delphi - DBXPool Corrupts Memory on Failure to Connect -

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when dbxpool used delegateconnection on tsqlconnection, if sqlserver unavailable when call tsqlconnection.open method, timeout first time. if subsequently call open again, misbehave. in production service, kills process without warning -- no exceptions raised, nothing. process disappears... in simple app created test dbxpool, thinks tsqlconnection connected, when not.

has had troubles dbxpool delegateconnection can offer suggestions?

thanks!

<<< 7/23 edit #2 >>>

i used code in edit #1 below trace through dbx framework. following method called when dbxpool used:

(unit dbxdelegate)

procedure tdbxdelegateconnection.open; begin   if not fconnection.isopen   begin     tdbxaccessorconnection(fconnection).open;   end; end;

... calls following method, called whether or not dbxpool used:

(unit dbxcommon)

procedure tdbxconnection.open; begin   // mark state open memory can deallocated   // if derived open or meta query fail   fopen := true;    derivedopen;   databasemetadata; end;

notice comment. when exception occurs (e.g., wrong username or timeout, etc.), following code called when dbxpool not used.

(unit dbxcommon)

procedure tdbxconnection.close; begin   closeallcommands;   rollbackalltransactions;   derivedclose;   settraceinfoevent(nil);   freeandnil(fdatabasemetadata);   fopen := false; end;

because fopen doesn't set false when dbxpool used, causes code execute shouldn't next time derivedopen called, results in accessviolation , memory corruption. rtl catches it, doesn't (e.g., production service killed windows). haven't been able trace deeper yet dbxdelegate determine why doesn't catch exception , call tdbxconnection.close.

<<< 7/23 edit #1 >>>

per ken's suggestion, attaching simple example app. service app dies. app showing access violation in dbxmss.dll (today). yesterday didn't raise exception on second click, returned 'connected' true. seems memory corruption me...

build , run app on machine or w/o sqlserver. click each button few times. both return error on first click. 'with dbxpool' think it's connected beginning second click. if lucky, might see av. 'w/o dbxpool' button fail every time, correct.

project1.dpr

program project1;  uses   forms,   unit1 in 'unit1.pas' {form1};  {$r *.res}  begin   application.initialize;   application.mainformontaskbar := true;   application.createform(tform1, form1);   application.run; end.

