/*-------------------------------------------------------------------------
*
* pg_stat_statements.c
- * Track statement execution times across a whole database cluster.
+ *
+ * Part of pg_stat_statements.c in PostgreSQL 9.6.
*
- * Execution costs are totalled for each distinct source query, and kept in
- * a shared hashtable. (We track only as many distinct queries as will fit
- * in the designated amount of shared memory.)
+ * Copyright (c) 2008-2016, PostgreSQL Global Development Group
*
- * As of Postgres 9.2, this module normalizes query entries. Normalization
- * is a process whereby similar queries, typically differing only in their
- * constants (though the exact rules are somewhat more subtle than that) are
- * recognized as equivalent, and are tracked as a single entry. This is
- * particularly useful for non-prepared queries.
- *
- * Normalization is implemented by fingerprinting queries, selectively
- * serializing those fields of each query tree's nodes that are judged to be
- * essential to the query. This is referred to as a query jumble. This is
- * distinct from a regular serialization in that various extraneous
- * information is ignored as irrelevant or not essential to the query, such
- * as the collations of Vars and, most notably, the values of constants.
- *
- * This jumble is acquired at the end of parse analysis of each query, and
- * a 32-bit hash of it is stored into the query's Query.queryId field.
- * The server then copies this value around, making it available in plan
- * tree(s) generated from the query. The executor can then use this value
- * to blame query costs on the proper queryId.
- *
- * To facilitate presenting entries to users, we create "representative" query
- * strings in which constants are replaced with '?' characters, to make it
- * clearer what a normalized entry can represent. To save on shared memory,
- * and to avoid having to truncate oversized query strings, we store these
- * strings in a temporary external query-texts file. Offsets into this
- * file are kept in shared memory.
- *
- * Note about locking issues: to create or delete an entry in the shared
- * hashtable, one must hold pgss->lock exclusively. Modifying any field
- * in an entry except the counters requires the same. To look up an entry,
- * one must hold the lock shared. To read or update the counters within
- * an entry, one must hold the lock shared or exclusive (so the entry doesn't
- * disappear!) and also take the entry's mutex spinlock.
- * The shared state variable pgss->extent (the next free spot in the external
- * query-text file) should be accessed only while holding either the
- * pgss->mutex spinlock, or exclusive lock on pgss->lock. We use the mutex to
- * allow reserving file space while holding only shared lock on pgss->lock.
- * Rewriting the entire external query-text file, eg for garbage collection,
- * requires holding pgss->lock exclusively; this allows individual entries
- * in the file to be read or written while holding only shared lock.
- *
- *
- * Copyright (c) 2008-2014, PostgreSQL Global Development Group
- *
- * IDENTIFICATION
- * contrib/pg_stat_statements/pg_stat_statements.c
- *
- *-------------------------------------------------------------------------
- */
-#include "postgres.h"
-
-#include <sys/stat.h>
-
-#ifdef NOT_USED
-#include <unistd.h>
-#endif
-
-#include "access/hash.h"
-#ifdef NOT_USED
-#include "executor/instrument.h"
-#include "funcapi.h"
-#include "mb/pg_wchar.h"
-#include "miscadmin.h"
-#include "parser/analyze.h"
-#include "parser/parsetree.h"
-#endif
-#include "parser/scanner.h"
-#ifdef NOT_USED
-#include "pgstat.h"
-#include "storage/fd.h"
-#include "storage/ipc.h"
-#include "storage/spin.h"
-#include "tcop/utility.h"
-#include "utils/builtins.h"
-#include "utils/memutils.h"
-
-PG_MODULE_MAGIC;
-
-/* Location of permanent stats file (valid when database is shut down) */
-#define PGSS_DUMP_FILE PGSTAT_STAT_PERMANENT_DIRECTORY "/pg_stat_statements.stat"
-
-/*
- * Location of external query text file. We don't keep it in the core
- * system's stats_temp_directory. The core system can safely use that GUC
- * setting, because the statistics collector temp file paths are set only once
- * as part of changing the GUC, but pg_stat_statements has no way of avoiding
- * race conditions. Besides, we only expect modest, infrequent I/O for query
- * strings, so placing the file on a faster filesystem is not compelling.
- */
-#define PGSS_TEXT_FILE PG_STAT_TMP_DIR "/pgss_query_texts.stat"
-
-/* Magic number identifying the stats file format */
-static const uint32 PGSS_FILE_HEADER = 0x20140125;
-
-/* PostgreSQL major version number, changes in which invalidate all entries */
-static const uint32 PGSS_PG_MAJOR_VERSION = PG_VERSION_NUM / 100;
-
-/* 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 */
-
-#define JUMBLE_SIZE 1024 /* query serialization buffer size */
-
-/*
- * Extension version number, for supporting older extension versions' objects
- */
-typedef enum pgssVersion
-{
- PGSS_V1_0 = 0,
- PGSS_V1_1,
- PGSS_V1_2
-} pgssVersion;
-
-/*
- * Hashtable key that defines the identity of a hashtable entry. We separate
- * queries by user and by database even if they are otherwise identical.
- */
-typedef struct pgssHashKey
-{
- Oid userid; /* user OID */
- Oid dbid; /* database OID */
- uint32 queryid; /* query identifier */
-} pgssHashKey;
-
-/*
- * The actual stats counters kept within pgssEntry.
- */
-typedef struct Counters
-{
- int64 calls; /* # of times executed */
- double total_time; /* total 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 usage; /* usage factor */
-} Counters;
-
-/*
- * Statistics per statement
- *
- * Note: in event of a failure in garbage collection of the query text file,
- * we reset query_offset to zero and query_len to -1. This will be seen as
- * an invalid state by qtext_fetch().
- */
-typedef struct pgssEntry
-{
- pgssHashKey key; /* hash key of entry - MUST BE FIRST */
- Counters counters; /* the statistics for this query */
- Size query_offset; /* query text offset in external file */
- int query_len; /* # of valid bytes in query string */
- int encoding; /* query text encoding */
- slock_t mutex; /* protects the counters only */
-} pgssEntry;
-
-/*
- * Global shared state
- */
-typedef struct pgssSharedState
-{
- LWLock *lock; /* protects hashtable search/modification */
- double cur_median_usage; /* current median usage in hashtable */
- Size mean_query_len; /* current mean entry text length */
- slock_t mutex; /* protects following fields only: */
- Size extent; /* current extent of query file */
- int n_writers; /* number of active writers to query file */
- int gc_count; /* query file garbage collection cycle count */
-} pgssSharedState;
-
-/*
- * Struct for tracking locations/lengths of constants during normalization
- */
-typedef struct pgssLocationLen
-{
- int location; /* start offset in query text */
- int length; /* length in bytes, or -1 to ignore */
-} pgssLocationLen;
-
-/*
- * Working state for computing a query jumble and producing a normalized
- * query string
- */
-typedef struct pgssJumbleState
-{
- /* Jumble of current query tree */
- unsigned char *jumble;
-
- /* Number of bytes used in jumble[] */
- Size jumble_len;
-
- /* Array of locations of constants that should be removed */
- pgssLocationLen *clocations;
-
- /* Allocated length of clocations array */
- int clocations_buf_size;
-
- /* Current number of valid entries in clocations array */
- int clocations_count;
-} pgssJumbleState;
-
-/*---- 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 post_parse_analyze_hook_type prev_post_parse_analyze_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 pgssSharedState *pgss = NULL;
