postgresql/src/backend/commands/explain.c

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/*-------------------------------------------------------------------------
*
* explain.c
* Explain query execution plans
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* IDENTIFICATION
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* src/backend/commands/explain.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
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#include "access/xact.h"
#include "catalog/pg_type.h"
#include "commands/createas.h"
#include "commands/defrem.h"
#include "commands/prepare.h"
#include "executor/hashjoin.h"
#include "foreign/fdwapi.h"
#include "optimizer/clauses.h"
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#include "parser/parsetree.h"
#include "rewrite/rewriteHandler.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/json.h"
#include "utils/lsyscache.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/tuplesort.h"
#include "utils/xml.h"
/* Hook for plugins to get control in ExplainOneQuery() */
ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
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/* Hook for plugins to get control in explain_get_index_name() */
explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
/* OR-able flags for ExplainXMLTag() */
#define X_OPENING 0
#define X_CLOSING 1
#define X_CLOSE_IMMEDIATE 2
#define X_NOWHITESPACE 4
static void ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
const char *queryString, ParamListInfo params);
static void report_triggers(ResultRelInfo *rInfo, bool show_relname,
ExplainState *es);
static double elapsed_time(instr_time *starttime);
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
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static void ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used);
static void ExplainPreScanMemberNodes(List *plans, PlanState **planstates,
Bitmapset **rels_used);
static void ExplainPreScanSubPlans(List *plans, Bitmapset **rels_used);
static void ExplainNode(PlanState *planstate, List *ancestors,
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const char *relationship, const char *plan_name,
ExplainState *es);
static void show_plan_tlist(PlanState *planstate, List *ancestors,
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ExplainState *es);
static void show_expression(Node *node, const char *qlabel,
PlanState *planstate, List *ancestors,
bool useprefix, ExplainState *es);
static void show_qual(List *qual, const char *qlabel,
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PlanState *planstate, List *ancestors,
bool useprefix, ExplainState *es);
static void show_scan_qual(List *qual, const char *qlabel,
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PlanState *planstate, List *ancestors,
ExplainState *es);
static void show_upper_qual(List *qual, const char *qlabel,
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PlanState *planstate, List *ancestors,
ExplainState *es);
static void show_sort_keys(SortState *sortstate, List *ancestors,
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ExplainState *es);
static void show_merge_append_keys(MergeAppendState *mstate, List *ancestors,
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ExplainState *es);
static void show_sort_keys_common(PlanState *planstate,
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int nkeys, AttrNumber *keycols,
List *ancestors, ExplainState *es);
static void show_sort_info(SortState *sortstate, ExplainState *es);
static void show_hash_info(HashState *hashstate, ExplainState *es);
static void show_instrumentation_count(const char *qlabel, int which,
PlanState *planstate, ExplainState *es);
static void show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es);
static const char *explain_get_index_name(Oid indexId);
static void ExplainIndexScanDetails(Oid indexid, ScanDirection indexorderdir,
ExplainState *es);
static void ExplainScanTarget(Scan *plan, ExplainState *es);
static void ExplainModifyTarget(ModifyTable *plan, ExplainState *es);
static void ExplainTargetRel(Plan *plan, Index rti, ExplainState *es);
static void ExplainMemberNodes(List *plans, PlanState **planstates,
List *ancestors, ExplainState *es);
static void ExplainSubPlans(List *plans, List *ancestors,
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const char *relationship, ExplainState *es);
static void ExplainProperty(const char *qlabel, const char *value,
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bool numeric, ExplainState *es);
static void ExplainOpenGroup(const char *objtype, const char *labelname,
bool labeled, ExplainState *es);
static void ExplainCloseGroup(const char *objtype, const char *labelname,
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bool labeled, ExplainState *es);
static void ExplainDummyGroup(const char *objtype, const char *labelname,
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ExplainState *es);
static void ExplainXMLTag(const char *tagname, int flags, ExplainState *es);
static void ExplainJSONLineEnding(ExplainState *es);
static void ExplainYAMLLineStarting(ExplainState *es);
static void escape_yaml(StringInfo buf, const char *str);
/*
* ExplainQuery -
* execute an EXPLAIN command
*/
void
ExplainQuery(ExplainStmt *stmt, const char *queryString,
ParamListInfo params, DestReceiver *dest)
{
ExplainState es;
TupOutputState *tstate;
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List *rewritten;
ListCell *lc;
bool timing_set = false;
/* Initialize ExplainState. */
ExplainInitState(&es);
/* Parse options list. */
foreach(lc, stmt->options)
{
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DefElem *opt = (DefElem *) lfirst(lc);
if (strcmp(opt->defname, "analyze") == 0)
es.analyze = defGetBoolean(opt);
else if (strcmp(opt->defname, "verbose") == 0)
es.verbose = defGetBoolean(opt);
else if (strcmp(opt->defname, "costs") == 0)
es.costs = defGetBoolean(opt);
else if (strcmp(opt->defname, "buffers") == 0)
es.buffers = defGetBoolean(opt);
else if (strcmp(opt->defname, "timing") == 0)
{
timing_set = true;
es.timing = defGetBoolean(opt);
}
else if (strcmp(opt->defname, "format") == 0)
{
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char *p = defGetString(opt);
if (strcmp(p, "text") == 0)
es.format = EXPLAIN_FORMAT_TEXT;
else if (strcmp(p, "xml") == 0)
es.format = EXPLAIN_FORMAT_XML;
else if (strcmp(p, "json") == 0)
es.format = EXPLAIN_FORMAT_JSON;
else if (strcmp(p, "yaml") == 0)
es.format = EXPLAIN_FORMAT_YAML;
else
ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
opt->defname, p)));
}
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unrecognized EXPLAIN option \"%s\"",
opt->defname)));
}
if (es.buffers && !es.analyze)
ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("EXPLAIN option BUFFERS requires ANALYZE")));
/* if the timing was not set explicitly, set default value */
es.timing = (timing_set) ? es.timing : es.analyze;
/* check that timing is used with EXPLAIN ANALYZE */
if (es.timing && !es.analyze)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("EXPLAIN option TIMING requires ANALYZE")));
/*
* Parse analysis was done already, but we still have to run the rule
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* rewriter. We do not do AcquireRewriteLocks: we assume the query either
* came straight from the parser, or suitable locks were acquired by
* plancache.c.
*
* Because the rewriter and planner tend to scribble on the input, we make
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* a preliminary copy of the source querytree. This prevents problems in
* the case that the EXPLAIN is in a portal or plpgsql function and is
* executed repeatedly. (See also the same hack in DECLARE CURSOR and
* PREPARE.) XXX FIXME someday.
*/
Assert(IsA(stmt->query, Query));
rewritten = QueryRewrite((Query *) copyObject(stmt->query));
/* emit opening boilerplate */
ExplainBeginOutput(&es);
if (rewritten == NIL)
{
/*
* In the case of an INSTEAD NOTHING, tell at least that. But in
* non-text format, the output is delimited, so this isn't necessary.
*/
if (es.format == EXPLAIN_FORMAT_TEXT)
appendStringInfoString(es.str, "Query rewrites to nothing\n");
}
else
{
ListCell *l;
/* Explain every plan */
foreach(l, rewritten)
{
ExplainOneQuery((Query *) lfirst(l), NULL, &es,
queryString, params);
/* Separate plans with an appropriate separator */
if (lnext(l) != NULL)
ExplainSeparatePlans(&es);
}
}
/* emit closing boilerplate */
ExplainEndOutput(&es);
Assert(es.indent == 0);
/* output tuples */
tstate = begin_tup_output_tupdesc(dest, ExplainResultDesc(stmt));
if (es.format == EXPLAIN_FORMAT_TEXT)
do_text_output_multiline(tstate, es.str->data);
else
do_text_output_oneline(tstate, es.str->data);
end_tup_output(tstate);
pfree(es.str->data);
}
/*
* Initialize ExplainState.
*/
void
ExplainInitState(ExplainState *es)
{
/* Set default options. */
memset(es, 0, sizeof(ExplainState));
es->costs = true;
/* Prepare output buffer. */
es->str = makeStringInfo();
}
/*
* ExplainResultDesc -
* construct the result tupledesc for an EXPLAIN
*/
TupleDesc
ExplainResultDesc(ExplainStmt *stmt)
{
TupleDesc tupdesc;
ListCell *lc;
Oid result_type = TEXTOID;
/* Check for XML format option */
foreach(lc, stmt->options)
{
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DefElem *opt = (DefElem *) lfirst(lc);
if (strcmp(opt->defname, "format") == 0)
{
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char *p = defGetString(opt);
if (strcmp(p, "xml") == 0)
result_type = XMLOID;
else if (strcmp(p, "json") == 0)
result_type = JSONOID;
else
result_type = TEXTOID;
/* don't "break", as ExplainQuery will use the last value */
}
}
/* Need a tuple descriptor representing a single TEXT or XML column */
tupdesc = CreateTemplateTupleDesc(1, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "QUERY PLAN",
result_type, -1, 0);
return tupdesc;
}
/*
* ExplainOneQuery -
* print out the execution plan for one Query
*
* "into" is NULL unless we are explaining the contents of a CreateTableAsStmt.
