IndexDefs not (always?) accurate after TDAMemDataset.RefreshFromServer

Data Abstract
1

Hello there,

I’m currently writing a WindowsService to sync some tables between databases. There’s one table which contains a list of produced items with at least two columns: ID (LargeAutoInc) and a serial number (Unique!).

In order to replicate tables with foreign keys on that Table-ID correctly I wrote a function to lookup the DatabaseB.ID for a given DatabaseA.ID (via Serial Number, tiTableInfo holds that information…).

Therefore I have to incrementally load rows for both databases.

While developing this service I had a lot of debug-output written to a text file and everything worked as expected. However after removing this debug output I run into a problem with the following:

[..] dtMapSource.DynamicWhere.Clear; dtMapSource.DynamicWhere.Expression := DAWhereValue( '', tiTableInfo.MapperTableField, vMappedValue ); 
  if dtMapSource.Active then
    dtMapSource.RefreshFromServer
  else
    dtMapSource.Open;

  //if here occurs something, e.g. write log message to a file
  //the error will not occur


  //--> if I'm using LocateByIndex the row may not be found... I don't know why...
  //if NOT dtMapSource.LocateByIndex( tiTableInfo.MapperTableField, vMappedValue ) then
  if NOT dtMapSource.Locate( tiTableInfo.MapperTableField, vMappedValue, [] )  then
      raise Exception.Create( 'GetMappedID.' + sTablename + ': Could not find row for source value ' + VarToStr( vMappedValue ) + ', ' + dtMapSource.DynamicWhere.Xml );
  [..]

The problem didn’t occur until i removed the output to the logfile… If I’m using .Locate instead of .LocateByIndex everythings fine.

How and when are the indizes of a TDAMemDataset refreshed and/or can I enforce an Update (IndexDefs.Update did not solve the problem)?
This method is part of a thread within a windows-service (with connections to multiple DA-Servers).
The tables are not in any special state (ControlsDisabled and so on…)

Thanks in advance,
Peter

2

Hello,

I can’t reproduce this situation with simple DA application. If I understand you right your WindowsService application is not a DA server, it is just connected to the DA servers. Is it organized like DA client? Please, descibe it in details or better send testcase reproducing situation.

Best regards

3

Hi again,

maybe I’ve some time after easter to send a little testcase… Is it possible to attach a file as non-public?

I’ve currently implented the lookup using a TDictionary which scales much better (and does not have to above problem) for looking up existing and new rows.

As for this (windows-)service: yes, it is a TServiceApplication which acts (for the DA-Server) as a normal client. Every possible task is in a seperate thread and has own connections to the DA-Server (the replication is just one thread/task). For debugging reasons I’m just calling TServiceApplication.ServiceStart(…) and TServiceApplication.ServiceStop directly instead of TSA.Run().

Best regards,
Peter

4
pmatjeschk said: Is it possible to attach a file as non-public?

You can send it to support@remobjects.com