-static HTAB *pgss_hash = NULL;
-
-/*---- GUC variables ----*/
-
-typedef enum
-{
- PGSS_TRACK_NONE, /* track no statements */
- PGSS_TRACK_TOP, /* only top level statements */
- PGSS_TRACK_ALL /* all statements, including nested ones */
-} PGSSTrackLevel;
-
-static const struct config_enum_entry track_options[] =
-{
- {"none", PGSS_TRACK_NONE, false},
- {"top", PGSS_TRACK_TOP, false},
- {"all", PGSS_TRACK_ALL, false},
- {NULL, 0, false}
-};
-
-static int pgss_max; /* max # statements to track */
-static int pgss_track; /* tracking level */
-static bool pgss_track_utility; /* whether to track utility commands */
-static bool pgss_save; /* whether to save stats across shutdown */
-
-
-#define pgss_enabled() \
- (pgss_track == PGSS_TRACK_ALL || \
- (pgss_track == PGSS_TRACK_TOP && nested_level == 0))
-
-#define record_gc_qtexts() \
- do { \
- volatile pgssSharedState *s = (volatile pgssSharedState *) pgss; \
- SpinLockAcquire(&s->mutex); \
- s->gc_count++; \
- SpinLockRelease(&s->mutex); \
- } while(0)
-
-/*---- Function declarations ----*/
-
-void _PG_init(void);
-void _PG_fini(void);
-
-PG_FUNCTION_INFO_V1(pg_stat_statements_reset);
-PG_FUNCTION_INFO_V1(pg_stat_statements_1_2);
-PG_FUNCTION_INFO_V1(pg_stat_statements);
-
-static void pgss_shmem_startup(void);
-static void pgss_shmem_shutdown(int code, Datum arg);
-static void pgss_post_parse_analyze(ParseState *pstate, Query *query);
-static void pgss_ExecutorStart(QueryDesc *queryDesc, int eflags);
-static void pgss_ExecutorRun(QueryDesc *queryDesc,
- ScanDirection direction,
- long count);
-static void pgss_ExecutorFinish(QueryDesc *queryDesc);
-static void pgss_ExecutorEnd(QueryDesc *queryDesc);
-static void pgss_ProcessUtility(Node *parsetree, const char *queryString,
- ProcessUtilityContext context, ParamListInfo params,
- DestReceiver *dest, char *completionTag);
-static uint32 pgss_hash_fn(const void *key, Size keysize);
-static int pgss_match_fn(const void *key1, const void *key2, Size keysize);
-static uint32 pgss_hash_string(const char *str);
-static void pgss_store(const char *query, uint32 queryId,
- double total_time, uint64 rows,
- const BufferUsage *bufusage,
- pgssJumbleState *jstate);
-static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
- pgssVersion api_version,
- bool showtext);
-static Size pgss_memsize(void);
-static pgssEntry *entry_alloc(pgssHashKey *key, Size query_offset, int query_len,
- int encoding, bool sticky);
-static void entry_dealloc(void);
-static bool qtext_store(const char *query, int query_len,
- Size *query_offset, int *gc_count);
-static char *qtext_load_file(Size *buffer_size);
-static char *qtext_fetch(Size query_offset, int query_len,
- char *buffer, Size buffer_size);
-static bool need_gc_qtexts(void);
-static void gc_qtexts(void);
-static void entry_reset(void);
-#endif
-static void AppendJumble(pgssJumbleState *jstate,
- const unsigned char *item, Size size);
-static void JumbleQuery(pgssJumbleState *jstate, Query *query);
-static void JumbleRangeTable(pgssJumbleState *jstate, List *rtable);
-static void JumbleExpr(pgssJumbleState *jstate, Node *node);
-static void RecordConstLocation(pgssJumbleState *jstate, int location);
-#ifdef NOT_USED
-static char *generate_normalized_query(pgssJumbleState *jstate, const char *query,
- int *query_len_p, int encoding);
-#endif
-static void fill_in_constant_lengths(pgssJumbleState *jstate, const char *query);
-static int comp_location(const void *a, const void *b);
-
-
-#ifdef NOT_USED
-/*
- * 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;
-
- /*
- * Define (or redefine) custom GUC variables.
- */
- DefineCustomIntVariable("pg_stat_statements.max",
- "Sets the maximum number of statements tracked by pg_stat_statements.",
- NULL,
- &pgss_max,
- 5000,
- 100,
- INT_MAX,
- PGC_POSTMASTER,
- 0,
- NULL,
- NULL,
- NULL);
-
- DefineCustomEnumVariable("pg_stat_statements.track",
- "Selects which statements are tracked by pg_stat_statements.",
- NULL,
- &pgss_track,
- PGSS_TRACK_TOP,
- track_options,
- PGC_SUSET,
- 0,
- NULL,
- NULL,
- NULL);
-
- DefineCustomBoolVariable("pg_stat_statements.track_utility",
- "Selects whether utility commands are tracked by pg_stat_statements.",
- NULL,
- &pgss_track_utility,
- true,
- PGC_SUSET,
- 0,
- NULL,
- NULL,
- NULL);
-
- DefineCustomBoolVariable("pg_stat_statements.save",
- "Save pg_stat_statements statistics across server shutdowns.",
- NULL,
- &pgss_save,
- true,
- PGC_SIGHUP,
- 0,
- NULL,
- NULL,
- NULL);
-
- EmitWarningsOnPlaceholders("pg_stat_statements");
-
- /*
- * Request additional shared resources. (These are no-ops if we're not in
- * the postmaster process.) We'll allocate or attach to the shared
- * resources in pgss_shmem_startup().
- */
- RequestAddinShmemSpace(pgss_memsize());
- RequestAddinLWLocks(1);
-
- /*
- * Install hooks.
- */
- prev_shmem_startup_hook = shmem_startup_hook;
- shmem_startup_hook = pgss_shmem_startup;
- prev_post_parse_analyze_hook = post_parse_analyze_hook;
- post_parse_analyze_hook = pgss_post_parse_analyze;
- prev_ExecutorStart = ExecutorStart_hook;
- ExecutorStart_hook = pgss_ExecutorStart;
- prev_ExecutorRun = ExecutorRun_hook;
- ExecutorRun_hook = pgss_ExecutorRun;
- prev_ExecutorFinish = ExecutorFinish_hook;
- ExecutorFinish_hook = pgss_ExecutorFinish;
- prev_ExecutorEnd = ExecutorEnd_hook;
- ExecutorEnd_hook = pgss_ExecutorEnd;
- prev_ProcessUtility = ProcessUtility_hook;
- ProcessUtility_hook = pgss_ProcessUtility;
-}
-
-/*
- * Module unload callback
- */
-void
-_PG_fini(void)
-{
- /* Uninstall hooks. */
- shmem_startup_hook = prev_shmem_startup_hook;
- post_parse_analyze_hook = prev_post_parse_analyze_hook;
- ExecutorStart_hook = prev_ExecutorStart;
- ExecutorRun_hook = prev_ExecutorRun;
- ExecutorFinish_hook = prev_ExecutorFinish;
- ExecutorEnd_hook = prev_ExecutorEnd;
- ProcessUtility_hook = prev_ProcessUtility;
-}
-
-/*
- * shmem_startup hook: allocate or attach to shared memory,
- * then load any pre-existing statistics from file.
- * Also create and load the query-texts file, which is expected to exist
- * (even if empty) while the module is enabled.
- */
-static void
-pgss_shmem_startup(void)
-{
- bool found;
- HASHCTL info;
- FILE *file = NULL;
- FILE *qfile = NULL;
- uint32 header;
- int32 num;
- int32 pgver;
- int32 i;
- 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 */
- pgss = NULL;
- pgss_hash = NULL;
-
- /*
- * Create or attach to the shared memory state, including hash table
- */
- LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
-
- pgss = ShmemInitStruct("pg_stat_statements",
- sizeof(pgssSharedState),
- &found);
-
- if (!found)
- {
- /* First time through ... */
- pgss->lock = LWLockAssign();
- pgss->cur_median_usage = ASSUMED_MEDIAN_INIT;
- pgss->mean_query_len = ASSUMED_LENGTH_INIT;
- SpinLockInit(&pgss->mutex);
- pgss->extent = 0;
- pgss->n_writers = 0;
- pgss->gc_count = 0;
- }
-
- memset(&info, 0, sizeof(info));
- info.keysize = sizeof(pgssHashKey);
- info.entrysize = sizeof(pgssEntry);
- info.hash = pgss_hash_fn;
- info.match = pgss_match_fn;
- pgss_hash = ShmemInitHash("pg_stat_statements hash",
- pgss_max, pgss_max,
- &info,
- HASH_ELEM | HASH_FUNCTION | HASH_COMPARE);
-
- 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(pgss_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(PGSS_TEXT_FILE);
-
- /* Allocate new query text temp file */
- qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
- if (qfile == 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 (!pgss_save)
- {
- FreeFile(qfile);
- return;
- }
-
- /*
- * Attempt to load old statistics from the dump file.
