On Sat, 20 Jan 2007 11:07:57 +0500, "Shoaib Mir" <[EMAIL PROTECTED]> wrote:
> I dont have the replication setup on my machine right now but I guess as
> far
> as I remember you can surely check for the master and slave nodes from a
> Slony schema table.
>
I think the notion of "master and slave server" is a little bit misleading
here:
We have sets and a node could be a origin or subscriber of them. Thinking that
way,
one idea to get that information is to issue
SELECT
a.set_id,
a.set_comment,
(SELECT last_value FROM _replication.sl_local_node_id) AS local_id,
CASE WHEN a.set_origin = (SELECT last_value FROM
_replication.sl_local_node_id) THEN
TRUE
ELSE
FALSE END AS master_node
FROM
_replication.sl_set a;
This gives you a result set which holds TRUE for every set the current node is
an origin node for.
> ------------
> Shoaib Mir
> EnterpriseDB (www.enterprisedb.com)
>
> On 19 Jan 2007 08:25:23 -0800, [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> wrote:
>>
>> I am using LinuxHA to manage the failover and Slony as part of to
>> failover to move to the healthy node. But my question was more along
>> the lines, if a user has access to both databases (master and slave)
>> but does not know which one is which, how can you tell?
>>
>> Take a scenario: you configure 2 servers as master and slave. You walk
>> for a period of time during which a number failovers occur. You come
>> back. Can I query a sl_???? table to determine which server is the
>> current master and which one is the current slave?
>>
If you are using LinuxHA you have a virtual IP adress for your Cluster which
points to the current
active "master" on your cluster. Connecting to the master node should always
happen through this
IP adress, so you always "know" you are on the master when using this IP. You
could then spread read
operations along the IPs assigned directly to each node, "declaring" these
connections read only.
Bernd
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