*/
static void
ExplainOneQuery(Query *query, IntoClause *into, ExplainState *es,
const char *queryString, ParamListInfo params)
{
/* planner will not cope with utility statements */
if (query->commandType == CMD_UTILITY)
{
ExplainOneUtility(query->utilityStmt, into, es, queryString, params);
return;
}
/* if an advisor plugin is present, let it manage things */
if (ExplainOneQuery_hook)
(*ExplainOneQuery_hook) (query, into, es, queryString, params);
else
{
PlannedStmt *plan;
/* plan the query */
plan = pg_plan_query(query, 0, params);
/* run it (if needed) and produce output */
ExplainOnePlan(plan, into, es, queryString, params);
}
}
/*
* ExplainOneUtility -
* print out the execution plan for one utility statement
* (In general, utility statements don't have plans, but there are some
* we treat as special cases)
*
* "into" is NULL unless we are explaining the contents of a CreateTableAsStmt.
*
* This is exported because it's called back from prepare.c in the
* EXPLAIN EXECUTE case.
*/
void
ExplainOneUtility(Node *utilityStmt, IntoClause *into, ExplainState *es,
const char *queryString, ParamListInfo params)
{
if (utilityStmt == NULL)
return;
if (IsA(utilityStmt, CreateTableAsStmt))
{
/*
* We have to rewrite the contained SELECT and then pass it back to
* ExplainOneQuery. It's probably not really necessary to copy the
* contained parsetree another time, but let's be safe.
*/
CreateTableAsStmt *ctas = (CreateTableAsStmt *) utilityStmt;
List *rewritten;
Assert(IsA(ctas->query, Query));
rewritten = QueryRewrite((Query *) copyObject(ctas->query));
Assert(list_length(rewritten) == 1);
ExplainOneQuery((Query *) linitial(rewritten), ctas->into, es,
queryString, params);
}
else if (IsA(utilityStmt, ExecuteStmt))
ExplainExecuteQuery((ExecuteStmt *) utilityStmt, into, es,
queryString, params);
else if (IsA(utilityStmt, NotifyStmt))
{
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfoString(es->str, "NOTIFY\n");
else
ExplainDummyGroup("Notify", NULL, es);
}
else
{
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfoString(es->str,
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"Utility statements have no plan structure\n");
else
ExplainDummyGroup("Utility Statement", NULL, es);
}
}
/*
* ExplainOnePlan -
* given a planned query, execute it if needed, and then print
* EXPLAIN output
*
* "into" is NULL unless we are explaining the contents of a CreateTableAsStmt,
* in which case executing the query should result in creating that table.
*
* Since we ignore any DeclareCursorStmt that might be attached to the query,
* if you say EXPLAIN ANALYZE DECLARE CURSOR then we'll actually run the
* query. This is different from pre-8.3 behavior but seems more useful than
* not running the query. No cursor will be created, however.
*
* This is exported because it's called back from prepare.c in the
* EXPLAIN EXECUTE case, and because an index advisor plugin would need
* to call it.
*/
void
ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into, ExplainState *es,
const char *queryString, ParamListInfo params)
{
DestReceiver *dest;
QueryDesc *queryDesc;
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instr_time starttime;
double totaltime = 0;
int eflags;
int instrument_option = 0;
if (es->analyze && es->timing)
instrument_option |= INSTRUMENT_TIMER;
else if (es->analyze)
instrument_option |= INSTRUMENT_ROWS;
if (es->buffers)
instrument_option |= INSTRUMENT_BUFFERS;
INSTR_TIME_SET_CURRENT(starttime);
/*
* Use a snapshot with an updated command ID to ensure this query sees
* results of any previously executed queries.
*/
PushCopiedSnapshot(GetActiveSnapshot());
UpdateActiveSnapshotCommandId();
/*
* Normally we discard the query's output, but if explaining CREATE TABLE
* AS, we'd better use the appropriate tuple receiver.
*/
if (into)
dest = CreateIntoRelDestReceiver(into);
else
dest = None_Receiver;
/* Create a QueryDesc for the query */
queryDesc = CreateQueryDesc(plannedstmt, queryString,
GetActiveSnapshot(), InvalidSnapshot,
dest, params, instrument_option);
/* Select execution options */
if (es->analyze)
eflags = 0; /* default run-to-completion flags */
else
eflags = EXEC_FLAG_EXPLAIN_ONLY;
if (into)
eflags |= GetIntoRelEFlags(into);
/* call ExecutorStart to prepare the plan for execution */
ExecutorStart(queryDesc, eflags);
/* Execute the plan for statistics if asked for */
if (es->analyze)
{
ScanDirection dir;
/* EXPLAIN ANALYZE CREATE TABLE AS WITH NO DATA is weird */
if (into && into->skipData)
dir = NoMovementScanDirection;
else
dir = ForwardScanDirection;
/* run the plan */
ExecutorRun(queryDesc, dir, 0L);
/* run cleanup too */
ExecutorFinish(queryDesc);
/* We can't run ExecutorEnd 'till we're done printing the stats... */
totaltime += elapsed_time(&starttime);
}
ExplainOpenGroup("Query", NULL, true, es);
/* Create textual dump of plan tree */
ExplainPrintPlan(es, queryDesc);
/* Print info about runtime of triggers */
if (es->analyze)
{
ResultRelInfo *rInfo;
bool show_relname;
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int numrels = queryDesc->estate->es_num_result_relations;
List *targrels = queryDesc->estate->es_trig_target_relations;
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int nr;
ListCell *l;
ExplainOpenGroup("Triggers", "Triggers", false, es);
show_relname = (numrels > 1 || targrels != NIL);
rInfo = queryDesc->estate->es_result_relations;
for (nr = 0; nr < numrels; rInfo++, nr++)
report_triggers(rInfo, show_relname, es);
foreach(l, targrels)
{
rInfo = (ResultRelInfo *) lfirst(l);
report_triggers(rInfo, show_relname, es);
}
ExplainCloseGroup("Triggers", "Triggers", false, es);
}
/*
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* Close down the query and free resources. Include time for this in the
* total runtime (although it should be pretty minimal).
*/
INSTR_TIME_SET_CURRENT(starttime);
ExecutorEnd(queryDesc);
FreeQueryDesc(queryDesc);
PopActiveSnapshot();
/* We need a CCI just in case query expanded to multiple plans */
if (es->analyze)
CommandCounterIncrement();
totaltime += elapsed_time(&starttime);
if (es->analyze)
{
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfo(es->str, "Total runtime: %.3f ms\n",
1000.0 * totaltime);
else
ExplainPropertyFloat("Total Runtime", 1000.0 * totaltime,
3, es);
}
ExplainCloseGroup("Query", NULL, true, es);
}
/*
* ExplainPrintPlan -
* convert a QueryDesc's plan tree to text and append it to es->str
*
* The caller should have set up the options fields of *es, as well as
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* initializing the output buffer es->str. Other fields in *es are
* initialized here.
*
* NB: will not work on utility statements
*/
void
ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc)
{
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
Bitmapset *rels_used = NULL;
Assert(queryDesc->plannedstmt != NULL);
es->pstmt = queryDesc->plannedstmt;
es->rtable = queryDesc->plannedstmt->rtable;
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
ExplainPreScanNode(queryDesc->planstate, &rels_used);
es->rtable_names = select_rtable_names_for_explain(es->rtable, rels_used);
ExplainNode(queryDesc->planstate, NIL, NULL, NULL, es);
}
/*
* ExplainQueryText -
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* add a "Query Text" node that contains the actual text of the query
*
* The caller should have set up the options fields of *es, as well as
2010-02-26 03:01:40 +01:00
* initializing the output buffer es->str.
*
*/
void
ExplainQueryText(ExplainState *es, QueryDesc *queryDesc)
{
if (queryDesc->sourceText)
ExplainPropertyText("Query Text", queryDesc->sourceText, es);
}
/*
* report_triggers -
* report execution stats for a single relation's triggers
*/
static void
report_triggers(ResultRelInfo *rInfo, bool show_relname, ExplainState *es)
{
int nt;
if (!rInfo->ri_TrigDesc || !rInfo->ri_TrigInstrument)
return;
for (nt = 0; nt < rInfo->ri_TrigDesc->numtriggers; nt++)
{
Trigger *trig = rInfo->ri_TrigDesc->triggers + nt;
Instrumentation *instr = rInfo->ri_TrigInstrument + nt;
char *relname;
char *conname = NULL;
/* Must clean up instrumentation state */
InstrEndLoop(instr);
/*
2007-11-15 22:14:46 +01:00
* We ignore triggers that were never invoked; they likely aren't
* relevant to the current query type.
*/
if (instr->ntuples == 0)
continue;
ExplainOpenGroup("Trigger", NULL, true, es);
relname = RelationGetRelationName(rInfo->ri_RelationDesc);
if (OidIsValid(trig->tgconstraint))
conname = get_constraint_name(trig->tgconstraint);
/*
* In text format, we avoid printing both the trigger name and the
2010-02-26 03:01:40 +01:00
* constraint name unless VERBOSE is specified. In non-text formats
* we just print everything.
