29 momjian Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/execute.sgml,v 1.3 2003/02/02 23:46:37 tgl Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
|
|
@ -99,9 +99,9 @@ PostgreSQL documentation
|
|||
|
||||
<para>
|
||||
Like <command>SELECT INTO</command>, <command>EXECUTE</command> can
|
||||
be used to store the results of executing the query in a table by
|
||||
specifying an INTO clause. For more information on this behabior,
|
||||
consult the reference for <xref linkend="sql-selectinto">.
|
||||
store the results of executing the query into a newly-created
|
||||
table, by specifying an INTO clause. For more information on this behavior,
|
||||
see <xref linkend="sql-selectinto" endterm="sql-selectinto-title">.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
|
|
|
|||
|
|
@ -1,5 +1,5 @@
|
|||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/explain.sgml,v 1.22 2003/01/19 00:13:29 momjian Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/explain.sgml,v 1.23 2003/02/02 23:46:37 tgl Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
|
|
@ -55,7 +55,8 @@ EXPLAIN [ ANALYZE ] [ VERBOSE ] <replaceable class="PARAMETER">query</replaceabl
|
|||
<term><replaceable class="PARAMETER">query</replaceable></term>
|
||||
<listitem>
|
||||
<para>
|
||||
Any <replaceable class="PARAMETER">query</replaceable>.
|
||||
Any <command>SELECT</>, <command>INSERT</>, <command>UPDATE</>,
|
||||
<command>DELETE</>, or <command>EXECUTE</> query.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
|
@ -132,13 +133,13 @@ EXPLAIN [ ANALYZE ] [ VERBOSE ] <replaceable class="PARAMETER">query</replaceabl
|
|||
<para>
|
||||
In order to allow the <productname>PostgreSQL</productname> query
|
||||
planner to make reasonably informed decisions when optimizing
|
||||
queries, the <command>ANALYZE</command> statement should be used
|
||||
queries, the <command>ANALYZE</command> statement should be run
|
||||
to record statistics about the distribution of data within the
|
||||
table. If you have not done this (or the statistical distribution
|
||||
table. If you have not done this (or if the statistical distribution
|
||||
of the data in the table has changed significantly since the last
|
||||
time <command>ANALYZE</command> was run), the estimated costs and
|
||||
the resulting query plan displayed by <command>EXPLAIN</command>
|
||||
are unlikely to conform to the real properties of the query.
|
||||
time <command>ANALYZE</command> was run), the estimated costs
|
||||
are unlikely to conform to the real properties of the query,
|
||||
and consequently an inferior query plan may be chosen.
|
||||
</para>
|
||||
</note>
|
||||
|
||||
|
|
@ -147,7 +148,7 @@ EXPLAIN [ ANALYZE ] [ VERBOSE ] <replaceable class="PARAMETER">query</replaceabl
|
|||
planned. The total elapsed time expended within each plan node (in
|
||||
milliseconds) and total number of rows it actually returned are added to
|
||||
the display. This is useful for seeing whether the planner's estimates
|
||||
are close to the actual performance of the query.
|
||||
are close to reality.
|
||||
</para>
|
||||
|
||||
<caution>
|
||||
|
|
@ -157,8 +158,8 @@ EXPLAIN [ ANALYZE ] [ VERBOSE ] <replaceable class="PARAMETER">query</replaceabl
|
|||
would return,
|
||||
other side-effects of the query will happen as usual.