- */
- file = AllocateFile(PGSS_DUMP_FILE, PG_BINARY_R);
- if (file == NULL)
- {
- if (errno != ENOENT)
- goto read_error;
- /* No existing persisted stats file, so we're done */
- FreeFile(qfile);
- return;
- }
-
- buffer_size = 2048;
- 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 != PGSS_FILE_HEADER ||
- pgver != PGSS_PG_MAJOR_VERSION)
- goto data_error;
-
- for (i = 0; i < num; i++)
- {
- pgssEntry temp;
- pgssEntry *entry;
- Size query_offset;
-
- if (fread(&temp, sizeof(pgssEntry), 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;
-
- /* Resize buffer as needed */
- if (temp.query_len >= buffer_size)
- {
- buffer_size = Max(buffer_size * 2, temp.query_len + 1);
- buffer = repalloc(buffer, buffer_size);
- }
-
- if (fread(buffer, 1, temp.query_len + 1, file) != temp.query_len + 1)
- goto read_error;
-
- /* Should have a trailing null, but let's make sure */
- buffer[temp.query_len] = '\0';
-
- /* Skip loading "sticky" entries */
- if (temp.counters.calls == 0)
- continue;
-
- /* Store the query text */
- query_offset = pgss->extent;
- if (fwrite(buffer, 1, temp.query_len + 1, qfile) != temp.query_len + 1)
- goto write_error;
- pgss->extent += temp.query_len + 1;
-
- /* make the hashtable entry (discards old entries if too many) */
- entry = entry_alloc(&temp.key, query_offset, temp.query_len,
- temp.encoding,
- false);
-
- /* copy in the actual stats */
- entry->counters = temp.counters;
- }
-
- pfree(buffer);
- FreeFile(file);
- FreeFile(qfile);
-
- /*
- * Remove the persisted stats file so it's not included in
- * backups/replication slaves, etc. A new file will be written on next
- * shutdown.
- *
- * Note: it's okay if the PGSS_TEXT_FILE is included in a basebackup,
- * because we remove that file on startup; it acts inversely to
- * PGSS_DUMP_FILE, in that it is only supposed to be around when the
- * server is running, whereas PGSS_DUMP_FILE is only supposed to be around
- * when the server is not running. Leaving the file creates no danger of
- * a newly restored database having a spurious record of execution costs,
- * which is what we're really concerned about here.
- */
- unlink(PGSS_DUMP_FILE);
-
- return;
-
-read_error:
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not read pg_stat_statement file \"%s\": %m",
- PGSS_DUMP_FILE)));
- goto fail;
-data_error:
- ereport(LOG,
- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("ignoring invalid data in pg_stat_statement file \"%s\"",
- PGSS_DUMP_FILE)));
- goto fail;
-write_error:
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not write pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
-fail:
- if (buffer)
- pfree(buffer);
- if (file)
- FreeFile(file);
- if (qfile)
- FreeFile(qfile);
- /* If possible, throw away the bogus file; ignore any error */
- unlink(PGSS_DUMP_FILE);
-
- /*
- * Don't unlink PGSS_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
-pgss_shmem_shutdown(int code, Datum arg)
-{
- FILE *file;
- char *qbuffer = NULL;
- Size qbuffer_size = 0;
- HASH_SEQ_STATUS hash_seq;
- int32 num_entries;
- pgssEntry *entry;
-
- /* Don't try to dump during a crash. */
- if (code)
- return;
-
- /* Safety check ... shouldn't get here unless shmem is set up. */
- if (!pgss || !pgss_hash)
- return;
-
- /* Don't dump if told not to. */
- if (!pgss_save)
- return;
-
- file = AllocateFile(PGSS_DUMP_FILE ".tmp", PG_BINARY_W);
- if (file == NULL)
- goto error;
-
- if (fwrite(&PGSS_FILE_HEADER, sizeof(uint32), 1, file) != 1)
- goto error;
- if (fwrite(&PGSS_PG_MAJOR_VERSION, sizeof(uint32), 1, file) != 1)
- goto error;
- num_entries = hash_get_num_entries(pgss_hash);
- if (fwrite(&num_entries, sizeof(int32), 1, file) != 1)
- goto error;
-
- qbuffer = qtext_load_file(&qbuffer_size);
- if (qbuffer == NULL)
- goto error;
-
- /*
- * When serializing to disk, we store query texts immediately after their
- * entry data. Any orphaned query texts are thereby excluded.
- */
- hash_seq_init(&hash_seq, pgss_hash);
- while ((entry = hash_seq_search(&hash_seq)) != NULL)
- {
- int len = entry->query_len;
- char *qstr = qtext_fetch(entry->query_offset, len,
- qbuffer, qbuffer_size);
-
- if (qstr == NULL)
- continue; /* Ignore any entries with bogus texts */
-
- if (fwrite(entry, sizeof(pgssEntry), 1, file) != 1 ||
- fwrite(qstr, 1, len + 1, file) != len + 1)
- {
- /* note: we assume hash_seq_term won't change errno */
- hash_seq_term(&hash_seq);
- goto error;
- }
- }
-
- free(qbuffer);
- qbuffer = NULL;
-
- if (FreeFile(file))
- {
- file = NULL;
- goto error;
- }
-
- /*
- * Rename file into place, so we atomically replace any old one.
- */
- if (rename(PGSS_DUMP_FILE ".tmp", PGSS_DUMP_FILE) != 0)
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not rename pg_stat_statement file \"%s\": %m",
- PGSS_DUMP_FILE ".tmp")));
-
- /* Unlink query-texts file; it's not needed while shutdown */
- unlink(PGSS_TEXT_FILE);
-
- return;
-
-error:
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not write pg_stat_statement file \"%s\": %m",
- PGSS_DUMP_FILE ".tmp")));
- if (qbuffer)
- free(qbuffer);
- if (file)
- FreeFile(file);
- unlink(PGSS_DUMP_FILE ".tmp");
- unlink(PGSS_TEXT_FILE);
-}
-
-/*
- * Post-parse-analysis hook: mark query with a queryId
- */
-static void
-pgss_post_parse_analyze(ParseState *pstate, Query *query)
-{
- pgssJumbleState jstate;
-
- if (prev_post_parse_analyze_hook)
- prev_post_parse_analyze_hook(pstate, query);
-
- /* Assert we didn't do this already */
- Assert(query->queryId == 0);
-
- /* Safety check... */
- if (!pgss || !pgss_hash)
- return;
-
- /*
- * Utility statements get queryId zero. We do this even in cases where
- * the statement contains an optimizable statement for which a queryId
- * could be derived (such as EXPLAIN or DECLARE CURSOR). For such cases,
- * runtime control will first go through ProcessUtility and then the
- * executor, and we don't want the executor hooks to do anything, since we
- * are already measuring the statement's costs at the utility level.
- */
- if (query->utilityStmt)
- {
- query->queryId = 0;
- return;
- }
-
- /* Set up workspace for query jumbling */
- jstate.jumble = (unsigned char *) palloc(JUMBLE_SIZE);
- jstate.jumble_len = 0;
- jstate.clocations_buf_size = 32;
- jstate.clocations = (pgssLocationLen *)
- palloc(jstate.clocations_buf_size * sizeof(pgssLocationLen));
- jstate.clocations_count = 0;
-
- /* Compute query ID and mark the Query node with it */
- JumbleQuery(&jstate, query);
- query->queryId = hash_any(jstate.jumble, jstate.jumble_len);
-
- /*
- * If we are unlucky enough to get a hash of zero, use 1 instead, to
- * prevent confusion with the utility-statement case.
- */
- if (query->queryId == 0)
- query->queryId = 1;
-
- /*
- * If we were able to identify any ignorable constants, we immediately
- * create a hash table entry for the query, so that we can record the
- * normalized form of the query string. If there were no such constants,
- * the normalized string would be the same as the query text anyway, so
- * there's no need for an early entry.
- */
- if (jstate.clocations_count > 0)
- pgss_store(pstate->p_sourcetext,
- query->queryId,
- 0,
- 0,
- NULL,
- &jstate);
-}
-
-/*
- * ExecutorStart hook: start up tracking if needed
- */
-static void
-pgss_ExecutorStart(QueryDesc *queryDesc, int eflags)
-{
- if (prev_ExecutorStart)
- prev_ExecutorStart(queryDesc, eflags);
- else
- standard_ExecutorStart(queryDesc, eflags);
-
- /*
- * If query has queryId zero, don't track it. This prevents double
- * counting of optimizable statements that are directly contained in
- * utility statements.
- */
- if (pgss_enabled() && queryDesc->plannedstmt->queryId != 0)
- {
- /*
- * Set up to track total elapsed time in ExecutorRun. Make sure the
- * space is allocated in the per-query context so it will go away at
- * ExecutorEnd.