*/
if (es->format == EXPLAIN_FORMAT_TEXT)
{
if (es->verbose || conname == NULL)
appendStringInfo(es->str, "Trigger %s", trig->tgname);
else
appendStringInfoString(es->str, "Trigger");
if (conname)
appendStringInfo(es->str, " for constraint %s", conname);
if (show_relname)
appendStringInfo(es->str, " on %s", relname);
appendStringInfo(es->str, ": time=%.3f calls=%.0f\n",
1000.0 * instr->total, instr->ntuples);
}
else
{
ExplainPropertyText("Trigger Name", trig->tgname, es);
if (conname)
ExplainPropertyText("Constraint Name", conname, es);
ExplainPropertyText("Relation", relname, es);
ExplainPropertyFloat("Time", 1000.0 * instr->total, 3, es);
ExplainPropertyFloat("Calls", instr->ntuples, 0, es);
}
if (conname)
pfree(conname);
ExplainCloseGroup("Trigger", NULL, true, es);
}
}
/* Compute elapsed time in seconds since given timestamp */
static double
elapsed_time(instr_time *starttime)
{
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instr_time endtime;
INSTR_TIME_SET_CURRENT(endtime);
INSTR_TIME_SUBTRACT(endtime, *starttime);
return INSTR_TIME_GET_DOUBLE(endtime);
}
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
/*
* ExplainPreScanNode -
* Prescan the planstate tree to identify which RTEs are referenced
*
* Adds the relid of each referenced RTE to *rels_used. The result controls
* which RTEs are assigned aliases by select_rtable_names_for_explain. This
* ensures that we don't confusingly assign un-suffixed aliases to RTEs that
* never appear in the EXPLAIN output (such as inheritance parents).
*/
static void
ExplainPreScanNode(PlanState *planstate, Bitmapset **rels_used)
{
Plan *plan = planstate->plan;
switch (nodeTag(plan))
{
case T_SeqScan:
case T_IndexScan:
case T_IndexOnlyScan:
case T_BitmapHeapScan:
case T_TidScan:
case T_SubqueryScan:
case T_FunctionScan:
case T_ValuesScan:
case T_CteScan:
case T_WorkTableScan:
case T_ForeignScan:
*rels_used = bms_add_member(*rels_used,
((Scan *) plan)->scanrelid);
break;
case T_ModifyTable:
/* cf ExplainModifyTarget */
*rels_used = bms_add_member(*rels_used,
linitial_int(((ModifyTable *) plan)->resultRelations));
break;
default:
break;
}
/* initPlan-s */
if (planstate->initPlan)
ExplainPreScanSubPlans(planstate->initPlan, rels_used);
/* lefttree */
if (outerPlanState(planstate))
ExplainPreScanNode(outerPlanState(planstate), rels_used);
/* righttree */
if (innerPlanState(planstate))
ExplainPreScanNode(innerPlanState(planstate), rels_used);
/* special child plans */
switch (nodeTag(plan))
{
case T_ModifyTable:
ExplainPreScanMemberNodes(((ModifyTable *) plan)->plans,
((ModifyTableState *) planstate)->mt_plans,
rels_used);
break;
case T_Append:
ExplainPreScanMemberNodes(((Append *) plan)->appendplans,
((AppendState *) planstate)->appendplans,
rels_used);
break;
case T_MergeAppend:
ExplainPreScanMemberNodes(((MergeAppend *) plan)->mergeplans,
((MergeAppendState *) planstate)->mergeplans,
rels_used);
break;
case T_BitmapAnd:
ExplainPreScanMemberNodes(((BitmapAnd *) plan)->bitmapplans,
((BitmapAndState *) planstate)->bitmapplans,
rels_used);
break;
case T_BitmapOr:
ExplainPreScanMemberNodes(((BitmapOr *) plan)->bitmapplans,
((BitmapOrState *) planstate)->bitmapplans,
rels_used);
break;
case T_SubqueryScan:
ExplainPreScanNode(((SubqueryScanState *) planstate)->subplan,
rels_used);
break;
default:
break;
}
/* subPlan-s */
if (planstate->subPlan)
ExplainPreScanSubPlans(planstate->subPlan, rels_used);
}
/*
* Prescan the constituent plans of a ModifyTable, Append, MergeAppend,
* BitmapAnd, or BitmapOr node.
*
* Note: we don't actually need to examine the Plan list members, but
* we need the list in order to determine the length of the PlanState array.
*/
static void
ExplainPreScanMemberNodes(List *plans, PlanState **planstates,
Bitmapset **rels_used)
{
int nplans = list_length(plans);
int j;
for (j = 0; j < nplans; j++)
ExplainPreScanNode(planstates[j], rels_used);
}
/*
* Prescan a list of SubPlans (or initPlans, which also use SubPlan nodes).
*/
static void
ExplainPreScanSubPlans(List *plans, Bitmapset **rels_used)
{
ListCell *lst;
foreach(lst, plans)
{
SubPlanState *sps = (SubPlanState *) lfirst(lst);
ExplainPreScanNode(sps->planstate, rels_used);
}
}
/*
* ExplainNode -
* Appends a description of a plan tree to es->str
*
* planstate points to the executor state node for the current plan node.
* We need to work from a PlanState node, not just a Plan node, in order to
* get at the instrumentation data (if any) as well as the list of subplans.
*
* ancestors is a list of parent PlanState nodes, most-closely-nested first.
* These are needed in order to interpret PARAM_EXEC Params.
*
* relationship describes the relationship of this plan node to its parent
* (eg, "Outer", "Inner"); it can be null at top level. plan_name is an
* optional name to be attached to the node.
*
* In text format, es->indent is controlled in this function since we only
* want it to change at plan-node boundaries. In non-text formats, es->indent
* corresponds to the nesting depth of logical output groups, and therefore
* is controlled by ExplainOpenGroup/ExplainCloseGroup.
*/
static void
ExplainNode(PlanState *planstate, List *ancestors,
const char *relationship, const char *plan_name,
ExplainState *es)
{
Plan *plan = planstate->plan;
const char *pname; /* node type name for text output */
const char *sname; /* node type name for non-text output */
const char *strategy = NULL;
const char *operation = NULL;
int save_indent = es->indent;
bool haschildren;
switch (nodeTag(plan))
{
case T_Result:
pname = sname = "Result";
break;
case T_ModifyTable:
sname = "ModifyTable";
switch (((ModifyTable *) plan)->operation)
{
case CMD_INSERT:
pname = operation = "Insert";
break;
case CMD_UPDATE:
pname = operation = "Update";
break;
case CMD_DELETE:
pname = operation = "Delete";
break;
default:
pname = "???";
break;
}
break;
case T_Append:
pname = sname = "Append";
break;
case T_MergeAppend:
pname = sname = "Merge Append";
break;
case T_RecursiveUnion:
pname = sname = "Recursive Union";
break;
case T_BitmapAnd:
pname = sname = "BitmapAnd";
break;
case T_BitmapOr:
pname = sname = "BitmapOr";
break;
case T_NestLoop:
pname = sname = "Nested Loop";
break;
case T_MergeJoin:
2010-02-26 03:01:40 +01:00
pname = "Merge"; /* "Join" gets added by jointype switch */
sname = "Merge Join";
break;
case T_HashJoin:
2010-02-26 03:01:40 +01:00
pname = "Hash"; /* "Join" gets added by jointype switch */
sname = "Hash Join";
break;
case T_SeqScan:
pname = sname = "Seq Scan";
break;
case T_IndexScan:
pname = sname = "Index Scan";
break;
case T_IndexOnlyScan:
pname = sname = "Index Only Scan";
break;
case T_BitmapIndexScan:
pname = sname = "Bitmap Index Scan";
break;
case T_BitmapHeapScan:
pname = sname = "Bitmap Heap Scan";
break;
case T_TidScan:
pname = sname = "Tid Scan";
break;
case T_SubqueryScan:
pname = sname = "Subquery Scan";
break;
case T_FunctionScan:
pname = sname = "Function Scan";
break;
case T_ValuesScan:
pname = sname = "Values Scan";
break;
case T_CteScan:
pname = sname = "CTE Scan";
break;
case T_WorkTableScan:
pname = sname = "WorkTable Scan";
break;
case T_ForeignScan:
pname = sname = "Foreign Scan";
break;
case T_Material:
pname = sname = "Materialize";
break;
case T_Sort:
pname = sname = "Sort";
break;
case T_Group:
pname = sname = "Group";
break;
case T_Agg:
sname = "Aggregate";
switch (((Agg *) plan)->aggstrategy)
{
case AGG_PLAIN:
pname = "Aggregate";
strategy = "Plain";
break;
case AGG_SORTED:
pname = "GroupAggregate";
strategy = "Sorted";
break;
case AGG_HASHED:
pname = "HashAggregate";
strategy = "Hashed";
break;
default:
pname = "Aggregate ???";