|
||||
If you wish to use <command>EXPLAIN ANALYZE</command> on an INSERT,
|
||||
UPDATE, or DELETE query without letting the query affect your data,
|
||||
use this approach:
|
||||
UPDATE, DELETE, or EXECUTE query without letting the query affect your
|
||||
data, use this approach:
|
||||
<programlisting>
|
||||
BEGIN;
|
||||
EXPLAIN ANALYZE ...;
|
||||
|
|
@ -244,13 +245,35 @@ EXPLAIN SELECT sum(i) FROM foo WHERE i < 10;
|
|||
</programlisting>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Here is an example of using EXPLAIN EXECUTE to display the query
|
||||
plan for a prepared query:
|
||||
|
||||
<programlisting>
|
||||
PREPARE query(int, int) AS SELECT sum(bar) FROM test
|
||||
WHERE id > $1 AND id < $2
|
||||
GROUP BY foo;
|
||||
|
||||
EXPLAIN ANALYZE EXECUTE query(100, 200);
|
||||
<computeroutput>
|
||||
QUERY PLAN
|
||||
-------------------------------------------------------------------------------------------------------------------------
|
||||
HashAggregate (cost=39.53..39.53 rows=1 width=8) (actual time=0.66..0.67 rows=7 loops=1)
|
||||
-> Index Scan using test_pkey on test (cost=0.00..32.97 rows=1311 width=8) (actual time=0.05..0.39 rows=99 loops=1)
|
||||
Index Cond: ((id > $1) AND (id < $2))
|
||||
Total runtime: 0.85 msec
|
||||
(4 rows)
|
||||
</computeroutput>
|
||||
</programlisting>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Note that the specific numbers shown, and even the selected query
|
||||
strategy, may vary between <productname>PostgreSQL</productname>
|
||||
releases due to planner improvements. In addition, the algorithm
|
||||
used by <command>ANALYZE</command> to generate statistics is not
|
||||
completely deterministic; therefore, it is possible (although not
|
||||
likely) for cost estimations to change between runs of
|
||||
releases due to planner improvements. In addition, the
|
||||
<command>ANALYZE</command> command uses random sampling to estimate
|
||||
data statistics; therefore, it is possible
|
||||
for cost estimates to change after a fresh run of
|
||||
<command>ANALYZE</command>, even if the actual distribution of data
|
||||
in the table has not changed.
|
||||
</para>
|
||||
|
|
|
|||
|
|
@ -1,5 +1,5 @@
|
|||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/prepare.sgml,v 1.1 2002/08/27 04:55:07 tgl Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/ref/prepare.sgml,v 1.2 2003/02/02 23:46:37 tgl Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
|
|
@ -156,7 +156,9 @@ PostgreSQL documentation
|
|||
constant values in a query to make guesses about the likely
|
||||
result of executing the query. Since this data is unavailable when
|
||||
planning prepared queries with parameters, the chosen plan may be
|
||||
sub-optimal.
|
||||
sub-optimal. To examine the query plan
|
||||
<productname>PostgreSQL</productname> has chosen for a prepared
|
||||
query, use <command>EXPLAIN EXECUTE</command>.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
|
|
|
|||
|
|
@ -1,5 +1,5 @@
|
|||
<!--
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.183 2003/02/02 19:48:20 tgl Exp $
|
||||
$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.184 2003/02/02 23:46:38 tgl Exp $
|
||||
-->
|
||||
|
||||
<appendix id="release">
|
||||
|
|
@ -24,6 +24,7 @@ CDATA means the content is "SGML-free", so you can write without
|
|||
worries about funny characters.
