我已经编写了自己的pgsql C-Function（在CentOS-5.2和pgsql-9.1上），它收集postgres后端进程正在使用的资源统计信息。
每个后端进程包含cpu_utime / cpu_stime / disk_read_size / disk_write_size。
我的代码如下......
#include "postgres.h"
#include "funcapi.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <unistd.h>
#define PGDATA_ENV_NM "PGDATA"
#define PROC_FULL_NAME_SIZE 1024
#define PROC_FULL_NAME "/proc/"
#define MAX_PG_PROC_CNT 4096
#define TEMP_BUFFER_LEN 1024
#define DISK_READ_TITLE "read_bytes"
#define DISK_WRITE_TITLE "write_bytes"
#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif
typedef struct _backend_rsc{
int si_proc_id;
unsigned long long sui_cpu_utime;
unsigned long long sui_cpu_stime;
unsigned long long sui_disk_read;
unsigned long long sui_disk_write;
} PROC_INFO;
PROC_INFO ST_PROC_NODES[MAX_PG_PROC_CNT];
int gi_tuple_idx = 0;
PG_FUNCTION_INFO_V1(v1c_get_backend_rsc);
Datum
v1c_get_backend_rsc(PG_FUNCTION_ARGS) {
FuncCallContext *funcctx;
int call_cntr;
int max_calls;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
if (SRF_IS_FIRSTCALL()) {
MemoryContext oldcontext;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/* switch to memory context appropriate for multiple function calls */
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* total number of tuples to be returned */
funcctx->max_calls = fill_backend_node();
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("function returning record called in context "
"that cannot accept type record")));
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
MemoryContextSwitchTo(oldcontext);
}
/* stuff done on every call of the function */
funcctx = SRF_PERCALL_SETUP();
call_cntr = funcctx->call_cntr;
max_calls = funcctx->max_calls;
attinmeta = funcctx->attinmeta;
if (call_cntr < max_calls) { /* do when there is more left to send */
char **values;
HeapTuple tuple;
Datum result;
values = (char **) palloc(5 * sizeof(char *));
values[0] = (char *) palloc(32 * sizeof(char));
values[1] = (char *) palloc(32 * sizeof(char));
values[2] = (char *) palloc(32 * sizeof(char));
values[3] = (char *) palloc(32 * sizeof(char));
values[4] = (char *) palloc(32 * sizeof(char));
snprintf( values[0], 32, "%d", ST_PROC_NODES[gi_tuple_idx].si_proc_id );
snprintf( values[1], 32, "%lu", ST_PROC_NODES[gi_tuple_idx].sui_cpu_utime );
snprintf( values[2], 32, "%lu", ST_PROC_NODES[gi_tuple_idx].sui_cpu_stime );
snprintf( values[3], 32, "%lu", ST_PROC_NODES[gi_tuple_idx].sui_disk_read );
snprintf( values[4], 32, "%lu", ST_PROC_NODES[gi_tuple_idx].sui_disk_write);
/* build a tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
/* clean up (this is not really necessary) */
pfree(values[0]);
pfree(values[1]);
pfree(values[2]);
pfree(values[3]);
pfree(values[4]);
pfree(values);
gi_tuple_idx++;
SRF_RETURN_NEXT(funcctx, result);
}
else { /* do when there is no more left */
gi_tuple_idx = 0;
SRF_RETURN_DONE(funcctx);
}
}
int fill_backend_node() {
int li_backend_count = 0;
// read postgresql data_directory
int li_parent_pid = 0;
char ls_pgdata_dir[1024] = { 0x00 };
strncpy(ls_pgdata_dir, getenv(PGDATA_ENV_NM), strlen(getenv(PGDATA_ENV_NM)));
strcat(ls_pgdata_dir, "/postmaster.pid");
