Update Release Notes and Configuration Guide on MXS_MODULE_PARAM_REGEX

Also added a new Upgrading-To-file with a note on the change.

Documentation/Getting-Started/Configuration-Guide.md

@@ -9,7 +9,9 @@ plugin modules that tailor the behavior of the program.
 
 # Table of Contents
 
+* [Glossary](#glossary)
 * [Configuration](#configuration)
+  * [Special Parameter Types](#special-parameter-types)
   * [Global Settings](#global-settings)
   * [Service](#service)
   * [Server](#server)
@@ -79,7 +81,9 @@ The values of the parameter that are not on the first line need to have at least
 one whitespace character before them in order for them to be recognized as a
 part of the multi-line parameter.
 
-### Sizes
+### Special Parameter Types
+
+#### Sizes
 
 Where _specifically noted_, a number denoting a size can be suffixed by a subset
 of the IEC binary prefixes or the SI prefixes. In the former case the number
@@ -104,6 +108,16 @@ max_size=1000000M
 max_size=1000G
 max_size=1T
 ```
+#### Regular Expressions
+
+When a regular expression (regex) parameter is accepted, the pattern string
+should be enclosed in slashes e.g. `match=/^select/` defines the pattern
+`^select`. The slashes allow whitespace to be read from the ends of the regex
+string contrary to a normal string parameter and are removed before compiling
+the pattern. For backwards compatibility, the slashes are not yet mandatory.
+Omitting them is, however, deprecated and will be rejected in the next release
+of MaxScale. Currently, *QLAFilter* accepts parameters in regular expression
+form.
 
 ### Global Settings
 

Documentation/Release-Notes/MaxScale-2.2.0-Release-Notes.md

@@ -17,11 +17,26 @@ Significant whitespace in object names is now deprecated. All object names
 squeezing repeating whitespace and replacing it with hyphens. If any
 object name conversions take place, a warning will be logged.
 
+### Regular Expression Parameters
+
+Modules may now use a built-in regular expression (regex) string parameter type
+instead of a normal string when accepting patterns. The regex parameters are
+checked by the config file loader to compile using the PCRE2 library embedded
+within MaxScale. The only module using the new regex parameter type is currently
+*QLAFilter*.
+
+The only action users should take is enclose their regular expressions in
+slashes, e.g. `match=/^select/` defines the pattern `^select`. The slashes allow
+whitespace to be read from the ends of the regex string contrary to a normal
+string parameter and are removed before compiling the pattern. For backwards
+compatibility, the slashes are not yet mandatory. Omitting them is, however,
+deprecated and will be rejected in the next release of MaxScale.
+
 ### NamedServerFilter
 
-This filter now uses the PCRE2-libarary to match queries. Previously, it used
-the POSIX-version of PCRE2. The filter also accepts multiple match-server pairs.
-Please see the NamedServerFilter documentation for details.
+The filter now accepts multiple match-server pairs. Please see the
+[NamedServerFilter](../Filters/Named-Server-Filter.md) documentation for
+details.
 
 ### Tee Filter
 

Documentation/Upgrading/Upgrading-To-MaxScale-2.2.md

@@ -0,0 +1,20 @@
+# Upgrading MariaDB MaxScale from 2.1 to 2.2
+
+This document describes possible issues upgrading MariaDB MaxScale from version
+2.1 to 2.2.
+
+For more information about MariaDB MaxScale 2.2, please refer to the
+[ChangeLog](../Changelog.md).
+
+For a complete list of changes in MaxScale 2.2.0, refer to the
+[MaxScale 2.2.0 Release Notes](../Release-Notes/MaxScale-2.2.0-Release-Notes.md).
+
+Before starting the upgrade, we recommend you back up your current configuration
+file.
+
+### Regular Expression Parameters
+
+Modules may now use a built-in regular expression string parameter type instead
+of a normal string when accepting patterns. The only module using the new regex
+parameter type is currently *QLAFilter*. When inputting pattern, enclose the
+string in slashes, e.g. `match=/^select/` defines the pattern `^select`.