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pg_stat_kcache.c
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/*---------------
* pg_stat_kcache
*
* Provides basic statistics about real I/O done by the filesystem layer.
* This way, calculating a real hit-ratio is doable. Also provides basis
* statistics about CPU usage.
*
* Large portions of code freely inspired by pg_stat_plans. Thanks to Peter
* Geoghegan for this great extension.
*
* This program is open source, licensed under the PostgreSQL license.
* For license terms, see the LICENSE file.
*
*/
#include "postgres.h"
#include <unistd.h>
/*
* pg16 removed the configure probe for getrusage. Simply define it for all
* platforms except Windows to keep existing code backward compatible.
*/
#if PG_VERSION_NUM >= 160000
#ifndef WIN32
#define HAVE_GETRUSAGE
#endif /* HAVE_GETRUSAGE */
#endif /* pg16+ */
#if PG_VERSION_NUM < 160000
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/time.h>
#include <sys/resource.h>
#endif /* HAVE_SYS_RESOURCE_H */
#ifndef HAVE_GETRUSAGE
#include "rusagestub.h"
#endif /* !HAVE_GETRUSAGE */
#endif /* pg16- */
#include "access/hash.h"
#if PG_VERSION_NUM >= 90600
#include "access/parallel.h"
#endif
#include "executor/executor.h"
#include "funcapi.h"
#include "miscadmin.h"
#if PG_VERSION_NUM >= 130000
#include "optimizer/planner.h"
#endif
#include "pgstat.h"
#if PG_VERSION_NUM >= 90600
#include "postmaster/autovacuum.h"
#endif
#if PG_VERSION_NUM >= 120000
#include "replication/walsender.h"
#endif
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/spin.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#if PG_VERSION_NUM >= 160000
#include "utils/pg_rusage.h"
#endif
#include "pg_stat_kcache.h"
PG_MODULE_MAGIC;
#if PG_VERSION_NUM >= 90300
#define PGSK_DUMP_FILE "pg_stat/pg_stat_kcache.stat"
#else
#define PGSK_DUMP_FILE "global/pg_stat_kcache.stat"
#endif
/* In PostgreSQL 11, queryid becomes a uint64 internally.
*/
#if PG_VERSION_NUM >= 110000
typedef uint64 pgsk_queryid;
#else
typedef uint32 pgsk_queryid;
#endif
#define USAGE_INCREASE (1.0)
#define USAGE_DECREASE_FACTOR (0.99) /* decreased every pgsk_entry_dealloc */
#define USAGE_DEALLOC_PERCENT 5 /* free this % of entries at once */
#define USAGE_INIT (1.0) /* including initial planning */
#define TIMEVAL_DIFF(start, end) ((double) end.tv_sec + (double) end.tv_usec / 1000000.0) \
- ((double) start.tv_sec + (double) start.tv_usec / 1000000.0)
#if PG_VERSION_NUM < 140000
#define ParallelLeaderBackendId ParallelMasterBackendId
#endif
#define PGSK_MAX_NESTED_LEVEL 64
/*
* Extension version number, for supporting older extension versions' objects
*/
typedef enum pgskVersion
{
PGSK_V2_0 = 0,
PGSK_V2_1,
PGSK_V2_2
} pgskVersion;
static const uint32 PGSK_FILE_HEADER = 0x0d756e11;
static struct rusage exec_rusage_start[PGSK_MAX_NESTED_LEVEL];
#if PG_VERSION_NUM >= 130000
static struct rusage plan_rusage_start[PGSK_MAX_NESTED_LEVEL];
#endif
static int pgsk_max = 0; /* max #queries to store. pg_stat_statements.max is used */
/*
* Hashtable key that defines the identity of a hashtable entry. We use the
* same hash as pg_stat_statements
*/
typedef struct pgskHashKey
{
Oid userid; /* user OID */
Oid dbid; /* database OID */
pgsk_queryid queryid; /* query identifier */
bool top; /* whether statement is top level */
} pgskHashKey;
/*
* Statistics per database
*/
