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pg_qualstats.c
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pg_qualstats.c
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/*-------------------------------------------------------------------------
*
* pg_qualstats.c
* Track frequently used quals.
*
* This extension works by installing a hooks on executor.
* The ExecutorStart hook will enable some instrumentation for the
* queries (INSTRUMENT_ROWS and INSTRUMENT_BUFFERS).
*
* The ExecutorEnd hook will look for every qual in the query, and
* stores the quals of the form:
* - EXPR OPERATOR CONSTANT
* - EXPR OPERATOR EXPR
*
* If pg_stat_statements is available, the statistics will be
* aggregated by queryid, and a not-normalized statement will be
* stored for each different queryid. This can allow third part tools
* to do some work on a real query easily.
*
* The implementation is heavily inspired by pg_stat_statements
*
* Copyright (c) 2014, Ronan Dunklau
*
*-------------------------------------------------------------------------
*/
#include <limits.h>
#include "postgres.h"
#include "access/hash.h"
#include "access/htup_details.h"
#if PG_VERSION_NUM >= 90600
#include "access/parallel.h"
#endif
#include "catalog/pg_class.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "fmgr.h"
#include "funcapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/execnodes.h"
#include "nodes/nodeFuncs.h"
#include "nodes/makefuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/planner.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/parse_node.h"
#include "parser/parsetree.h"
#include "postmaster/autovacuum.h"
#include "storage/ipc.h"
#include "storage/lwlock.h"
#if PG_VERSION_NUM >= 100000
#include "storage/shmem.h"
#endif
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/tuplestore.h"
PG_MODULE_MAGIC;
#define PGQS_COLUMNS 18 /* number of columns in pg_qualstats SRF */
#define PGQS_NAME_COLUMNS 7 /* number of column added when using
pg_qualstats_column SRF */
#define PGQS_USAGE_DEALLOC_PERCENT 5 /* free this % of entries at once */
#define PGQS_MAX_LOCAL_ENTRIES (pgqs_max * 0.2) /* do not track more of 20%
of possible entries in
shared mem */
#define PGQS_CONSTANT_SIZE 80 /* Truncate constant representation at 80 */
/*---- Function declarations ----*/
void _PG_init(void);
void _PG_fini(void);
extern Datum pg_qualstats_reset(PG_FUNCTION_ARGS);
extern Datum pg_qualstats(PG_FUNCTION_ARGS);
extern Datum pg_qualstats_names(PG_FUNCTION_ARGS);
static Datum pg_qualstats_common(PG_FUNCTION_ARGS, bool include_names);
extern Datum pg_qualstats_example_query(PG_FUNCTION_ARGS);
extern Datum pg_qualstats_example_queries(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(pg_qualstats_reset);
PG_FUNCTION_INFO_V1(pg_qualstats);
PG_FUNCTION_INFO_V1(pg_qualstats_names);
PG_FUNCTION_INFO_V1(pg_qualstats_example_query);
PG_FUNCTION_INFO_V1(pg_qualstats_example_queries);
static void pgqs_shmem_startup(void);
static void pgqs_ExecutorStart(QueryDesc *queryDesc, int eflags);
static void pgqs_ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction,
#if PG_VERSION_NUM >= 90600
uint64 count
#else
long count
#endif
);
static void pgqs_ExecutorFinish(QueryDesc *queryDesc);
static void pgqs_ExecutorEnd(QueryDesc *queryDesc);
static ExecutorStart_hook_type prev_ExecutorStart = NULL;
static ExecutorRun_hook_type prev_ExecutorRun = NULL;
static ExecutorFinish_hook_type prev_ExecutorFinish = NULL;
static ExecutorEnd_hook_type prev_ExecutorEnd = NULL;