- */
- if (queryDesc->totaltime == NULL)
- {
- MemoryContext oldcxt;
-
- oldcxt = MemoryContextSwitchTo(queryDesc->estate->es_query_cxt);
- queryDesc->totaltime = InstrAlloc(1, INSTRUMENT_ALL);
- MemoryContextSwitchTo(oldcxt);
- }
- }
-}
-
-/*
- * ExecutorRun hook: all we need do is track nesting depth
- */
-static void
-pgss_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, long count)
-{
- nested_level++;
- PG_TRY();
- {
- if (prev_ExecutorRun)
- prev_ExecutorRun(queryDesc, direction, count);
- else
- standard_ExecutorRun(queryDesc, direction, count);
- nested_level--;
- }
- PG_CATCH();
- {
- nested_level--;
- PG_RE_THROW();
- }
- PG_END_TRY();
-}
-
-/*
- * ExecutorFinish hook: all we need do is track nesting depth
- */
-static void
-pgss_ExecutorFinish(QueryDesc *queryDesc)
-{
- nested_level++;
- PG_TRY();
- {
- if (prev_ExecutorFinish)
- prev_ExecutorFinish(queryDesc);
- else
- standard_ExecutorFinish(queryDesc);
- nested_level--;
- }
- PG_CATCH();
- {
- nested_level--;
- PG_RE_THROW();
- }
- PG_END_TRY();
-}
-
-/*
- * ExecutorEnd hook: store results if needed
- */
-static void
-pgss_ExecutorEnd(QueryDesc *queryDesc)
-{
- uint32 queryId = queryDesc->plannedstmt->queryId;
-
- if (queryId != 0 && queryDesc->totaltime && pgss_enabled())
- {
- /*
- * Make sure stats accumulation is done. (Note: it's okay if several
- * levels of hook all do this.)
- */
- InstrEndLoop(queryDesc->totaltime);
-
- pgss_store(queryDesc->sourceText,
- queryId,
- queryDesc->totaltime->total * 1000.0, /* convert to msec */
- queryDesc->estate->es_processed,
- &queryDesc->totaltime->bufusage,
- NULL);
- }
-
- if (prev_ExecutorEnd)
- prev_ExecutorEnd(queryDesc);
- else
- standard_ExecutorEnd(queryDesc);
-}
-
-/*
- * ProcessUtility hook
- */
-static void
-pgss_ProcessUtility(Node *parsetree, const char *queryString,
- ProcessUtilityContext context, ParamListInfo params,
- DestReceiver *dest, char *completionTag)
-{
- /*
- * If it's an EXECUTE statement, we don't track it and don't increment the
- * nesting level. This allows the cycles to be charged to the underlying
- * PREPARE instead (by the Executor hooks), which is much more useful.
- *
- * We also don't track execution of PREPARE. If we did, we would get one
- * hash table entry for the PREPARE (with hash calculated from the query
- * string), and then a different one with the same query string (but hash
- * calculated from the query tree) would be used to accumulate costs of
- * ensuing EXECUTEs. This would be confusing, and inconsistent with other
- * cases where planning time is not included at all.
- *
- * Likewise, we don't track execution of DEALLOCATE.
- */
- if (pgss_track_utility && pgss_enabled() &&
- !IsA(parsetree, ExecuteStmt) &&
- !IsA(parsetree, PrepareStmt) &&
- !IsA(parsetree, DeallocateStmt))
- {
- instr_time start;
- instr_time duration;
- uint64 rows;
- BufferUsage bufusage_start,
- bufusage;
- uint32 queryId;
-
- bufusage_start = pgBufferUsage;
- INSTR_TIME_SET_CURRENT(start);
-
- nested_level++;
- PG_TRY();
- {
- if (prev_ProcessUtility)
- prev_ProcessUtility(parsetree, queryString,
- context, params,
- dest, completionTag);
- else
- standard_ProcessUtility(parsetree, queryString,
- context, params,
- dest, completionTag);
- nested_level--;
- }
- PG_CATCH();
- {
- nested_level--;
- PG_RE_THROW();
- }
- PG_END_TRY();
-
- INSTR_TIME_SET_CURRENT(duration);
- INSTR_TIME_SUBTRACT(duration, start);
-
- /* parse command tag to retrieve the number of affected rows. */
- if (completionTag &&
- strncmp(completionTag, "COPY ", 5) == 0)
- {
-#ifdef HAVE_STRTOULL
- rows = strtoull(completionTag + 5, NULL, 10);
-#else
- rows = strtoul(completionTag + 5, NULL, 10);
-#endif
- }
- else
- rows = 0;
-
- /* calc differences of buffer counters. */
- bufusage.shared_blks_hit =
- pgBufferUsage.shared_blks_hit - bufusage_start.shared_blks_hit;
- bufusage.shared_blks_read =
- pgBufferUsage.shared_blks_read - bufusage_start.shared_blks_read;
- bufusage.shared_blks_dirtied =
- pgBufferUsage.shared_blks_dirtied - bufusage_start.shared_blks_dirtied;
- bufusage.shared_blks_written =
- pgBufferUsage.shared_blks_written - bufusage_start.shared_blks_written;
- bufusage.local_blks_hit =
- pgBufferUsage.local_blks_hit - bufusage_start.local_blks_hit;
- bufusage.local_blks_read =
- pgBufferUsage.local_blks_read - bufusage_start.local_blks_read;
- bufusage.local_blks_dirtied =
- pgBufferUsage.local_blks_dirtied - bufusage_start.local_blks_dirtied;
- bufusage.local_blks_written =
- pgBufferUsage.local_blks_written - bufusage_start.local_blks_written;
- bufusage.temp_blks_read =
- pgBufferUsage.temp_blks_read - bufusage_start.temp_blks_read;
- bufusage.temp_blks_written =
- pgBufferUsage.temp_blks_written - bufusage_start.temp_blks_written;
- bufusage.blk_read_time = pgBufferUsage.blk_read_time;
- INSTR_TIME_SUBTRACT(bufusage.blk_read_time, bufusage_start.blk_read_time);
- bufusage.blk_write_time = pgBufferUsage.blk_write_time;
- INSTR_TIME_SUBTRACT(bufusage.blk_write_time, bufusage_start.blk_write_time);
-
- /* For utility statements, we just hash the query string directly */
- queryId = pgss_hash_string(queryString);
-
- pgss_store(queryString,
- queryId,
- INSTR_TIME_GET_MILLISEC(duration),
- rows,
- &bufusage,
- NULL);
- }
- else
- {
- if (prev_ProcessUtility)
- prev_ProcessUtility(parsetree, queryString,
- context, params,
- dest, completionTag);
- else
- standard_ProcessUtility(parsetree, queryString,
- context, params,
- dest, completionTag);
- }
-}
-
-/*
- * Calculate hash value for a key
- */
-static uint32
-pgss_hash_fn(const void *key, Size keysize)
-{
- const pgssHashKey *k = (const pgssHashKey *) key;
-
- return hash_uint32((uint32) k->userid) ^
- hash_uint32((uint32) k->dbid) ^
- hash_uint32((uint32) k->queryid);
-}
-
-/*
- * Compare two keys - zero means match
- */
-static int
-pgss_match_fn(const void *key1, const void *key2, Size keysize)
-{
- const pgssHashKey *k1 = (const pgssHashKey *) key1;
- const pgssHashKey *k2 = (const pgssHashKey *) key2;
-
- if (k1->userid == k2->userid &&
- k1->dbid == k2->dbid &&
- k1->queryid == k2->queryid)
- return 0;
- else
- return 1;
-}
-
-/*
- * Given an arbitrarily long query string, produce a hash for the purposes of
- * identifying the query, without normalizing constants. Used when hashing
- * utility statements.
- */
-static uint32
-pgss_hash_string(const char *str)
-{
- return hash_any((const unsigned char *) str, strlen(str));
-}
-
-/*
- * Store some statistics for a statement.
- *
- * If jstate is not NULL then we're trying to create an entry for which
- * we have no statistics as yet; we just want to record the normalized
- * query string. total_time, rows, bufusage are ignored in this case.
- */
-static void
-pgss_store(const char *query, uint32 queryId,
- double total_time, uint64 rows,
- const BufferUsage *bufusage,
- pgssJumbleState *jstate)
-{
- pgssHashKey key;
- pgssEntry *entry;
- char *norm_query = NULL;
- int encoding = GetDatabaseEncoding();
- int query_len;
-
- Assert(query != NULL);
-
- /* Safety check... */
- if (!pgss || !pgss_hash)
- return;
-
- query_len = strlen(query);
-
- /* Set up key for hashtable search */
- key.userid = GetUserId();
- key.dbid = MyDatabaseId;
- key.queryid = queryId;
-
- /* Lookup the hash table entry with shared lock. */
- LWLockAcquire(pgss->lock, LW_SHARED);
-
- entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
-
- /* Create new entry, if not present */
- if (!entry)
- {
- Size query_offset;
- int gc_count;
- bool stored;
- bool do_gc;
-
- /*
- * Create a new, normalized query string if caller asked. We don't
- * need to hold the lock while doing this work. (Note: in any case,
- * it's possible that someone else creates a duplicate hashtable entry
- * in the interval where we don't hold the lock below. That case is
- * handled by entry_alloc.)