|
||||
-->
|
||||
<literallayout><![CDATA[
|
||||
Can now do EXPLAIN ... EXECUTE to see plan used for a prepared query
|
||||
Explicit JOINs no longer constrain query plan, unless JOIN_COLLAPSE_LIMIT = 1
|
||||
Performance of "foo IN (SELECT ...)" queries has been considerably improved
|
||||
FETCH 0 now re-fetches cursor's current row, per SQL spec
|
||||
|
|
|
|||
|
|
@ -1,20 +1,23 @@
|
|||
/*
|
||||
/*-------------------------------------------------------------------------
|
||||
*
|
||||
* explain.c
|
||||
* Explain the query execution plan
|
||||
* Explain query execution plans
|
||||
*
|
||||
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994-5, Regents of the University of California
|
||||
*
|
||||
* $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.99 2002/12/15 16:17:38 tgl Exp $
|
||||
* IDENTIFICATION
|
||||
* $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.100 2003/02/02 23:46:38 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
||||
#include "postgres.h"
|
||||
|
||||
#include "access/genam.h"
|
||||
#include "access/heapam.h"
|
||||
#include "catalog/pg_type.h"
|
||||
#include "commands/explain.h"
|
||||
#include "commands/prepare.h"
|
||||
#include "executor/executor.h"
|
||||
#include "executor/instrument.h"
|
||||
#include "lib/stringinfo.h"
|
||||
|
|
@ -81,8 +84,11 @@ ExplainQuery(ExplainStmt *stmt, CommandDest dest)
|
|||
|
||||
if (query->commandType == CMD_UTILITY)
|
||||
{
|
||||
/* rewriter will not cope with utility statements */
|
||||
do_text_output_oneline(tstate, "Utility statements have no plan structure");
|
||||
/* Rewriter will not cope with utility statements */
|
||||
if (query->utilityStmt && IsA(query->utilityStmt, ExecuteStmt))
|
||||
ExplainExecuteQuery(stmt, tstate);
|
||||
else
|
||||
do_text_output_oneline(tstate, "Utility statements have no plan structure");
|
||||
}
|
||||
else
|
||||
{
|
||||
|
|
@ -119,10 +125,6 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, TupOutputState *tstate)
|
|||
{
|
||||
Plan *plan;
|
||||
QueryDesc *queryDesc;
|
||||
ExplainState *es;
|
||||
StringInfo str;
|
||||
double totaltime = 0;
|
||||
struct timeval starttime;
|
||||
|
||||
/* planner will not cope with utility statements */
|
||||
if (query->commandType == CMD_UTILITY)
|
||||
|
|
@ -134,6 +136,13 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, TupOutputState *tstate)
|
|||
return;
|
||||
}
|
||||
|
||||
/*
|
||||
* We don't support DECLARE CURSOR in EXPLAIN, but parser will take it
|
||||
* because it's an OptimizableStmt
|
||||
*/
|
||||
if (query->isPortal)
|
||||
elog(ERROR, "EXPLAIN / DECLARE CURSOR is not supported");
|
||||
|
||||
/* plan the query */
|
||||
plan = planner(query);
|
||||
|
||||
|
|
@ -141,15 +150,34 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, TupOutputState *tstate)
|
|||
if (plan == NULL)
|
||||
return;
|
||||
|
||||
/* We don't support DECLARE CURSOR here */
|
||||
Assert(!query->isPortal);
|
||||
|
||||
gettimeofday(&starttime, NULL);
|
||||
|
||||
/* Create a QueryDesc requesting no output */
|
||||
queryDesc = CreateQueryDesc(query, plan, None, NULL, NULL,
|
||||
stmt->analyze);
|
||||
|
||||
ExplainOnePlan(queryDesc, stmt, tstate);
|
||||
}
|
||||
|
||||
/*
|
||||
* ExplainOnePlan -
|
||||
* given a planned query, execute it if needed, and then print
|
||||
* EXPLAIN output
|
||||
*
|
||||
* This is exported because it's called back from prepare.c in the
|
||||
* EXPLAIN EXECUTE case
|
||||
*
|
||||
* Note: the passed-in QueryDesc is freed when we're done with it
|
||||
*/
|
||||
void
|
||||
ExplainOnePlan(QueryDesc *queryDesc, ExplainStmt *stmt,
|
||||
TupOutputState *tstate)
|
||||
{
|
||||
struct timeval starttime;
|
||||
double totaltime = 0;
|
||||
ExplainState *es;
|
||||
StringInfo str;
|
||||
|
||||
gettimeofday(&starttime, NULL);
|
||||
|
||||
/* call ExecutorStart to prepare the plan for execution */
|
||||
ExecutorStart(queryDesc);
|
||||
|
||||
|
|
