Devart Forums

We have come across a problem in the recent versions of Delphi, XE8 and 10 Seattle, that there is a memory leak reported when we exit our application. We have raised this with Embarcadero, but I am posting here also in case anyone can help, or at least say that they have had the same problem also?

The leak can be reproduced with a very simple two line program:

SQLQuery1.SQL.Add('SELECT columns.table_name, columns.column_name FROM information_schema.columns'
+ ' WHERE columns.table_schema = ''public'' ORDER BY columns.table_name, columns.column_name;');
SQLQuery1.Active := true;

Adding this simple block of code to a FormCreate, for a form with TSQLQuery and TSQLConnection objects with properties set up so that a connection to a database is successful, gives a memory leak (as reported by EurekaLog). Here is an excerpt from the call stack:

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Methods |Details|Stack |Address |Module |Offset |Unit |Class |Procedure/Method |Line |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|+Leak #1: Type=Data at $0700AE40; Total size=512; Count=1 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|00000002|04 |00000000|0083CA20|Project4.exe|0043CA20|Data.DBXDynalink |TDBXDynalinkDriverCommonLoader|LoadDriverLibraryAndMethodTable |873[24] |
|00000002|04 |00000000|0083C6CF|Project4.exe|0043C6CF|Data.DBXDynalink |TDBXDynalinkDriver |LoadDriver |769[5] |
|00000002|04 |00000000|0083F46C|Project4.exe|0043F46C|Data.DBXDynalinkNative |TDBXDynalinkDriverNative |CreateConnection |87[1] |
|00000002|04 |00000000|0078D8EB|Project4.exe|0038D8EB|Data.DBXCommon |TDBXConnectionFactory |GetConnection |6661[12] |
|00000002|04 |00000000|0078D801|Project4.exe|0038D801|Data.DBXCommon |TDBXConnectionFactory |GetConnection |6640[0] |
|00000002|04 |00000000|007183E5|Project4.exe|003183E5|Data.DB |TCustomConnection |SetConnected |3567[8] |
|00000002|04 |00000000|00829241|Project4.exe|00429241|Data.SqlExpr |TCustomSQLDataSet |OpenCursor |4066[2] |
|00000002|04 |00000000|0072BC91|Project4.exe|0032BC91|Data.DB |TDataSet |SetActive |12470[12] |
|00000002|04 |00000000|00868C68|Project4.exe|00468C68|Unit6 |TForm6 |FormCreate |35[6] |
|00000002|04 |00000000|006C6295|Project4.exe|002C6295|Vcl.Forms |TCustomForm |DoCreate |3758[3] |
|00000002|04 |00000000|006C5EB5|Project4.exe|002C5EB5|Vcl.Forms |TCustomForm |AfterConstruction |3642[1] |
|00000002|04 |00000000|006C5E65|Project4.exe|002C5E65|Vcl.Forms |TCustomForm |Create |3632[35] |
|00000002|04 |00000000|006D0DEA|Project4.exe|002D0DEA|Vcl.Forms |TApplication |CreateForm |10557[13] |
|00000002|04 |00000000|008755D5|Project4.exe|004755D5|Project4 | |Initialization |23[3] |
|00000002|03 |00000000|76F17BFC|kernel32.dll|00017BFC|KERNEL32 | |BaseThreadInitThunk | |
|00000002|03 |00000000|7769AD1D|ntdll.dll |0005AD1D|ntdll | | (possible RtlInitializeExceptionChain+141)| |
|00000002|03 |00000000|7769ACE5|ntdll.dll |0005ACE5|ntdll | | (possible RtlInitializeExceptionChain+85) | |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|


We are not suggesting that the Devart DBExpress PostgreSQL driver is leaking memory - it appears that we have simply uncovered a memory leak in Embarcadero's source code used in XE8 and 10 Seattle. Running the same exact code in XE7 does not give the leak (and we have tried using the last few versions of the Devart DBExpress PostgreSQL driver i.e. all combinations of driver version and Delphi version, and regardless of what driver version we use, the leak only occurs in XE8 and 10 Seattle, and never in XE7).

If anyone can shed any insight into this issue it would be much appreciated!

Hello,

Thank you for the information, we have reproduced and fixed the issue. This fix will be included in the next version.

Thanks for looking into this! Can I ask when the next version of the drivers, containing this fix, will be released? We cannot deploy our application built under 10 Seattle until this is resolved.

Many thanks!

We can send you a night build. For this, please send your license number to alexp*devart*com.

Alex - I haven't heard back from you since my last couple of emails to you on this matter. If you want me to re-send or post the details here, that's fine, but we really do need a full solution to this. Thanks!

We have investigated your sample. Our dbExpress driver for PostgreSQL doesn't cause memory leak. The issue with memory leak is also reproduced with the standard dbExpress drivers for the other databases (Firebird, MSSQL, MySQL) starting from RAD Studio XE8 and higher.

To resolve the issue, please contact RAD Studio developers.