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pg_store_plans.c
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pg_store_plans.c
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/*-------------------------------------------------------------------------
*
* pg_store_plans.c
* Take statistics of plan selection across a whole database cluster.
*
* Execution costs are totaled for each distinct plan for each query,
* and plan and queryid are kept in a shared hashtable, each record in
* which is associated with a record in pg_stat_statements, if any, by
* the queryid.
*
* For Postgres 9.3 or earlier does not expose query id so
* pg_store_plans needs to calculate it based on the given query
* string using different algorithm from pg_stat_statements, and later
* the id will be matched against the one made from query string
* stored in pg_stat_statements. For the reason, queryid matching in
* this way will fail if the query string kept in pg_stat_statements
* is truncated in the middle.
*
* Plans are identified by fingerprinting plan representations in
* "shortened" JSON format with constants and unstable values such as
* rows, width, loops ignored. Nevertheless, stored plan entries hold
* them of the latest execution. Entry eviction is done in the same
* way to pg_stat_statements.
*
* Copyright (c) 2008-2024, PostgreSQL Global Development Group
* Copyright (c) 2012-2024, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
*
* IDENTIFICATION
* pg_store_plans/pg_store_plans.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/stat.h>
#include <unistd.h>
#include <dlfcn.h>
#include <math.h>
#include "catalog/pg_authid.h"
#include "commands/explain.h"
#include "access/hash.h"
#include "executor/instrument.h"
#include "funcapi.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/lwlock.h"
#include "storage/spin.h"
#include "storage/shmem.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#if PG_VERSION_NUM >= 160000
#include "nodes/queryjumble.h"
#elif PG_VERSION_NUM >= 140000
#include "utils/queryjumble.h"
#endif
#include "utils/timestamp.h"
#include "pgsp_json.h"
#include "pgsp_explain.h"
PG_MODULE_MAGIC;
/* Location of stats file */
#define PGSP_DUMP_FILE "global/pg_store_plans.stat"
#define PGSP_TEXT_FILE PG_STAT_TMP_DIR "/pgsp_plan_texts.stat"
/* PostgreSQL major version number, changes in which invalidate all entries */
static const uint32 PGSP_PG_MAJOR_VERSION = PG_VERSION_NUM / 100;
/* This constant defines the magic number in the stats file header */
static const uint32 PGSP_FILE_HEADER = 0x20221214;
static int max_plan_len = 5000;
/* XXX: Should USAGE_EXEC reflect execution time and/or buffer usage? */
#define USAGE_EXEC(duration) (1.0)
#define USAGE_INIT (1.0) /* including initial planning */
#define ASSUMED_MEDIAN_INIT (10.0) /* initial assumed median usage */
#define ASSUMED_LENGTH_INIT 1024 /* initial assumed mean query length */
#define USAGE_DECREASE_FACTOR (0.99) /* decreased every entry_dealloc */
#define STICKY_DECREASE_FACTOR (0.50) /* factor for sticky entries */
#define USAGE_DEALLOC_PERCENT 5 /* free this % of entries at once */
/* In PostgreSQL 11, queryid becomes a uint64 internally. */
#if PG_VERSION_NUM >= 110000
typedef uint64 queryid_t;
#define PGSP_NO_QUERYID UINT64CONST(0)
#else
typedef uint32 queryid_t;
#define PGSP_NO_QUERYID 0
#endif
/*
* Extension version number, for supporting older extension versions' objects
*/
typedef enum pgspVersion
{
PGSP_V1_5 = 0,
PGSP_V1_6,
PGSP_V1_7
} pgspVersion;
/*
* Hashtable key that defines the identity of a hashtable entry. We separate
* queries by user and by database even if they are otherwise identical.
*
* Presently, the query encoding is fully determined by the source database
* and so we don't really need it to be in the key. But that might not always
* be true. Anyway it's notationally convenient to pass it as part of the key.
*/
typedef struct pgspHashKey
{
Oid userid; /* user OID */
Oid dbid; /* database OID */
queryid_t queryid; /* query identifier */
uint32 planid; /* plan identifier */
} pgspHashKey;
/*
* The actual stats counters kept within pgspEntry.