@ -160,7 +188,6 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, TupOutputState *tstate)
|
|||
ExecutorRun(queryDesc, ForwardScanDirection, 0L);
|
||||
|
||||
/* We can't clean up 'till we're done printing the stats... */
|
||||
|
||||
totaltime += elapsed_time(&starttime);
|
||||
}
|
||||
|
||||
|
|
@ -169,14 +196,14 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, TupOutputState *tstate)
|
|||
es->printCost = true; /* default */
|
||||
es->printNodes = stmt->verbose;
|
||||
es->printAnalyze = stmt->analyze;
|
||||
es->rtable = query->rtable;
|
||||
es->rtable = queryDesc->parsetree->rtable;
|
||||
|
||||
if (es->printNodes)
|
||||
{
|
||||
char *s;
|
||||
char *f;
|
||||
|
||||
s = nodeToString(plan);
|
||||
s = nodeToString(queryDesc->plantree);
|
||||
if (s)
|
||||
{
|
||||
if (Explain_pretty_print)
|
||||
|
|
@ -195,7 +222,7 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, TupOutputState *tstate)
|
|||
|
||||
if (es->printCost)
|
||||
{
|
||||
explain_outNode(str, plan, queryDesc->planstate,
|
||||
explain_outNode(str, queryDesc->plantree, queryDesc->planstate,
|
||||
NULL, 0, es);
|
||||
}
|
||||
|
||||
|
|
|
|||
|
|
@ -6,12 +6,13 @@
|
|||
* Copyright (c) 2002, PostgreSQL Global Development Group
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $Header: /cvsroot/pgsql/src/backend/commands/prepare.c,v 1.12 2002/12/15 21:01:34 tgl Exp $
|
||||
* $Header: /cvsroot/pgsql/src/backend/commands/prepare.c,v 1.13 2003/02/02 23:46:38 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
#include "postgres.h"
|
||||
|
||||
#include "commands/explain.h"
|
||||
#include "commands/prepare.h"
|
||||
#include "executor/executor.h"
|
||||
#include "utils/guc.h"
|
||||
|
|
@ -47,9 +48,10 @@ static HTAB *prepared_queries = NULL;
|
|||
|
||||
static void InitQueryHashTable(void);
|
||||
static void StoreQuery(const char *stmt_name, List *query_list,
|
||||
List *plan_list, List *argtype_list);
|
||||
List *plan_list, List *argtype_list);
|
||||
static QueryHashEntry *FetchQuery(const char *plan_name);
|
||||
|
||||
static ParamListInfo EvaluateParams(EState *estate,
|
||||
List *params, List *argtypes);
|
||||
|
||||
/*
|
||||
* Implements the 'PREPARE' utility statement.
|
||||
|
|
@ -94,7 +96,7 @@ ExecuteQuery(ExecuteStmt *stmt, CommandDest outputDest)
|
|||
*query_list,
|
||||
*plan_list;
|
||||
ParamListInfo paramLI = NULL;
|
||||
EState *estate;
|
||||
EState *estate = NULL;
|
||||
|
||||
/* Look it up in the hash table */
|
||||
entry = FetchQuery(stmt->name);
|
||||
|
|
@ -104,51 +106,22 @@ ExecuteQuery(ExecuteStmt *stmt, CommandDest outputDest)
|
|||
|
||||
Assert(length(query_list) == length(plan_list));
|
||||
|
||||
/*
|
||||
* Need an EState to evaluate parameters; must not delete it till end
|
||||
* of query, in case parameters are pass-by-reference.
|
||||
*/
|
||||
estate = CreateExecutorState();
|
||||
|
||||
/* Evaluate parameters, if any */
|
||||
if (entry->argtype_list != NIL)
|
||||
{
|
||||
int nargs = length(entry->argtype_list);
|
||||
int i = 0;
|
||||
List *exprstates;
|
||||
|
||||
/* Parser should have caught this error, but check */
|
||||
if (nargs != length(stmt->params))
|
||||
elog(ERROR, "ExecuteQuery: wrong number of arguments");
|
||||
|
||||
exprstates = (List *) ExecPrepareExpr((Expr *) stmt->params, estate);
|
||||
|
||||
paramLI = (ParamListInfo)
|
||||
palloc0((nargs + 1) * sizeof(ParamListInfoData));
|
||||
|
||||
foreach(l, exprstates)
|
||||
{
|
||||
ExprState *n = lfirst(l);
|
||||
bool isNull;
|
||||
|
||||
paramLI[i].value = ExecEvalExprSwitchContext(n,
|
||||
GetPerTupleExprContext(estate),
|
||||
&isNull,
|
||||
NULL);
|
||||
paramLI[i].kind = PARAM_NUM;
|
||||
paramLI[i].id = i + 1;
|
||||
paramLI[i].isnull = isNull;
|
||||
|
||||
i++;
|
||||
}
|
||||
paramLI[i].kind = PARAM_INVALID;
|
||||
/*
|
||||
* Need an EState to evaluate parameters; must not delete it
|
||||
* till end of query, in case parameters are pass-by-reference.