strategy = "???";
break;
}
break;
case T_WindowAgg:
pname = sname = "WindowAgg";
break;
case T_Unique:
pname = sname = "Unique";
break;
case T_SetOp:
sname = "SetOp";
switch (((SetOp *) plan)->strategy)
{
case SETOP_SORTED:
pname = "SetOp";
strategy = "Sorted";
break;
case SETOP_HASHED:
pname = "HashSetOp";
strategy = "Hashed";
break;
default:
pname = "SetOp ???";
strategy = "???";
break;
}
break;
case T_LockRows:
pname = sname = "LockRows";
break;
case T_Limit:
pname = sname = "Limit";
break;
case T_Hash:
pname = sname = "Hash";
break;
default:
pname = sname = "???";
break;
}
ExplainOpenGroup("Plan",
relationship ? NULL : "Plan",
true, es);
if (es->format == EXPLAIN_FORMAT_TEXT)
{
if (plan_name)
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfo(es->str, "%s\n", plan_name);
es->indent++;
}
if (es->indent)
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfoString(es->str, "-> ");
es->indent += 2;
}
appendStringInfoString(es->str, pname);
es->indent++;
}
else
{
ExplainPropertyText("Node Type", sname, es);
if (strategy)
ExplainPropertyText("Strategy", strategy, es);
if (operation)
ExplainPropertyText("Operation", operation, es);
if (relationship)
ExplainPropertyText("Parent Relationship", relationship, es);
if (plan_name)
ExplainPropertyText("Subplan Name", plan_name, es);
}
switch (nodeTag(plan))
{
case T_SeqScan:
case T_BitmapHeapScan:
case T_TidScan:
case T_SubqueryScan:
case T_FunctionScan:
case T_ValuesScan:
case T_CteScan:
case T_WorkTableScan:
case T_ForeignScan:
ExplainScanTarget((Scan *) plan, es);
break;
case T_IndexScan:
{
IndexScan *indexscan = (IndexScan *) plan;
ExplainIndexScanDetails(indexscan->indexid,
indexscan->indexorderdir,
es);
ExplainScanTarget((Scan *) indexscan, es);
}
break;
case T_IndexOnlyScan:
{
IndexOnlyScan *indexonlyscan = (IndexOnlyScan *) plan;
ExplainIndexScanDetails(indexonlyscan->indexid,
indexonlyscan->indexorderdir,
es);
ExplainScanTarget((Scan *) indexonlyscan, es);
}
break;
case T_BitmapIndexScan:
{
BitmapIndexScan *bitmapindexscan = (BitmapIndexScan *) plan;
const char *indexname =
2010-02-26 03:01:40 +01:00
explain_get_index_name(bitmapindexscan->indexid);
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfo(es->str, " on %s", indexname);
else
ExplainPropertyText("Index Name", indexname, es);
}
break;
case T_ModifyTable:
ExplainModifyTarget((ModifyTable *) plan, es);
break;
case T_NestLoop:
case T_MergeJoin:
case T_HashJoin:
{
const char *jointype;
switch (((Join *) plan)->jointype)
{
case JOIN_INNER:
jointype = "Inner";
break;
case JOIN_LEFT:
jointype = "Left";
break;
case JOIN_FULL:
jointype = "Full";
break;
case JOIN_RIGHT:
jointype = "Right";
break;
case JOIN_SEMI:
jointype = "Semi";
break;
case JOIN_ANTI:
jointype = "Anti";
break;
default:
jointype = "???";
break;
}
if (es->format == EXPLAIN_FORMAT_TEXT)
{
/*
* For historical reasons, the join type is interpolated
* into the node type name...
*/
if (((Join *) plan)->jointype != JOIN_INNER)
appendStringInfo(es->str, " %s Join", jointype);
else if (!IsA(plan, NestLoop))
appendStringInfo(es->str, " Join");
}
else
ExplainPropertyText("Join Type", jointype, es);
}
break;
case T_SetOp:
{
const char *setopcmd;
switch (((SetOp *) plan)->cmd)
{
case SETOPCMD_INTERSECT:
setopcmd = "Intersect";
break;
case SETOPCMD_INTERSECT_ALL:
setopcmd = "Intersect All";
break;
case SETOPCMD_EXCEPT:
setopcmd = "Except";
break;
case SETOPCMD_EXCEPT_ALL:
setopcmd = "Except All";
break;
default:
setopcmd = "???";
break;
}
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfo(es->str, " %s", setopcmd);
else
ExplainPropertyText("Command", setopcmd, es);
}
break;
default:
break;
}
2005-10-15 04:49:52 +02:00
if (es->costs)
{
if (es->format == EXPLAIN_FORMAT_TEXT)
{
appendStringInfo(es->str, " (cost=%.2f..%.2f rows=%.0f width=%d)",
plan->startup_cost, plan->total_cost,
plan->plan_rows, plan->plan_width);
}
else
{
ExplainPropertyFloat("Startup Cost", plan->startup_cost, 2, es);
ExplainPropertyFloat("Total Cost", plan->total_cost, 2, es);
ExplainPropertyFloat("Plan Rows", plan->plan_rows, 0, es);
ExplainPropertyInteger("Plan Width", plan->plan_width, es);
}
}
/*
2005-10-15 04:49:52 +02:00
* We have to forcibly clean up the instrumentation state because we
* haven't done ExecutorEnd yet. This is pretty grotty ...
*/
if (planstate->instrument)
InstrEndLoop(planstate->instrument);
if (planstate->instrument && planstate->instrument->nloops > 0)
{
double nloops = planstate->instrument->nloops;
double startup_sec = 1000.0 * planstate->instrument->startup / nloops;
double total_sec = 1000.0 * planstate->instrument->total / nloops;
double rows = planstate->instrument->ntuples / nloops;
if (es->format == EXPLAIN_FORMAT_TEXT)
{
if (planstate->instrument->need_timer)
appendStringInfo(es->str,
" (actual time=%.3f..%.3f rows=%.0f loops=%.0f)",
startup_sec, total_sec, rows, nloops);
else
appendStringInfo(es->str,
" (actual rows=%.0f loops=%.0f)",
rows, nloops);
}
else
{
if (planstate->instrument->need_timer)
{
ExplainPropertyFloat("Actual Startup Time", startup_sec, 3, es);
ExplainPropertyFloat("Actual Total Time", total_sec, 3, es);
}
ExplainPropertyFloat("Actual Rows", rows, 0, es);
ExplainPropertyFloat("Actual Loops", nloops, 0, es);
}
}
else if (es->analyze)
{
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfo(es->str, " (never executed)");
else if (planstate->instrument->need_timer)
{
ExplainPropertyFloat("Actual Startup Time", 0.0, 3, es);
ExplainPropertyFloat("Actual Total Time", 0.0, 3, es);
}
else
{
ExplainPropertyFloat("Actual Rows", 0.0, 0, es);
ExplainPropertyFloat("Actual Loops", 0.0, 0, es);
}
}
/* in text format, first line ends here */
if (es->format == EXPLAIN_FORMAT_TEXT)
appendStringInfoChar(es->str, '\n');
/* target list */
if (es->verbose)
show_plan_tlist(planstate, ancestors, es);
/* quals, sort keys, etc */
switch (nodeTag(plan))
{
case T_IndexScan:
show_scan_qual(((IndexScan *) plan)->indexqualorig,
"Index Cond", planstate, ancestors, es);
if (((IndexScan *) plan)->indexqualorig)
show_instrumentation_count("Rows Removed by Index Recheck", 2,
planstate, es);
show_scan_qual(((IndexScan *) plan)->indexorderbyorig,
"Order By", planstate, ancestors, es);
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
break;
case T_IndexOnlyScan:
show_scan_qual(((IndexOnlyScan *) plan)->indexqual,
"Index Cond", planstate, ancestors, es);
if (((IndexOnlyScan *) plan)->indexqual)
show_instrumentation_count("Rows Removed by Index Recheck", 2,
planstate, es);
show_scan_qual(((IndexOnlyScan *) plan)->indexorderby,
"Order By", planstate, ancestors, es);
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
if (es->analyze)
ExplainPropertyLong("Heap Fetches",
((IndexOnlyScanState *) planstate)->ioss_HeapFetches, es);
break;
case T_BitmapIndexScan:
show_scan_qual(((BitmapIndexScan *) plan)->indexqualorig,
"Index Cond", planstate, ancestors, es);
break;
case T_BitmapHeapScan:
show_scan_qual(((BitmapHeapScan *) plan)->bitmapqualorig,
"Recheck Cond", planstate, ancestors, es);
if (((BitmapHeapScan *) plan)->bitmapqualorig)
show_instrumentation_count("Rows Removed by Index Recheck", 2,
planstate, es);
/* FALL THRU */
case T_SeqScan:
case T_ValuesScan:
case T_CteScan:
case T_WorkTableScan:
case T_SubqueryScan:
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
break;
case T_FunctionScan:
if (es->verbose)
show_expression(((FunctionScan *) plan)->funcexpr,
"Function Call", planstate, ancestors,
es->verbose, es);
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
break;
case T_TidScan:
{
/*
* The tidquals list has OR semantics, so be sure to show it
* as an OR condition.
