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POIncreasing memory usage in sqlite3?
 

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  1. POIncreasing memory usage in sqlite3?
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    <p>I've written a console app which receives events via boost::interprocess memory and dumps the info into an sqlite3 database. While running the app I've noticed that, in the Windows task manager, the memory usage was cyclically increasing every... 30s-1min. This led me to believe that the problem lies within the main loop in which I execute my SQL. I've added some monitoring and apparently the sqlite3_memory_usage returns increasing results every couple loop iterations.</p> <p>Can somebody tell me what am I doing wrong? Am I missing something I should de-allocate ?</p> <p>Here are 2 strings I use to generate SQL</p> <pre><code> const std::string sql_insert = "INSERT INTO EventsLog " "(Sec, uSec, DeviceId, PmuId, EventId, Error, Msg) " "VALUES (%ld, %ld, %ld, %d, %ld, %d, %Q)"; const std::string sql_create = "CREATE TABLE IF NOT EXISTS EventsLog(" "Id INTEGER PRIMARY KEY AUTOINCREMENT, " "Sec INTEGER NOT NULL, " "uSec INTEGER NOT NULL, " "DeviceId INTEGER NOT NULL, " "PmuId INTEGER NOT NULL, " "EventId INTEGER NOT NULL, " "Error INTEGER NOT NULL, " "Msg TEXT" ")"; </code></pre> <p>In here, I generate the SQL INSERT command</p> <pre><code>std::string construct_sql_query (const ELMessageData &amp; data) { std::string query = ""; ptime jan1st1970 = ptime(date(1970,1,1)); ptime now = boost::posix_time::microsec_clock::universal_time(); time_duration delta = now - jan1st1970; TimeVal time((uint32)delta.total_seconds(), (uint32)now.time_of_day().fractional_seconds()); char * const sql = sqlite3_mprintf(sql_insert.c_str(), time.tv_sec, time.tv_usec, data.getDeviceId(), data.getPmuId(), data.getEventId(), (data.getIsError() ? 1 : 0), data.getExMsg().c_str()); if(sql == NULL) post_event(EvIOError("Failed to create the SQL command", "StLoggingEvents::_construct_sql_query")); query = std::string(sql); sqlite3_free(sql); return query; } // construct_sql_query </code></pre> <p>Here's the main loop in which I execute the INSERT commands</p> <pre><code> while(true) { m_exchange_obj-&gt;wait(); // wait for the semaphore to be raised const std::string sql = construct_sql_query (m_exchange_obj-&gt;receive()); char ** err = NULL; const int rc = sqlite3_exec(m_db_handle, sql.c_str(), NULL, NULL, err); sqlite3_free(err); if(rc != SQLITE_OK) { LERR_ &lt;&lt; "Error while inserting into the database"; LERR_ &lt;&lt; "Last SQL Query : "; LERR_ &lt;&lt; sql; } else { LDBG_ &lt;&lt; "Event logged..."; LDBG_ &lt;&lt; "Sqlite3 memory usage : " &lt;&lt; sqlite3_memory_used(); } } </code></pre>
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    1. USMaciek
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    1. COHi. Looking at the code I can't see anything wrong... It has to be related to something else (receiving events, maybe, the receive() call allocating memory that's not freed, etc.)
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      1. USDiego Sevilla
    2. COI forgot to mention, too, that maybe sqlite can have some internal storage that uses discretionary to a maximum before releasing internal memory... It may come to a maximum and stay stable afterwards.
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      1. USDiego Sevilla
    3. COIs there a way to force an internal release ?
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      1. USMaciek
 

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