|
||||
*/
|
||||
estate = CreateExecutorState();
|
||||
paramLI = EvaluateParams(estate, stmt->params, entry->argtype_list);
|
||||
}
|
||||
|
||||
/* Execute each query */
|
||||
foreach(l, query_list)
|
||||
{
|
||||
Query *query = lfirst(l);
|
||||
Plan *plan = lfirst(plan_list);
|
||||
Query *query = (Query *) lfirst(l);
|
||||
Plan *plan = (Plan *) lfirst(plan_list);
|
||||
bool is_last_query;
|
||||
|
||||
plan_list = lnext(plan_list);
|
||||
|
|
@ -196,11 +169,59 @@ ExecuteQuery(ExecuteStmt *stmt, CommandDest outputDest)
|
|||
CommandCounterIncrement();
|
||||
}
|
||||
|
||||
FreeExecutorState(estate);
|
||||
if (estate)
|
||||
FreeExecutorState(estate);
|
||||
|
||||
/* No need to pfree other memory, MemoryContext will be reset */
|
||||
}
|
||||
|
||||
/*
|
||||
* Evaluates a list of parameters, using the given executor state. It
|
||||
* requires a list of the parameter values themselves, and a list of
|
||||
* their types. It returns a filled-in ParamListInfo -- this can later
|
||||
* be passed to CreateQueryDesc(), which allows the executor to make use
|
||||
* of the parameters during query execution.
|
||||
*/
|
||||
static ParamListInfo
|
||||
EvaluateParams(EState *estate, List *params, List *argtypes)
|
||||
{
|
||||
int nargs = length(argtypes);
|
||||
ParamListInfo paramLI;
|
||||
List *exprstates;
|
||||
List *l;
|
||||
int i = 0;
|
||||
|
||||
/* Parser should have caught this error, but check anyway */
|
||||
if (length(params) != nargs)
|
||||
elog(ERROR, "EvaluateParams: wrong number of arguments");
|
||||
|
||||
exprstates = (List *) ExecPrepareExpr((Expr *) params, estate);
|
||||
|
||||
paramLI = (ParamListInfo)
|
||||
palloc0((nargs + 1) * sizeof(ParamListInfoData));
|
||||
|
||||
foreach(l, exprstates)
|
||||
{
|
||||
ExprState *n = lfirst(l);
|
||||
bool isNull;
|
||||
|
||||
paramLI[i].value = ExecEvalExprSwitchContext(n,
|
||||
GetPerTupleExprContext(estate),
|
||||
&isNull,
|
||||
NULL);
|
||||
paramLI[i].kind = PARAM_NUM;
|
||||
paramLI[i].id = i + 1;
|
||||
paramLI[i].isnull = isNull;
|
||||
|
||||
i++;
|
||||
}
|
||||
|
||||
paramLI[i].kind = PARAM_INVALID;
|
||||
|
||||
return paramLI;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Initialize query hash table upon first use.
|
||||
*/
|
||||
|
|
@ -229,8 +250,8 @@ InitQueryHashTable(void)
|
|||
* to the hash entry, so the caller can dispose of their copy.
