CVS User Account cvsuser
Mon Jul 24 09:04:12 PDT 2006
Log Message:
-----------
Add a description to DDL docs as to how the removal/readdition of log triggers
addresses table alterations

Modified Files:
--------------
    slony1-engine/doc/adminguide:
        ddlchanges.sgml (r1.22 -> r1.23)

-------------- next part --------------
Index: ddlchanges.sgml
===================================================================
RCS file: /usr/local/cvsroot/slony1/slony1-engine/doc/adminguide/ddlchanges.sgml,v
retrieving revision 1.22
retrieving revision 1.23
diff -Ldoc/adminguide/ddlchanges.sgml -Ldoc/adminguide/ddlchanges.sgml -u -w -r1.22 -r1.23
--- doc/adminguide/ddlchanges.sgml
+++ doc/adminguide/ddlchanges.sgml
@@ -23,9 +23,9 @@
 transactions are still winding their way through your systems, this is
 necessary.  </para>
 
-<para>It is also necessary to use <command>EXECUTE SCRIPT</command> if
-you alter tables so as to change their schemas.  If you do not, then
-you may run into the problems <link linkend="neededexecddl"> described
+<para>It is essential to use <command>EXECUTE SCRIPT</command> if you
+alter tables so as to change their schemas.  If you do not, then you
+may run into the problems <link linkend="neededexecddl"> described
 here </link> where triggers on modified tables do not take account of
 the schema change.  This has the potential to corrupt data on
 subscriber nodes.  </para>
@@ -94,6 +94,14 @@
 COMMIT;
 </screen></para>
 
+<para>Note that this is what allows &slony1; to take notice of
+alterations to tables: <emphasis>before</emphasis>
+that <command>SYNC</command>, &slony1; has been replicating tuples
+based on the <emphasis>old</emphasis>
+schema; <emphasis>after</emphasis> the <command>DDL_SCRIPT</command>,
+tuples are being replicated based on the <emphasis>new<emphasis>
+schema. </para></listitem>
+
 <para> On a system which is busily taking updates, it may be
 troublesome to <quote>get in edgewise</quote> to actually successfully
 engage all the required locks.  The locks may run into deadlocks.



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