static shmem_startup_hook_type prev_shmem_startup_hook = NULL;
static uint32 pgqs_hash_fn(const void *key, Size keysize);
#if PG_VERSION_NUM < 90500
static uint32 pgqs_uint32_hashfn(const void *key, Size keysize);
#endif
static int pgqs_query_size;
static int pgqs_max; /* max # statements to track */
static bool pgqs_track_pgcatalog; /* track queries on pg_catalog */
static bool pgqs_resolve_oids; /* resolve oids */
static bool pgqs_enabled;
static bool pgqs_track_constants;
static double pgqs_sample_rate;
static int query_is_sampled;/* Is the current query sampled, per backend */
static int nesting_level = 0; /* Current nesting depth of ExecutorRun calls */
static bool pgqs_assign_sample_rate_check_hook(double * newval, void **extra, GucSource source);
#if PG_VERSION_NUM > 90600
static void pgqs_set_query_sampled(bool sample);
#endif
static bool pgqs_is_query_sampled(void);
/*---- Data structures declarations ----*/
typedef struct pgqsSharedState
{
#if PG_VERSION_NUM >= 90400
LWLock *lock; /* protects counters hashtable search/modification */
LWLock *querylock; /* protects query hashtable search/modification */
#else
LWLockId lock; /* protects counters hashtable search/modification */
LWLockId querylock; /* protects query hashtable search/modification */
#endif
#if PG_VERSION_NUM >= 90600
LWLock *sampledlock; /* protects sampled array search/modification */
bool sampled[FLEXIBLE_ARRAY_MEMBER]; /* should we sample this query? */
#endif
} pgqsSharedState;
typedef struct pgqsHashKey
{
Oid userid; /* user OID */
Oid dbid; /* database OID */
uint32 queryid; /* query identifier (if set by another plugin */
uint32 uniquequalnodeid; /* Hash of the const */
uint32 uniquequalid; /* Hash of the parent, including the consts */
char evaltype; /* Evaluation type. Can be 'f' to mean a qual
* executed after a scan, or 'i' for an
* indexqual */
} pgqsHashKey;
typedef struct pgqsNames
{
NameData rolname;
NameData datname;
NameData lrelname;
NameData lattname;
NameData opname;
NameData rrelname;
NameData rattname;
} pgqsNames;
typedef struct pgqsEntry
{
pgqsHashKey key;
Oid lrelid; /* relation OID or NULL if not var */
AttrNumber lattnum; /* Attribute Number or NULL if not var */
Oid opoid; /* Operator OID */
Oid rrelid; /* relation OID or NULL if not var */
AttrNumber rattnum; /* Attribute Number or NULL if not var */
char constvalue[PGQS_CONSTANT_SIZE]; /* Textual representation of
* the right hand constant, if
* any */
uint32 qualid; /* Hash of the parent AND expression if any, 0
* otherwise. */
uint32 qualnodeid; /* Hash of the node itself */
int64 count; /* # of operator execution */
int64 nbfiltered; /* # of lines discarded by the operator */
int position; /* content position in query text */
double usage; /* # of qual execution, used for deallocation */
int64 occurences;
} pgqsEntry;
typedef struct pgqsEntryWithNames
{
pgqsEntry entry;
pgqsNames names;
} pgqsEntryWithNames;
typedef struct pgqsQueryStringHashKey {
uint32 queryid;
} pgqsQueryStringHashKey;
typedef struct pgqsQueryStringEntry
{
pgqsQueryStringHashKey key;
/* Imperatively at the end of the struct
This is actually of length query_size, which is track_activity_query_size
*/
char querytext[1];
} pgqsQueryStringEntry;
/*
* Transient state of the query tree walker - for the meaning of the counters,
* see pgqsEntry comments.
*/
typedef struct pgqsWalkerContext
{
uint32 queryId;
List *rtable;
PlanState *planstate;
PlanState *inner_planstate;
PlanState *outer_planstate;
List *outer_tlist;
List *inner_tlist;
List *index_tlist;
