Seems I have an additional data point: the sync test always takes longer (> 20 secs) if I include conninfo for all cluster nodes instead of just the local node. I had previously thought conninfo data was only used when needed. Is this not the case?

                Tom    ☺


From: Tom Tignor <ttignor at akamai.com>
Date: Monday, September 12, 2016 at 10:52 AM
To: "slony1-general at lists.slony.info" <slony1-general at lists.slony.info>
Subject: sync performance


                Hello slony1 community,
                We’ve recently been testing communication reliability between our cluster nodes. Our config is a simple setup with one provider producing a modest volume of changes (measured in KB/s) consumed by 5 direct subscribers, though these are geographically distributed. The test is just a sync event followed by a wait on the sync originator. Example:

cluster name = ams_cluster;
node 5 admin
      conninfo='dbname=ams
      host=23.79.242.182
      user=ams_slony
      sslmode=verify-ca
      sslcert=/usr/local/akamai/.ams_certs/complete-ams_slony.crt
      sslkey=/usr/local/akamai/.ams_certs/ams_slony.private_key
      sslrootcert=/usr/local/akamai/etc/ssl_ca/canonical_ca_roots.pem';
node 2 admin conninfo = 'dbname=ams user=ams_slony';

sync(id=2);
wait for event (origin=2, confirmed=5, wait on=2, timeout=30);

                Tests show the script takes 10-20 secs to run on different nodes.
                Can anyone explain what’s happening internally during this time, and why it takes so long? On a healthy, lightly loaded system, we might have hoped for a sync response in just a couple seconds. Our slon daemons are running with mostly default startup options.
                Thanks in advance,

                Tom    ☺


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