[Mono-devel-list] DbDataAdapter fix for out of memory errors when filling datasets

[Keith Dreibelbis]

Francisco,

I looked into this some, and ended up filing this bug: (does this sound  
like the same error you are describing?)

http://bugzilla.ximian.com/show_bug.cgi?id=64674

Looking and bugzilla further, it seems there is also this similar bug,  
which already has a patch.  I need to check to see if it fixes the bug  
I filed.

http://bugzilla.ximian.com/show_bug.cgi?id=59556


-kd


Francisco Figueiredo Jr.   <fxjrlists at yahoo.com.br> wrote:

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>
> Hi all,
>
> Here is a patch for handling out of memory exceptions when trying to
> fill datasets with queries which doesn't return a resultset like  
> insert,
> delete, update.
>
> The out of memory exception happens in the following line of
> DbDataAdapter.cs:
>
> around line 502.
> int[] mapping = new int[reader.FieldCount]; // mapping the reader
> indexes to the datatable indexes
>
> The problem is that when the query is an insert, update or delete, the
> FieldCount property is -1 which gives the problem.
>
> The compiler can detect when you try to create an array with a negative
> index. But when this index is in a var, the runtime doesn't handle it
> and gives the error. The error is like that:
>
>
> System.OutOfMemoryException: Out of memory.
> in (unmanaged) (wrapper managed-to-native)
> System.Object:__icall_wrapper_mono_array_new_specific (intptr,int)
> in <0x00004> (wrapper managed-to-native)
> System.Object:__icall_wrapper_mono_array_new_specific (intptr,int)
> in <0x00091> System.Data.Common.DbDataAdapter:BuildSchema
> (System.Data.IDataReader,System.Data.DataTable,System.Data.SchemaType)
> in <0x00079> (wrapper remoting-invoke-with-check)
> System.Data.Common.DbDataAdapter:BuildSchema
> (System.Data.IDataReader,System.Data.DataTable,System.Data.SchemaType)
> in <0x00086> System.Data.Common.DbDataAdapter:FillTable
> (System.Data.DataTable,System.Data.IDataReader,int,int,int&)
> in <0x000ad> (wrapper remoting-invoke-with-check)
> System.Data.Common.DbDataAdapter:FillTable
> (System.Data.DataTable,System.Data.IDataReader,int,int,int&)
> in <0x0017d> System.Data.Common.DbDataAdapter:Fill
> (System.Data.DataSet,string,System.Data.IDataReader,int,int)
> in <0x000da> System.Data.Common.DbDataAdapter:Fill
> (System.Data.DataSet,int,int,string,System.Data.IDbCommand,System.Data. 
> CommandBehavior)
> in <0x00049> System.Data.Common.DbDataAdapter:Fill
> (System.Data.DataSet,string)
> in <0x0006b> (wrapper remoting-invoke-with-check)
> System.Data.Common.DbDataAdapter:Fill (System.Data.DataSet,string)
>
>
>
> May I have to add a bugzilla entry?
>
> The patch is attached.
>
> Regards,
>
> Francisco Figueiredo Jr.
>
>
>
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>  name="DbDataAdapter.diff"
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>  filename="DbDataAdapter.diff"
>
> ? DbDataAdapter.diff
> Index: DbDataAdapter.cs
> ===================================================================
> RCS file:  
> /cvs/public/mcs/class/System.Data/System.Data.Common/ 
> DbDataAdapter.cs,v
> retrieving revision 1.44
> diff -u -r1.44 DbDataAdapter.cs
> --- DbDataAdapter.cs    24 Jun 2004 16:25:02 -0000      1.44
> +++ DbDataAdapter.cs    28 Aug 2004 03:01:27 -0000
> @@ -285,25 +285,31 @@
>                         try {
>                                 string tableName = srcTable;
>                                 do {
> -                                       tableName = SetupSchema  
> (SchemaType.Mapped, tableName);
> -                                       if (tableName != null) {
> -                                               // check if the table  
> exists in the dataset
> -                                               if  
> (dataSet.Tables.Contains (tableName))
> -                                                       // get the  
> table from the dataset
> -                                                       dataTable =  
> dataSet.Tables [tableName];
> -                                               else {
> -                                                       dataTable =  
> new DataTable(tableName);
> -                                                        
> dataSet.Tables.Add (dataTable);
> -                                               }
> -
> -                                               if (!FillTable  
> (dataTable, dataReader, startRecord, maxRecords, ref count)) {
> -                                                       continue;
> +                                       .
> +                                       // Non-resultset queries like  
> insert, delete or update aren't processed.
> +                    if (dataReader.FieldCount != -1)
> +                                       {
> +                                               tableName =  
> SetupSchema (SchemaType.Mapped, tableName);
> +                                               if (tableName != null)  
> {
> +
> +                                                       // check if  
> the table exists in the dataset
> +                                                       if  
> (dataSet.Tables.Contains (tableName))
> +                                                               // get  
> the table from the dataset
> +                                                                
> dataTable = dataSet.Tables [tableName];
> +                                                       else {
> +                                                                
> dataTable = new DataTable(tableName);
> +                                                                
> dataSet.Tables.Add (dataTable);
> +                                                       }
> +
> +                                                       if (!FillTable  
> (dataTable, dataReader, startRecord, maxRecords, ref count)) {
> +                                                                
> continue;
> +                                                       }
> +
> +                                                       tableName =  
> String.Format ("{0}{1}", srcTable, ++resultIndex);
> +
> +                                                       startRecord =  
> 0;
> +                                                       maxRecords = 0;
>                                                 }
> -
> -                                               tableName =  
> String.Format ("{0}{1}", srcTable, ++resultIndex);
> -
> -                                               startRecord = 0;
> -                                               maxRecords = 0;
>                                         }
>                                 } while (dataReader.NextResult ());
>                         }
> @@ -490,6 +496,7 @@
>                 private int[] BuildSchema (IDataReader reader,  
> DataTable table, SchemaType schemaType)
>                 {
>                         int readerIndex = 0;
> +
>                         int[] mapping = new int[reader.FieldCount]; //  
> mapping the reader indexes to the datatable indexes
>                         ArrayList primaryKey = new ArrayList ();
>                         ArrayList sourceColumns = new ArrayList ();
>
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