*/
typedef struct Counters
{
int64 calls; /* # of times executed */
double total_time; /* total execution time, in msec */
double min_time; /* minimum execution time in msec */
double max_time; /* maximum execution time in msec */
double mean_time; /* mean execution time in msec */
double sum_var_time; /* sum of variances in execution time in msec */
int64 rows; /* total # of retrieved or affected rows */
int64 shared_blks_hit; /* # of shared buffer hits */
int64 shared_blks_read; /* # of shared disk blocks read */
int64 shared_blks_dirtied;/* # of shared disk blocks dirtied */
int64 shared_blks_written;/* # of shared disk blocks written */
int64 local_blks_hit; /* # of local buffer hits */
int64 local_blks_read; /* # of local disk blocks read */
int64 local_blks_dirtied; /* # of local disk blocks dirtied */
int64 local_blks_written; /* # of local disk blocks written */
int64 temp_blks_read; /* # of temp blocks read */
int64 temp_blks_written; /* # of temp blocks written */
double blk_read_time; /* time spent reading, in msec */
double blk_write_time; /* time spent writing, in msec */
double temp_blk_read_time; /* time spent reading temp blocks,
in msec */
double temp_blk_write_time;/* time spent writing temp blocks,
in msec */
TimestampTz first_call; /* timestamp of first call */
TimestampTz last_call; /* timestamp of last call */
double usage; /* usage factor */
} Counters;
/*
* Global statistics for pg_store_plans
*/
typedef struct pgspGlobalStats
{
int64 dealloc; /* # of times entries were deallocated */
TimestampTz stats_reset; /* timestamp with all stats reset */
} pgspGlobalStats;
/*
* Statistics per plan
*
* NB: see the file read/write code before changing field order here.
*/
typedef struct pgspEntry
{
pgspHashKey key; /* hash key of entry - MUST BE FIRST */
Counters counters; /* the statistics for this query */
Size plan_offset; /* plan text offset in extern file */
int plan_len; /* # of valid bytes in query string */
int encoding; /* query encoding */
slock_t mutex; /* protects the counters only */
} pgspEntry;
/*
* Global shared state
*/
typedef struct pgspSharedState
{
LWLock *lock; /* protects hashtable search/modification */
int plan_size; /* max query length in bytes */
double cur_median_usage; /* current median usage in hashtable */
Size mean_plan_len; /* current mean entry text length */
slock_t mutex; /* protects following fields only: */
Size extent; /* current extent of plan file */
int n_writers; /* number of active writers to query file */
int gc_count; /* plan file garbage collection cycle count */
pgspGlobalStats stats; /* global statistics for pgsp */
} pgspSharedState;
/*---- Local variables ----*/
/* Current nesting depth of ExecutorRun+ProcessUtility calls */
static int nested_level = 0;
/* Saved hook values in case of unload */
static shmem_startup_hook_type prev_shmem_startup_hook = NULL;
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 ProcessUtility_hook_type prev_ProcessUtility = NULL;
/* Links to shared memory state */
static pgspSharedState *shared_state = NULL;
static HTAB *hash_table = NULL;
/*---- GUC variables ----*/
typedef enum
{
TRACK_LEVEL_NONE, /* track no statements */
TRACK_LEVEL_TOP, /* only top level statements */
TRACK_LEVEL_ALL, /* all statements, including nested ones */
TRACK_LEVEL_VERBOSE /* all statements, including internal ones */
} PGSPTrackLevel;
static const struct config_enum_entry track_options[] =
{
{"none", TRACK_LEVEL_NONE, false},
{"top", TRACK_LEVEL_TOP, false},
{"all", TRACK_LEVEL_ALL, false},
{"verbose", TRACK_LEVEL_VERBOSE, false},
{NULL, 0, false}
};
typedef enum
{
PLAN_FORMAT_RAW, /* No conversion. Shorten JSON */
PLAN_FORMAT_TEXT, /* Traditional text representation */
PLAN_FORMAT_JSON, /* JSON representation */
PLAN_FORMAT_YAML, /* YAML */
PLAN_FORMAT_XML, /* XML */
} PGSPPlanFormats;
