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A memory leak in Delphi XE3 when an error occurs while inserting into sqlite db

... Query: TSQLQuery ... Query.SQL.Clear; Query.SQL.Add('INSERT INTO pumps'#13#10 + 'VALUES (NULL, :title, :power)'); Query.ParamByName('title').AsString:= title; Query.ParamByName('power').AsFloat:= power; try Query.ExecSQL; except on E: Exception do begin ShowMessage(E.Message); end; end;

The request is associated with SQLConnection with driver = Sqlite. All operations really work, but when I try to insert a unique value in a column with a unique index, I get an exception due to the value. OK, my code catches it and shows the message “The column heading is not unique”, but before the debugger shows me this TWICE exception. When I close the program, the memory manager reports memory leaks, and these leaks:

  • 21 - 28 bytes: UnicodeString x 4
  • 61 - 68 bytes: TDBXSqliteCommand x2
  • 69 - 76 bytes: TDBXMorphicCommand x 2
  • 221 - 236 bytes: Unknown x 2

Can this be avoided?

UPD: I used FastMM4 to get a verbose log, and below is part of a memory leak:

 A memory block has been leaked. The size is: 68 This block was allocated by thread 0xB18, and the stack trace (return addresses) at the time was: 4068A6 [System.pas][System][@GetMem$qqri][4203] 4082BB [System.pas][System][TObject.NewInstance$qqrv][14969] 4089D2 [System.pas][System][@ClassCreate$qqrpvzc][16231] 7D5A91 [Data.DbxSqlite.pas][Data.DbxSqlite][Dbxsqlite.TDBXSqliteCommand.$bctr$qqrp26Data.Dbxcommon.TDBXContextp35Data.Dbxsqlite.TDBXSqliteConnection][567] 6E3DFE [Data.DBXCommon][Generics.Collections.%TDictionary__2$20System.UnicodeStringp32Data.Dbxcommon.TDBXCreateCommand%.GetBucketIndex$qqrx20System.UnicodeStringi] 7D4C8E [Data.DbxSqlite.pas][Data.DbxSqlite][Dbxsqlite.TDBXSqliteDriver.CreateSqliteCommand$qqrp26Data.Dbxcommon.TDBXContextp29Data.Dbxcommon.TDBXConnectionp26Data.Dbxcommon.TDBXCommand][295] 6CE4DA [Data.DBXCommon.pas][Data.DBXCommon][Dbxcommon.TDBXDriver.CreateMorphCommand$qqrp26Data.Dbxcommon.TDBXContextp29Data.Dbxcommon.TDBXConnectionp26Data.Dbxcommon.TDBXCommand][7569] 6D5177 [Data.DBXCommon.pas][Data.DBXCommon][Dbxcommon.TDBXDelegateDriver.CreateMorphCommand$qqrp26Data.Dbxcommon.TDBXContextp29Data.Dbxcommon.TDBXConnectionp26Data.Dbxcommon.TDBXCommand][11061] 6D09F4 [Data.DBXCommon.pas][Data.DBXCommon][Dbxcommon.TDBXConnection.CreateMorphCommand$qqrp26Data.Dbxcommon.TDBXCommand][8480] 6D1C21 [Data.DBXCommon.pas][Data.DBXCommon][Dbxcommon.TDBXMorphicCommand.DerivedOpen$qqrv][9084] 6D1974 [Data.DBXCommon.pas][Data.DBXCommon][Dbxcommon.TDBXCommand.Open$qqrv][8962] The block is currently used for an object of class: TDBXSqliteCommand
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I run tests using the dbXpress SQLite and MySQL driver (XE3), and your code just leaks using SQLite (also get a double exception in debug mode), but it is not with MySQL .

IMHO is a bug that should be reported in QC.

Stack trace when the first exception occurs in the debugger

 :769cc41f KERNELBASE.RaiseException + 0x58 Data.DBXCommon.TDBXContext.Error(???,'column title is not unique') Data.DbxSqlite.CheckError(19,???,$2F12738) Data.DbxSqlite.TDBXSqliteCommand.DerivedExecuteQuery Data.DBXCommon.TDBXCommand.ExecuteQuery Data.DBXCommon.TDBXMorphicCommand.ExecuteQuery Data.SqlExpr.TCustomSQLDataSet.ExecuteStatement Data.SqlExpr.TCustomSQLDataSet.ExecSQL(???) Data.SqlExpr.TSQLQuery.ExecSQL(???) Main_ViewU.TForm1.RunQuery($2E7B870,'Title',10) Main_ViewU.TForm1.Button1Click($2E85AD0)

Stack trace when a second error occurs in the debugger

 :769cc41f KERNELBASE.RaiseException + 0x58 // <-- Exception interrupts Destroy Data.DBXCommon.TDBXContext.Error(???,'column title is not unique') Data.DbxSqlite.CheckError(19,???,$2F12738) Data.DbxSqlite.TDBXSqliteCommand.DerivedClose Data.DBXCommon.TDBXCommand.Close Data.DBXCommon.TDBXMorphicCommand.DerivedClose Data.DBXCommon.TDBXCommand.Close Data.DBXCommon.TDBXCommand.Destroy // <-- DESTROY Data.DBXCommon.TDBXMorphicCommand.Destroy // <-- DESTROY System.TObject.Free Data.SqlExpr.TCustomSQLDataSet.CloseStatement Data.SqlExpr.TCustomSQLDataSet.InternalFreeCommand Data.SqlExpr.TCustomSQLDataSet.FreeCommand Data.SqlExpr.TCustomSQLDataSet.ExecSQL(???) Data.SqlExpr.TSQLQuery.ExecSQL(???) Main_ViewU.TForm1.RunQuery($2E7B870,'Title',10) Main_ViewU.TForm1.Button1Click($2E85AD0)

And this causes a memory leak ...

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