- */
- if (jstate)
- {
- LWLockRelease(pgss->lock);
- norm_query = generate_normalized_query(jstate, query,
- &query_len,
- encoding);
- LWLockAcquire(pgss->lock, LW_SHARED);
- }
-
- /* Append new query text to file with only shared lock held */
- stored = qtext_store(norm_query ? norm_query : query, query_len,
- &query_offset, &gc_count);
-
- /*
- * Determine whether we need to garbage collect external query texts
- * while the shared lock is still held. This micro-optimization
- * avoids taking the time to decide this while holding exclusive lock.
- */
- do_gc = need_gc_qtexts();
-
- /* Need exclusive lock to make a new hashtable entry - promote */
- LWLockRelease(pgss->lock);
- LWLockAcquire(pgss->lock, LW_EXCLUSIVE);
-
- /*
- * A garbage collection may have occurred while we weren't holding the
- * lock. In the unlikely event that this happens, the query text we
- * stored above will have been garbage collected, so write it again.
- * This should be infrequent enough that doing it while holding
- * exclusive lock isn't a performance problem.
- */
- if (!stored || pgss->gc_count != gc_count)
- stored = qtext_store(norm_query ? norm_query : query, query_len,
- &query_offset, NULL);
-
- /* If we failed to write to the text file, give up */
- if (!stored)
- goto done;
-
- /* OK to create a new hashtable entry */
- entry = entry_alloc(&key, query_offset, query_len, encoding,
- jstate != NULL);
-
- /* If needed, perform garbage collection while exclusive lock held */
- if (do_gc)
- gc_qtexts();
- }
-
- /* Increment the counts, except when jstate is not NULL */
- if (!jstate)
- {
- /*
- * Grab the spinlock while updating the counters (see comment about
- * locking rules at the head of the file)
- */
- volatile pgssEntry *e = (volatile pgssEntry *) entry;
-
- SpinLockAcquire(&e->mutex);
-
- /* "Unstick" entry if it was previously sticky */
- if (e->counters.calls == 0)
- e->counters.usage = USAGE_INIT;
-
- e->counters.calls += 1;
- e->counters.total_time += total_time;
- e->counters.rows += rows;
- e->counters.shared_blks_hit += bufusage->shared_blks_hit;
- e->counters.shared_blks_read += bufusage->shared_blks_read;
- e->counters.shared_blks_dirtied += bufusage->shared_blks_dirtied;
- e->counters.shared_blks_written += bufusage->shared_blks_written;
- e->counters.local_blks_hit += bufusage->local_blks_hit;
- e->counters.local_blks_read += bufusage->local_blks_read;
- e->counters.local_blks_dirtied += bufusage->local_blks_dirtied;
- e->counters.local_blks_written += bufusage->local_blks_written;
- e->counters.temp_blks_read += bufusage->temp_blks_read;
- e->counters.temp_blks_written += bufusage->temp_blks_written;
- e->counters.blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->blk_read_time);
- e->counters.blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->blk_write_time);
- e->counters.usage += USAGE_EXEC(total_time);
-
- SpinLockRelease(&e->mutex);
- }
-
-done:
- LWLockRelease(pgss->lock);
-
- /* We postpone this clean-up until we're out of the lock */
- if (norm_query)
- pfree(norm_query);
-}
-
-/*
- * Reset all statement statistics.
- */
-Datum
-pg_stat_statements_reset(PG_FUNCTION_ARGS)
-{
- if (!pgss || !pgss_hash)
- ereport(ERROR,
- (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
- errmsg("pg_stat_statements must be loaded via shared_preload_libraries")));
- entry_reset();
- PG_RETURN_VOID();
-}
-
-/* Number of output arguments (columns) for various API versions */
-#define PG_STAT_STATEMENTS_COLS_V1_0 14
-#define PG_STAT_STATEMENTS_COLS_V1_1 18
-#define PG_STAT_STATEMENTS_COLS_V1_2 19
-#define PG_STAT_STATEMENTS_COLS 19 /* maximum of above */
-
-/*
- * Retrieve statement statistics.
- *
- * The SQL API of this function has changed multiple times, and will likely
- * do so again in future. To support the case where a newer version of this
- * loadable module is being used with an old SQL declaration of the function,
- * we continue to support the older API versions. For 1.2 and later, the
- * expected API version is identified by embedding it in the C name of the
- * function. Unfortunately we weren't bright enough to do that for 1.1.
- */
-Datum
-pg_stat_statements_1_2(PG_FUNCTION_ARGS)
-{
- bool showtext = PG_GETARG_BOOL(0);
-
- pg_stat_statements_internal(fcinfo, PGSS_V1_2, showtext);
-
- return (Datum) 0;
-}
-
-/*
- * Legacy entry point for pg_stat_statements() API versions 1.0 and 1.1.
- * This can be removed someday, perhaps.
- */
-Datum
-pg_stat_statements(PG_FUNCTION_ARGS)
-{
- /* If it's really API 1.1, we'll figure that out below */
- pg_stat_statements_internal(fcinfo, PGSS_V1_0, true);
-
- return (Datum) 0;
-}
-
-/* Common code for all versions of pg_stat_statements() */
-static void
-pg_stat_statements_internal(FunctionCallInfo fcinfo,
- pgssVersion api_version,
- bool showtext)
-{
- ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
- TupleDesc tupdesc;
- Tuplestorestate *tupstore;
- MemoryContext per_query_ctx;
- MemoryContext oldcontext;
- Oid userid = GetUserId();
- bool is_superuser = superuser();
- char *qbuffer = NULL;
- Size qbuffer_size = 0;
- Size extent = 0;
- int gc_count = 0;
- HASH_SEQ_STATUS hash_seq;
- pgssEntry *entry;
-
- /* hash table must exist already */
- if (!pgss || !pgss_hash)
- ereport(ERROR,
- (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
- errmsg("pg_stat_statements must be loaded via shared_preload_libraries")));
-
- /* check to see if caller supports us returning a tuplestore */
- if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("set-valued function called in context that cannot accept a set")));
- if (!(rsinfo->allowedModes & SFRM_Materialize))
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("materialize mode required, but it is not " \
- "allowed in this context")));
-
- /* Switch into long-lived context to construct returned data structures */
- per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
- oldcontext = MemoryContextSwitchTo(per_query_ctx);
-
- /* Build a tuple descriptor for our result type */
- if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
- elog(ERROR, "return type must be a row type");
-
- /*
- * Check we have the expected number of output arguments. Aside from
- * being a good safety check, we need a kluge here to detect API version
- * 1.1, which was wedged into the code in an ill-considered way.
- */
- switch (tupdesc->natts)
- {
- case PG_STAT_STATEMENTS_COLS_V1_0:
- if (api_version != PGSS_V1_0)
- elog(ERROR, "incorrect number of output arguments");
- break;
- case PG_STAT_STATEMENTS_COLS_V1_1:
- /* pg_stat_statements() should have told us 1.0 */
- if (api_version != PGSS_V1_0)
- elog(ERROR, "incorrect number of output arguments");
- api_version = PGSS_V1_1;
- break;
- case PG_STAT_STATEMENTS_COLS_V1_2:
- if (api_version != PGSS_V1_2)
- elog(ERROR, "incorrect number of output arguments");
- break;
- default:
- elog(ERROR, "incorrect number of output arguments");
- }
-
- tupstore = tuplestore_begin_heap(true, false, work_mem);
- rsinfo->returnMode = SFRM_Materialize;
- rsinfo->setResult = tupstore;
- rsinfo->setDesc = tupdesc;
-
- MemoryContextSwitchTo(oldcontext);
-
- /*
- * We'd like to load the query text file (if needed) while not holding any
- * lock on pgss->lock. In the worst case we'll have to do this again
- * after we have the lock, but it's unlikely enough to make this a win
- * despite occasional duplicated work. We need to reload if anybody
- * writes to the file (either a retail qtext_store(), or a garbage
- * collection) between this point and where we've gotten shared lock. If
- * a qtext_store is actually in progress when we look, we might as well
- * skip the speculative load entirely.