uint32 qualid;
uint32 uniquequalid; /* Hash of the parent, including the consts */
int64 count;
int64 nbfiltered;
int nentries; /* number of entries found so far */
char evaltype;
const char * querytext;
} pgqsWalkerContext;
static bool pgqs_whereclause_tree_walker(Node *node, pgqsWalkerContext * query);
static pgqsEntry *pgqs_process_opexpr(OpExpr *expr, pgqsWalkerContext * context);
static pgqsEntry *pgqs_process_scalararrayopexpr(ScalarArrayOpExpr *expr, pgqsWalkerContext * context);
static pgqsEntry *pgqs_process_booltest(BooleanTest *expr, pgqsWalkerContext * context);
static void pgqs_collectNodeStats(PlanState *planstate, List *ancestors, pgqsWalkerContext * context);
static void pgqs_collectMemberNodeStats(List *plans, PlanState **planstates, List *ancestors, pgqsWalkerContext * context);
static void pgqs_collectSubPlanStats(List *plans, List *ancestors, pgqsWalkerContext * context);
static uint32 hashExpr(Expr *expr, pgqsWalkerContext * context, bool include_const);
static void exprRepr(Expr *expr, StringInfo buffer, pgqsWalkerContext * context, bool include_const);
static void pgqs_set_planstates(PlanState *planstate, pgqsWalkerContext * context);
static Expr *pgqs_resolve_var(Var *var, pgqsWalkerContext * context);
static void pgqs_entry_dealloc(void);
static void pgqs_queryentry_dealloc(void);
static void pgqs_localentry_dealloc(int nvictims);
static void pgqs_fillnames(pgqsEntryWithNames * entry);
static Size pgqs_memsize(void);
#if PG_VERSION_NUM >= 90600
static Size pgqs_sampled_array_size(void);
#endif
/* Global Hash */
static HTAB *pgqs_hash = NULL;
static HTAB *pgqs_query_examples_hash = NULL;
static pgqsSharedState *pgqs = NULL;
/* Local Hash */
static HTAB *pgqs_localhash = NULL;
void
_PG_init(void)
{
if (!process_shared_preload_libraries_in_progress)
{
elog(ERROR, "This module can only be loaded via shared_preload_libraries");
return;
}
prev_ExecutorStart = ExecutorStart_hook;
ExecutorStart_hook = pgqs_ExecutorStart;
prev_ExecutorRun = ExecutorRun_hook;
ExecutorRun_hook = pgqs_ExecutorRun;
prev_ExecutorFinish = ExecutorFinish_hook;
ExecutorFinish_hook = pgqs_ExecutorFinish;
prev_ExecutorEnd = ExecutorEnd_hook;
ExecutorEnd_hook = pgqs_ExecutorEnd;
prev_shmem_startup_hook = shmem_startup_hook;
shmem_startup_hook = pgqs_shmem_startup;
DefineCustomBoolVariable("pg_qualstats.enabled",
"Enable / Disable pg_qualstats",
NULL,
&pgqs_enabled,
true,
PGC_USERSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_qualstats.track_constants",
"Enable / Disable pg_qualstats constants tracking",
NULL,
&pgqs_track_constants,
true,
PGC_USERSET,
0,
NULL,
NULL,
NULL);
DefineCustomIntVariable("pg_qualstats.max",
"Sets the maximum number of statements tracked by pg_qualstats.",
NULL,
&pgqs_max,
1000,
100,
INT_MAX,
PGC_POSTMASTER,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_qualstats.resolve_oids",
"Store names alongside the oid. Eats MUCH more space!",
NULL,
&pgqs_resolve_oids,
false,
PGC_POSTMASTER,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_qualstats.track_pg_catalog",
"Track quals on system catalogs too.",
NULL,
&pgqs_track_pgcatalog,
false,
PGC_USERSET,
0,
NULL,
NULL,
NULL);
DefineCustomRealVariable("pg_qualstats.sample_rate",
"Sampling rate. 1 means every query, 0.2 means 1 in five queries",
NULL,
&pgqs_sample_rate,
-1,
-1,
1,
PGC_USERSET,
0,
pgqs_assign_sample_rate_check_hook,
NULL,
NULL);
parse_int(GetConfigOption("track_activity_query_size", false, false),
&pgqs_query_size, 0, NULL);
RequestAddinShmemSpace(pgqs_memsize());
#if PG_VERSION_NUM >= 90600
