SAXONICA

Saxon Documentation
Full Contents
About Saxon
Changes in this Release
Conditions of Use
Using XSLT 2.0
Using XQuery
Handling Source Documents
XML Schema Processing
The XPath API
Saxon on .NET
Extensibility
Saxon Extensions
| Introduction
| EXSLT Extensions
» | Extension attributes (XSLT only)
| Additional serialization parameters
| Extension functions
| Extension instructions
Sample Saxon Applications
The Saxon SQL Extension
XSLT Elements
XPath 2.0 Expression Syntax
Function Library
Standards Conformance

# saxon:read-once

This attribute may be set on the `xsl:copy-of` element. The allowed values are "yes" and "no". If set to yes, this attribute enables the optimization described in Serial Processing of Large Documents.

The attribute should be set to "yes" only if any external document read by this instruction is read at most once by the stylesheet. If this is not the case, the optimization is unsafe, since the functions `doc()` and `document()` are required to return the same results each time they are called.

This optimization is available only with Saxon-SA.

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