PlanExporter XML format

The PlanExporter tool extracts the query plan of an executed query as a XML document by using the statistics captured from Derby XPLAIN style tables.

An XML document generated by the PlanExporter tool has the following structure.

The basic tree structure:
- plan: The root of the XML tree
  - statement: First child, the query executed
  - time: Second child, the time that this query executed
  - stmt_id : Third child, the STMT_ID of the query
  - details: Fourth child, containing the query plan
The statement element:
This element has only its value. That value implies the query executed, as retrieved from the STMT_TEXT row of the SYSXPLAIN_STATEMENTS table.

For example:
```
<statement>select * from my_table</statement>
```
The time element:
This element has only its value. That value implies the date and time when the query executed, as retrieved from the XPLAIN_TIME row of the SYSXPLAIN_STATEMENTS table.

For example:
```
<time>2010-07-13 14:27:59.405</time>
```
The stmt_id element:
This element has only its value. That value implies the statement ID of the query executed, as retrieved from the STMT_ID row of the SYSXPLAIN_STATEMENTS table.

For example:
```
<stmt_id>9ac8804c-0129-cc31-ca9a-00000047f1e8</stmt_id>
```
The details element:
This element contains the query plan, as a tree structure of plan nodes.

For a particular query there is only one root plan node.

A node element:

Contains the details of a plan node of the query plan. This element can contain zero or many child elements of the same type (node elements).

This element contains one or more attributes, given that they are not null. The possible attributes and their meanings are shown in the following table.

Table 1. Attributes of the `node` element
Attribute Name	Meaning
`name`	Name of the plan node
`input_rows`	Retrieved from the INPUT_ROWS row of the SYSXPLAIN_RESULTSETS system table
`returned_rows`	Retrieved from the RETURNED_ROWS row of the SYSXPLAIN_RESULTSETS system table
`no_opens`	Retrieved from the NO_OPENS row of the SYSXPLAIN_RESULTSETS system table
`visited_pages`	Retrieved from the NO_VISITED_PAGES row of the SYSXPLAIN_SCAN_PROPS system table
`scan_qualifiers`	Retrieved from the SCAN_QUALIFIERS row of the SYSXPLAIN_SCAN_PROPS system table
`next_qualifiers`	Retrieved from the NEXT_QUALIFIERS row of the SYSXPLAIN_SCAN_PROPS system table
`scanned_object`	Retrieved from the SCAN_OBJECT_NAME row of the SYSXPLAIN_SCAN_PROPS system table
`scan_type`	Retrieved from the SCAN_TYPE row of the SYSXPLAIN_SCAN_PROPS system table
`sort_type`	Retrieved from the SORT_TYPE row of the SYSXPLAIN_SORT_PROPS system table
`sorter_output`	Retrieved from the NO_OUTPUT_ROWS row of the SYSXPLAIN_SORT_PROPS system table

For example:

<node name="TABLESCAN" returned_rows="100000" no_opens="1"
visited_pages="2165" scan_qualifiers="None" scanned_object="USERS" 
scan_type="HEAP">