typedef struct pgskEntry
{
pgskHashKey key; /* hash key of entry - MUST BE FIRST */
pgskCounters counters[PGSK_NUMKIND]; /* statistics for this query */
slock_t mutex; /* protects the counters only */
} pgskEntry;
/*
* Global shared state
*/
typedef struct pgskSharedState
{
LWLock *lock; /* protects hashtable search/modification */
#if PG_VERSION_NUM >= 90600
pgsk_queryid queryids[FLEXIBLE_ARRAY_MEMBER]; /* queryid info for
parallel leaders */
#endif
} pgskSharedState;
/*---- Local variables ----*/
/* Current nesting depth of ExecutorRun+ProcessUtility calls */
static int exec_nested_level = 0;
#if PG_VERSION_NUM >= 130000
/* Current nesting depth of planner calls */
static int plan_nested_level = 0;
#endif
/* saved hook address in case of unload */
#if PG_VERSION_NUM >= 150000
static shmem_request_hook_type prev_shmem_request_hook = NULL;
#endif
static shmem_startup_hook_type prev_shmem_startup_hook = NULL;
#if PG_VERSION_NUM >= 130000
static planner_hook_type prev_planner_hook = NULL;
#endif
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;
/* Links to shared memory state */
static pgskSharedState *pgsk = NULL;
static HTAB *pgsk_hash = NULL;
/*---- GUC variables ----*/
typedef enum
{
PGSK_TRACK_NONE, /* track no statements */
PGSK_TRACK_TOP, /* only top level statements */
PGSK_TRACK_ALL /* all statements, including nested ones */
} PGSKTrackLevel;
static const struct config_enum_entry pgs_track_options[] =
{
{"none", PGSK_TRACK_NONE, false},
{"top", PGSK_TRACK_TOP, false},
{"all", PGSK_TRACK_ALL, false},
{NULL, 0, false}
};
static int pgsk_track = PGSK_TRACK_TOP; /* tracking level */
#if PG_VERSION_NUM >= 130000
static bool pgsk_track_planning = false; /* whether to track planning duration */
#endif
#define pgsk_enabled(level) \
((pgsk_track == PGSK_TRACK_ALL && (level) < PGSK_MAX_NESTED_LEVEL) || \
(pgsk_track == PGSK_TRACK_TOP && (level) == 0))
#define is_top(level) (level) == 0
/*--- Functions --- */
void _PG_init(void);
extern PGDLLEXPORT Datum pg_stat_kcache_reset(PG_FUNCTION_ARGS);
extern PGDLLEXPORT Datum pg_stat_kcache(PG_FUNCTION_ARGS);
extern PGDLLEXPORT Datum pg_stat_kcache_2_1(PG_FUNCTION_ARGS);
extern PGDLLEXPORT Datum pg_stat_kcache_2_2(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(pg_stat_kcache_reset);
PG_FUNCTION_INFO_V1(pg_stat_kcache);
PG_FUNCTION_INFO_V1(pg_stat_kcache_2_1);
PG_FUNCTION_INFO_V1(pg_stat_kcache_2_2);
static void pg_stat_kcache_internal(FunctionCallInfo fcinfo, pgskVersion
api_version);
static void pgsk_setmax(void);
static Size pgsk_memsize(void);
#if PG_VERSION_NUM >= 150000
static void pgsk_shmem_request(void);
#endif
static void pgsk_shmem_startup(void);
static void pgsk_shmem_shutdown(int code, Datum arg);
#if PG_VERSION_NUM >= 130000
static PlannedStmt *pgsk_planner(Query *parse,
const char *query_string,
int cursorOptions,
ParamListInfo boundParams);
#endif
static void pgsk_ExecutorStart(QueryDesc *queryDesc, int eflags);
static void pgsk_ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction,
#if PG_VERSION_NUM >= 90600
uint64 count
#else
long count
#endif
#if PG_VERSION_NUM >= 100000
, bool execute_once
#endif
);
static void pgsk_ExecutorFinish(QueryDesc *queryDesc);
static void pgsk_ExecutorEnd(QueryDesc *queryDesc);
static pgskEntry *pgsk_entry_alloc(pgskHashKey *key);
static void pgsk_entry_dealloc(void);
static void pgsk_entry_reset(void);