- */
- if (showtext)
- {
- int n_writers;
-
- /* Take the mutex so we can examine variables */
- {
- volatile pgssSharedState *s = (volatile pgssSharedState *) pgss;
-
- SpinLockAcquire(&s->mutex);
- extent = s->extent;
- n_writers = s->n_writers;
- gc_count = s->gc_count;
- SpinLockRelease(&s->mutex);
- }
-
- /* No point in loading file now if there are active writers */
- if (n_writers == 0)
- qbuffer = qtext_load_file(&qbuffer_size);
- }
-
- /*
- * Get shared lock, load or reload the query text file if we must, and
- * iterate over the hashtable entries.
- *
- * With a large hash table, we might be holding the lock rather longer
- * than one could wish. However, this only blocks creation of new hash
- * table entries, and the larger the hash table the less likely that is to
- * be needed. So we can hope this is okay. Perhaps someday we'll decide
- * we need to partition the hash table to limit the time spent holding any
- * one lock.
- */
- LWLockAcquire(pgss->lock, LW_SHARED);
-
- if (showtext)
- {
- /*
- * Here it is safe to examine extent and gc_count without taking the
- * mutex. Note that although other processes might change
- * pgss->extent just after we look at it, the strings they then write
- * into the file cannot yet be referenced in the hashtable, so we
- * don't care whether we see them or not.
- *
- * If qtext_load_file fails, we just press on; we'll return NULL for
- * every query text.
- */
- if (qbuffer == NULL ||
- pgss->extent != extent ||
- pgss->gc_count != gc_count)
- {
- if (qbuffer)
- free(qbuffer);
- qbuffer = qtext_load_file(&qbuffer_size);
- }
- }
-
- hash_seq_init(&hash_seq, pgss_hash);
- while ((entry = hash_seq_search(&hash_seq)) != NULL)
- {
- Datum values[PG_STAT_STATEMENTS_COLS];
- bool nulls[PG_STAT_STATEMENTS_COLS];
- int i = 0;
- Counters tmp;
- int64 queryid = entry->key.queryid;
-
- memset(values, 0, sizeof(values));
- memset(nulls, 0, sizeof(nulls));
-
- values[i++] = ObjectIdGetDatum(entry->key.userid);
- values[i++] = ObjectIdGetDatum(entry->key.dbid);
-
- if (is_superuser || entry->key.userid == userid)
- {
- if (api_version >= PGSS_V1_2)
- values[i++] = Int64GetDatumFast(queryid);
-
- if (showtext)
- {
- char *qstr = qtext_fetch(entry->query_offset,
- entry->query_len,
- qbuffer,
- qbuffer_size);
-
- if (qstr)
- {
- char *enc;
-
- enc = pg_any_to_server(qstr,
- entry->query_len,
- entry->encoding);
-
- values[i++] = CStringGetTextDatum(enc);
-
- if (enc != qstr)
- pfree(enc);
- }
- else
- {
- /* Just return a null if we fail to find the text */
- nulls[i++] = true;
- }
- }
- else
- {
- /* Query text not requested */
- nulls[i++] = true;
- }
- }
- else
- {
- /* Don't show queryid */
- if (api_version >= PGSS_V1_2)
- nulls[i++] = true;
-
- /*
- * Don't show query text, but hint as to the reason for not doing
- * so if it was requested
- */
- if (showtext)
- values[i++] = CStringGetTextDatum("<insufficient privilege>");
- else
- nulls[i++] = true;
- }
-
- /* copy counters to a local variable to keep locking time short */
- {
- volatile pgssEntry *e = (volatile pgssEntry *) entry;
-
- SpinLockAcquire(&e->mutex);
- tmp = e->counters;
- SpinLockRelease(&e->mutex);
- }
-
- /* Skip entry if unexecuted (ie, it's a pending "sticky" entry) */
- if (tmp.calls == 0)
- continue;
-
- values[i++] = Int64GetDatumFast(tmp.calls);
- values[i++] = Float8GetDatumFast(tmp.total_time);
- values[i++] = Int64GetDatumFast(tmp.rows);
- values[i++] = Int64GetDatumFast(tmp.shared_blks_hit);
- values[i++] = Int64GetDatumFast(tmp.shared_blks_read);
- if (api_version >= PGSS_V1_1)
- values[i++] = Int64GetDatumFast(tmp.shared_blks_dirtied);
- values[i++] = Int64GetDatumFast(tmp.shared_blks_written);
- values[i++] = Int64GetDatumFast(tmp.local_blks_hit);
- values[i++] = Int64GetDatumFast(tmp.local_blks_read);
- if (api_version >= PGSS_V1_1)
- values[i++] = Int64GetDatumFast(tmp.local_blks_dirtied);
- values[i++] = Int64GetDatumFast(tmp.local_blks_written);
- values[i++] = Int64GetDatumFast(tmp.temp_blks_read);
- values[i++] = Int64GetDatumFast(tmp.temp_blks_written);
- if (api_version >= PGSS_V1_1)
- {
- values[i++] = Float8GetDatumFast(tmp.blk_read_time);
- values[i++] = Float8GetDatumFast(tmp.blk_write_time);
- }
-
- Assert(i == (api_version == PGSS_V1_0 ? PG_STAT_STATEMENTS_COLS_V1_0 :
- api_version == PGSS_V1_1 ? PG_STAT_STATEMENTS_COLS_V1_1 :
- api_version == PGSS_V1_2 ? PG_STAT_STATEMENTS_COLS_V1_2 :
- -1 /* fail if you forget to update this assert */ ));
-
- tuplestore_putvalues(tupstore, tupdesc, values, nulls);
- }
-
- /* clean up and return the tuplestore */
- LWLockRelease(pgss->lock);
-
- if (qbuffer)
- free(qbuffer);
-
- tuplestore_donestoring(tupstore);
-}
-
-/*
- * Estimate shared memory space needed.
- */
-static Size
-pgss_memsize(void)
-{
- Size size;
-
- size = MAXALIGN(sizeof(pgssSharedState));
- size = add_size(size, hash_estimate_size(pgss_max, sizeof(pgssEntry)));
-
- return size;
-}
-
-/*
- * Allocate a new hashtable entry.
- * caller must hold an exclusive lock on pgss->lock
- *
- * "query" need not be null-terminated; we rely on query_len instead
- *
- * If "sticky" is true, make the new entry artificially sticky so that it will
- * probably still be there when the query finishes execution. We do this by
- * giving it a median usage value rather than the normal value. (Strictly
- * speaking, query strings are normalized on a best effort basis, though it
- * would be difficult to demonstrate this even under artificial conditions.)
- *
- * Note: despite needing exclusive lock, it's not an error for the target
- * entry to already exist. This is because pgss_store releases and
- * reacquires lock after failing to find a match; so someone else could
- * have made the entry while we waited to get exclusive lock.
- */
-static pgssEntry *
-entry_alloc(pgssHashKey *key, Size query_offset, int query_len, int encoding,
- bool sticky)
-{
- pgssEntry *entry;
- bool found;
-
- /* Make space if needed */
- while (hash_get_num_entries(pgss_hash) >= pgss_max)
- entry_dealloc();
-
- /* Find or create an entry with desired hash code */
- entry = (pgssEntry *) hash_search(pgss_hash, key, HASH_ENTER, &found);
-
- if (!found)
- {
- /* New entry, initialize it */
-
- /* reset the statistics */
- memset(&entry->counters, 0, sizeof(Counters));
- /* set the appropriate initial usage count */
- entry->counters.usage = sticky ? pgss->cur_median_usage : USAGE_INIT;
- /* re-initialize the mutex each time ... we assume no one using it */
- SpinLockInit(&entry->mutex);
- /* ... and don't forget the query text metadata */
- Assert(query_len >= 0);
- entry->query_offset = query_offset;
- entry->query_len = query_len;
- entry->encoding = encoding;
- }
-
- return entry;
-}
-
-/*
- * qsort comparator for sorting into increasing usage order
- */
-static int
-entry_cmp(const void *lhs, const void *rhs)
-{
- double l_usage = (*(pgssEntry *const *) lhs)->counters.usage;
- double r_usage = (*(pgssEntry *const *) rhs)->counters.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 pgss->lock.
