Logging large messages with Log4Net AdoNetAppender

Question

I have a library which has a couple of web service calls. Now it is a requirement to log all requests made to external web services and to log all responses received. This is for internal audits later.

My sql table looks like this.

CREATE TABLE [dbo].[WebServiceLog](
    [Id] [int] IDENTITY(1,1) NOT NULL,
    [Date] [datetime] NOT NULL,
    [Thread] [nvarchar](255) NOT NULL,
    [Level] [nvarchar](50) NOT NULL,
    [Logger] [nvarchar](255) NOT NULL,
    [Message] [ntext] NOT NULL,
    [SessionID] [nvarchar](50) NOT NULL,
    [SearchID] [nvarchar](25) NULL
)

Note that the Message field is where the request and responses from the web service are stored. The responses sometimes are very large in the order of more than 90k characters, sometimes even more. (Flight/hotel availability search - might return a lot of data)

My appender config is as follows.

<appender name="InfoAppender" type="log4net.Appender.AdoNetAppender">
        <bufferSize value="1"/>
        <connectionType value="System.Data.SqlClient.SqlConnection, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
        <connectionString value="Data Source=tcexpress;Initial Catalog=test;Persist Security Info=True;User ID=testUser;Password=**"/>
        <commandText value="INSERT INTO WebServiceLog ([Date],[Thread],[Level],[Logger],[Message],[SessionID], [SearchID]) VALUES (@log_date, @thread, @log_level, @logger, @message, @session_id, @search_id)"/>
        <parameter>
            <parameterName value="@log_date"/>
            <dbType value="DateTime"/>
            <layout type="log4net.Layout.RawTimeStampLayout"/>
        </parameter>
        <parameter>
            <parameterName value="@thread"/>
            <dbType value="String"/>
            <size value="255"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%thread"/>
            </layout>
        </parameter>
        <parameter>
            <parameterName value="@log_level"/>
            <dbType value="String"/>
            <size value="50"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%level"/>
            </layout>
        </parameter>
        <parameter>
            <parameterName value="@logger"/>
            <dbType value="String"/>
            <size value="255"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%logger"/>
            </layout>
        </parameter>
        <parameter>
            <parameterName value="@message"/>
            <dbType value="String"/>
            <size value="454751"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%message"/>
            </layout>
        </parameter>
        <parameter>
            <parameterName value="@session_id"/>
            <dbType value="String"/>
            <size value="50"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%X{sessionID}"/>
            </layout>
        </parameter>
        <parameter>
            <parameterName value="@search_id"/>
            <dbType value="String"/>
            <size value="25"/>
            <layout type="log4net.Layout.PatternLayout">
                <conversionPattern value="%X{searchID}"/>
            </layout>
        </parameter>
    </appender>

Is there anyway of telling the appender that my field is nText and could have any amount of data given to it? I did try setting a very high value for the field length with string, but it always seems to truncate at a value of 454751.
Has anyone come across this problem? Or is there a better way to log large messages to the database using log4net? Any help will be much appreciated.

Answer 1

Maybe that does not answer your question properly, but if you use nvarchar(max) instead of nText then this should work fine for you:

<parameter>
  <parameterName value="@message"/>
  <dbType value="String"/>
  <layout type="log4net.Layout.PatternLayout">
    <conversionPattern value="%message" />
  </layout>
</parameter>

This is what I use to log exceptions (with the stack trace). Setting it to -1 should also work as Dmitriy suggested.