static void pgsk_entry_store(pgsk_queryid queryId, pgskStoreKind kind,
int level, pgskCounters counters);
static uint32 pgsk_hash_fn(const void *key, Size keysize);
static int pgsk_match_fn(const void *key1, const void *key2, Size keysize);
static bool pgsk_assign_linux_hz_check_hook(int *newval, void **extra, GucSource source);
static void pgsk_compute_counters(pgskCounters *counters,
struct rusage *rusage_start,
struct rusage *rusage_end,
QueryDesc *queryDesc);
#if PG_VERSION_NUM >= 90600
static Size pgsk_queryids_array_size(void);
static void pgsk_set_queryid(pgsk_queryid queryid);
#endif
static int pgsk_linux_hz = 0;
void
_PG_init(void)
{
if (!process_shared_preload_libraries_in_progress)
{
elog(ERROR, "This module can only be loaded via shared_preload_libraries");
return;
}
DefineCustomIntVariable("pg_stat_kcache.linux_hz",
"Inform pg_stat_kcache of the linux CONFIG_HZ config option",
"This is used by pg_stat_kcache to compensate for sampling errors "
"in getrusage due to the kernel adhering to its ticks. The default value, -1, "
"tries to guess it at startup. ",
&pgsk_linux_hz,
-1,
-1,
INT_MAX,
PGC_USERSET,
0,
pgsk_assign_linux_hz_check_hook,
NULL,
NULL);
DefineCustomEnumVariable("pg_stat_kcache.track",
"Selects which statements are tracked by pg_stat_kcache.",
NULL,
&pgsk_track,
PGSK_TRACK_TOP,
pgs_track_options,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
#if PG_VERSION_NUM >= 130000
DefineCustomBoolVariable("pg_stat_kcache.track_planning",
"Selects whether planning duration is tracked by pg_stat_cache.",
NULL,
&pgsk_track_planning,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
#endif
EmitWarningsOnPlaceholders("pg_stat_kcache");
/* set pgsk_max if needed */
pgsk_setmax();
/*
* If you change code here, don't forget to also report the modifications
* in pgsk_shmem_request() for pg15 and later.
*/
#if PG_VERSION_NUM < 150000
RequestAddinShmemSpace(pgsk_memsize());
#if PG_VERSION_NUM >= 90600
RequestNamedLWLockTranche("pg_stat_kcache", 1);
#else
RequestAddinLWLocks(1);
#endif /* pg 9.6+ */
#endif /* pg 15- */
/* Install hook */
#if PG_VERSION_NUM >= 150000
prev_shmem_request_hook = shmem_request_hook;
shmem_request_hook = pgsk_shmem_request;
#endif
prev_shmem_startup_hook = shmem_startup_hook;
shmem_startup_hook = pgsk_shmem_startup;
#if PG_VERSION_NUM >= 130000
prev_planner_hook = planner_hook;
planner_hook = pgsk_planner;
#endif
prev_ExecutorStart = ExecutorStart_hook;
ExecutorStart_hook = pgsk_ExecutorStart;
prev_ExecutorRun = ExecutorRun_hook;
ExecutorRun_hook = pgsk_ExecutorRun;
prev_ExecutorFinish = ExecutorFinish_hook;
ExecutorFinish_hook = pgsk_ExecutorFinish;
prev_ExecutorEnd = ExecutorEnd_hook;
ExecutorEnd_hook = pgsk_ExecutorEnd;
}
static bool
pgsk_assign_linux_hz_check_hook(int *newval, void **extra, GucSource source)
{
int val = *newval;
struct rusage myrusage;
struct timeval previous_value;
/* In that case we try to guess it */
if (val == -1)
{
elog(LOG, "Auto detecting pg_stat_kcache.linux_hz parameter...");
getrusage(RUSAGE_SELF, &myrusage);
previous_value = myrusage.ru_utime;
while (myrusage.ru_utime.tv_usec == previous_value.tv_usec &&
myrusage.ru_utime.tv_sec == previous_value.tv_sec)
{
getrusage(RUSAGE_SELF, &myrusage);
}
*newval = (int) (1 / ((myrusage.ru_utime.tv_sec - previous_value.tv_sec) +
(myrusage.ru_utime.tv_usec - previous_value.tv_usec) / 1000000.));