static const struct config_enum_entry plan_formats[] =
{
{"raw" , PLAN_FORMAT_RAW , false},
{"text", PLAN_FORMAT_TEXT, false},
{"json", PLAN_FORMAT_JSON, false},
{"yaml", PLAN_FORMAT_YAML, false},
{"xml" , PLAN_FORMAT_XML , false},
{NULL, 0, false}
};
/* options for plan storage */
typedef enum
{
PLAN_STORAGE_SHMEM, /* plan is stored as a part of hash entry */
PLAN_STORAGE_FILE /* plan is stored in a separate file */
} pgspPlanStorage;
static const struct config_enum_entry plan_storage_options[] =
{
{"shmem", PLAN_STORAGE_SHMEM, false},
{"file", PLAN_STORAGE_FILE, false},
{NULL, 0, false}
};
static int store_size; /* max # statements to track */
static int track_level = TRACK_LEVEL_TOP; /* tracking level */
static int min_duration; /* min duration to record */
static bool dump_on_shutdown; /* whether to save stats across shutdown */
static bool log_analyze; /* Similar to EXPLAIN (ANALYZE *) */
static bool log_verbose; /* Similar to EXPLAIN (VERBOSE *) */
static bool log_buffers; /* Similar to EXPLAIN (BUFFERS *) */
static bool log_timing; /* Similar to EXPLAIN (TIMING *) */
static bool log_triggers; /* whether to log trigger statistics */
static int plan_format= PLAN_FORMAT_TEXT; /* Plan representation style in
* pg_store_plans.plan */
static int plan_storage = PLAN_STORAGE_FILE; /* Plan storage type */
/* disables tracking overriding track_level */
static bool force_disabled = false;
#if PG_VERSION_NUM >= 140000
/*
* For pg14 and later, we rely on core queryid calculation. If
* it's not available it means that the admin explicitly refused to
* compute it, for performance reason or other. In that case, we
* will also consider that this extension is disabled.
*/
#define pgsp_enabled(q) \
(!force_disabled && \
(track_level >= TRACK_LEVEL_ALL || \
(track_level == TRACK_LEVEL_TOP && nested_level == 0)) && \
(q != PGSP_NO_QUERYID))
#else
#define pgsp_enabled(q) \
(!force_disabled && \
(track_level >= TRACK_LEVEL_ALL || \
(track_level == TRACK_LEVEL_TOP && nested_level == 0)))
#endif
#define SHMEM_PLAN_PTR(ent) (((char *) ent) + sizeof(pgspEntry))
/*---- Function declarations ----*/
void _PG_init(void);
void _PG_fini(void);
Datum pg_store_plans_reset(PG_FUNCTION_ARGS);
Datum pg_store_plans_hash_query(PG_FUNCTION_ARGS);
Datum pg_store_plans(PG_FUNCTION_ARGS);
Datum pg_store_plans_shorten(PG_FUNCTION_ARGS);
Datum pg_store_plans_normalize(PG_FUNCTION_ARGS);
Datum pg_store_plans_jsonplan(PG_FUNCTION_ARGS);
Datum pg_store_plans_yamlplan(PG_FUNCTION_ARGS);
Datum pg_store_plans_xmlplan(PG_FUNCTION_ARGS);
Datum pg_store_plans_textplan(PG_FUNCTION_ARGS);
Datum pg_store_plans_info(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(pg_store_plans_reset);
PG_FUNCTION_INFO_V1(pg_store_plans_hash_query);
PG_FUNCTION_INFO_V1(pg_store_plans);
PG_FUNCTION_INFO_V1(pg_store_plans_1_6);
PG_FUNCTION_INFO_V1(pg_store_plans_1_7);
PG_FUNCTION_INFO_V1(pg_store_plans_shorten);
PG_FUNCTION_INFO_V1(pg_store_plans_normalize);
PG_FUNCTION_INFO_V1(pg_store_plans_jsonplan);
PG_FUNCTION_INFO_V1(pg_store_plans_yamlplan);
PG_FUNCTION_INFO_V1(pg_store_plans_xmlplan);
PG_FUNCTION_INFO_V1(pg_store_plans_textplan);
PG_FUNCTION_INFO_V1(pg_store_plans_info);
#if PG_VERSION_NUM < 130000
#define COMPTAG_TYPE char
#else
#define COMPTAG_TYPE QueryCompletion
#endif
#if PG_VERSION_NUM < 140000
#define ROLE_PG_READ_ALL_STATS DEFAULT_ROLE_READ_ALL_STATS
#endif
#if PG_VERSION_NUM >= 150000
static shmem_request_hook_type prev_shmem_request_hook = NULL;
#endif
static void pgsp_shmem_request(void);
static void pgsp_shmem_startup(void);
static void pgsp_shmem_shutdown(int code, Datum arg);
static void pgsp_ExecutorStart(QueryDesc *queryDesc, int eflags);
static void pgsp_ExecutorRun(QueryDesc *queryDesc,
ScanDirection direction,
uint64 count, bool execute_once);
static void pgsp_ExecutorFinish(QueryDesc *queryDesc);
static void pgsp_ExecutorEnd(QueryDesc *queryDesc);
