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Merge pull request #99 from darkfronza/PG-224_fix_memory_leak 

PG-224: Fix memory leak on extract_query_comments.
pull/100/head
Ibrar Ahmed 2021-09-01 14:57:11 +05:00 committed by GitHub
parent 7a543bafb0 b5aa300e82
commit 6695670d73
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 25 additions and 21 deletions
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pg_stat_monitor.c
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@ -56,6 +56,8 @@ static int plan_nested_level = 0;
/* The array to store outer layer query id*/ /* The array to store outer layer query id*/
uint64 *nested_queryids; uint64 *nested_queryids;
/* Regex object used to extract query comments. */
static regex_t preg_query_comments;
static char relations[REL_LST][REL_LEN]; static char relations[REL_LST][REL_LEN];
static int num_relations; /* Number of relation in the query */ static int num_relations; /* Number of relation in the query */
static bool system_init = false; static bool system_init = false;
@ -67,7 +69,7 @@ static char *pgss_explain(QueryDesc *queryDesc);
static struct pg_hook_stats_t *pg_hook_stats; static struct pg_hook_stats_t *pg_hook_stats;
#endif #endif
static char *extract_query_comments(const char *query); static void extract_query_comments(const char *query, char *comments, size_t max_len);
static int get_histogram_bucket(double q_time); static int get_histogram_bucket(double q_time);
static bool IsSystemInitialized(void); static bool IsSystemInitialized(void);
static void dump_queries_buffer(int bucket_id, unsigned char *buf, int buf_len); static void dump_queries_buffer(int bucket_id, unsigned char *buf, int buf_len);
@ -219,7 +221,8 @@ static uint64 djb2_hash(unsigned char *str, size_t len);
void void
_PG_init(void) _PG_init(void)
{ {
int i; int i, rc;
elog(DEBUG2, "pg_stat_monitor: %s()", __FUNCTION__); elog(DEBUG2, "pg_stat_monitor: %s()", __FUNCTION__);
/* /*
* In order to create our shared memory area, we have to be loaded via * In order to create our shared memory area, we have to be loaded via
@ -252,6 +255,15 @@ _PG_init(void)
EmitWarningsOnPlaceholders("pg_stat_monitor"); EmitWarningsOnPlaceholders("pg_stat_monitor");
/*
* Compile regular expression for extracting out query comments only once.
*/
rc = regcomp(&preg_query_comments, "/\\*.*\\*/", 0);
if (rc != 0)
{
elog(ERROR, "pg_stat_monitor: query comments regcomp() failed, return code=(%d)\n", rc);
}
/* /*
* Request additional shared resources. (These are no-ops if we're not in * Request additional shared resources. (These are no-ops if we're not in
* the postmaster process.) We'll allocate or attach to the shared * the postmaster process.) We'll allocate or attach to the shared
@ -307,6 +319,7 @@ _PG_fini(void)
ProcessUtility_hook = prev_ProcessUtility; ProcessUtility_hook = prev_ProcessUtility;
free(nested_queryids); free(nested_queryids);
regfree(&preg_query_comments);
hash_entry_reset(); hash_entry_reset();
} }
@ -1483,7 +1496,7 @@ pgss_store(uint64 queryid,
uint64 ip = pg_get_client_addr(); uint64 ip = pg_get_client_addr();
uint64 planid = plan_info ? plan_info->planid: 0; uint64 planid = plan_info ? plan_info->planid: 0;
uint64 appid = djb2_hash((unsigned char *)application_name, application_name_len); uint64 appid = djb2_hash((unsigned char *)application_name, application_name_len);
char *comments; char comments[512] = "";
/* Monitoring is disabled */ /* Monitoring is disabled */
if (!PGSM_ENABLED) if (!PGSM_ENABLED)
return; return;
@ -1494,7 +1507,7 @@ pgss_store(uint64 queryid,
else else
userid = GetUserId(); userid = GetUserId();
comments = extract_query_comments(query); extract_query_comments(query, comments, sizeof(comments));
/* Safety check... */ /* Safety check... */
if (!IsSystemInitialized() || !pgss_qbuf[pgss->current_wbucket]) if (!IsSystemInitialized() || !pgss_qbuf[pgss->current_wbucket])
@ -3407,29 +3420,20 @@ get_histogram_timings(PG_FUNCTION_ARGS)
return CStringGetTextDatum(text_str); return CStringGetTextDatum(text_str);
} }
char * static void
extract_query_comments(const char *query) extract_query_comments(const char *query, char *comments, size_t max_len)
{ {
regex_t preg;
char *pattern = "/\\*.*\\*/";
int rc; int rc;
size_t nmatch = 1; size_t nmatch = 1;
regmatch_t pmatch; regmatch_t pmatch;
char *comments = palloc0(512);
rc = regcomp(&preg, pattern, 0); rc = regexec(&preg_query_comments, query, nmatch, &pmatch, 0);
if (rc != 0) if (rc != 0)
{ return;
printf("regcomp() failed, returning nonzero (%d)\n", rc);
return ""; snprintf(comments, max_len, "%.*s", pmatch.rm_eo - pmatch.rm_so -4, &query[pmatch.rm_so + 2]);
}
rc = regexec(&preg, query, nmatch, &pmatch, 0);
if (rc != 0)
return "";
sprintf(comments, "%.*s", pmatch.rm_eo - pmatch.rm_so -4, &query[pmatch.rm_so + 2]);
regfree(&preg);
return comments;
} }
#if PG_VERSION_NUM < 140000 #if PG_VERSION_NUM < 140000
static uint64 static uint64
get_query_id(JumbleState *jstate, Query *query) get_query_id(JumbleState *jstate, Query *query)