RequestNamedLWLockTranche("pg_qualstats", 3);
#else
RequestAddinLWLocks(2);
#endif
}
void
_PG_fini(void)
{
/* Uninstall hooks. */
shmem_startup_hook = prev_shmem_startup_hook;
ExecutorStart_hook = prev_ExecutorStart;
ExecutorRun_hook = prev_ExecutorRun;
ExecutorFinish_hook = prev_ExecutorFinish;
ExecutorEnd_hook = prev_ExecutorEnd;
}
/*
* Check that the sample ratio is in the correct interval
*/
static bool
pgqs_assign_sample_rate_check_hook(double * newval, void **extra, GucSource source)
{
double val = *newval;
if((val < 0 && val != -1) || (val > 1))
return false;
if(val == -1)
*newval = 1. / MaxConnections;
return true;
}
#if PG_VERSION_NUM >= 90600
static void
pgqs_set_query_sampled(bool sample)
{
/* the decisions should only be made in leader */
Assert(! IsParallelWorker());
/* in worker processes we need to get the info from shared memory */
LWLockAcquire(pgqs->sampledlock, LW_EXCLUSIVE);
pgqs->sampled[MyBackendId] = sample;
LWLockRelease(pgqs->sampledlock);
}
#endif
static bool
pgqs_is_query_sampled(void)
{
#if PG_VERSION_NUM >= 90600
bool sampled;
/* in leader we can just check the global variable */
if (! IsParallelWorker())
return query_is_sampled;
/* in worker processes we need to get the info from shared memory */
LWLockAcquire(pgqs->sampledlock, LW_SHARED);
sampled = pgqs->sampled[ParallelMasterBackendId];
LWLockRelease(pgqs->sampledlock);
return sampled;
#else
return query_is_sampled;
#endif
}
/*
* Do catalog search to replace oids with corresponding objects name
*/
void
pgqs_fillnames(pgqsEntryWithNames * entry)
{
HeapTuple tp;
#if PG_VERSION_NUM >= 90500
namestrcpy(&(entry->names.rolname), GetUserNameFromId(entry->entry.key.userid, true));
#else
namestrcpy(&(entry->names.rolname), GetUserNameFromId(entry->entry.key.userid));
#endif
namestrcpy(&(entry->names.datname), get_database_name(entry->entry.key.dbid));
if (entry->entry.lrelid != InvalidOid)
{
tp = SearchSysCache1(RELOID, ObjectIdGetDatum(entry->entry.lrelid));
if (!HeapTupleIsValid(tp))
{
elog(ERROR, "Invalid lreloid");
}
namecpy(&(entry->names.lrelname), &(((Form_pg_class) GETSTRUCT(tp))->relname));
ReleaseSysCache(tp);
tp = SearchSysCache2(ATTNUM, ObjectIdGetDatum(entry->entry.lrelid),
entry->entry.lattnum);
if (!HeapTupleIsValid(tp))
{
elog(ERROR, "Invalid lattr");
}
namecpy(&(entry->names.lattname), &(((Form_pg_attribute) GETSTRUCT(tp))->attname));
ReleaseSysCache(tp);
}
if (entry->entry.opoid != InvalidOid)
{
tp = SearchSysCache1(OPEROID, ObjectIdGetDatum(entry->entry.opoid));
if (!HeapTupleIsValid(tp))
{
elog(ERROR, "Invalid operator");
}
namecpy(&(entry->names.opname), &(((Form_pg_operator) GETSTRUCT(tp))->oprname));
ReleaseSysCache(tp);
}
if (entry->entry.rrelid != InvalidOid)
{
tp = SearchSysCache1(RELOID, ObjectIdGetDatum(entry->entry.rrelid));
if (!HeapTupleIsValid(tp))
{
elog(ERROR, "Invalid rreloid");
}
namecpy(&(entry->names.rrelname), &(((Form_pg_class) GETSTRUCT(tp))->relname));
ReleaseSysCache(tp);
tp = SearchSysCache2(ATTNUM, ObjectIdGetDatum(entry->entry.rrelid),
entry->entry.rattnum);
if (!HeapTupleIsValid(tp))
{
elog(ERROR, "Invalid rattr");
}
namecpy(&(entry->names.rattname), &(((Form_pg_attribute) GETSTRUCT(tp))->attname));
ReleaseSysCache(tp);
}
}
/*
* Request rows and buffers instrumentation if pgqs is enabled
*/
static void
pgqs_ExecutorStart(QueryDesc *queryDesc, int eflags)
{
/* Setup instrumentation */
if (pgqs_enabled)
{
/*
* For rate sampling, randomly choose top-level statement. Either all
* nested statements will be explained or none will.