static void pgsp_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
#if PG_VERSION_NUM >= 140000
bool readOnlyTree,
#endif
ProcessUtilityContext context, ParamListInfo params,
QueryEnvironment *queryEnv,
DestReceiver *dest, COMPTAG_TYPE *completionTag);
static uint32 hash_query(const char* query);
static void pgsp_store(char *plan, queryid_t queryId,
double total_time, uint64 rows,
const BufferUsage *bufusage);
static void pg_store_plans_internal(FunctionCallInfo fcinfo,
pgspVersion api_version);
static Size shared_mem_size(void);
static pgspEntry *entry_alloc(pgspHashKey *key, Size plan_offset, int plan_len,
bool sticky);
static bool ptext_store(const char *plan, int plan_len, Size *plan_offset,
int *gc_count);
static char *ptext_load_file(Size *buffer_size);
static char *ptext_fetch(Size plan_offset, int plan_len, char *buffer,
Size buffer_size);
static bool need_gc_ptexts(void);
static void gc_ptexts(void);
static void entry_dealloc(void);
static void entry_reset(void);
/*
* Module load callback
*/
void
_PG_init(void)
{
/*
* In order to create our shared memory area, we have to be loaded via
* shared_preload_libraries. If not, fall out without hooking into any of
* the main system. (We don't throw error here because it seems useful to
* allow the pg_stat_statements functions to be created even when the
* module isn't active. The functions must protect themselves against
* being called then, however.)
*/
if (!process_shared_preload_libraries_in_progress)
return;
#if PG_VERSION_NUM >= 140000
/*
* Inform the postmaster that we want to enable query_id calculation if
* compute_query_id is set to auto.
*/
EnableQueryId();
#endif
/*
* Define (or redefine) custom GUC variables.
*/
DefineCustomIntVariable("pg_store_plans.max",
"Sets the maximum number of plans tracked by pg_store_plans.",
NULL,
&store_size,
1000,
100,
INT_MAX,
PGC_POSTMASTER,
0,
NULL,
NULL,
NULL);
DefineCustomIntVariable("pg_store_plans.max_plan_length",
"Sets the maximum length of plans stored by pg_store_plans.",
NULL,
&max_plan_len,
5000,
100,
INT32_MAX,
PGC_POSTMASTER,
0,
NULL,
NULL,
NULL);
DefineCustomEnumVariable("pg_store_plans.plan_storage",
"Selects where to store plan texts.",
NULL,
&plan_storage,
PLAN_STORAGE_FILE,
plan_storage_options,
PGC_POSTMASTER,
0,
NULL,
NULL,
NULL);
DefineCustomEnumVariable("pg_store_plans.track",
"Selects which plans are tracked by pg_store_plans.",
NULL,
&track_level,
TRACK_LEVEL_TOP,
track_options,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomEnumVariable("pg_store_plans.plan_format",
"Selects which format to be appied for plan representation in pg_store_plans.",
NULL,
&plan_format,
PLAN_FORMAT_TEXT,
plan_formats,
PGC_USERSET,
0,
NULL,
NULL,
NULL);
DefineCustomIntVariable("pg_store_plans.min_duration",
"Minimum duration to record plan in milliseconds.",
NULL,
&min_duration,
0,
0,
INT_MAX,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_store_plans.save",
"Save pg_store_plans statistics across server shutdowns.",
NULL,
&dump_on_shutdown,
true,
PGC_SIGHUP,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_store_plans.log_analyze",
"Use EXPLAIN ANALYZE for plan logging.",
NULL,
&log_analyze,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_store_plans.log_buffers",
"Log buffer usage.",
NULL,
&log_buffers,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_store_plans.log_timing",
"Log timings.",
NULL,
&log_timing,
true,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_store_plans.log_triggers",
"Log trigger trace.",
NULL,
&log_triggers,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
DefineCustomBoolVariable("pg_store_plans.log_verbose",
"Set VERBOSE for EXPLAIN on logging.",
NULL,
&log_verbose,
false,
PGC_SUSET,
0,
NULL,
NULL,
NULL);
EmitWarningsOnPlaceholders("pg_store_plans");
#if PG_VERSION_NUM < 150000
pgsp_shmem_request();
#endif
/*
* Install hooks.