unit1.dfm

object form1: tform1   left = 0   top = 0   caption = 'form1'   clientheight = 301   clientwidth = 562   color = clbtnface   font.charset = default_charset   font.color = clwindowtext   font.height = -11   font.name = 'tahoma'   font.style = []   oldcreateorder = false   oncreate = formcreate   pixelsperinch = 96   textheight = 13   object button1: tbutton     left = 40     top = 8     width = 75     height = 25     caption = 'with dbxpool'     taborder = 0     onclick = button1click   end   object button2: tbutton     left = 40     top = 39     width = 75     height = 25     caption = 'w/o dbxpool'     taborder = 1     onclick = button2click   end   object sqlconnection1: tsqlconnection     drivername = 'mssql'     getdriverfunc = 'getsqldrivermssql'     libraryname = 'dbxmss.dll'     loginprompt = false     params.strings = (       'driverunit=dbxmssql'          'driverpackageloader=tdbxdynalinkdriverloader,dbxcommondriver150.' +         'bpl'          'driverassemblyloader=borland.data.tdbxdynalinkdriverloader,borla' +         'nd.data.dbxcommondriver,version=15.0.0.0,culture=neutral,publick' +         'eytoken=91d62ebb5b0d1b1b'          'metadatapackageloader=tdbxmssqlmetadatacommandfactory,dbxmssqldr' +         'iver150.bpl'          'metadataassemblyloader=borland.data.tdbxmssqlmetadatacommandfact' +         'ory,borland.data.dbxmssqldriver,version=15.0.0.0,culture=neutral' +         ',publickeytoken=91d62ebb5b0d1b1b'       'getdriverfunc=getsqldrivermssql'       'libraryname=dbxmss.dll'       'vendorlib=sqlncli10.dll'       'maxblobsize=-1'       'osauthentication=false'       'preparesql=true'       'errorresourcefile='       'drivername=mssql'       'schemaoverride=%.dbo'       'hostname=127.0.0.1'       'database=database'       'user_name=username'       'password=password'       'blobsize=-1'       'localecode=0000'       'isolationlevel=readcommitted'       'os authentication=false'       'prepare sql=false'       'delegateconnection=dbxpool'       'dbxpool.maxconnections=20'       'dbxpool.minconnections=1'       'dbxpool.connecttimeout=1000'       'dbxpool.driverunit=dbxpool'       'dbxpool.delegatedriver=true'       'dbxpool.dbxpool.maxconnections=20'       'dbxpool.dbxpool.minconnections=1'       'dbxpool.dbxpool.connecttimeout=1000'       'dbxpool.dbxpool.driverunit=dbxpool'       'dbxpool.dbxpool.delegatedriver=true'       'dbxpool.dbxpool.drivername=dbxpool'       'dbxpool.drivername=dbxpool')     vendorlib = 'sqlncli10.dll'     left = 8     top = 8   end   object sqlconnection2: tsqlconnection     drivername = 'mssql'     getdriverfunc = 'getsqldrivermssql'     libraryname = 'dbxmss.dll'     loginprompt = false     params.strings = (       'driverunit=dbxmssql'          'driverpackageloader=tdbxdynalinkdriverloader,dbxcommondriver150.' +         'bpl'          'driverassemblyloader=borland.data.tdbxdynalinkdriverloader,borla' +         'nd.data.dbxcommondriver,version=15.0.0.0,culture=neutral,publick' +         'eytoken=91d62ebb5b0d1b1b'          'metadatapackageloader=tdbxmssqlmetadatacommandfactory,dbxmssqldr' +         'iver150.bpl'          'metadataassemblyloader=borland.data.tdbxmssqlmetadatacommandfact' +         'ory,borland.data.dbxmssqldriver,version=15.0.0.0,culture=neutral' +         ',publickeytoken=91d62ebb5b0d1b1b'       'getdriverfunc=getsqldrivermssql'       'libraryname=dbxmss.dll'       'vendorlib=sqlncli10.dll'       'maxblobsize=-1'       'osauthentication=false'       'preparesql=true'       'errorresourcefile='       'drivername=mssql'       'schemaoverride=%.dbo'       'hostname=127.0.0.1'       'database=database'       'user_name=username'       'password=password'       'blobsize=-1'       'localecode=0000'       'isolationlevel=readcommitted'       'os authentication=false'       'prepare sql=false')     vendorlib = 'sqlncli10.dll'     left = 8     top = 39   end end

unit1.pas

unit unit1;  interface  uses   windows, messages, sysutils, variants, classes, graphics, controls, forms,   dialogs, dbxmssql, stdctrls, db, sqlexpr, dbxpool;  type   tform1 = class(tform)     button1: tbutton;     sqlconnection1: tsqlconnection;     sqlconnection2: tsqlconnection;     button2: tbutton;     procedure button1click(sender: tobject);     procedure formcreate(sender: tobject);     procedure button2click(sender: tobject);   private     { private declarations }   public     { public declarations }   end;  var   form1: tform1;  implementation  uses   dbxcommon;  {$r *.dfm}  procedure tform1.button1click(sender: tobject); begin   sqlconnection1.close;   sqlconnection1.open;   if sqlconnection1.connected     messagedlg('connected connection 1', mtinformation, [mbok], 0); end;  procedure tform1.button2click(sender: tobject); begin   sqlconnection2.close;   sqlconnection2.open;   if sqlconnection2.connected     messagedlg('connected connection 2', mtinformation, [mbok], 0); end;  procedure tform1.formcreate(sender: tobject); begin   // testing purposes, shorten timeout timeout occurs   sqlconnection1.params.values[tdbxpropertynames.connecttimeout] := '1';   sqlconnection2.params.values[tdbxpropertynames.connecttimeout] := '1'; end;  end.

embarcadero support notified me today issue has been fixed , available in next general release (e.g., xe2).


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