*/
if (nesting_level == 0
#if PG_VERSION_NUM >= 90600
&& (! IsParallelWorker())
#endif
)
{
query_is_sampled = (random() <= (MAX_RANDOM_VALUE *
pgqs_sample_rate));
#if PG_VERSION_NUM >= 90600
pgqs_set_query_sampled(query_is_sampled);
#endif
}
if (pgqs_is_query_sampled())
{
queryDesc->instrument_options |= INSTRUMENT_ROWS;
queryDesc->instrument_options |= INSTRUMENT_BUFFERS;
}
}
if (prev_ExecutorStart)
prev_ExecutorStart(queryDesc, eflags);
else
standard_ExecutorStart(queryDesc, eflags);
}
/*
* ExecutorRun hook: all we need do is track nesting depth
*/
static void
pgqs_ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction,
#if PG_VERSION_NUM >= 90600
uint64 count
#else
long count
#endif
)
{
nesting_level++;
PG_TRY();
{
if (prev_ExecutorRun)
prev_ExecutorRun(queryDesc, direction, count);
else
standard_ExecutorRun(queryDesc, direction, count);
nesting_level--;
}
PG_CATCH();
{
nesting_level--;
PG_RE_THROW();
}
PG_END_TRY();
}
/*
* ExecutorFinish hook: all we need do is track nesting depth
*/
static void
pgqs_ExecutorFinish(QueryDesc *queryDesc)
{
nesting_level++;
PG_TRY();
{
if (prev_ExecutorFinish)
prev_ExecutorFinish(queryDesc);
else
standard_ExecutorFinish(queryDesc);
nesting_level--;
}
PG_CATCH();
{
nesting_level--;
PG_RE_THROW();
}
PG_END_TRY();
}
/*
* Save a non normalized query for the queryid if no one already exists, and
* do all the stat collecting job
*/
static void
pgqs_ExecutorEnd(QueryDesc *queryDesc)
{
pgqsQueryStringHashKey queryKey;
pgqsQueryStringEntry * queryEntry;
bool found;
if (pgqs_enabled && pgqs_is_query_sampled()
#if PG_VERSION_NUM >= 90600
&& (! IsParallelWorker())
#endif
)
{
HASHCTL info;
pgqsEntry *localentry;
pgqsEntry *newEntry;
HASH_SEQ_STATUS local_hash_seq;
pgqsWalkerContext *context = palloc(sizeof(pgqsWalkerContext));
context->queryId = queryDesc->plannedstmt->queryId;
context->rtable = queryDesc->plannedstmt->rtable;
context->count = 0;
context->qualid = 0;
context->uniquequalid = 0;
context->nbfiltered = 0;
context->evaltype = 0;
context->nentries = 0;
context->querytext = queryDesc->sourceText;
queryKey.queryid = context->queryId;
/* keep an unormalized query example for each queryid if needed */
if (pgqs_track_constants)
{
/* Lookup the hash table entry with a shared lock. */
LWLockAcquire(pgqs->querylock, LW_SHARED);
queryEntry = (pgqsQueryStringEntry *) hash_search_with_hash_value(pgqs_query_examples_hash, &queryKey,
context->queryId,
HASH_FIND, &found);
/* Create the new entry if not present */
if(!found)
{
bool excl_found;
/* Need exclusive lock to add a new hashtable entry - promote */
LWLockRelease(pgqs->querylock);
LWLockAcquire(pgqs->querylock, LW_EXCLUSIVE);
while (hash_get_num_entries(pgqs_query_examples_hash) >= pgqs_max)
pgqs_queryentry_dealloc();
queryEntry = (pgqsQueryStringEntry *) hash_search_with_hash_value(pgqs_query_examples_hash, &queryKey,
context->queryId,
HASH_ENTER, &excl_found);
/* Make sure it wasn't added by another backend */
if(!excl_found)
strncpy(queryEntry->querytext, context->querytext, pgqs_query_size);
}
LWLockRelease(pgqs->querylock);
}
/* create local hash table if it hasn't been created yet */
if (! pgqs_localhash)
{
memset(&info, 0, sizeof(info));
info.keysize = sizeof(pgqsHashKey);
if (pgqs_resolve_oids)
{
info.entrysize = sizeof(pgqsEntryWithNames);
}
else
{
info.entrysize = sizeof(pgqsEntry);
}
info.hash = pgqs_hash_fn;
pgqs_localhash = hash_create("pgqs_localhash",
50,
&info,
HASH_ELEM | HASH_FUNCTION);
}
/* retrieve quals informations, main work starts from here */
pgqs_collectNodeStats(queryDesc->planstate, NIL, context);
/* if any quals found, store them in shared memory */
if (context->nentries)
{
/*
* Before acquiring exlusive lwlock, check if there's enough room to
* store local hash. Also, do not remove more than 20% of maximum
* number of entries in shared memory (wether they are used or not).
* This should not happen since we shouldn't store that much entries
* in localhash in the first place.