elog(LOG, "pg_stat_kcache.linux_hz is set to %d", *newval);
}
return true;
}
static void
pgsk_compute_counters(pgskCounters *counters,
struct rusage *rusage_start,
struct rusage *rusage_end,
QueryDesc *queryDesc)
{
/* Compute CPU time delta */
counters->utime = TIMEVAL_DIFF(rusage_start->ru_utime, rusage_end->ru_utime);
counters->stime = TIMEVAL_DIFF(rusage_start->ru_stime, rusage_end->ru_stime);
if (queryDesc && queryDesc->totaltime)
{
/* Make sure stats accumulation is done */
InstrEndLoop(queryDesc->totaltime);
/*
* We only consider values greater than 3 * linux tick, otherwise the
* bias is too big
*/
if (queryDesc->totaltime->total < (3. / pgsk_linux_hz))
{
counters->stime = 0;
counters->utime = queryDesc->totaltime->total;
}
}
#ifdef HAVE_GETRUSAGE
/* Compute the rest of the counters */
counters->minflts = rusage_end->ru_minflt - rusage_start->ru_minflt;
counters->majflts = rusage_end->ru_majflt - rusage_start->ru_majflt;
counters->nswaps = rusage_end->ru_nswap - rusage_start->ru_nswap;
counters->reads = rusage_end->ru_inblock - rusage_start->ru_inblock;
counters->writes = rusage_end->ru_oublock - rusage_start->ru_oublock;
counters->msgsnds = rusage_end->ru_msgsnd - rusage_start->ru_msgsnd;
counters->msgrcvs = rusage_end->ru_msgrcv - rusage_start->ru_msgrcv;
counters->nsignals = rusage_end->ru_nsignals - rusage_start->ru_nsignals;
counters->nvcsws = rusage_end->ru_nvcsw - rusage_start->ru_nvcsw;
counters->nivcsws = rusage_end->ru_nivcsw - rusage_start->ru_nivcsw;
#endif
}
#if PG_VERSION_NUM >= 90600
static void
pgsk_set_queryid(pgsk_queryid queryid)
{
/* Only the leader knows the queryid. */
Assert(!IsParallelWorker());
pgsk->queryids[MyBackendId] = queryid;
}
#endif
#if PG_VERSION_NUM >= 150000
/*
* Request additional shared memory resources.
*
* If you change code here, don't forget to also report the modifications in
* _PG_init() for pg14 and below.
*/
static void
pgsk_shmem_request(void)
{
if (prev_shmem_request_hook)
prev_shmem_request_hook();
RequestAddinShmemSpace(pgsk_memsize());
RequestNamedLWLockTranche("pg_stat_kcache", 1);
}
#endif
static void
pgsk_shmem_startup(void)
{
bool found;
HASHCTL info;
FILE *file;
int i;
uint32 header;
int32 num;
pgskEntry *buffer = NULL;
if (prev_shmem_startup_hook)
prev_shmem_startup_hook();
/* reset in case this is a restart within the postmaster */
pgsk = NULL;
/* Create or attach to the shared memory state */
LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
/* global access lock */
pgsk = ShmemInitStruct("pg_stat_kcache",
(sizeof(pgskSharedState)
#if PG_VERSION_NUM >= 90600
+ pgsk_queryids_array_size()
#endif
),
&found);
if (!found)
{
/* First time through ... */
#if PG_VERSION_NUM >= 90600
pgsk->lock = &(GetNamedLWLockTranche("pg_stat_kcache"))->lock;
#else
pgsk->lock = LWLockAssign();
#endif
}
/* set pgsk_max if needed */
pgsk_setmax();
memset(&info, 0, sizeof(info));
info.keysize = sizeof(pgskHashKey);
info.entrysize = sizeof(pgskEntry);
info.hash = pgsk_hash_fn;
info.match = pgsk_match_fn;
/* allocate stats shared memory hash */
pgsk_hash = ShmemInitHash("pg_stat_kcache hash",
pgsk_max, pgsk_max,
&info,
HASH_ELEM | HASH_FUNCTION | HASH_COMPARE);
LWLockRelease(AddinShmemInitLock);
if (!IsUnderPostmaster)
on_shmem_exit(pgsk_shmem_shutdown, (Datum) 0);
/*
* Done if some other process already completed our initialization.
