/usr/share/doc/slony1-2-doc/adminguide/function.failednode-integer-integer.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>       failednode(integer, integer)
      </TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REV="MADE"
HREF="mailto:slony1-general@lists.slony.info"><LINK
REL="HOME"
TITLE="Slony-I 2.0.7 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Schema schemadoc"
HREF="schema.html"><LINK
REL="PREVIOUS"
TITLE="       enablesubscription_int(integer, integer, integer)
      "
HREF="function.enablesubscription-int-integer-integer-integer.html"><LINK
REL="NEXT"
TITLE="       failednode2(integer, integer, integer, bigint, bigint)
      "
HREF="function.failednode2-integer-integer-integer-bigint-bigint.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="stylesheet.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=ISO-8859-1"><META
NAME="creation"
CONTENT="2011-12-03T11:44:27"></HEAD
><BODY
CLASS="SECTION"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="5"
ALIGN="center"
VALIGN="bottom"
><SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 2.0.7 Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="function.enablesubscription-int-integer-integer-integer.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="schema.html"
>Fast Backward</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 6. Schema schemadoc</TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="schema.html"
>Fast Forward</A
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="function.failednode2-integer-integer-integer-bigint-bigint.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECTION"
><H1
CLASS="SECTION"
><A
NAME="FUNCTION.FAILEDNODE-INTEGER-INTEGER"
>6.63. failednode(integer, integer)</A
></H1
><P
>       <P
><B
>Function Properties</B
></P
><P
><B
>Language: </B
>PLPGSQL</P
><P
><B
>Return Type: </B
>integer</P
>
 
       Initiate failover from failed_node to backup_node.  This function must be called on all nodes, 
and then waited for the restart of all node daemons.
        </P><PRE
CLASS="PROGRAMLISTING"
>declare
	p_failed_node		alias for $1;
	p_backup_node		alias for $2;
	v_row				record;
	v_row2				record;
	v_n					int4;
begin
	-- ----
	-- Grab the central configuration lock
	-- ----
	lock table sl_config_lock;

	-- ----
	-- All consistency checks first
	-- Check that every node that has a path to the failed node
	-- also has a path to the backup node.
	-- ----
	for v_row in select P.pa_client
			from sl_path P
			where P.pa_server = p_failed_node
				and P.pa_client &lt;&gt; p_backup_node
				and not exists (select true from sl_path PP
							where PP.pa_server = p_backup_node
								and PP.pa_client = P.pa_client)
	loop
		raise exception 'Slony-I: cannot failover - node % has no path to the backup node',
				v_row.pa_client;
	end loop;

	-- ----
	-- Check all sets originating on the failed node
	-- ----
	for v_row in select set_id
			from sl_set
			where set_origin = p_failed_node
	loop
		-- ----
		-- Check that the backup node is subscribed to all sets
		-- that originate on the failed node
		-- ----
		select into v_row2 sub_forward, sub_active
				from sl_subscribe
				where sub_set = v_row.set_id
					and sub_receiver = p_backup_node;
		if not found then
			raise exception 'Slony-I: cannot failover - node % is not subscribed to set %',
					p_backup_node, v_row.set_id;
		end if;

		-- ----
		-- Check that the subscription is active
		-- ----
		if not v_row2.sub_active then
			raise exception 'Slony-I: cannot failover - subscription for set % is not active',
					v_row.set_id;
		end if;

		-- ----
		-- If there are other subscribers, the backup node needs to
		-- be a forwarder too.
		-- ----
		select into v_n count(*)
				from sl_subscribe
				where sub_set = v_row.set_id
					and sub_receiver &lt;&gt; p_backup_node;
		if v_n &gt; 0 and not v_row2.sub_forward then
			raise exception 'Slony-I: cannot failover - node % is not a forwarder of set %',
					p_backup_node, v_row.set_id;
		end if;
	end loop;

	-- ----
	-- Terminate all connections of the failed node the hard way
	-- ----
	perform terminateNodeConnections(p_failed_node);

