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MSSQL connection cause memory leak [message #47838]

Mon, 10 April 2017 09:01

akebee
Messages: 90
Registered: August 2011
Location: China

Member

my application frequently attempts to connect to the database server.
see the pic:
index.php?t=getfile&id=5224&private=0

and the code:

	while(1)
	{
		MSSQLSession mssql;
		for(;;) {
			String cs = "Driver={SQL Server};";
			cs << "Server=" << "127.0.0.1" << ';';
			String h = "sa";
			if(IsNull(h))
				cs << "Trusted_Connection=Yes;";
			else {
				cs << "UID=" << h << ';';
			//	Cout() << "Password:";
				cs << "PWD=" << pass << ';';
			//	Cout() << "Database (empty for default):";
				h = "";
				if(IsNull(h))
					cs << "Database=" << h << ';';
			}
			Cout() << "Connect mssql:" << cs << "\n";
			if(!mssql.Connect(cs))
				Cout() << "Connect failed: " << mssql.GetLastError() << '\n';
			else
				break;
		}
	
		#ifdef _DEBUG
			mssql.SetTrace();
		#endif			
		
		//do some work
		Sleep(1000);
		
		mssql.Close();
	}

Attachment: QQ图片20170410144515.png
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Re: MSSQL connection cause memory leak [message #47839 is a reply to message #47838]

Mon, 10 April 2017 11:25

mirek
Messages: 14255
Registered: November 2005

Ultimate Member

Thanks, that is weird. Will look into it asap.

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Re: MSSQL connection cause memory leak [message #47840 is a reply to message #47839]

Mon, 10 April 2017 11:55

akebee
Messages: 90
Registered: August 2011
Location: China

Member

Yes, momoery increased when ODBCSession::Connect > SQLAllocHandle(SQL_HANDLE_STMT, hdbc, &hstmt);

but the ODBCSession::Close() > SQLFreeHandle(SQL_HANDLE_DBC, hdbc); seems no effect!

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Re: MSSQL connection cause memory leak [message #47842 is a reply to message #47840]

Mon, 10 April 2017 12:19

mirek
Messages: 14255
Registered: November 2005

Ultimate Member

Now looking at Close, maybe try to swap

		SQLFreeHandle(SQL_HANDLE_DBC, hdbc);
		SQLFreeHandle(SQL_HANDLE_STMT, hstmt);

		SQLFreeHandle(SQL_HANDLE_STMT, hstmt);
		SQLFreeHandle(SQL_HANDLE_DBC, hdbc);

(maybe it does not get freed because there is still statement in it...)

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Re: MSSQL connection cause memory leak [message #47843 is a reply to message #47842]

Mon, 10 April 2017 12:32

akebee
Messages: 90
Registered: August 2011
Location: China

Member

i debug again, i must correct my earlier comment,
is the

if(IsOk(SQLDriverConnect(hdbc, NULL, (SQLCHAR *)cs, SQL_NTS, NULL, 0, NULL, SQL_DRIVER_NOPROMPT))) {
...

cause memory increase, not SQLAllocHandle

the swap didn`t working Confused

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Re: MSSQL connection cause memory leak [message #47844 is a reply to message #47843]

Mon, 10 April 2017 12:47

mirek
Messages: 14255
Registered: November 2005

Ultimate Member

Maybe it needs

SQLDisconnect(hdbc);

before FreeHandle (in Close)?

Mirek

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Re: MSSQL connection cause memory leak [message #47845 is a reply to message #47844]

Mon, 10 April 2017 16:11

akebee
Messages: 90
Registered: August 2011
Location: China

Member

yes,you`re right! Twisted Evil

add
SQLDisconnect(hdbc);
before
SQLFreeHandle(SQL_HANDLE_DBC, hdbc);

by the way,why not add "Close()" in "ODBCSession::~ODBCSession()"?

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Re: MSSQL connection cause memory leak [message #47846 is a reply to message #47845]

Mon, 10 April 2017 16:39

mirek
Messages: 14255
Registered: November 2005

Ultimate Member

akebee wrote on Mon, 10 April 2017 16:11

yes,you`re right!

add
SQLDisconnect(hdbc);
before
SQLFreeHandle(SQL_HANDLE_DBC, hdbc);

by the way,why not add "Close()" in "ODBCSession::~ODBCSession()"?

Perfect! Can you please, just to be sure, if the fix in trunk is OK?

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Re: MSSQL connection cause memory leak [message #47850 is a reply to message #47846]

Tue, 11 April 2017 03:12

akebee
Messages: 90
Registered: August 2011
Location: China

Member

yes its OK!

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