Message Tree Copying Part II

The Compute node contains the following code:

DECLARE rVersion REFERENCE TO InputRoot.XMLNSC.ns:Inventory.ns:header.ns:version;
PROPAGATE TO LABEL(rVersion);
RETURN FALSE;

Message tree copying summary

This section contained a large amount of information relating to message tree copying, therefore this summary might be useful:

Table 1.

Don't change a message tree and copy it	If a message tree is ever changed, then the bitstream copy cannot take place, and extra parsing is needed.
Always copy at the parser folder level for the bitstream transfer to take place	When a message tree is copied, the high-speed bitstream transfer takes place only at the parser folder level.
Parsers must be created when not copying to OutputRoot	Only the OutputRoot correlation name in ESQL has the special property that a parser is created for parser name folders. Not copying to OutputRoot means that the bitstream copy cannot take place, and the whole of the source tree is parsed and then copied to the Environment tree.
Avoid overwriting fields when a tree is copied	When a message tree is copied, any existing children of target message tree field are detached first. Detaching fields is not the same as deleting fields, so they are still in scope, but are no longer attached to the tree.
Setting a field to NULL is NOT the same as deleting it	When you attempt to improve the memory usage of message tree usage, setting a field to NULL should never be used.
XML, XMLNS, and XMLNSC are not the same domains	The efficient bitstream transfer does not take place when the tree is copied between these domains. Both XML and XMLNS are deprecated.

• Don't change a message tree and copy it:
• Always copy at the parser folder level for the bitstream transfer to take place:
• Parsers must be created when not copying to OutputRoot
• Avoid overwriting fields when a tree is copied
• Forcing a copy of the message tree fields when required
• Setting a field to NULL is NOT the same as deleting it
• XML, XMLNS, and XMLNSC are not the same domains
• Avoid tree copying