*/
int nvictims = hash_get_num_entries(pgqs_localhash) -
PGQS_MAX_LOCAL_ENTRIES;
if (nvictims > 0)
pgqs_localentry_dealloc(nvictims);
LWLockAcquire(pgqs->lock, LW_EXCLUSIVE);
while (hash_get_num_entries(pgqs_hash) +
hash_get_num_entries(pgqs_localhash) >= pgqs_max)
pgqs_entry_dealloc();
hash_seq_init(&local_hash_seq, pgqs_localhash);
while ((localentry = hash_seq_search(&local_hash_seq)) != NULL)
{
newEntry = (pgqsEntry *) hash_search(pgqs_hash, &localentry->key,
HASH_ENTER, &found);
if (!found)
{
/* raw copy the local entry */
memcpy(&(newEntry->lrelid), &(localentry->lrelid),
sizeof(pgqsEntry) - sizeof(pgqsHashKey));
}
else
{
/* only update counters value */
newEntry->count += localentry->count;
newEntry->nbfiltered += localentry->nbfiltered;
newEntry->position += localentry->position;
newEntry->usage += localentry->usage;
newEntry->occurences += localentry->occurences;
}
/* cleanup local hash */
hash_search(pgqs_localhash, &localentry->key, HASH_REMOVE, NULL);
}
LWLockRelease(pgqs->lock);
}
}
if (prev_ExecutorEnd)
prev_ExecutorEnd(queryDesc);
else
standard_ExecutorEnd(queryDesc);
}
/*
* qsort comparator for sorting into increasing usage order
*/
static int
entry_cmp(const void *lhs, const void *rhs)
{
double l_usage = (*(pgqsEntry * const *) lhs)->usage;
double r_usage = (*(pgqsEntry * const *) rhs)->usage;
if (l_usage < r_usage)
return -1;
else if (l_usage > r_usage)
return +1;
else
return 0;
}
/*
* Deallocate least used entries.
* Caller must hold an exlusive lock on pgqs->lock
*/
static void
pgqs_entry_dealloc(void)
{
HASH_SEQ_STATUS hash_seq;
pgqsEntry **entries;
pgqsEntry *entry;
int nvictims;
int i;
int base_size;
/*
* Sort entries by usage and deallocate PGQS_USAGE_DEALLOC_PERCENT of
* them. While we're scanning the table, apply the decay factor to the
* usage values.
*/
if (pgqs_resolve_oids)
{
base_size = sizeof(pgqsEntryWithNames *);
}
else
{
base_size = sizeof(pgqsEntry *);
}
entries = palloc(hash_get_num_entries(pgqs_hash) * base_size);
i = 0;
hash_seq_init(&hash_seq, pgqs_hash);
while ((entry = hash_seq_search(&hash_seq)) != NULL)
{
entries[i++] = entry;
entry->usage *= 0.99;
}
qsort(entries, i, base_size, entry_cmp);
nvictims = Max(10, i * PGQS_USAGE_DEALLOC_PERCENT / 100);
nvictims = Min(nvictims, i);
for (i = 0; i < nvictims; i++)
{
hash_search(pgqs_hash, &entries[i]->key, HASH_REMOVE, NULL);
}
pfree(entries);
}
/*
* Deallocate the first example query.
* Caller must hold an exlusive lock on pgqs->querylock
*/
static void
pgqs_queryentry_dealloc(void)
{
HASH_SEQ_STATUS hash_seq;
pgqsQueryStringEntry *entry;
hash_seq_init(&hash_seq, pgqs_query_examples_hash);
entry = hash_seq_search(&hash_seq);
if (entry != NULL)
hash_search_with_hash_value(pgqs_query_examples_hash, &entry->key, ((pgqsQueryStringHashKey) entry->key).queryid, HASH_REMOVE, NULL);
hash_seq_term(&hash_seq);
}
/*
* Remove the requested number of entries from pgqs_localhash */
static void
pgqs_localentry_dealloc(int nvictims)
{
pgqsEntry *localentry;
HASH_SEQ_STATUS local_hash_seq;
pgqsHashKey *victims[nvictims];
bool need_seq_term = true;
int i, ptr = 0;
if (nvictims <= 0)
return;
hash_seq_init(&local_hash_seq, pgqs_localhash);
while (nvictims-- >= 0)
{
localentry = hash_seq_search(&local_hash_seq);
/* check if caller required too many victims */
if (!localentry)
{
need_seq_term = false;
break;
}
victims[ptr++] = &localentry->key;
}
if (need_seq_term)
hash_seq_term(&local_hash_seq);
for (i=0; i<ptr; i++)
hash_search(pgqs_localhash, victims[i], HASH_REMOVE, NULL);
}
static void
