Docs: add database and object name limitation.
"Migrating Data with Gptransfer" in the <cite>Greenplum Database Administrator
Guide</cite>.</p>
</section>
+ <section>
+ <title>About Database, Schema, and Table Names</title>
+ <p>When you transfer an entire database, schema and table names in the database can
+ contain only alphanumeric characters and the underscore character
+ (<codeph>_</codeph>). Also, Unicode characters are not supported. The same
+ naming restrictions apply when you specify a database, schema, or table as an option
+ or in a file.</p>
+ </section>
<section id="section4">
<title>Notes</title>
<p>The <cmdname>gptransfer</cmdname> utility efficiently transfers tables with large
