SQLITE2.8.17 database is locked!
进程运行时,时常出现 database is locked 错误,查询官网文档,说的是由于递归调用sqlite_exec()函数引起的,未能明白怎么会出现这种情况。
进程有两个线程访问数据库,在访问的接口处加上了互斥量,代码如下:
pthread_mutex_lock (&query_mutex);
int retv = sqlite2_query(conn, sql); //对sqlite_exec()的封装,统一到mysql的C语言API形式
if(0 != retv)
{
PRINT(SRC,LEVEL,"ERROR: %s, when %s!!!\n",DB_ERROR(conn),sql);
DB_FREEERR(conn); //释放错误字符串
retv = ERR_DB_QUERY;
sleep(1); //sleep(1) to slow down closely followed database calls
}
pthread_mutex_unlock (&query_mutex);
int sqlite2_query(SQLITE2_CONN *conn,const char *sql)
{//error: non-zero, success: zero
if(0 <= IsSQLType(sql,"select"))//SELECT SQL statement
{return sqlite_get_table(conn->connection, sql,
&conn->result.data,&conn->result.nrow,
&conn->result.ncolumn,&conn->errmsg);
}
else//other SQL statements
{return sqlite_exec(conn->connection,sql,0,0,&conn->errmsg);
}
}