pgqs_collectNodeStats(PlanState *planstate, List *ancestors, pgqsWalkerContext * context)
{
Plan *plan = planstate->plan;
int64 oldcount = context->count;
double oldfiltered = context->nbfiltered;
double total_filtered = 0;
ListCell *lc;
List *parent = 0;
List *indexquals = 0;
List *quals = 0;
context->planstate = planstate;
/*
* 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);
switch (nodeTag(plan))
{
case T_IndexOnlyScan:
indexquals = ((IndexOnlyScan *) plan)->indexqual;
quals = plan->qual;
break;
case T_IndexScan:
case T_BitmapIndexScan:
indexquals = ((IndexScan *) plan)->indexqualorig;
quals = plan->qual;
break;
case T_CteScan:
case T_SeqScan:
case T_BitmapHeapScan:
case T_TidScan:
case T_SubqueryScan:
case T_FunctionScan:
case T_ValuesScan:
case T_WorkTableScan:
case T_ForeignScan:
case T_ModifyTable:
quals = plan->qual;
break;
case T_NestLoop:
quals = ((NestLoop *) plan)->join.joinqual;
break;
case T_MergeJoin:
quals = ((MergeJoin *) plan)->mergeclauses;
break;
case T_HashJoin:
quals = ((HashJoin *) plan)->hashclauses;
break;
default:
break;
}
pgqs_set_planstates(planstate, context);
parent = list_union(indexquals, quals);
if (list_length(parent) > 1)
{
context->uniquequalid = hashExpr((Expr *) parent, context, true);
context->qualid = hashExpr((Expr *) parent, context, false);
}
total_filtered = planstate->instrument->nfiltered1 + planstate->instrument->nfiltered2;
context->nbfiltered = planstate->instrument->nfiltered1 + planstate->instrument->nfiltered2;
context->count = planstate->instrument->tuplecount + planstate->instrument->ntuples + total_filtered;
/* Add the indexquals */
context->evaltype = 'i';
expression_tree_walker((Node *) indexquals, pgqs_whereclause_tree_walker, context);
/* Add the generic quals */
context->evaltype = 'f';
expression_tree_walker((Node *) quals, pgqs_whereclause_tree_walker, context);
context->qualid = 0;
context->uniquequalid = 0;
context->count = oldcount;
context->nbfiltered = oldfiltered;
foreach(lc, planstate->initPlan)
{
SubPlanState *sps = (SubPlanState *) lfirst(lc);
pgqs_collectNodeStats(sps->planstate, ancestors, context);
}
/* lefttree */
if (outerPlanState(planstate))
pgqs_collectNodeStats(outerPlanState(planstate), ancestors, context);
/* righttree */
if (innerPlanState(planstate))
pgqs_collectNodeStats(innerPlanState(planstate), ancestors, context);
/* special child plans */
switch (nodeTag(plan))
{
case T_ModifyTable:
pgqs_collectMemberNodeStats(((ModifyTable *) plan)->plans,
((ModifyTableState *) planstate)->mt_plans,
ancestors, context);
break;
case T_Append:
pgqs_collectMemberNodeStats(((Append *) plan)->appendplans,
((AppendState *) planstate)->appendplans,
ancestors, context);
break;
case T_MergeAppend:
pgqs_collectMemberNodeStats(((MergeAppend *) plan)->mergeplans,
((MergeAppendState *) planstate)->mergeplans,
ancestors, context);
break;
case T_BitmapAnd:
pgqs_collectMemberNodeStats(((BitmapAnd *) plan)->bitmapplans,
((BitmapAndState *) planstate)->bitmapplans,
ancestors, context);
break;
case T_BitmapOr:
pgqs_collectMemberNodeStats(((BitmapOr *) plan)->bitmapplans,
((BitmapOrState *) planstate)->bitmapplans,
ancestors, context);
break;
case T_SubqueryScan:
pgqs_collectNodeStats(((SubqueryScanState *) planstate)->subplan, ancestors, context);
break;
default:
break;
}
/* subPlan-s */
if (planstate->subPlan)
pgqs_collectSubPlanStats(planstate->subPlan, ancestors, context);
}
static void
pgqs_collectMemberNodeStats(List *plans, PlanState **planstates,
List *ancestors, pgqsWalkerContext * context)
{
int nplans = list_length(plans);
int j;