|
||||
*/
|
||||
static void
|
||||
StoreQuery(const char *stmt_name, List *query_list, List *plan_list,
|
||||
List *argtype_list)
|
||||
StoreQuery(const char *stmt_name, List *query_list,
|
||||
List *plan_list, List *argtype_list)
|
||||
{
|
||||
QueryHashEntry *entry;
|
||||
MemoryContext oldcxt,
|
||||
|
|
@ -278,7 +299,7 @@ StoreQuery(const char *stmt_name, List *query_list, List *plan_list,
|
|||
HASH_ENTER,
|
||||
&found);
|
||||
|
||||
/* Shouldn't get a failure, nor duplicate entry */
|
||||
/* Shouldn't get a failure, nor a duplicate entry */
|
||||
if (!entry || found)
|
||||
elog(ERROR, "Unable to store prepared statement \"%s\"!",
|
||||
stmt_name);
|
||||
|
|
@ -293,7 +314,8 @@ StoreQuery(const char *stmt_name, List *query_list, List *plan_list,
|
|||
}
|
||||
|
||||
/*
|
||||
* Lookup an existing query in the hash table.
|
||||
* Lookup an existing query in the hash table. If the query does not
|
||||
* actually exist, an elog(ERROR) is thrown.
|
||||
*/
|
||||
static QueryHashEntry *
|
||||
FetchQuery(const char *plan_name)
|
||||
|
|
@ -346,52 +368,104 @@ FetchQueryParams(const char *plan_name)
|
|||
/*
|
||||
* Implements the 'DEALLOCATE' utility statement: deletes the
|
||||
* specified plan from storage.
|
||||
*
|
||||
* The initial part of this routine is identical to FetchQuery(),
|
||||
* but we repeat the coding because we need to use the key twice.
|
||||
*/
|
||||
void
|
||||
DeallocateQuery(DeallocateStmt *stmt)
|
||||
{
|
||||
char key[HASH_KEY_LEN];
|
||||
QueryHashEntry *entry;
|
||||
|
||||
/*
|
||||
* If the hash table hasn't been initialized, it can't be storing
|
||||
* anything, therefore it couldn't possibly store our plan.
|
||||
*/
|
||||
if (!prepared_queries)
|
||||
elog(ERROR, "Prepared statement with name \"%s\" does not exist",
|
||||
stmt->name);
|
||||
|
||||
/*
|
||||
* We can't just use the statement name as supplied by the user: the
|
||||
* hash package is picky enough that it needs to be NULL-padded out to
|
||||
* the appropriate length to work correctly.
|
||||
*/
|
||||
MemSet(key, 0, sizeof(key));
|
||||
strncpy(key, stmt->name, sizeof(key));
|
||||
|
||||
/*
|
||||
* First lookup the entry, so we can release all the subsidiary memory
|
||||
* it has allocated (when it's removed, hash_search() will return a
|
||||
* dangling pointer, so it needs to be done prior to HASH_REMOVE).
|
||||
* This requires an extra hash-table lookup, but DEALLOCATE isn't
|
||||
* exactly a performance bottleneck.
|
||||
*/
|
||||
entry = (QueryHashEntry *) hash_search(prepared_queries,
|
||||
key,
|
||||
HASH_FIND,
|
||||
NULL);
|
||||
|
||||
if (!entry)
|
||||
elog(ERROR, "Prepared statement with name \"%s\" does not exist",
|
||||
stmt->name);
|
||||
/* Find the query's hash table entry */
|
||||
entry = FetchQuery(stmt->name);
|
||||
|
||||
/* Flush the context holding the subsidiary data */
|
||||
Assert(MemoryContextIsValid(entry->context));
|
||||
MemoryContextDelete(entry->context);
|
||||
|
||||
/* Now we can remove the hash table entry */
|
||||
hash_search(prepared_queries, key, HASH_REMOVE, NULL);
|
||||
hash_search(prepared_queries, entry->key, HASH_REMOVE, NULL);
|
||||
}
|
||||
|
||||
/*
|
||||
* Implements the 'EXPLAIN EXECUTE' utility statement.