- */
-static void
-entry_dealloc(void)
-{
- HASH_SEQ_STATUS hash_seq;
- pgssEntry **entries;
- pgssEntry *entry;
- int nvictims;
- int i;
- Size totlen = 0;
-
- /*
- * 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(pgss_hash) * sizeof(pgssEntry *));
-
- i = 0;
- hash_seq_init(&hash_seq, pgss_hash);
- while ((entry = hash_seq_search(&hash_seq)) != NULL)
- {
- entries[i++] = entry;
- /* "Sticky" entries get a different usage decay rate. */
- if (entry->counters.calls == 0)
- entry->counters.usage *= STICKY_DECREASE_FACTOR;
- else
- entry->counters.usage *= USAGE_DECREASE_FACTOR;
- /* Accumulate total size, too. */
- totlen += entry->query_len + 1;
- }
-
- qsort(entries, i, sizeof(pgssEntry *), entry_cmp);
-
- if (i > 0)
- {
- /* Record the (approximate) median usage */
- pgss->cur_median_usage = entries[i / 2]->counters.usage;
- /* Record the mean query length */
- pgss->mean_query_len = totlen / i;
- }
-
- nvictims = Max(10, i * USAGE_DEALLOC_PERCENT / 100);
- nvictims = Min(nvictims, i);
-
- for (i = 0; i < nvictims; i++)
- {
- hash_search(pgss_hash, &entries[i]->key, HASH_REMOVE, NULL);
- }
-
- pfree(entries);
-}
-
-/*
- * Given a null-terminated string, allocate a new entry in the external query
- * text file and store the string there.
- *
- * Although we could compute the string length via strlen(), callers already
- * have it handy, so we require them to pass it too.
- *
- * If successful, returns true, and stores the new entry's offset in the file
- * into *query_offset. Also, if gc_count isn't NULL, *gc_count is set to the
- * number of garbage collections that have occurred so far.
- *
- * On failure, returns false.
- *
- * At least a shared lock on pgss->lock must be held by the caller, so as
- * to prevent a concurrent garbage collection. Share-lock-holding callers
- * should pass a gc_count pointer to obtain the number of garbage collections,
- * so that they can recheck the count after obtaining exclusive lock to
- * detect whether a garbage collection occurred (and removed this entry).
- */
-static bool
-qtext_store(const char *query, int query_len,
- Size *query_offset, int *gc_count)
-{
- Size off;
- int fd;
-
- /*
- * We use a spinlock to protect extent/n_writers/gc_count, so that
- * multiple processes may execute this function concurrently.
- */
- {
- volatile pgssSharedState *s = (volatile pgssSharedState *) pgss;
-
- SpinLockAcquire(&s->mutex);
- off = s->extent;
- s->extent += query_len + 1;
- s->n_writers++;
- if (gc_count)
- *gc_count = s->gc_count;
- SpinLockRelease(&s->mutex);
- }
-
- *query_offset = off;
-
- /* Now write the data into the successfully-reserved part of the file */
- fd = OpenTransientFile(PGSS_TEXT_FILE, O_RDWR | O_CREAT | PG_BINARY,
- S_IRUSR | S_IWUSR);
- if (fd < 0)
- goto error;
-
- if (lseek(fd, off, SEEK_SET) != off)
- goto error;
-
- if (write(fd, query, query_len + 1) != query_len + 1)
- goto error;
-
- CloseTransientFile(fd);
-
- /* Mark our write complete */
- {
- volatile pgssSharedState *s = (volatile pgssSharedState *) pgss;
-
- SpinLockAcquire(&s->mutex);
- s->n_writers--;
- SpinLockRelease(&s->mutex);
- }
-
- return true;
-
-error:
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not write pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
-
- if (fd >= 0)
- CloseTransientFile(fd);
-
- /* Mark our write complete */
- {
- volatile pgssSharedState *s = (volatile pgssSharedState *) pgss;
-
- SpinLockAcquire(&s->mutex);
- s->n_writers--;
- SpinLockRelease(&s->mutex);
- }
-
- return false;
-}
-
-/*
- * Read the external query text file into a malloc'd buffer.
- *
- * Returns NULL (without throwing an error) if unable to read, eg
- * file not there or insufficient memory.
- *
- * On success, the buffer size is also returned into *buffer_size.
- *
- * This can be called without any lock on pgss->lock, but in that case
- * the caller is responsible for verifying that the result is sane.
- */
-static char *
-qtext_load_file(Size *buffer_size)
-{
- char *buf;
- int fd;
- struct stat stat;
-
- fd = OpenTransientFile(PGSS_TEXT_FILE, O_RDONLY | PG_BINARY, 0);
- if (fd < 0)
- {
- if (errno != ENOENT)
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not read pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- return NULL;
- }
-
- /* Get file length */
- if (fstat(fd, &stat))
- {
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not stat pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- CloseTransientFile(fd);
- return NULL;
- }
-
- /* Allocate buffer; beware that off_t might be wider than size_t */
- if (stat.st_size <= MaxAllocSize)
- buf = (char *) malloc(stat.st_size);
- else
- buf = NULL;
- if (buf == NULL)
- {
- ereport(LOG,
- (errcode(ERRCODE_OUT_OF_MEMORY),
- errmsg("out of memory")));
- CloseTransientFile(fd);
- return NULL;
- }
-
- /*
- * OK, slurp in the file. If we get a short read and errno doesn't get
- * set, the reason is probably that garbage collection truncated the file
- * since we did the fstat(), so we don't log a complaint --- but we don't
- * return the data, either, since it's most likely corrupt due to
- * concurrent writes from garbage collection.
- */
- errno = 0;
- if (read(fd, buf, stat.st_size) != stat.st_size)
- {
- if (errno)
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not read pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- free(buf);
- CloseTransientFile(fd);
- return NULL;
- }
-
- CloseTransientFile(fd);
-
- *buffer_size = stat.st_size;
- return buf;
-}
-
-/*
- * Locate a query text in the file image previously read by qtext_load_file().
- *
- * We validate the given offset/length, and return NULL if bogus. Otherwise,
- * the result points to a null-terminated string within the buffer.
- */
-static char *
-qtext_fetch(Size query_offset, int query_len,
- char *buffer, Size buffer_size)
-{
- /* File read failed? */
- if (buffer == NULL)
- return NULL;
- /* Bogus offset/length? */
- if (query_len < 0 ||
- query_offset + query_len >= buffer_size)
- return NULL;
- /* As a further sanity check, make sure there's a trailing null */
- if (buffer[query_offset + query_len] != '\0')
- return NULL;
- /* Looks OK */
- return buffer + query_offset;
-}
-
-/*
- * Do we need to garbage-collect the external query text file?
- *
- * Caller should hold at least a shared lock on pgss->lock.
- */
-static bool
-need_gc_qtexts(void)
-{
- Size extent;
-
- /* Read shared extent pointer */
- {
- volatile pgssSharedState *s = (volatile pgssSharedState *) pgss;
-
- SpinLockAcquire(&s->mutex);
- extent = s->extent;
- SpinLockRelease(&s->mutex);
- }
-
- /* Don't proceed if file does not exceed 512 bytes per possible entry */
- if (extent < 512 * pgss_max)
- return false;
-
- /*
- * Don't proceed if file is less than about 50% bloat. Nothing can or
- * should be done in the event of unusually large query texts accounting
- * for file's large size. We go to the trouble of maintaining the mean
- * query length in order to prevent garbage collection from thrashing
- * uselessly.
- */
- if (extent < pgss->mean_query_len * pgss_max * 2)
- return false;
-
- return true;
-}
-
-/*
- * Garbage-collect orphaned query texts in external file.
- *
- * This won't be called often in the typical case, since it's likely that
- * there won't be too much churn, and besides, a similar compaction process
- * occurs when serializing to disk at shutdown or as part of resetting.
- * Despite this, it seems prudent to plan for the edge case where the file
- * becomes unreasonably large, with no other method of compaction likely to
- * occur in the foreseeable future.
- *
- * The caller must hold an exclusive lock on pgss->lock.
- */
-static void
-gc_qtexts(void)
-{
- char *qbuffer;
- Size qbuffer_size;
- FILE *qfile;
- HASH_SEQ_STATUS hash_seq;
- pgssEntry *entry;
- Size extent;
- int nentries;
-
- /*
- * When called from pgss_store, some other session might have proceeded
- * with garbage collection in the no-lock-held interim of lock strength
- * escalation. Check once more that this is actually necessary.
- */
- if (!need_gc_qtexts())
- return;
-
- /*
- * Load the old texts file. If we fail (out of memory, for instance) just
- * skip the garbage collection.
- */
- qbuffer = qtext_load_file(&qbuffer_size);
- if (qbuffer == NULL)
- return;
-
- /*
- * We overwrite the query texts file in place, so as to reduce the risk of
- * an out-of-disk-space failure. Since the file is guaranteed not to get
- * larger, this should always work on traditional filesystems; though we
- * could still lose on copy-on-write filesystems.
