Re: Ping handler during initial wamup
I put in a fix a long time ago, so it wouldn't be too hard to redo. 1. Send 500 error until core 0 numFound. 2. Give it a list of cores. localhost:8983/solr/ping?check=core1,core2,core3 Then the Amazon load balancer can just check this url with HTTP check On Thu, Sep 18, 2014 at 3:57 AM, Ere Maijala ere.maij...@helsinki.fi wrote: So, is it possible to configure a ping handler to return quickly with non-OK status if a search handler is not yet available? This would allow the load balancer to quickly fail over to another server. I couldn't find anything like this in the docs, but I'm still hopeful. I'm aware of the possibility of using a health state file, but I'd rather have a way of doing this automatically. If it's not horribly messy to implement, returning a non-OK status immediately when there is no available searcher seems like a good idea. Please file an improvement issue in Jira. Thanks, I've filed https://issues.apache.org/jira/browse/SOLR-6532. --Ere -- Bill Bell billnb...@gmail.com cell 720-256-8076
Re: Ping handler during initial wamup
So, is it possible to configure a ping handler to return quickly with non-OK status if a search handler is not yet available? This would allow the load balancer to quickly fail over to another server. I couldn't find anything like this in the docs, but I'm still hopeful. I'm aware of the possibility of using a health state file, but I'd rather have a way of doing this automatically. If it's not horribly messy to implement, returning a non-OK status immediately when there is no available searcher seems like a good idea. Please file an improvement issue in Jira. Thanks, I've filed https://issues.apache.org/jira/browse/SOLR-6532. --Ere
Ping handler during initial wamup
As far as I can see, when a Solr instance is started (whether standalone or SolrCloud), a PingRequestHandler will wait until index warmup is complete before returning (at least with useColdSearcher=false) which may take a while. This poses a problem in that a load balancer either needs to wait for the result or employ a short timeout for timely failover. Of course the request is eventually served, but it would be better to be able to switch over to another server until warmup is complete. So, is it possible to configure a ping handler to return quickly with non-OK status if a search handler is not yet available? This would allow the load balancer to quickly fail over to another server. I couldn't find anything like this in the docs, but I'm still hopeful. I'm aware of the possibility of using a health state file, but I'd rather have a way of doing this automatically. --Ere
Re: Ping handler during initial wamup
On 9/17/2014 7:06 AM, Ere Maijala wrote: As far as I can see, when a Solr instance is started (whether standalone or SolrCloud), a PingRequestHandler will wait until index warmup is complete before returning (at least with useColdSearcher=false) which may take a while. This poses a problem in that a load balancer either needs to wait for the result or employ a short timeout for timely failover. Of course the request is eventually served, but it would be better to be able to switch over to another server until warmup is complete. So, is it possible to configure a ping handler to return quickly with non-OK status if a search handler is not yet available? This would allow the load balancer to quickly fail over to another server. I couldn't find anything like this in the docs, but I'm still hopeful. I'm aware of the possibility of using a health state file, but I'd rather have a way of doing this automatically. If it's not horribly messy to implement, returning a non-OK status immediately when there is no available searcher seems like a good idea. Please file an improvement issue in Jira. This can be handled on the load balancer end by configuring a quick timeout on load balancer health checks, and doing them very frequently. I've got haproxy in front of my solr servers. My checks happen every five seconds, with a 4990 millisecond timeout. My ping handler query (defined in solrconfig.xml) is q=*:*rows=1 ... so it's very simple and fast. Because of efficiencies in the *:* query and caching, I doubt this is putting much of a load on Solr. It would probably be acceptable to do the health checks once a second, although with typical Solr logging configs you'd end up with a LOT of log data. If you configure logging at the WARN level, this would not be a worry. Thanks, Shawn
Re: Ping handler during initial wamup
On 9/17/2014 8:07 PM, Shawn Heisey wrote: I've got haproxy in front of my solr servers. My checks happen every five seconds, with a 4990 millisecond timeout. My ping handler query (defined in solrconfig.xml) is q=*:*rows=1 ... so it's very simple and fast. Because of efficiencies in the *:* query and caching, I doubt this is putting much of a load on Solr. It would probably be acceptable to do the health checks once a second, although with typical Solr logging configs you'd end up with a LOT of log data. If you configure logging at the WARN level, this would not be a worry. At the URL below, you can see a trimmed version of my haproxy config. I've got more than I show here, but this is the part that handles my main Solr index: http://apaste.info/0vk The ncmain core is a core that has no index, with the shards parameter built into the config, so the application has no idea that it's talking to a sharded index that actually lives on two separate servers. Thanks, Shawn