|
||||
*/
|
||||
void
|
||||
ExplainExecuteQuery(ExplainStmt *stmt, TupOutputState *tstate)
|
||||
{
|
||||
ExecuteStmt *execstmt = (ExecuteStmt *) stmt->query->utilityStmt;
|
||||
QueryHashEntry *entry;
|
||||
List *l,
|
||||
*query_list,
|
||||
*plan_list;
|
||||
ParamListInfo paramLI = NULL;
|
||||
EState *estate = NULL;
|
||||
|
||||
/* explain.c should only call me for EXECUTE stmt */
|
||||
Assert(execstmt && IsA(execstmt, ExecuteStmt));
|
||||
|
||||
/* Look it up in the hash table */
|
||||
entry = FetchQuery(execstmt->name);
|
||||
|
||||
query_list = entry->query_list;
|
||||
plan_list = entry->plan_list;
|
||||
|
||||
Assert(length(query_list) == length(plan_list));
|
||||
|
||||
/* Evaluate parameters, if any */
|
||||
if (entry->argtype_list != NIL)
|
||||
{
|
||||
/*
|
||||
* Need an EState to evaluate parameters; must not delete it
|
||||
* till end of query, in case parameters are pass-by-reference.
|
||||
*/
|
||||
estate = CreateExecutorState();
|
||||
paramLI = EvaluateParams(estate, execstmt->params,
|
||||
entry->argtype_list);
|
||||
}
|
||||
|
||||
/* Explain each query */
|
||||
foreach(l, query_list)
|
||||
{
|
||||
Query *query = (Query *) lfirst(l);
|
||||
Plan *plan = (Plan *) lfirst(plan_list);
|
||||
bool is_last_query;
|
||||
|
||||
plan_list = lnext(plan_list);
|
||||
is_last_query = (plan_list == NIL);
|
||||
|
||||
if (query->commandType == CMD_UTILITY)
|
||||
{
|
||||
if (query->utilityStmt && IsA(query->utilityStmt, NotifyStmt))
|
||||
do_text_output_oneline(tstate, "NOTIFY");
|
||||
else
|
||||
do_text_output_oneline(tstate, "UTILITY");
|
||||
}
|
||||
else
|
||||
{
|
||||
QueryDesc *qdesc;
|
||||
|
||||
/* Create a QueryDesc requesting no output */
|
||||
qdesc = CreateQueryDesc(query, plan, None, NULL,
|
||||
paramLI, stmt->analyze);
|
||||
|
||||
if (execstmt->into)
|
||||
{
|
||||
if (qdesc->operation != CMD_SELECT)
|
||||
elog(ERROR, "INTO clause specified for non-SELECT query");
|
||||
|
||||
query->into = execstmt->into;
|
||||
qdesc->dest = None;
|
||||
}
|
||||
|
||||
ExplainOnePlan(qdesc, stmt, tstate);
|
||||
}
|
||||
|
||||
/* No need for CommandCounterIncrement, as ExplainOnePlan did it */
|
||||
|
||||
/* put a blank line between plans */
|
||||
if (!is_last_query)
|
||||
do_text_output_oneline(tstate, "");
|
||||
}
|
||||
|
||||
if (estate)
|
||||
FreeExecutorState(estate);
|
||||
}
|
||||
|
|
|
|||
|
|
@ -11,7 +11,7 @@
|
|||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.396 2003/01/23 23:38:56 petere Exp $
|
||||
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.397 2003/02/02 23:46:38 tgl Exp $
|
||||
*
|
||||
* HISTORY
|
||||
* AUTHOR DATE MAJOR EVENT
|
||||
|
|
@ -241,7 +241,7 @@ static void doNegateFloat(Value *v);
|
|||
%type <ival> opt_interval
|
||||
%type <node> overlay_placing substr_from substr_for
|
||||
|
||||
%type <boolean> opt_instead opt_cursor
|
||||
%type <boolean> opt_instead opt_cursor opt_analyze
|
||||
%type <boolean> index_opt_unique opt_verbose opt_full
|
||||
