DATASET:WRITE-XML leaks dynamic queries when using NESTED Data-Relation

Using WRITE-XML on a ProDataSet which contains nested data relations appears to cause a memory leak. Dynamic queries are automatically generated but are not being cleaned up as expected.

Sep 19, 2016
Knowledge

Title

URL Name

DATASET-WRITE-XML-leaks-dynamic-queries-when-using-NESTED-Data-Relation

Article Number

000151644

Environment

Product: OpenEdge Version: 10.2x , 11.x, 12.0, 12.1, 12.2 OS: All supported platforms

Question/Problem Description

Apaprent memory Leak during DATASET:WRITE-XML when using NESTED Data-Relation.
Navigating from SESSION:FIRST-QUERY after calling WRITE-XML shows there are dynamic queries left over.
Those queries are on the child tables of the NESTED relations.

Steps to Reproduce

Clarifying Information

Following code shows a dynamic query is left behind after calling WRITE-XML:

DEFINE TEMP-TABLE ttChild2
   FIELD ChildId    AS CHARACTER
   FIELD ParentId   AS CHARACTER.
   
DEFINE TEMP-TABLE ttParent2
  FIELD ParentId   AS CHARACTER.

DEFINE DATASET dsTest2 FOR ttParent2, ttChild2                                
   DATA-RELATION drParentChild FOR ttParent2, ttChild2
      RELATION-FIELDS (ParentId, ParentId) NESTED.  /*  << NESTED KEYWORD */

DEFINE VARIABLE lcTest AS LONGCHAR NO-UNDO.

CREATE ttParent2.
ASSIGN ttParent2.ParentId = '12345'.
       
CREATE ttChild2.
ASSIGN ttChild2.ParentId = '12345'
       ttChild2.ChildId  = '54321'.

MESSAGE VALID-HANDLE( SESSION:FIRST-QUERY ) SESSION:FIRST-QUERY VIEW-AS ALERT-BOX.

DATASET dsTest2:WRITE-XML ("LONGCHAR", lcTest, TRUE, ?, ?, FALSE, FALSE, FALSE).

MESSAGE VALID-HANDLE( SESSION:FIRST-QUERY ) SESSION:FIRST-QUERY SESSION:FIRST-QUERY:PREPARE-STRING VIEW-AS ALERT-BOX.

The query prepare string queries the child table based on the parent record

Queries created during WRITE-XML cannot be explicitly deleted by ABL code. Trying to do so triggers error "Cannot delete a dataset relation auto-generated query. (12349)"

Error Message

Defect Number

OCTA-2802

Enhancement Number

Cause

There are two potential causes for this:

FIRST

Automatically generated queries to handle the nested data relations are not deleted immediately after the WRITE-XML completes. Instead:

These queries are created the first time WRITE-XML is called for the dataset.
They are then re-used as long as the dataset stays in memory.
They are deleted when the dataset is deleted / goes out of scope.

This can be proven by expanding the test case and tracking it with the client logging features, see the expanded test case attached as 000031266.zip.
For further verification that dynamic objects do get deleted as expected, see article How to detect ABL Memory Leaks with Dynamic Objects Logging

SECOND

When using the classic REST Adapter this does result in a leak where a dynamic query is created on the AppServer agent and cannot be deleted.

Resolution

Fixed version(s): OpenEdge 11.7.16, 12.2.11, 12.3

Workaround

Notes

References to Other Documentation:

Progress Article(s):
How to detect ABL Memory Leaks with Dynamic Objects Logging

Keyword Phrase

Last Modified Date

11/29/2023 4:51 PM

DATASET:WRITE-XML leaks dynamic queries when using NESTED Data-Relation

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