*/
2006-10-04 02:30:14 +02:00
List *tidquals = ((TidScan *) plan)->tidquals;
if (list_length(tidquals) > 1)
tidquals = list_make1(make_orclause(tidquals));
show_scan_qual(tidquals, "TID Cond", planstate, ancestors, es);
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
}
break;
case T_ForeignScan:
show_scan_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
show_foreignscan_info((ForeignScanState *) planstate, es);
break;
case T_NestLoop:
show_upper_qual(((NestLoop *) plan)->join.joinqual,
"Join Filter", planstate, ancestors, es);
if (((NestLoop *) plan)->join.joinqual)
show_instrumentation_count("Rows Removed by Join Filter", 1,
planstate, es);
show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 2,
planstate, es);
break;
case T_MergeJoin:
show_upper_qual(((MergeJoin *) plan)->mergeclauses,
"Merge Cond", planstate, ancestors, es);
show_upper_qual(((MergeJoin *) plan)->join.joinqual,
"Join Filter", planstate, ancestors, es);
if (((MergeJoin *) plan)->join.joinqual)
show_instrumentation_count("Rows Removed by Join Filter", 1,
planstate, es);
show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 2,
planstate, es);
break;
case T_HashJoin:
show_upper_qual(((HashJoin *) plan)->hashclauses,
"Hash Cond", planstate, ancestors, es);
show_upper_qual(((HashJoin *) plan)->join.joinqual,
"Join Filter", planstate, ancestors, es);
if (((HashJoin *) plan)->join.joinqual)
show_instrumentation_count("Rows Removed by Join Filter", 1,
planstate, es);
show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 2,
planstate, es);
break;
case T_Agg:
case T_Group:
show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
break;
case T_Sort:
show_sort_keys((SortState *) planstate, ancestors, es);
show_sort_info((SortState *) planstate, es);
break;
case T_MergeAppend:
show_merge_append_keys((MergeAppendState *) planstate,
ancestors, es);
break;
case T_Result:
show_upper_qual((List *) ((Result *) plan)->resconstantqual,
"One-Time Filter", planstate, ancestors, es);
show_upper_qual(plan->qual, "Filter", planstate, ancestors, es);
if (plan->qual)
show_instrumentation_count("Rows Removed by Filter", 1,
planstate, es);
break;
case T_Hash:
show_hash_info((HashState *) planstate, es);
break;
default:
break;
}
/* Show buffer usage */
if (es->buffers)
{
const BufferUsage *usage = &planstate->instrument->bufusage;
if (es->format == EXPLAIN_FORMAT_TEXT)
{
2010-02-26 03:01:40 +01:00
bool has_shared = (usage->shared_blks_hit > 0 ||
usage->shared_blks_read > 0 ||
usage->shared_blks_dirtied > 0 ||
usage->shared_blks_written > 0);
2010-02-26 03:01:40 +01:00
bool has_local = (usage->local_blks_hit > 0 ||
usage->local_blks_read > 0 ||
usage->local_blks_dirtied > 0 ||
usage->local_blks_written > 0);
2010-02-26 03:01:40 +01:00
bool has_temp = (usage->temp_blks_read > 0 ||
usage->temp_blks_written > 0);
bool has_timing = (!INSTR_TIME_IS_ZERO(usage->blk_read_time) ||
!INSTR_TIME_IS_ZERO(usage->blk_write_time));
/* Show only positive counter values. */
if (has_shared || has_local || has_temp)
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfoString(es->str, "Buffers:");
if (has_shared)
{
appendStringInfoString(es->str, " shared");
if (usage->shared_blks_hit > 0)
appendStringInfo(es->str, " hit=%ld",
2010-02-26 03:01:40 +01:00
usage->shared_blks_hit);
if (usage->shared_blks_read > 0)
appendStringInfo(es->str, " read=%ld",
2010-02-26 03:01:40 +01:00
usage->shared_blks_read);
if (usage->shared_blks_dirtied > 0)
appendStringInfo(es->str, " dirtied=%ld",
usage->shared_blks_dirtied);
if (usage->shared_blks_written > 0)
appendStringInfo(es->str, " written=%ld",
2010-02-26 03:01:40 +01:00
usage->shared_blks_written);
if (has_local || has_temp)
appendStringInfoChar(es->str, ',');
}
if (has_local)
{
appendStringInfoString(es->str, " local");
if (usage->local_blks_hit > 0)
appendStringInfo(es->str, " hit=%ld",
2010-02-26 03:01:40 +01:00
usage->local_blks_hit);
if (usage->local_blks_read > 0)
appendStringInfo(es->str, " read=%ld",
2010-02-26 03:01:40 +01:00
usage->local_blks_read);
if (usage->local_blks_dirtied > 0)
appendStringInfo(es->str, " dirtied=%ld",
usage->local_blks_dirtied);
if (usage->local_blks_written > 0)
appendStringInfo(es->str, " written=%ld",
2010-02-26 03:01:40 +01:00
usage->local_blks_written);
if (has_temp)
appendStringInfoChar(es->str, ',');
}
if (has_temp)
{
appendStringInfoString(es->str, " temp");
if (usage->temp_blks_read > 0)
appendStringInfo(es->str, " read=%ld",
2010-02-26 03:01:40 +01:00
usage->temp_blks_read);
if (usage->temp_blks_written > 0)
appendStringInfo(es->str, " written=%ld",
2010-02-26 03:01:40 +01:00
usage->temp_blks_written);
}
appendStringInfoChar(es->str, '\n');
}
/* As above, show only positive counter values. */
if (has_timing)
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfoString(es->str, "I/O Timings:");
if (!INSTR_TIME_IS_ZERO(usage->blk_read_time))
appendStringInfo(es->str, " read=%0.3f",
INSTR_TIME_GET_MILLISEC(usage->blk_read_time));
if (!INSTR_TIME_IS_ZERO(usage->blk_write_time))
appendStringInfo(es->str, " write=%0.3f",
INSTR_TIME_GET_MILLISEC(usage->blk_write_time));
appendStringInfoChar(es->str, '\n');
}
}
else
{
ExplainPropertyLong("Shared Hit Blocks", usage->shared_blks_hit, es);
ExplainPropertyLong("Shared Read Blocks", usage->shared_blks_read, es);
ExplainPropertyLong("Shared Dirtied Blocks", usage->shared_blks_dirtied, es);
ExplainPropertyLong("Shared Written Blocks", usage->shared_blks_written, es);
ExplainPropertyLong("Local Hit Blocks", usage->local_blks_hit, es);
ExplainPropertyLong("Local Read Blocks", usage->local_blks_read, es);
ExplainPropertyLong("Local Dirtied Blocks", usage->local_blks_dirtied, es);
ExplainPropertyLong("Local Written Blocks", usage->local_blks_written, es);
ExplainPropertyLong("Temp Read Blocks", usage->temp_blks_read, es);
ExplainPropertyLong("Temp Written Blocks", usage->temp_blks_written, es);
ExplainPropertyFloat("I/O Read Time", INSTR_TIME_GET_MILLISEC(usage->blk_read_time), 3, es);
ExplainPropertyFloat("I/O Write Time", INSTR_TIME_GET_MILLISEC(usage->blk_write_time), 3, es);
}
}
/* Get ready to display the child plans */
haschildren = planstate->initPlan ||
outerPlanState(planstate) ||
innerPlanState(planstate) ||
IsA(plan, ModifyTable) ||
IsA(plan, Append) ||
IsA(plan, MergeAppend) ||
IsA(plan, BitmapAnd) ||
IsA(plan, BitmapOr) ||
IsA(plan, SubqueryScan) ||
planstate->subPlan;
if (haschildren)
{
ExplainOpenGroup("Plans", "Plans", false, es);
/* Pass current PlanState as head of ancestors list for children */
ancestors = lcons(planstate, ancestors);
}
1998-02-13 04:21:30 +01:00
/* initPlan-s */
if (planstate->initPlan)
ExplainSubPlans(planstate->initPlan, ancestors, "InitPlan", es);
/* lefttree */
if (outerPlanState(planstate))
ExplainNode(outerPlanState(planstate), ancestors,
"Outer", NULL, es);
/* righttree */
if (innerPlanState(planstate))
ExplainNode(innerPlanState(planstate), ancestors,
"Inner", NULL, es);
/* special child plans */
switch (nodeTag(plan))
{
case T_ModifyTable:
ExplainMemberNodes(((ModifyTable *) plan)->plans,
((ModifyTableState *) planstate)->mt_plans,
ancestors, es);
break;
case T_Append:
ExplainMemberNodes(((Append *) plan)->appendplans,
((AppendState *) planstate)->appendplans,
ancestors, es);
break;
case T_MergeAppend:
ExplainMemberNodes(((MergeAppend *) plan)->mergeplans,
((MergeAppendState *) planstate)->mergeplans,
ancestors, es);
break;
case T_BitmapAnd:
ExplainMemberNodes(((BitmapAnd *) plan)->bitmapplans,
((BitmapAndState *) planstate)->bitmapplans,
ancestors, es);
break;
case T_BitmapOr:
ExplainMemberNodes(((BitmapOr *) plan)->bitmapplans,
((BitmapOrState *) planstate)->bitmapplans,
ancestors, es);
break;
case T_SubqueryScan:
ExplainNode(((SubqueryScanState *) planstate)->subplan, ancestors,
"Subquery", NULL, es);
break;
default:
break;
}
/* subPlan-s */
if (planstate->subPlan)
