INFO: Truncated Results When Calling IDirectorySearch::GetNextRow (325189)

MORE INFORMATION

When the IDirectorySearch::GetNextRow function returns S_ADS_NOMORE_ROWS, it may not have retrieved all the data from the server. In some cases, S_ADS_NOMORE_ROWS is returned by GetNextRow function when the server was unable to find an entry that matched the search criteria within a predefined two-minute time limit. This two-minute time limit is defined by means of an LDAP policy. For additional information about LDAP policies, click the article number below to view the article in the Microsoft Knowledge Base: If the server exceeds the two-minute time limit, it returns an LDAP cookie in the response so that you can restart the search where it left off. Inefficient searches and heavily loaded systems can cause the server to exceed the time limit. When the server cannot find an efficient index to search, the server may have to apply the filter to every object in the directory, in which case it can run through many entries and not find a match within the two-minute time limit.

Therefore, when returning S_ADS_NOMORE_ROWS, ADSI also sets an extended error code, which can be queried using ADsGetLastError function. If ADsGetLastError returns ERROR_MORE_DATA, it means that the server has not completed the query and must call GetNextRow again.

The Platform SDK sample file, DsSrch, can be modified to handle this search method as shown in the following code sample:

"MAIN.CXX" file
//------------------------------------------------------------------
// 
//  Function:   Q325189_GetNextRow
// 
//  Synopsis:
// 
//------------------------------------------------------------------
HRESULT Q325189_GetNextRow(IDirectorySearch *pDSSearch, ADS_SEARCH_HANDLE hSearchHandle)
{
	HRESULT hr = S_OK;
	DWORD dwADsExtError = ERROR_SUCCESS;
	WCHAR szErrorBuf[512];
	WCHAR szNameBuf[128];

	do
	{
		// Clear ADSI extended error
		dwADsExtError = ERROR_SUCCESS;
		ADsSetLastError(ERROR_SUCCESS, NULL, NULL);

		// Next row
		hr = pDSSearch->GetNextRow(hSearchHandle);
		BAIL_ON_FAILURE(hr);

		// Check ADSI extend error if we got S_ADS_NOMORE_ROWS
		if (S_ADS_NOMORE_ROWS == hr)
		{
			hr = ADsGetLastError(&dwADsExtError, szErrorBuf, 512, szNameBuf, 128);
			BAIL_ON_FAILURE(hr);

			if (ERROR_MORE_DATA != dwADsExtError)
				// All data received
				return ERROR_NO_DATA;
		}

	} while (ERROR_MORE_DATA == dwADsExtError);

	return ERROR_MORE_DATA;

error:
	return hr;
}


//------------------------------------------------------------------
// 
//  Function:   main
// 
//  Synopsis:
// 
//------------------------------------------------------------------
INT _CRTAPI1
main(int argc, char * argv[])
{
...
	// *** MODIFIED FOR Q325189 *** 
	//hr = pDSSearch->GetNextRow(
	//         hSearchHandle
	//         );
	//BAIL_ON_FAILURE(hr);
	hr = Q325189_GetNextRow(pDSSearch, hSearchHandle); 
	// *** EOM ***

	// *** MODIFIED FOR Q325189 *** 
	//while (hr != S_ADS_NOMORE_ROWS && nRows < dwMaxRows) {<BR/>
         BAIL_ON_FAILURE(hr);
	while (nRows < dwMaxRows) {
	// *** EOM ***
        nRows++;

        if (dwNumberAttributes == -1) {
            hr = pDSSearch->GetNextColumnName(
                     hSearchHandle,
                     &pszColumnName
                     );
            BAIL_ON_FAILURE(hr);

            while (hr != S_ADS_NOMORE_COLUMNS) {
                hr = pDSSearch->GetColumn(
                         hSearchHandle,
                         pszColumnName,
                         &Column
                         );

                if (FAILED(hr)  && hr != E_ADS_COLUMN_NOT_SET)
                    goto error;

                if (SUCCEEDED(hr)) {
                    PrintColumn(&Column, pszColumnName);
                    pDSSearch->FreeColumn(&Column);
                }

                FreeADsMem(pszColumnName);
                hr = pDSSearch->GetNextColumnName(
                         hSearchHandle,
                         &pszColumnName
                         );
                BAIL_ON_FAILURE(hr);
            }
            printf("\n");
        }
        else {
            for (DWORD i=0; i<dwNumberAttributes; i++) {
                hr = pDSSearch->GetColumn(
                         hSearchHandle,
                         pszAttrNames[i],
                         &Column
                         );

                if (hr == E_ADS_COLUMN_NOT_SET)
                    continue;

                BAIL_ON_FAILURE(hr);

                PrintColumn(&Column, pszAttrNames[i]);

                pDSSearch->FreeColumn(&Column);
            }
        printf("\n");
        }

	// *** MODIFIED FOR Q325189 *** 
        //hr = pDSSearch->GetNextRow(
        //         hSearchHandle
        //         );
        //BAIL_ON_FAILURE(hr);
		hr = Q325189_GetNextRow(pDSSearch, hSearchHandle); 
	// *** END OF MODIFICATION ***
    }

    wprintf (L"Total Rows: %d\n", nRows);
...
}