	-- ----
	-- Move the sets
	-- ----
	for v_row in select S.set_id, (select count(*)
					from sl_subscribe SUB
					where S.set_id = SUB.sub_set
						and SUB.sub_receiver &lt;&gt; p_backup_node
						and SUB.sub_provider = p_failed_node)
					as num_direct_receivers 
			from sl_set S
			where S.set_origin = p_failed_node
			for update
	loop
		-- ----
		-- If the backup node is the only direct subscriber ...
		-- ----
		if v_row.num_direct_receivers = 0 then
		        raise notice 'failedNode: set % has no other direct receivers - move now', v_row.set_id;
			-- ----
			-- backup_node is the only direct subscriber, move the set
			-- right now. On the backup node itself that includes restoring
			-- all user mode triggers, removing the protection trigger,
			-- adding the log trigger, removing the subscription and the
			-- obsolete setsync status.
			-- ----
			if p_backup_node = getLocalNodeId('_schemadoc') then
				update sl_set set set_origin = p_backup_node
						where set_id = v_row.set_id;

				delete from sl_setsync
						where ssy_setid = v_row.set_id;

				for v_row2 in select * from sl_table
						where tab_set = v_row.set_id
						order by tab_id
				loop
					perform alterTableConfigureTriggers(v_row2.tab_id);
				end loop;
			end if;

			delete from sl_subscribe
					where sub_set = v_row.set_id
						and sub_receiver = p_backup_node;
		else
			raise notice 'failedNode: set % has other direct receivers - change providers only', v_row.set_id;
			-- ----
			-- Backup node is not the only direct subscriber or not
			-- a direct subscriber at all. 
			-- This means that at this moment, we redirect all possible
			-- direct subscribers to receive from the backup node, and the
			-- backup node itself to receive from another one.
			-- The admin utility will wait for the slon engine to
			-- restart and then call failedNode2() on the node with
			-- the highest SYNC and redirect this to it on
			-- backup node later.
			-- ----
			update sl_subscribe
					set sub_provider = (select min(SS.sub_receiver)
							from sl_subscribe SS
							where SS.sub_set = v_row.set_id
								and SS.sub_receiver &lt;&gt; p_backup_node
								and SS.sub_forward
								and exists (
									select 1 from sl_path
										where pa_server = SS.sub_receiver
										  and pa_client = p_backup_node
								))
					where sub_set = v_row.set_id
						and sub_receiver = p_backup_node;		
			  update sl_subscribe
                   set sub_provider = (select min(SS.sub_receiver)
                           from sl_subscribe SS
                           where SS.sub_set = v_row.set_id
                               and SS.sub_receiver &lt;&gt; p_failed_node
                               and SS.sub_forward
                               and exists (
                                   select 1 from sl_path
                                       where pa_server = SS.sub_receiver
                                         and pa_client = sl_subscribe.sub_receiver
                               ))
                   where sub_set = v_row.set_id
                       and sub_receiver &lt;&gt; p_backup_node;

			update sl_subscribe
					set sub_provider = p_backup_node
					where sub_set = v_row.set_id
						and sub_receiver &lt;&gt; p_backup_node
						and exists (
							select 1 from sl_path
								where pa_server = p_backup_node
								  and pa_client = sl_subscribe.sub_receiver
						);						
			delete from sl_subscribe
                   where sub_set = v_row.set_id
                       and sub_receiver = p_backup_node;

		end if;
	end loop;
	

	-- Rewrite sl_listen table
	perform RebuildListenEntries();

	-- Run addPartialLogIndices() to try to add indices to unused sl_log_? table
	perform addPartialLogIndices();

	-- ----
	-- Make sure the node daemon will restart
	-- ----
	notify &quot;_schemadoc_Restart&quot;;

	-- ----
	-- That is it - so far.
	-- ----
	return p_failed_node;
end;</PRE
><P>
      </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="function.enablesubscription-int-integer-integer-integer.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="function.failednode2-integer-integer-integer-bigint-bigint.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>enablesubscription_int(integer, integer, integer)</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="schema.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>failednode2(integer, integer, integer, bigint, bigint)</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
slony1-2-doc 2.0.7-3build1 / usr / share / doc / slony1-2-doc / adminguide / function.failednode-integer-integer.html