%type <boolean> opt_freeze opt_default opt_recheck
|
||||
%type <defelt> opt_binary opt_oids copy_delimiter
|
||||
|
|
@ -3953,28 +3953,32 @@ opt_name_list:
|
|||
/*****************************************************************************
|
||||
*
|
||||
* QUERY:
|
||||
* EXPLAIN query
|
||||
* EXPLAIN ANALYZE query
|
||||
* EXPLAIN [ANALYZE] [VERBOSE] query
|
||||
*
|
||||
*****************************************************************************/
|
||||
|
||||
ExplainStmt:
|
||||
EXPLAIN opt_verbose OptimizableStmt
|
||||
{
|
||||
ExplainStmt *n = makeNode(ExplainStmt);
|
||||
n->verbose = $2;
|
||||
n->analyze = FALSE;
|
||||
n->query = (Query*)$3;
|
||||
$$ = (Node *)n;
|
||||
}
|
||||
| EXPLAIN analyze_keyword opt_verbose OptimizableStmt
|
||||
EXPLAIN opt_analyze opt_verbose OptimizableStmt
|
||||
{
|
||||
ExplainStmt *n = makeNode(ExplainStmt);
|
||||
n->analyze = $2;
|
||||
n->verbose = $3;
|
||||
n->analyze = TRUE;
|
||||
n->query = (Query*)$4;
|
||||
$$ = (Node *)n;
|
||||
}
|
||||
| EXPLAIN opt_analyze opt_verbose ExecuteStmt
|
||||
{
|
||||
ExplainStmt *n = makeNode(ExplainStmt);
|
||||
n->analyze = $2;
|
||||
n->verbose = $3;
|
||||
n->query = (Query*)$4;
|
||||
$$ = (Node *)n;
|
||||
}
|
||||
;
|
||||
|
||||
opt_analyze:
|
||||
analyze_keyword { $$ = TRUE; }
|
||||
| /* EMPTY */ { $$ = FALSE; }
|
||||
;
|
||||
|
||||
/*****************************************************************************
|
||||
|
|
|
|||
|
|
@ -6,16 +6,20 @@
|
|||
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994-5, Regents of the University of California
|
||||
*
|
||||
* $Id: explain.h,v 1.17 2002/06/20 20:29:49 momjian Exp $
|
||||
* $Id: explain.h,v 1.18 2003/02/02 23:46:38 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
#ifndef EXPLAIN_H
|
||||
#define EXPLAIN_H
|
||||
|
||||
#include "executor/executor.h"
|
||||
#include "nodes/parsenodes.h"
|
||||
#include "tcop/dest.h"
|
||||
|
||||
|
||||
extern void ExplainQuery(ExplainStmt *stmt, CommandDest dest);
|
||||
extern void ExplainOnePlan(QueryDesc *queryDesc, ExplainStmt *stmt,
|
||||
TupOutputState *tstate);
|
||||
|
||||
#endif /* EXPLAIN_H */
|
||||
|
|
|
|||
|
|
@ -6,24 +6,22 @@
|
|||
*
|
||||
* Copyright (c) 2002, PostgreSQL Global Development Group
|
||||
*
|
||||
* $Id: prepare.h,v 1.2 2002/09/04 20:31:42 momjian Exp $
|
||||
* $Id: prepare.h,v 1.3 2003/02/02 23:46:38 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
||||
#ifndef PREPARE_H
|
||||
#define PREPARE_H
|
||||
|
||||
#include "executor/executor.h"
|
||||
#include "nodes/parsenodes.h"
|
||||
#include "tcop/dest.h"
|
||||
|
||||
|
||||
extern void PrepareQuery(PrepareStmt *stmt);
|
||||
|
||||
extern void ExecuteQuery(ExecuteStmt *stmt, CommandDest outputDest);
|
||||
|
||||
extern void DeallocateQuery(DeallocateStmt *stmt);
|
||||
|
||||
extern List *FetchQueryParams(const char *plan_name);
|
||||
extern void ExplainExecuteQuery(ExplainStmt *stmt, TupOutputState *tstate);
|
||||
|
||||
#endif /* PREPARE_H */
|
||||
|
|
|
|||
Loading…
Reference in New Issue