// get postgresql group pid from postmaster.pid
FILE *lfp_pg_pid_file = fopen(ls_pgdata_dir, "r");
if( !lfp_pg_pid_file ) {
return 1;
}
char temp[1024]={ 0x00 };
fgets( temp, 1023, lfp_pg_pid_file );
//fscanf(lfp_pg_pid_file, "%d", &li_parent_pid);
sscanf( temp, "%d", &li_parent_pid );
fclose(lfp_pg_pid_file);
// read child process list from /proc/[1-9]*/status files which stores parent PID
int li_temp_pid = 0;
int li_temp_ppid = 0;
unsigned long long lui_temp_cpu_utime=0, lui_temp_cpu_stime=0;
DIR *dir_info;
struct dirent *dir_entry;
FILE *lfp_stat_file = NULL;
FILE *lfp_io_file = NULL;
dir_info = opendir(PROC_FULL_NAME);
char ls_stat_file_nm[PROC_FULL_NAME_SIZE];
char ls_io_file_nm[PROC_FULL_NAME_SIZE];
char ls_temp_string[TEMP_BUFFER_LEN] = { 0x00 };
char *lcp_string_cursor = NULL;
if(NULL != dir_info) {
while(dir_entry = readdir(dir_info)) {
if (dir_entry->d_type == DT_DIR && *dir_entry->d_name > '0' && *dir_entry->d_name <= '9') {
memset(ls_stat_file_nm, 0x00, PROC_FULL_NAME_SIZE);
strcat(ls_stat_file_nm, PROC_FULL_NAME);
strcat(ls_stat_file_nm, dir_entry->d_name);
strcat(ls_stat_file_nm, "/stat");
lfp_stat_file = fopen(ls_stat_file_nm, "r");
if( !lfp_stat_file ) {
return 1;
}
fscanf(lfp_stat_file, "%d %*s %*s %d %*s %*s %*s %*s %*s %*s %*s %*s %llu %llu", &li_temp_pid, &li_temp_ppid, &lui_temp_cpu_utime, &lui_temp_cpu_stime);
if( li_temp_ppid == li_parent_pid ) {
ST_PROC_NODES[li_backend_count].si_proc_id = li_temp_pid ;
ST_PROC_NODES[li_backend_count].sui_cpu_utime = lui_temp_cpu_utime;
ST_PROC_NODES[li_backend_count].sui_cpu_stime = lui_temp_cpu_stime;
memset(ls_io_file_nm, 0x00, PROC_FULL_NAME_SIZE);
strcat(ls_io_file_nm, PROC_FULL_NAME);
strcat(ls_io_file_nm, dir_entry->d_name);
strcat(ls_io_file_nm, "/io");
lfp_io_file = fopen(ls_io_file_nm, "r");
if( !lfp_io_file ) {
return 1;
}
while( fgets(ls_temp_string, TEMP_BUFFER_LEN-1, lfp_io_file) ) {
if( lcp_string_cursor = strstr(ls_temp_string, DISK_READ_TITLE) ) sscanf(ls_temp_string, "%*s %lu", &ST_PROC_NODES[li_backend_count].sui_disk_read);
// not cancelled_write_bytes
else if( *ls_temp_string != 'c' && (lcp_string_cursor = strstr(ls_temp_string, DISK_WRITE_TITLE)) ) sscanf(ls_temp_string, "%*s %lu", &ST_PROC_NODES[li_backend_count].sui_disk_write);
else continue;
}
fclose(lfp_io_file);
li_backend_count++;
}
fclose(lfp_stat_file);
}
}
closedir(dir_info);
}
//closedir(dir_info);
return li_backend_count;
}
和contrib目录中的SQL文件位于......
之下\echo Use "CREATE EXTENSION get_backend_rsc" to load this file. \quit
-- Register functions.
CREATE TYPE utype_get_backend_rsc AS
(
proc_id int,
cpu_utime numeric,
cpu_stime numeric,
disk_read numeric,
disk_write numeric
);
CREATE OR REPLACE FUNCTION get_backend_rsc()
RETURNS SETOF utype_get_backend_rsc
AS '$libdir/get_backend_rsc.so' , 'v1c_get_backend_rsc'
LANGUAGE C IMMUTABLE STRICT;
-- Register a view on the function for ease of use.
CREATE VIEW get_backend_rsc AS
SELECT * FROM get_backend_rsc();
GRANT SELECT ON get_backend_rsc TO PUBLIC;
问题是每当我执行该功能时，VmRSS中/proc/$$/status增加4KB。我确信palloc和pfree在那里，无处可能发生内存泄漏。
我错过了什么？任何建议都将深表感谢。
答案 0 :(得分：0)
flose，但我仍然想知道为什么非关闭文件会导致内存泄漏。