ExplainSubPlans(planstate->subPlan, ancestors, "SubPlan", es);
/* end of child plans */
if (haschildren)
{
ancestors = list_delete_first(ancestors);
ExplainCloseGroup("Plans", "Plans", false, es);
}
/* in text format, undo whatever indentation we added */
if (es->format == EXPLAIN_FORMAT_TEXT)
es->indent = save_indent;
ExplainCloseGroup("Plan",
relationship ? NULL : "Plan",
true, es);
}
/*
* Show the targetlist of a plan node
*/
static void
show_plan_tlist(PlanState *planstate, List *ancestors, ExplainState *es)
{
Plan *plan = planstate->plan;
List *context;
List *result = NIL;
bool useprefix;
ListCell *lc;
/* No work if empty tlist (this occurs eg in bitmap indexscans) */
if (plan->targetlist == NIL)
return;
/* The tlist of an Append isn't real helpful, so suppress it */
if (IsA(plan, Append))
return;
/* Likewise for MergeAppend and RecursiveUnion */
if (IsA(plan, MergeAppend))
return;
if (IsA(plan, RecursiveUnion))
return;
/* Set up deparsing context */
context = deparse_context_for_planstate((Node *) planstate,
ancestors,
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
es->rtable,
es->rtable_names);
useprefix = list_length(es->rtable) > 1;
/* Deparse each result column (we now include resjunk ones) */
foreach(lc, plan->targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
result = lappend(result,
2010-02-26 03:01:40 +01:00
deparse_expression((Node *) tle->expr, context,
useprefix, false));
}
/* Print results */
ExplainPropertyList("Output", result, es);
}
/*
* Show a generic expression
*/
static void
show_expression(Node *node, const char *qlabel,
PlanState *planstate, List *ancestors,
bool useprefix, ExplainState *es)
{
List *context;
char *exprstr;
/* Set up deparsing context */
context = deparse_context_for_planstate((Node *) planstate,
ancestors,
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
es->rtable,
es->rtable_names);
/* Deparse the expression */
exprstr = deparse_expression(node, context, useprefix, false);
/* And add to es->str */
ExplainPropertyText(qlabel, exprstr, es);
}
/*
* Show a qualifier expression (which is a List with implicit AND semantics)
*/
static void
show_qual(List *qual, const char *qlabel,
PlanState *planstate, List *ancestors,
bool useprefix, ExplainState *es)
{
Node *node;
/* No work if empty qual */
if (qual == NIL)
return;
/* Convert AND list to explicit AND */
node = (Node *) make_ands_explicit(qual);
/* And show it */
show_expression(node, qlabel, planstate, ancestors, useprefix, es);
}
/*
* Show a qualifier expression for a scan plan node
*/
static void
show_scan_qual(List *qual, const char *qlabel,
PlanState *planstate, List *ancestors,
ExplainState *es)
{
bool useprefix;
2011-04-10 17:42:00 +02:00
useprefix = (IsA(planstate->plan, SubqueryScan) ||es->verbose);
show_qual(qual, qlabel, planstate, ancestors, useprefix, es);
}
/*
* Show a qualifier expression for an upper-level plan node
*/
static void
show_upper_qual(List *qual, const char *qlabel,
PlanState *planstate, List *ancestors,
ExplainState *es)
{
bool useprefix;
useprefix = (list_length(es->rtable) > 1 || es->verbose);
show_qual(qual, qlabel, planstate, ancestors, useprefix, es);
}
/*
* Show the sort keys for a Sort node.
*/
static void
show_sort_keys(SortState *sortstate, List *ancestors, ExplainState *es)
{
Sort *plan = (Sort *) sortstate->ss.ps.plan;
show_sort_keys_common((PlanState *) sortstate,
plan->numCols, plan->sortColIdx,
ancestors, es);
}
/*
* Likewise, for a MergeAppend node.
*/
static void
show_merge_append_keys(MergeAppendState *mstate, List *ancestors,
ExplainState *es)
{
MergeAppend *plan = (MergeAppend *) mstate->ps.plan;
show_sort_keys_common((PlanState *) mstate,
plan->numCols, plan->sortColIdx,
ancestors, es);
}
static void
show_sort_keys_common(PlanState *planstate, int nkeys, AttrNumber *keycols,
List *ancestors, ExplainState *es)
{
Plan *plan = planstate->plan;
List *context;
List *result = NIL;
bool useprefix;
int keyno;
char *exprstr;
if (nkeys <= 0)
return;
/* Set up deparsing context */
context = deparse_context_for_planstate((Node *) planstate,
ancestors,
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
es->rtable,
es->rtable_names);
useprefix = (list_length(es->rtable) > 1 || es->verbose);
for (keyno = 0; keyno < nkeys; keyno++)
{
/* find key expression in tlist */
AttrNumber keyresno = keycols[keyno];
TargetEntry *target = get_tle_by_resno(plan->targetlist,
keyresno);
if (!target)
elog(ERROR, "no tlist entry for key %d", keyresno);
/* Deparse the expression, showing any top-level cast */
exprstr = deparse_expression((Node *) target->expr, context,
useprefix, true);
result = lappend(result, exprstr);
}
ExplainPropertyList("Sort Key", result, es);
}
/*
* If it's EXPLAIN ANALYZE, show tuplesort stats for a sort node
*/
static void
show_sort_info(SortState *sortstate, ExplainState *es)
{
Assert(IsA(sortstate, SortState));
if (es->analyze && sortstate->sort_Done &&
sortstate->tuplesortstate != NULL)
{
2010-02-26 03:01:40 +01:00
Tuplesortstate *state = (Tuplesortstate *) sortstate->tuplesortstate;
const char *sortMethod;
const char *spaceType;
long spaceUsed;
tuplesort_get_stats(state, &sortMethod, &spaceType, &spaceUsed);
if (es->format == EXPLAIN_FORMAT_TEXT)
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfo(es->str, "Sort Method: %s %s: %ldkB\n",
sortMethod, spaceType, spaceUsed);
}
else
{
ExplainPropertyText("Sort Method", sortMethod, es);
ExplainPropertyLong("Sort Space Used", spaceUsed, es);
ExplainPropertyText("Sort Space Type", spaceType, es);
}
}
}
/*
* Show information on hash buckets/batches.
*/
static void
show_hash_info(HashState *hashstate, ExplainState *es)
{
HashJoinTable hashtable;
Assert(IsA(hashstate, HashState));
hashtable = hashstate->hashtable;
if (hashtable)
{
2010-02-26 03:01:40 +01:00
long spacePeakKb = (hashtable->spacePeak + 1023) / 1024;
if (es->format != EXPLAIN_FORMAT_TEXT)
{
ExplainPropertyLong("Hash Buckets", hashtable->nbuckets, es);
ExplainPropertyLong("Hash Batches", hashtable->nbatch, es);
ExplainPropertyLong("Original Hash Batches",
hashtable->nbatch_original, es);
ExplainPropertyLong("Peak Memory Usage", spacePeakKb, es);
}
else if (hashtable->nbatch_original != hashtable->nbatch)
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfo(es->str,
2010-02-26 03:01:40 +01:00
"Buckets: %d Batches: %d (originally %d) Memory Usage: %ldkB\n",
hashtable->nbuckets, hashtable->nbatch,
hashtable->nbatch_original, spacePeakKb);
}
else
{
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfo(es->str,
2010-02-26 03:01:40 +01:00
"Buckets: %d Batches: %d Memory Usage: %ldkB\n",
hashtable->nbuckets, hashtable->nbatch,
spacePeakKb);
}
}
}
/*
* If it's EXPLAIN ANALYZE, show instrumentation information for a plan node
*
* "which" identifies which instrumentation counter to print
*/
static void
show_instrumentation_count(const char *qlabel, int which,
PlanState *planstate, ExplainState *es)
{
double nfiltered;
double nloops;
if (!es->analyze || !planstate->instrument)
return;
if (which == 2)
nfiltered = planstate->instrument->nfiltered2;
else
nfiltered = planstate->instrument->nfiltered1;
nloops = planstate->instrument->nloops;
/* In text mode, suppress zero counts; they're not interesting enough */
if (nfiltered > 0 || es->format != EXPLAIN_FORMAT_TEXT)
{
if (nloops > 0)
ExplainPropertyFloat(qlabel, nfiltered / nloops, 0, es);
else
ExplainPropertyFloat(qlabel, 0.0, 0, es);
}
}
/*
* Show extra information for a ForeignScan node.
*/
static void
show_foreignscan_info(ForeignScanState *fsstate, ExplainState *es)
{
FdwRoutine *fdwroutine = fsstate->fdwroutine;
/* Let the FDW emit whatever fields it wants */
fdwroutine->ExplainForeignScan(fsstate, es);
}
/*
* Fetch the name of an index in an EXPLAIN
*
* We allow plugins to get control here so that plans involving hypothetical
* indexes can be explained.