*/
#if PG_VERSION_NUM >= 150000
prev_shmem_request_hook = shmem_request_hook;
shmem_request_hook = pgsp_shmem_request;
#endif
prev_shmem_startup_hook = shmem_startup_hook;
shmem_startup_hook = pgsp_shmem_startup;
prev_ExecutorStart = ExecutorStart_hook;
ExecutorStart_hook = pgsp_ExecutorStart;
prev_ExecutorRun = ExecutorRun_hook;
ExecutorRun_hook = pgsp_ExecutorRun;
prev_ExecutorFinish = ExecutorFinish_hook;
ExecutorFinish_hook = pgsp_ExecutorFinish;
prev_ExecutorEnd = ExecutorEnd_hook;
ExecutorEnd_hook = pgsp_ExecutorEnd;
prev_ProcessUtility = ProcessUtility_hook;
ProcessUtility_hook = pgsp_ProcessUtility;
}
/*
* Module unload callback
*/
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;
ProcessUtility_hook = prev_ProcessUtility;
}
/*
* pgsp_shmem_request: request shared memory to the core.
* Called as a hook in PG15 or later, otherwise called from _PG_init().
*/
static void
pgsp_shmem_request(void)
{
#if PG_VERSION_NUM >= 150000
if (prev_shmem_request_hook)
prev_shmem_request_hook();
#endif
RequestAddinShmemSpace(shared_mem_size());
RequestNamedLWLockTranche("pg_store_plans", 1);
}
/*
* shmem_startup hook: allocate or attach to shared memory,
* then load any pre-existing statistics from file.
*/
static void
pgsp_shmem_startup(void)
{
bool found;
HASHCTL info;
FILE *file = NULL;
FILE *pfile = NULL;
uint32 header;
int32 num;
int32 pgver;
int32 i;
int plan_size;
int buffer_size;
char *buffer = NULL;
if (prev_shmem_startup_hook)
prev_shmem_startup_hook();
/* reset in case this is a restart within the postmaster */
shared_state = NULL;
hash_table = NULL;
/*
* Create or attach to the shared memory state, including hash table
*/
LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
shared_state = ShmemInitStruct("pg_store_plans",
sizeof(pgspSharedState),
&found);
if (!found)
{
/* First time through ... */
shared_state->lock = &(GetNamedLWLockTranche("pg_store_plans"))->lock;
shared_state->plan_size = max_plan_len;
shared_state->cur_median_usage = ASSUMED_MEDIAN_INIT;
shared_state->mean_plan_len = ASSUMED_LENGTH_INIT;
SpinLockInit(&shared_state->mutex);
shared_state->extent = 0;
shared_state->n_writers = 0;
shared_state->gc_count = 0;
shared_state->stats.dealloc = 0;
shared_state->stats.stats_reset = GetCurrentTimestamp();
}
/* Be sure everyone agrees on the hash table entry size */
plan_size = shared_state->plan_size;
memset(&info, 0, sizeof(info));
info.keysize = sizeof(pgspHashKey);
info.entrysize = sizeof(pgspEntry);
if (plan_storage == PLAN_STORAGE_SHMEM)
info.entrysize += max_plan_len;
hash_table = ShmemInitHash("pg_store_plans hash",
store_size, store_size,
&info, HASH_ELEM |
HASH_BLOBS);
LWLockRelease(AddinShmemInitLock);
/*
* If we're in the postmaster (or a standalone backend...), set up a shmem
* exit hook to dump the statistics to disk.
*/
if (!IsUnderPostmaster)
on_shmem_exit(pgsp_shmem_shutdown, (Datum) 0);
/*
* Done if some other process already completed our initialization.