- */
- qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
- if (qfile == NULL)
- {
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not write pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- goto gc_fail;
- }
-
- extent = 0;
- nentries = 0;
-
- hash_seq_init(&hash_seq, pgss_hash);
- while ((entry = hash_seq_search(&hash_seq)) != NULL)
- {
- int query_len = entry->query_len;
- char *qry = qtext_fetch(entry->query_offset,
- query_len,
- qbuffer,
- qbuffer_size);
-
- if (qry == NULL)
- {
- /* Trouble ... drop the text */
- entry->query_offset = 0;
- entry->query_len = -1;
- continue;
- }
-
- if (fwrite(qry, 1, query_len + 1, qfile) != query_len + 1)
- {
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not write pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- hash_seq_term(&hash_seq);
- goto gc_fail;
- }
-
- entry->query_offset = extent;
- extent += query_len + 1;
- nentries++;
- }
-
- /*
- * Truncate away any now-unused space. If this fails for some odd reason,
- * we log it, but there's no need to fail.
- */
- if (ftruncate(fileno(qfile), extent) != 0)
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not truncate pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
-
- if (FreeFile(qfile))
- {
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not write pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- qfile = NULL;
- goto gc_fail;
- }
-
- elog(DEBUG1, "pgss gc of queries file shrunk size from %zu to %zu",
- pgss->extent, extent);
-
- /* Reset the shared extent pointer */
- pgss->extent = extent;
-
- /*
- * Also update the mean query length, to be sure that need_gc_qtexts()
- * won't still think we have a problem.
- */
- if (nentries > 0)
- pgss->mean_query_len = extent / nentries;
- else
- pgss->mean_query_len = ASSUMED_LENGTH_INIT;
-
- free(qbuffer);
-
- /*
- * OK, count a garbage collection cycle. (Note: even though we have
- * exclusive lock on pgss->lock, we must take pgss->mutex for this, since
- * other processes may examine gc_count while holding only the mutex.
- * Also, we have to advance the count *after* we've rewritten the file,
- * else other processes might not realize they read a stale file.)
- */
- record_gc_qtexts();
-
- return;
-
-gc_fail:
- /* clean up resources */
- if (qfile)
- FreeFile(qfile);
- if (qbuffer)
- free(qbuffer);
-
- /*
- * Since the contents of the external file are now uncertain, mark all
- * hashtable entries as having invalid texts.
- */
- hash_seq_init(&hash_seq, pgss_hash);
- while ((entry = hash_seq_search(&hash_seq)) != NULL)
- {
- entry->query_offset = 0;
- entry->query_len = -1;
- }
-
- /* Seems like a good idea to bump the GC count even though we failed */
- record_gc_qtexts();
-}
-
-/*
- * Release all entries.
+ *-------------------------------------------------------------------------
*/
-static void
-entry_reset(void)
-{
- HASH_SEQ_STATUS hash_seq;
- pgssEntry *entry;
- FILE *qfile;
-
- LWLockAcquire(pgss->lock, LW_EXCLUSIVE);
-
- hash_seq_init(&hash_seq, pgss_hash);
- while ((entry = hash_seq_search(&hash_seq)) != NULL)
- {
- hash_search(pgss_hash, &entry->key, HASH_REMOVE, NULL);
- }
-
- /*
- * Write new empty query file, perhaps even creating a new one to recover
- * if the file was missing.
- */
- qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
- if (qfile == NULL)
- {
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not create pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
- goto done;
- }
-
- /* If ftruncate fails, log it, but it's not a fatal problem */
- if (ftruncate(fileno(qfile), 0) != 0)
- ereport(LOG,
- (errcode_for_file_access(),
- errmsg("could not truncate pg_stat_statement file \"%s\": %m",
- PGSS_TEXT_FILE)));
-
- FreeFile(qfile);
+#include "postgres.h"
-done:
- pgss->extent = 0;
- /* This counts as a query text garbage collection for our purposes */
- record_gc_qtexts();
+#include "access/hash.h"
+#include "parser/scanner.h"
- LWLockRelease(pgss->lock);
-}
-#endif
+static void AppendJumble(pgssJumbleState *jstate,
+ const unsigned char *item, Size size);
+static void JumbleQuery(pgssJumbleState *jstate, Query *query);
+static void JumbleRangeTable(pgssJumbleState *jstate, List *rtable);
+static void JumbleExpr(pgssJumbleState *jstate, Node *node);
+static void RecordConstLocation(pgssJumbleState *jstate, int location);
+static void fill_in_constant_lengths(pgssJumbleState *jstate, const char *query);
+static int comp_location(const void *a, const void *b);
/*
* AppendJumble: Append a value that is substantive in a given query to
JumbleRangeTable(jstate, query->rtable);
JumbleExpr(jstate, (Node *) query->jointree);
JumbleExpr(jstate, (Node *) query->targetList);
+ JumbleExpr(jstate, (Node *) query->onConflict);
JumbleExpr(jstate, (Node *) query->returningList);
JumbleExpr(jstate, (Node *) query->groupClause);
+ JumbleExpr(jstate, (Node *) query->groupingSets);
JumbleExpr(jstate, query->havingQual);
JumbleExpr(jstate, (Node *) query->windowClause);
JumbleExpr(jstate, (Node *) query->distinctClause);
{
case RTE_RELATION:
APP_JUMB(rte->relid);
+ JumbleExpr(jstate, (Node *) rte->tablesample);
break;
case RTE_SUBQUERY:
JumbleQuery(jstate, rte->subquery);
JumbleExpr(jstate, (Node *) expr->aggfilter);
}
break;
+ case T_GroupingFunc:
+ {
+ GroupingFunc *grpnode = (GroupingFunc *) node;
+
+ JumbleExpr(jstate, (Node *) grpnode->refs);
+ }
+ break;
case T_WindowFunc:
{
WindowFunc *expr = (WindowFunc *) node;
APP_JUMB(ce->cursor_param);
}
break;
+ case T_InferenceElem:
+ {
+ InferenceElem *ie = (InferenceElem *) node;
+
+ APP_JUMB(ie->infercollid);
+ APP_JUMB(ie->inferopclass);
+ JumbleExpr(jstate, ie->expr);
+ }
+ break;
case T_TargetEntry:
{
TargetEntry *tle = (TargetEntry *) node;
JumbleExpr(jstate, from->quals);
}
break;
+ case T_OnConflictExpr:
+ {
+ OnConflictExpr *conf = (OnConflictExpr *) node;
+
+ APP_JUMB(conf->action);
+ JumbleExpr(jstate, (Node *) conf->arbiterElems);
+ JumbleExpr(jstate, conf->arbiterWhere);
+ JumbleExpr(jstate, (Node *) conf->onConflictSet);
+ JumbleExpr(jstate, conf->onConflictWhere);
+ APP_JUMB(conf->constraint);
+ APP_JUMB(conf->exclRelIndex);
+ JumbleExpr(jstate, (Node *) conf->exclRelTlist);
+ }
+ break;
case T_List:
foreach(temp, (List *) node)
{
JumbleExpr(jstate, (Node *) lfirst(temp));
}
break;
+ case T_IntList:
+ foreach(temp, (List *) node)
+ {
+ APP_JUMB(lfirst_int(temp));
+ }
+ break;
case T_SortGroupClause:
{
SortGroupClause *sgc = (SortGroupClause *) node;
APP_JUMB(sgc->nulls_first);
}
break;
+ case T_GroupingSet:
+ {
+ GroupingSet *gsnode = (GroupingSet *) node;
+
+ JumbleExpr(jstate, (Node *) gsnode->content);
+ }
+ break;
case T_WindowClause:
{
WindowClause *wc = (WindowClause *) node;
JumbleExpr(jstate, rtfunc->funcexpr);
}
break;
+ case T_TableSampleClause:
+ {
+ TableSampleClause *tsc = (TableSampleClause *) node;
+
+ APP_JUMB(tsc->tsmhandler);
+ JumbleExpr(jstate, (Node *) tsc->args);
+ JumbleExpr(jstate, (Node *) tsc->repeatable);
+ }
+ break;
default:
/* Only a warning, since we can stumble along anyway */
elog(WARNING, "unrecognized node type: %d",
ScanKeywords,
NumScanKeywords);
+ /* we don't want to re-emit any escape string warnings */
+ yyextra.escape_string_warning = false;
+
/* Search for each constant, in sequence */
for (i = 0; i < jstate->clocations_count; i++)
{