*/
static const char *
explain_get_index_name(Oid indexId)
{
2007-11-15 22:14:46 +01:00
const char *result;
if (explain_get_index_name_hook)
result = (*explain_get_index_name_hook) (indexId);
else
result = NULL;
if (result == NULL)
{
/* default behavior: look in the catalogs and quote it */
result = get_rel_name(indexId);
if (result == NULL)
elog(ERROR, "cache lookup failed for index %u", indexId);
result = quote_identifier(result);
}
return result;
}
/*
* Add some additional details about an IndexScan or IndexOnlyScan
*/
static void
ExplainIndexScanDetails(Oid indexid, ScanDirection indexorderdir,
ExplainState *es)
{
const char *indexname = explain_get_index_name(indexid);
if (es->format == EXPLAIN_FORMAT_TEXT)
{
if (ScanDirectionIsBackward(indexorderdir))
appendStringInfoString(es->str, " Backward");
appendStringInfo(es->str, " using %s", indexname);
}
else
{
const char *scandir;
switch (indexorderdir)
{
case BackwardScanDirection:
scandir = "Backward";
break;
case NoMovementScanDirection:
scandir = "NoMovement";
break;
case ForwardScanDirection:
scandir = "Forward";
break;
default:
scandir = "???";
break;
}
ExplainPropertyText("Scan Direction", scandir, es);
ExplainPropertyText("Index Name", indexname, es);
}
}
/*
* Show the target of a Scan node
*/
static void
ExplainScanTarget(Scan *plan, ExplainState *es)
{
ExplainTargetRel((Plan *) plan, plan->scanrelid, es);
}
/*
* Show the target of a ModifyTable node
*/
static void
ExplainModifyTarget(ModifyTable *plan, ExplainState *es)
{
Index rti;
/*
* We show the name of the first target relation. In multi-target-table
* cases this should always be the parent of the inheritance tree.
*/
Assert(plan->resultRelations != NIL);
rti = linitial_int(plan->resultRelations);
ExplainTargetRel((Plan *) plan, rti, es);
}
/*
* Show the target relation of a scan or modify node
*/
static void
ExplainTargetRel(Plan *plan, Index rti, ExplainState *es)
{
char *objectname = NULL;
char *namespace = NULL;
const char *objecttag = NULL;
RangeTblEntry *rte;
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
char *refname;
rte = rt_fetch(rti, es->rtable);
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
refname = (char *) list_nth(es->rtable_names, rti - 1);
switch (nodeTag(plan))
{
case T_SeqScan:
case T_IndexScan:
case T_IndexOnlyScan:
case T_BitmapHeapScan:
case T_TidScan:
case T_ForeignScan:
case T_ModifyTable:
/* Assert it's on a real relation */
Assert(rte->rtekind == RTE_RELATION);
objectname = get_rel_name(rte->relid);
if (es->verbose)
namespace = get_namespace_name(get_rel_namespace(rte->relid));
objecttag = "Relation Name";
break;
case T_FunctionScan:
{
Node *funcexpr;
/* Assert it's on a RangeFunction */
Assert(rte->rtekind == RTE_FUNCTION);
/*
* If the expression is still a function call, we can get the
* real name of the function. Otherwise, punt (this can
* happen if the optimizer simplified away the function call,
* for example).
*/
funcexpr = ((FunctionScan *) plan)->funcexpr;
if (funcexpr && IsA(funcexpr, FuncExpr))
{
Oid funcid = ((FuncExpr *) funcexpr)->funcid;
objectname = get_func_name(funcid);
if (es->verbose)
namespace =
get_namespace_name(get_func_namespace(funcid));
}
objecttag = "Function Name";
}
break;
case T_ValuesScan:
Assert(rte->rtekind == RTE_VALUES);
break;
case T_CteScan:
/* Assert it's on a non-self-reference CTE */
Assert(rte->rtekind == RTE_CTE);
Assert(!rte->self_reference);
objectname = rte->ctename;
objecttag = "CTE Name";
break;
case T_WorkTableScan:
/* Assert it's on a self-reference CTE */
Assert(rte->rtekind == RTE_CTE);
Assert(rte->self_reference);
objectname = rte->ctename;
objecttag = "CTE Name";
break;
default:
break;
}
if (es->format == EXPLAIN_FORMAT_TEXT)
{
appendStringInfoString(es->str, " on");
if (namespace != NULL)
appendStringInfo(es->str, " %s.%s", quote_identifier(namespace),
quote_identifier(objectname));
else if (objectname != NULL)
appendStringInfo(es->str, " %s", quote_identifier(objectname));
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
if (refname != NULL &&
(objectname == NULL || strcmp(refname, objectname) != 0))
appendStringInfo(es->str, " %s", quote_identifier(refname));
}
else
{
if (objecttag != NULL && objectname != NULL)
ExplainPropertyText(objecttag, objectname, es);
if (namespace != NULL)
ExplainPropertyText("Schema", namespace, es);
Improve ruleutils.c's heuristics for dealing with rangetable aliases. The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.
2012-09-22 01:03:10 +02:00
if (refname != NULL)
ExplainPropertyText("Alias", refname, es);
}
}
/*
* Explain the constituent plans of a ModifyTable, Append, MergeAppend,
* BitmapAnd, or BitmapOr node.
*
* The ancestors list should already contain the immediate parent of these
* plans.
*
* Note: we don't actually need to examine the Plan list members, but
* we need the list in order to determine the length of the PlanState array.
*/
static void
ExplainMemberNodes(List *plans, PlanState **planstates,
List *ancestors, ExplainState *es)
{
int nplans = list_length(plans);
int j;
for (j = 0; j < nplans; j++)
ExplainNode(planstates[j], ancestors,
"Member", NULL, es);
}
/*
* Explain a list of SubPlans (or initPlans, which also use SubPlan nodes).
*
* The ancestors list should already contain the immediate parent of these
* SubPlanStates.
*/
static void
ExplainSubPlans(List *plans, List *ancestors,
const char *relationship, ExplainState *es)
{
ListCell *lst;
foreach(lst, plans)
{
SubPlanState *sps = (SubPlanState *) lfirst(lst);
SubPlan *sp = (SubPlan *) sps->xprstate.expr;
ExplainNode(sps->planstate, ancestors,
relationship, sp->plan_name, es);
}
}
/*
* Explain a property, such as sort keys or targets, that takes the form of
* a list of unlabeled items. "data" is a list of C strings.
*/
void
ExplainPropertyList(const char *qlabel, List *data, ExplainState *es)
{
ListCell *lc;
bool first = true;
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfo(es->str, "%s: ", qlabel);
foreach(lc, data)
{
if (!first)
appendStringInfoString(es->str, ", ");
appendStringInfoString(es->str, (const char *) lfirst(lc));
first = false;
}
appendStringInfoChar(es->str, '\n');
break;
case EXPLAIN_FORMAT_XML:
ExplainXMLTag(qlabel, X_OPENING, es);
foreach(lc, data)
{
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char *str;
appendStringInfoSpaces(es->str, es->indent * 2 + 2);
appendStringInfoString(es->str, "<Item>");
str = escape_xml((const char *) lfirst(lc));
appendStringInfoString(es->str, str);
pfree(str);
appendStringInfoString(es->str, "</Item>\n");
}
ExplainXMLTag(qlabel, X_CLOSING, es);
break;
case EXPLAIN_FORMAT_JSON:
ExplainJSONLineEnding(es);
appendStringInfoSpaces(es->str, es->indent * 2);
escape_json(es->str, qlabel);
appendStringInfoString(es->str, ": [");
foreach(lc, data)
{
if (!first)
appendStringInfoString(es->str, ", ");
escape_json(es->str, (const char *) lfirst(lc));
first = false;
}
appendStringInfoChar(es->str, ']');
break;
case EXPLAIN_FORMAT_YAML:
ExplainYAMLLineStarting(es);
appendStringInfo(es->str, "%s: ", qlabel);
foreach(lc, data)
{
appendStringInfoChar(es->str, '\n');
appendStringInfoSpaces(es->str, es->indent * 2 + 2);
appendStringInfoString(es->str, "- ");
escape_yaml(es->str, (const char *) lfirst(lc));
}
break;
}
}
/*
* Explain a simple property.
*
* If "numeric" is true, the value is a number (or other value that
* doesn't need quoting in JSON).
*
* This usually should not be invoked directly, but via one of the datatype
* specific routines ExplainPropertyText, ExplainPropertyInteger, etc.
*/
static void
ExplainProperty(const char *qlabel, const char *value, bool numeric,
ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
appendStringInfoSpaces(es->str, es->indent * 2);
appendStringInfo(es->str, "%s: %s\n", qlabel, value);
break;
case EXPLAIN_FORMAT_XML:
{
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char *str;
appendStringInfoSpaces(es->str, es->indent * 2);
ExplainXMLTag(qlabel, X_OPENING | X_NOWHITESPACE, es);
str = escape_xml(value);
appendStringInfoString(es->str, str);
pfree(str);
ExplainXMLTag(qlabel, X_CLOSING | X_NOWHITESPACE, es);
appendStringInfoChar(es->str, '\n');
}
break;
case EXPLAIN_FORMAT_JSON:
ExplainJSONLineEnding(es);
appendStringInfoSpaces(es->str, es->indent * 2);
escape_json(es->str, qlabel);
appendStringInfoString(es->str, ": ");
if (numeric)
appendStringInfoString(es->str, value);
else
escape_json(es->str, value);
break;
case EXPLAIN_FORMAT_YAML:
ExplainYAMLLineStarting(es);
appendStringInfo(es->str, "%s: ", qlabel);
if (numeric)
appendStringInfoString(es->str, value);
else
escape_yaml(es->str, value);
break;
}
}
/*
* Explain a string-valued property.
*/
void
ExplainPropertyText(const char *qlabel, const char *value, ExplainState *es)
{
ExplainProperty(qlabel, value, false, es);
}
/*
* Explain an integer-valued property.