*/
if (found)
return;
/* Load stat file, don't care about locking */
file = AllocateFile(PGSK_DUMP_FILE, PG_BINARY_R);
if (file == NULL)
{
if (errno == ENOENT)
return; /* ignore not-found error */
goto error;
}
/* check is header is valid */
if (fread(&header, sizeof(uint32), 1, file) != 1 ||
header != PGSK_FILE_HEADER)
goto error;
/* get number of entries */
if (fread(&num, sizeof(int32), 1, file) != 1)
goto error;
for (i = 0; i < num ; i++)
{
pgskEntry temp;
pgskEntry *entry;
if (fread(&temp, sizeof(pgskEntry), 1, file) != 1)
goto error;
entry = pgsk_entry_alloc(&temp.key);
/* copy in the actual stats */
entry->counters[0] = temp.counters[0];
entry->counters[1] = temp.counters[1];
/* don't initialize spinlock, already done */
}
FreeFile(file);
/*
* Remove the file so it's not included in backups/replication slaves,
* etc. A new file will be written on next shutdown.
*/
unlink(PGSK_DUMP_FILE);
return;
error:
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not read pg_stat_kcache file \"%s\": %m",
PGSK_DUMP_FILE)));
if (buffer)
pfree(buffer);
if (file)
FreeFile(file);
/* delete bogus file, don't care of errors in this case */
unlink(PGSK_DUMP_FILE);
}
/*
* shmem_shutdown hook: dump statistics into file.
*
*/
static void
pgsk_shmem_shutdown(int code, Datum arg)
{
FILE *file;
HASH_SEQ_STATUS hash_seq;
int32 num_entries;
pgskEntry *entry;
/* Don't try to dump during a crash. */
if (code)
return;
if (!pgsk)
return;
file = AllocateFile(PGSK_DUMP_FILE ".tmp", PG_BINARY_W);
if (file == NULL)
goto error;
if (fwrite(&PGSK_FILE_HEADER, sizeof(uint32), 1, file) != 1)
goto error;
num_entries = hash_get_num_entries(pgsk_hash);
if (fwrite(&num_entries, sizeof(int32), 1, file) != 1)
goto error;
hash_seq_init(&hash_seq, pgsk_hash);
while ((entry = hash_seq_search(&hash_seq)) != NULL)
{
if (fwrite(entry, sizeof(pgskEntry), 1, file) != 1)
{
/* note: we assume hash_seq_term won't change errno */
hash_seq_term(&hash_seq);
goto error;
}
}
if (FreeFile(file))
{
file = NULL;
goto error;
}
/*
* Rename file inplace
*/
if (rename(PGSK_DUMP_FILE ".tmp", PGSK_DUMP_FILE) != 0)
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not rename pg_stat_kcache file \"%s\": %m",
PGSK_DUMP_FILE ".tmp")));
return;
error:
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not read pg_stat_kcache file \"%s\": %m",
PGSK_DUMP_FILE)));
if (file)
FreeFile(file);
unlink(PGSK_DUMP_FILE);
}
/*
* Retrieve pg_stat_statement.max GUC value and store it into pgsk_max, since
* we want to store the same number of entries as pg_stat_statements. Don't do
* anything if pgsk_max is already set.
*/
static void pgsk_setmax(void)
{
const char *pgss_max;
const char *name = "pg_stat_statements.max";
if (pgsk_max != 0)
return;
pgss_max = GetConfigOption(name, true, false);
/*
* Retrieving pg_stat_statements.max can fail if pgss is loaded after pgsk
* in shared_preload_libraries. Hint user in case this happens.
*/
if (!pgss_max)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("unrecognized configuration parameter \"%s\"",
name),
errhint("make sure pg_stat_statements is loaded,\n"
"and make sure pg_stat_kcache is present after pg_stat_statements"
" in the shared_preload_libraries setting")));
pgsk_max = atoi(pgss_max);
}
static Size pgsk_memsize(void)
{
Size size;
Assert(pgsk_max != 0);
size = MAXALIGN(sizeof(pgskSharedState));
size = add_size(size, hash_estimate_size(pgsk_max, sizeof(pgskEntry)));
#if PG_VERSION_NUM >= 90600
size = add_size(size, MAXALIGN(pgsk_queryids_array_size()));
#endif
return size;
}
#if PG_VERSION_NUM >= 90600
static Size
pgsk_queryids_array_size(void)
{
/*
* queryid isn't pushed to parallel workers. We store them in shared mem
* for each query, identified by their BackendId. It therefore needs room
* for all possible backends, plus autovacuum launcher and workers, plus bg
* workers and an extra one since BackendId numerotation starts at 1.
