Hello Michael, Thank you for pointing that out. Today I am planning to try this out along with the insights Shawn had shared.
Thanks! Mark. On Mon, Aug 19, 2019 at 9:21 AM Michael Gibney <mich...@michaelgibney.net> wrote: > Mark, > > Another thing to check is that I believe the configuration you posted may > not actually be taking effect. Unless I'm mistaken, I think the correct > element name to configure the shardHandler is "shardHandler*Factory*", not > "shardHandler" ... as in, '<shardHandlerFactory > class="HttpShardHandlerFactory">...' > > The element name is documented correctly in the refGuide page for "Format > of solr.xml": > > https://lucene.apache.org/solr/guide/8_1/format-of-solr-xml.html#the-shardhandlerfactory-element > > ... but the incorrect (?) element name is included in the refGuide page for > "Distributed Requests": > > https://lucene.apache.org/solr/guide/8_1/distributed-requests.html#configuring-the-shardhandlerfactory > > Michael > > On Fri, Aug 16, 2019 at 9:40 AM Shawn Heisey <apa...@elyograg.org> wrote: > > > On 8/16/2019 3:51 AM, Mark Robinson wrote: > > > I am trying to understand the socket time out and connection time out > in > > > the HttpShardHandlerFactory:- > > > > > > <shardHandler class="HttpShardHandlerFactory"> > > > <int name="socketTimeOut">10</int> > > > <int name="connTimeOut">20</int> > > > </shardHandler> > > > > The shard handler is used when that Solr instance needs to make > > connections to another Solr instance (which could be itself, as odd as > > that might sound). It does not apply to the requests that you make from > > outside Solr. > > > > > 1.Could some one please help me understand the effect of using such low > > > values of 10 ms > > > and 20ms as given above inside my /select handler? > > > > A connection timeout of 10 milliseconds *might* result in connections > > not establishing at all. This is translated down to the TCP socket as > > the TCP connection timeout -- the time limit imposed on making the TCP > > connection itself. Which as I understand it, is the completion of the > > "SYN", "SYN/ACK", and "ACK" sequence. If the two endpoints of the > > connection are on a LAN, you might never see a problem from this -- LAN > > connections are very low latency. But if they are across the Internet, > > they might never work. > > > > The socket timeout of 20 milliseconds means that if the connection goes > > idle for 20 milliseconds, it will be forcibly closed. So if it took 25 > > milliseconds for the remote Solr instance to respond, this Solr instance > > would have given up and closed the connection. It is extremely common > > for requests to take 100, 500, 2000, or more milliseconds to respond. > > > > > 2. What is the guidelines for setting these parameters? Should they be > > low > > > or high > > > > I would probably use a value of about 5000 (five seconds) for the > > connection timeout if everything's on a local LAN. I might go as high > > as 15 seconds if there's a high latency network between them, but five > > seconds is probably long enough too. > > > > For the socket timeout, you want a value that's considerably longer than > > you expect requests to ever take. Probably somewhere between two and > > five minutes. > > > > > 3. How can I test the effect of this chunk of code after adding it to > my > > > /select handler ie I want to > > > make sure the above code snippet is working. That is why I gave > > such > > > low values and > > > thought when I fire a query I would get both time out errors in > the > > > logs. But did not! > > > Or is it that within the above time frame (10 ms, 20ms) if no > > request > > > comes the socket will > > > time out and the connection will be lost. So to test this should > I > > > give a say 100 TPS load with > > > these low values and then increase the values to maybe 1000 ms > and > > > 1500 ms respectively > > > and see lesser time out error messages? > > > > If you were running a multi-server SolrCloud setup (or a single-server > > setup with multiple shards and/or replicas), you probably would see > > problems from values that low. But if Solr never has any need to make > > connections to satisfy a request, then the values will never take effect. > > > > If you want to control these values for requests made from outside Solr, > > you will need to do it in your client software that is making the > request. > > > > Thanks, > > Shawn > > >