*/
void
ExplainPropertyInteger(const char *qlabel, int value, ExplainState *es)
{
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char buf[32];
snprintf(buf, sizeof(buf), "%d", value);
ExplainProperty(qlabel, buf, true, es);
}
/*
* Explain a long-integer-valued property.
*/
void
ExplainPropertyLong(const char *qlabel, long value, ExplainState *es)
{
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char buf[32];
snprintf(buf, sizeof(buf), "%ld", value);
ExplainProperty(qlabel, buf, true, es);
}
/*
* Explain a float-valued property, using the specified number of
* fractional digits.
*/
void
ExplainPropertyFloat(const char *qlabel, double value, int ndigits,
ExplainState *es)
{
2010-02-26 03:01:40 +01:00
char buf[256];
snprintf(buf, sizeof(buf), "%.*f", ndigits, value);
ExplainProperty(qlabel, buf, true, es);
}
/*
* Open a group of related objects.
*
* objtype is the type of the group object, labelname is its label within
* a containing object (if any).
*
* If labeled is true, the group members will be labeled properties,
* while if it's false, they'll be unlabeled objects.
*/
static void
ExplainOpenGroup(const char *objtype, const char *labelname,
bool labeled, ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
/* nothing to do */
break;
case EXPLAIN_FORMAT_XML:
ExplainXMLTag(objtype, X_OPENING, es);
es->indent++;
break;
case EXPLAIN_FORMAT_JSON:
ExplainJSONLineEnding(es);
appendStringInfoSpaces(es->str, 2 * es->indent);
if (labelname)
{
escape_json(es->str, labelname);
appendStringInfoString(es->str, ": ");
}
appendStringInfoChar(es->str, labeled ? '{' : '[');
/*
* In JSON format, the grouping_stack is an integer list. 0 means
* we've emitted nothing at this grouping level, 1 means we've
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* emitted something (and so the next item needs a comma). See
* ExplainJSONLineEnding().
*/
es->grouping_stack = lcons_int(0, es->grouping_stack);
es->indent++;
break;
case EXPLAIN_FORMAT_YAML:
/*
* In YAML format, the grouping stack is an integer list. 0 means
* we've emitted nothing at this grouping level AND this grouping
* level is unlabelled and must be marked with "- ". See
* ExplainYAMLLineStarting().
*/
ExplainYAMLLineStarting(es);
if (labelname)
{
appendStringInfo(es->str, "%s: ", labelname);
es->grouping_stack = lcons_int(1, es->grouping_stack);
}
else
{
appendStringInfoString(es->str, "- ");
es->grouping_stack = lcons_int(0, es->grouping_stack);
}
es->indent++;
break;
}
}
/*
* Close a group of related objects.
* Parameters must match the corresponding ExplainOpenGroup call.
*/
static void
ExplainCloseGroup(const char *objtype, const char *labelname,
bool labeled, ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
/* nothing to do */
break;
case EXPLAIN_FORMAT_XML:
es->indent--;
ExplainXMLTag(objtype, X_CLOSING, es);
break;
case EXPLAIN_FORMAT_JSON:
es->indent--;
appendStringInfoChar(es->str, '\n');
appendStringInfoSpaces(es->str, 2 * es->indent);
appendStringInfoChar(es->str, labeled ? '}' : ']');
es->grouping_stack = list_delete_first(es->grouping_stack);
break;
case EXPLAIN_FORMAT_YAML:
es->indent--;
es->grouping_stack = list_delete_first(es->grouping_stack);
break;
}
}
/*
* Emit a "dummy" group that never has any members.
*
* objtype is the type of the group object, labelname is its label within
* a containing object (if any).
*/
static void
ExplainDummyGroup(const char *objtype, const char *labelname, ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
/* nothing to do */
break;
case EXPLAIN_FORMAT_XML:
ExplainXMLTag(objtype, X_CLOSE_IMMEDIATE, es);
break;
case EXPLAIN_FORMAT_JSON:
ExplainJSONLineEnding(es);
appendStringInfoSpaces(es->str, 2 * es->indent);
if (labelname)
{
escape_json(es->str, labelname);
appendStringInfoString(es->str, ": ");
}
escape_json(es->str, objtype);
break;
case EXPLAIN_FORMAT_YAML:
ExplainYAMLLineStarting(es);
if (labelname)
{
escape_yaml(es->str, labelname);
appendStringInfoString(es->str, ": ");
}
else
{
appendStringInfoString(es->str, "- ");
}
escape_yaml(es->str, objtype);
break;
}
}
/*
* Emit the start-of-output boilerplate.
*
* This is just enough different from processing a subgroup that we need
* a separate pair of subroutines.
*/
void
ExplainBeginOutput(ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
/* nothing to do */
break;
case EXPLAIN_FORMAT_XML:
appendStringInfoString(es->str,
2010-02-26 03:01:40 +01:00
"<explain xmlns=\"http://www.postgresql.org/2009/explain\">\n");
es->indent++;
break;
case EXPLAIN_FORMAT_JSON:
/* top-level structure is an array of plans */
appendStringInfoChar(es->str, '[');
es->grouping_stack = lcons_int(0, es->grouping_stack);
es->indent++;
break;
case EXPLAIN_FORMAT_YAML:
es->grouping_stack = lcons_int(0, es->grouping_stack);
break;
}
}
/*
* Emit the end-of-output boilerplate.
*/
void
ExplainEndOutput(ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
/* nothing to do */
break;
case EXPLAIN_FORMAT_XML:
es->indent--;
appendStringInfoString(es->str, "</explain>");
break;
case EXPLAIN_FORMAT_JSON:
es->indent--;
appendStringInfoString(es->str, "\n]");
es->grouping_stack = list_delete_first(es->grouping_stack);
break;
case EXPLAIN_FORMAT_YAML:
es->grouping_stack = list_delete_first(es->grouping_stack);
break;
}
}
/*
* Put an appropriate separator between multiple plans
*/
void
ExplainSeparatePlans(ExplainState *es)
{
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
/* add a blank line */
appendStringInfoChar(es->str, '\n');
break;
case EXPLAIN_FORMAT_XML:
case EXPLAIN_FORMAT_JSON:
case EXPLAIN_FORMAT_YAML:
/* nothing to do */
break;
}
}
/*
* Emit opening or closing XML tag.
*
* "flags" must contain X_OPENING, X_CLOSING, or X_CLOSE_IMMEDIATE.
* Optionally, OR in X_NOWHITESPACE to suppress the whitespace we'd normally
* add.
*
* XML tag names can't contain white space, so we replace any spaces in
* "tagname" with dashes.
*/
static void
ExplainXMLTag(const char *tagname, int flags, ExplainState *es)
{
const char *s;
if ((flags & X_NOWHITESPACE) == 0)
appendStringInfoSpaces(es->str, 2 * es->indent);
appendStringInfoCharMacro(es->str, '<');
if ((flags & X_CLOSING) != 0)
appendStringInfoCharMacro(es->str, '/');
for (s = tagname; *s; s++)
appendStringInfoCharMacro(es->str, (*s == ' ') ? '-' : *s);
if ((flags & X_CLOSE_IMMEDIATE) != 0)
appendStringInfoString(es->str, " /");
appendStringInfoCharMacro(es->str, '>');
if ((flags & X_NOWHITESPACE) == 0)
appendStringInfoCharMacro(es->str, '\n');
}
/*
* Emit a JSON line ending.
*
2010-02-26 03:01:40 +01:00
* JSON requires a comma after each property but the last. To facilitate this,
* in JSON format, the text emitted for each property begins just prior to the
* preceding line-break (and comma, if applicable).
*/
static void
ExplainJSONLineEnding(ExplainState *es)
{
Assert(es->format == EXPLAIN_FORMAT_JSON);
if (linitial_int(es->grouping_stack) != 0)
appendStringInfoChar(es->str, ',');
else
linitial_int(es->grouping_stack) = 1;
appendStringInfoChar(es->str, '\n');
}
/*
* Indent a YAML line.
*
* YAML lines are ordinarily indented by two spaces per indentation level.
* The text emitted for each property begins just prior to the preceding
* line-break, except for the first property in an unlabelled group, for which
2010-02-26 03:01:40 +01:00
* it begins immediately after the "- " that introduces the group. The first
* property of the group appears on the same line as the opening "- ".
*/
static void
ExplainYAMLLineStarting(ExplainState *es)
{
Assert(es->format == EXPLAIN_FORMAT_YAML);
if (linitial_int(es->grouping_stack) == 0)
{
linitial_int(es->grouping_stack) = 1;
}
else
{
appendStringInfoChar(es->str, '\n');
appendStringInfoSpaces(es->str, es->indent * 2);
}
}
/*
* YAML is a superset of JSON; unfortuantely, the YAML quoting rules are
* ridiculously complicated -- as documented in sections 5.3 and 7.3.3 of
* http://yaml.org/spec/1.2/spec.html -- so we chose to just quote everything.
* Empty strings, strings with leading or trailing whitespace, and strings
* containing a variety of special characters must certainly be quoted or the
* output is invalid; and other seemingly harmless strings like "0xa" or
* "true" must be quoted, lest they be interpreted as a hexadecimal or Boolean
* constant rather than a string.
*/
static void
escape_yaml(StringInfo buf, const char *str)
{
escape_json(buf, str);
}