*/
if (found)
return;
/*
* Note: we don't bother with locks here, because there should be no other
* processes running when this code is reached.
*/
/* Unlink query text file possibly left over from crash */
unlink(PGSP_TEXT_FILE);
if (plan_storage == PLAN_STORAGE_FILE)
{
/* Allocate new query text temp file */
pfile = AllocateFile(PGSP_TEXT_FILE, PG_BINARY_W);
if (pfile == NULL)
goto write_error;
}
/*
* If we were told not to load old statistics, we're done. (Note we do
* not try to unlink any old dump file in this case. This seems a bit
* questionable but it's the historical behavior.)
*/
if (!dump_on_shutdown)
{
if (pfile)
FreeFile(pfile);
return;
}
/*
* Attempt to load old statistics from the dump file.
*/
file = AllocateFile(PGSP_DUMP_FILE, PG_BINARY_R);
if (file == NULL)
{
/* ignore not-found error */
if (errno != ENOENT)
goto read_error;
/* No existing persisted stats file, so we're done */
if (pfile)
FreeFile(pfile);
return;
}
buffer_size = plan_size;
buffer = (char *) palloc(buffer_size);
if (fread(&header, sizeof(uint32), 1, file) != 1 ||
fread(&pgver, sizeof(uint32), 1, file) != 1 ||
fread(&num, sizeof(int32), 1, file) != 1)
goto read_error;
if (header != PGSP_FILE_HEADER ||
pgver != PGSP_PG_MAJOR_VERSION)
goto data_error;
for (i = 0; i < num; i++)
{
pgspEntry temp;
pgspEntry *entry;
Size plan_offset = 0;
if (fread(&temp, sizeof(pgspEntry), 1, file) != 1)
goto read_error;
/* Encoding is the only field we can easily sanity-check */
if (!PG_VALID_BE_ENCODING(temp.encoding))
goto data_error;
/* Previous incarnation might have had a larger plan_size */
if (temp.plan_len >= buffer_size)
{
buffer = (char *) repalloc(buffer, temp.plan_len + 1);
buffer_size = temp.plan_len + 1;
}
if (fread(buffer, 1, temp.plan_len + 1, file) != temp.plan_len + 1)
goto read_error;
/* Skip loading "sticky" entries */
if (temp.counters.calls == 0)
continue;
/* Clip to available length if needed */
if (temp.plan_len >= plan_size)
temp.plan_len = pg_encoding_mbcliplen(temp.encoding,
buffer,
temp.plan_len,
plan_size - 1);
buffer[temp.plan_len] = '\0';
if (plan_storage == PLAN_STORAGE_FILE)
{
/* Store the plan text */
plan_offset = shared_state->extent;
if (fwrite(buffer, 1, temp.plan_len + 1, pfile) !=
temp.plan_len + 1)
goto write_error;
shared_state->extent += temp.plan_len + 1;
}
/* make the hashtable entry (discards old entries if too many) */
entry = entry_alloc(&temp.key, plan_offset, temp.plan_len, false);
if (plan_storage == PLAN_STORAGE_SHMEM)
memcpy(SHMEM_PLAN_PTR(entry), buffer, temp.plan_len + 1);
/* copy in the actual stats */
entry->counters = temp.counters;
}
pfree(buffer);
FreeFile(file);
if (pfile)
FreeFile(pfile);
/*
* Remove the file so it's not included in backups/replication slaves,
* etc. A new file will be written on next shutdown.
*/
unlink(PGSP_DUMP_FILE);
return;
read_error:
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m",
PGSP_DUMP_FILE)));
goto fail;
data_error:
ereport(LOG,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("ignoring invalid data in file \"%s\"",
PGSP_DUMP_FILE)));
goto fail;
write_error:
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not write file \"%s\": %m",
PGSP_TEXT_FILE)));
fail:
if (buffer)
pfree(buffer);
if (file)
FreeFile(file);
if (pfile)
FreeFile(pfile);
/* If possible, throw away the bogus file; ignore any error */
unlink(PGSP_DUMP_FILE);
/*
* Don't unlink PGSP_TEXT_FILE here; it should always be around while the
* server is running with pg_stat_statements enabled
*/
}
/*
* shmem_shutdown hook: Dump statistics into file.