* Starting with pg12, wal senders aren't part of MaxConnections anymore,
* so they need to be accounted for.
*/
#if PG_VERSION_NUM >= 150000
Assert (MaxBackends > 0);
return (sizeof(pgsk_queryid) * (MaxBackends + 1));
#else
return (sizeof(pgsk_queryid) * (MaxConnections + autovacuum_max_workers + 1
+ max_worker_processes
#if PG_VERSION_NUM >= 120000
+ max_wal_senders
#endif /* pg12+ */
+ 1));
#endif /* pg15- */
}
#endif
/*
* support functions
*/
static void
pgsk_entry_store(pgsk_queryid queryId, pgskStoreKind kind,
int level, pgskCounters counters)
{
volatile pgskEntry *e;
pgskHashKey key;
pgskEntry *entry;
/* Safety check... */
if (!pgsk || !pgsk_hash)
return;
/* Set up key for hashtable search */
key.userid = GetUserId();
key.dbid = MyDatabaseId;
key.queryid = queryId;
key.top = is_top(level);
/* Lookup the hash table entry with shared lock. */
LWLockAcquire(pgsk->lock, LW_SHARED);
entry = (pgskEntry *) hash_search(pgsk_hash, &key, HASH_FIND, NULL);
/* Create new entry, if not present */
if (!entry)
{
/* Need exclusive lock to make a new hashtable entry - promote */
LWLockRelease(pgsk->lock);
LWLockAcquire(pgsk->lock, LW_EXCLUSIVE);
/* OK to create a new hashtable entry */
entry = pgsk_entry_alloc(&key);
}
/*
* Grab the spinlock while updating the counters (see comment about
* locking rules at the head of the file)
*/
e = (volatile pgskEntry *) entry;
SpinLockAcquire(&e->mutex);
e->counters[0].usage += USAGE_INCREASE;
e->counters[kind].utime += counters.utime;
e->counters[kind].stime += counters.stime;
#ifdef HAVE_GETRUSAGE
e->counters[kind].minflts += counters.minflts;
e->counters[kind].majflts += counters.majflts;
e->counters[kind].nswaps += counters.nswaps;
e->counters[kind].reads += counters.reads;
e->counters[kind].writes += counters.writes;
e->counters[kind].msgsnds += counters.msgsnds;
e->counters[kind].msgrcvs += counters.msgrcvs;
e->counters[kind].nsignals += counters.nsignals;
e->counters[kind].nvcsws += counters.nvcsws;
e->counters[kind].nivcsws += counters.nivcsws;
#endif
SpinLockRelease(&e->mutex);
LWLockRelease(pgsk->lock);
}
/*
* Allocate a new hashtable entry.
* caller must hold an exclusive lock on pgsk->lock
*/
static pgskEntry *pgsk_entry_alloc(pgskHashKey *key)
{
pgskEntry *entry;
bool found;
/* Make space if needed */
while (hash_get_num_entries(pgsk_hash) >= pgsk_max)
pgsk_entry_dealloc();
/* Find or create an entry with desired hash code */
entry = (pgskEntry *) hash_search(pgsk_hash, key, HASH_ENTER, &found);
if (!found)
{
/* New entry, initialize it */
/* reset the statistics */
memset(&entry->counters, 0, sizeof(pgskCounters) * PGSK_NUMKIND);
/* set the appropriate initial usage count */
entry->counters[0].usage = USAGE_INIT;
/* re-initialize the mutex each time ... we assume no one using it */
SpinLockInit(&entry->mutex);
}
return entry;
}
/*
* qsort comparator for sorting into increasing usage order
*/
static int
entry_cmp(const void *lhs, const void *rhs)
{
double l_usage = (*(pgskEntry *const *) lhs)->counters[0].usage;
double r_usage = (*(pgskEntry *const *) rhs)->counters[0].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 exclusive lock on pgsk->lock.
*/
static void
pgsk_entry_dealloc(void)
{
HASH_SEQ_STATUS hash_seq;
pgskEntry **entries;
pgskEntry *entry;
int nvictims;
int i;
/*
* Sort entries by usage and deallocate USAGE_DEALLOC_PERCENT of them.
