sorry for multi-send the message.
I just test the code again. And sqlite3_finalize() may free the memory. I'm
wrong in the first post.
But I test the routine of sqlite3_prepare_v2() + sqlite3_step() +
sqlite3_finalize() in my real code.
And the test result say when sqlite3_step() is shadowed, the leak is zero.
When doing the sqlite3_step(), the leak is about 1k byte. And another
curious phenomenon is that while there are many datas in the data file, the
leak is more bigger than while there are few datas in the data file.
Marcus Grimm wrote:
>
> it is not necessary to send your question multible times... ;)
>
> to answer: what makes you think that sqlite3_finalize can't
> free the prepared statement ?
>
> liubin liu wrote:
>> Is there any memory leak in the code?
>>
>> Below is the code. Is there any memory leak in the pthread2?
>>
>> While pthread1 is using test.db exclusively, the sqlite3_prepare_v2() of
>> pthread2 still prepares the p_stmt pointer to a piece of memory malloced
>> by
>> sqlite3_preapare_v2(). And then the sqlite3_finalize() can't free the
>> memory
>> still because pthread1 is using test.db exclusively. Does it cause a
>> memory
>> leak?
>>
>>
>>
>> ______code__________________________________________________________
>>
>> #include <stdio.h>
>> #include <unistd.h> // for usleep()
>> #include <sys/time.h> // for gettimeofday()
>> #include <pthread.h>
>> #include <sqlite3.h>
>>
>> void pthread1 (void);
>> void pthread2 (void);
>>
>>
>> int main (void)
>> {
>> int ret = -1;
>>
>> sqlite3 *g_db = NULL;
>> ret = sqlite3_open ("test.db", &g_db);
>> ret = sqlite3_exec (g_db, "CREATE TABLE t1 (id INTEGER PRIMARY KEY,
>> d1
>> TEXT)", NULL,NULL,NULL);
>> ret = sqlite3_close (g_db);
>>
>> usleep (500000);
>>
>>
>> pthread_t pthr1, pthr2;
>> ret = pthread_create (&pthr1, NULL, (void *) pthread1, NULL);
>> ret = pthread_create (&pthr2, NULL, (void *) pthread2, NULL);
>>
>>
>> ret = pthread_join (pthr1, NULL);
>> printf ("thread1 end\n");
>> ret = pthread_join (pthr2, NULL);
>> printf ("thread2 end\n");
>>
>> return 0;
>> }
>>
>>
>> void pthread1 (void)
>> {
>> int ret = -1;
>> sqlite3 *db1 = NULL;
>> ret = sqlite3_open ("test.db", &db1);
>>
>> char *sql_f = "INSERT OR REPLACE INTO t1 VALUES (%d,
>> 'aaabbbcccddd1122')";
>> char *sql = NULL;
>>
>> sqlite3_stmt *p_stmt = NULL;
>>
>> struct timeval tv1, tv2;
>> ret = gettimeofday (&tv1, NULL);
>>
>> ret = sqlite3_prepare_v2 (db1, "BEGIN TRANSACTION", -1, &p_stmt,
>> NULL);
>> ret = sqlite3_step (p_stmt);
>> ret = sqlite3_finalize (p_stmt);
>>
>> // n=1000000, test.db is 25843712 bytes, 25M;
>> int i=0, n=1000000;
>> for (i=0; i<n; i++)
>> {
>> sql = sqlite3_mprintf (sql_f, i);
>> ret = sqlite3_prepare_v2 (db1, sql, -1, &p_stmt, NULL);
>> ret = sqlite3_step (p_stmt);
>> ret = sqlite3_finalize (p_stmt);
>> }
>>
>> printf ("pthread1: ret: %d\n", ret);
>> ret = sqlite3_prepare_v2 (db1, "COMMIT TRANSACTION", -1, &p_stmt,
>> NULL);
>> ret = sqlite3_step (p_stmt);
>> ret = sqlite3_finalize (p_stmt);
>>
>> ret = gettimeofday (&tv2, NULL);
>> printf ("time is : %ds\n", (int) (tv2.tv_sec - tv1.tv_sec));
>>
>>
>> ret = sqlite3_close (db1);
>> }
>>
>>
>>
>> void pthread2 (void)
>> {
>> int ret = -1;
>>
>> sqlite3 *db2 = NULL;
>> ret = sqlite3_open ("test.db", &db2);
>>
>> usleep (2000000);
>>
>>
>> sqlite3_stmt *p_stmt = NULL;
>> int i=0, n=10;
>> for (i=0; i<n; i++)
>> {
>> char *sql_f = "INSERT OR REPLACE INTO t1 VALUES (%d,
>> 'bbbbbbbbbbbb1122')";
>> char *sql = NULL;
>>
>> sql = sqlite3_mprintf (sql_f, i);
>> ret = sqlite3_prepare_v2 (db2, sql, -1, &p_stmt, NULL);
>> printf ("pthread2: prepare: %d, p_stmt: %p, errmsg: %s\n",
>> ret,
>> p_stmt, sqlite3_errmsg(db2));
>> ret = sqlite3_step (p_stmt);
>> printf ("pthread2: step: %d, p_stmt: %p, errmsg: %s\n",
>> ret,
>> p_stmt, sqlite3_errmsg(db2));
>> ret = sqlite3_finalize (p_stmt);
>> printf ("pthread2: finalize: %d, p_stmt: %p, errmsg: %s\n",
>> ret,
>> p_stmt, sqlite3_errmsg(db2));
>> printf ("\n");
>>
>> usleep (300000);
>> }
>>
>> ret = sqlite3_close (db2);
>> printf ("pthread2: close: %d, p_stmt: %p, errmsg: %s\n", ret,
>> p_stmt, sqlite3_errmsg(db2));
>> }
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