*
* Note: we don't bother with acquiring lock, because there should be no
* other processes running when this is called.
*/
static void
pgsp_shmem_shutdown(int code, Datum arg)
{
FILE *file;
char *pbuffer = NULL;
Size pbuffer_size = 0;
HASH_SEQ_STATUS hash_seq;
int32 num_entries;
pgspEntry *entry;
/* Don't try to dump during a crash. */
if (code)
return;
/* Safety check ... shouldn't get here unless shmem is set up. */
if (!shared_state || !hash_table)
return;
/* Don't dump if told not to. */
if (!dump_on_shutdown)
return;
file = AllocateFile(PGSP_DUMP_FILE ".tmp", PG_BINARY_W);
if (file == NULL)
goto error;
if (fwrite(&PGSP_FILE_HEADER, sizeof(uint32), 1, file) != 1)
goto error;
if (fwrite(&PGSP_PG_MAJOR_VERSION, sizeof(uint32), 1, file) != 1)
goto error;
num_entries = hash_get_num_entries(hash_table);
if (fwrite(&num_entries, sizeof(int32), 1, file) != 1)
goto error;
if (plan_storage == PLAN_STORAGE_FILE)
{
pbuffer = ptext_load_file(&pbuffer_size);
if (pbuffer == NULL)
goto error;
}
hash_seq_init(&hash_seq, hash_table);
while ((entry = hash_seq_search(&hash_seq)) != NULL)
{
int len = entry->plan_len;
char *pstr;
if (plan_storage == PLAN_STORAGE_FILE)
pstr = ptext_fetch(entry->plan_offset, len,
pbuffer, pbuffer_size);
else
pstr = SHMEM_PLAN_PTR(entry);
if (pstr == NULL)
continue; /* Ignore any entries with bogus texts */
if (fwrite(entry, sizeof(pgspEntry), 1, file) != 1 ||
fwrite(pstr, 1, len + 1, file) != len + 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 into place, so we atomically replace the old one.
*/
if (rename(PGSP_DUMP_FILE ".tmp", PGSP_DUMP_FILE) != 0)
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not rename pg_store_plans file \"%s\": %m",
PGSP_DUMP_FILE ".tmp")));
/* Unlink query-texts file; it's not needed while shutdown */
unlink(PGSP_TEXT_FILE);
return;
error:
ereport(LOG,
(errcode_for_file_access(),
errmsg("could not write pg_store_plans file \"%s\": %m",
PGSP_DUMP_FILE ".tmp")));
if (file)
FreeFile(file);
unlink(PGSP_DUMP_FILE ".tmp");
}
/*
* ExecutorStart hook: start up tracking if needed
*/
static void
pgsp_ExecutorStart(QueryDesc *queryDesc, int eflags)
{
if (log_analyze &&
(eflags & EXEC_FLAG_EXPLAIN_ONLY) == 0)
{
queryDesc->instrument_options |=
(log_timing ? INSTRUMENT_TIMER : 0)|
(log_timing ? 0: INSTRUMENT_ROWS)|
(log_buffers ? INSTRUMENT_BUFFERS : 0);
}
if (prev_ExecutorStart)
prev_ExecutorStart(queryDesc, eflags);
else
standard_ExecutorStart(queryDesc, eflags);
/*
* Set up to track total elapsed time in ExecutorRun. Allocate in per-query
* context so as to be free at ExecutorEnd.
*/
if (queryDesc->totaltime == NULL &&
pgsp_enabled(queryDesc->plannedstmt->queryId))
{
MemoryContext oldcxt;
oldcxt = MemoryContextSwitchTo(queryDesc->estate->es_query_cxt);
queryDesc->totaltime = InstrAlloc(1, INSTRUMENT_ALL
#if PG_VERSION_NUM >= 140000
, false
#endif
);
MemoryContextSwitchTo(oldcxt);
}
}
/*
* ExecutorRun hook: all we need do is track nesting depth
*/
static void
pgsp_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, uint64 count,
bool execute_once)
{
nested_level++;
PG_TRY();
{
if (prev_ExecutorRun)
prev_ExecutorRun(queryDesc, direction, count, execute_once);
else
standard_ExecutorRun(queryDesc, direction, count, execute_once);
nested_level--;