* While we're scanning the table, apply the decay factor to the usage
* values.
*/
entries = palloc(hash_get_num_entries(pgsk_hash) * sizeof(pgskEntry *));
i = 0;
hash_seq_init(&hash_seq, pgsk_hash);
while ((entry = hash_seq_search(&hash_seq)) != NULL)
{
entries[i++] = entry;
entry->counters[0].usage *= USAGE_DECREASE_FACTOR;
}
qsort(entries, i, sizeof(pgskEntry *), entry_cmp);
nvictims = Max(10, i * USAGE_DEALLOC_PERCENT / 100);
nvictims = Min(nvictims, i);
for (i = 0; i < nvictims; i++)
{
hash_search(pgsk_hash, &entries[i]->key, HASH_REMOVE, NULL);
}
pfree(entries);
}
static void pgsk_entry_reset(void)
{
HASH_SEQ_STATUS hash_seq;
pgskEntry *entry;
LWLockAcquire(pgsk->lock, LW_EXCLUSIVE);
hash_seq_init(&hash_seq, pgsk_hash);
while ((entry = hash_seq_search(&hash_seq)) != NULL)
{
hash_search(pgsk_hash, &entry->key, HASH_REMOVE, NULL);
}
LWLockRelease(pgsk->lock);
}
/*
* Hooks
*/
#if PG_VERSION_NUM >= 130000
/*
* Planner hook: forward to regular planner, but measure planning time
* if needed.
*/
static PlannedStmt *
pgsk_planner(Query *parse,
const char *query_string,
int cursorOptions,
ParamListInfo boundParams)
{
PlannedStmt *result;
/*
* We can't process the query if no queryid has been computed.
*
* Note that planner_hook can be called from the planner itself, so we
* have a specific nesting level for the planner. However, utility
* commands containing optimizable statements can also call the planner,
* same for regular DML (for instance for underlying foreign key queries).
* So testing the planner nesting level only is not enough to detect real
* top level planner call.
*/
if (pgsk_enabled(plan_nested_level + exec_nested_level)
&& pgsk_track_planning
&& parse->queryId != UINT64CONST(0))
{
struct rusage *rusage_start = &plan_rusage_start[plan_nested_level];
struct rusage rusage_end;
pgskCounters counters;
/* capture kernel usage stats in rusage_start */
getrusage(RUSAGE_SELF, rusage_start);
plan_nested_level++;
PG_TRY();
{
if (prev_planner_hook)
result = prev_planner_hook(parse, query_string, cursorOptions,
boundParams);
else
result = standard_planner(parse, query_string, cursorOptions,
boundParams);
plan_nested_level--;
}
PG_CATCH();
{
plan_nested_level--;
PG_RE_THROW();
}
PG_END_TRY();
/* capture kernel usage stats in rusage_end */
getrusage(RUSAGE_SELF, &rusage_end);
pgsk_compute_counters(&counters, rusage_start, &rusage_end, NULL);
/* store current number of block reads and writes */
pgsk_entry_store(parse->queryId, PGSK_PLAN, plan_nested_level + exec_nested_level, counters);
if (pgsk_counters_hook)
pgsk_counters_hook(&counters,
query_string,
plan_nested_level + exec_nested_level,
PGSK_PLAN);
}
else
{
if (prev_planner_hook)
result = prev_planner_hook(parse, query_string, cursorOptions,
boundParams);
else
result = standard_planner(parse, query_string, cursorOptions,
boundParams);
}
return result;
}
#endif
static void
pgsk_ExecutorStart (QueryDesc *queryDesc, int eflags)
{
if (pgsk_enabled(exec_nested_level))
{
struct rusage *rusage_start = &exec_rusage_start[exec_nested_level];
/* capture kernel usage stats in rusage_start */
getrusage(RUSAGE_SELF, rusage_start);
#if PG_VERSION_NUM >= 90600
/* Save the queryid so parallel worker can retrieve it */
if (!IsParallelWorker())
{
pgsk_set_queryid(queryDesc->plannedstmt->queryId);
}
#endif
}
/* give control back to PostgreSQL */
if (prev_ExecutorStart)
prev_ExecutorStart(queryDesc, eflags);