Oups I did not read the thread carrefully. *The problem is with the same query as phrase. q="network se*".* I was not aware that you could do that with Solr ;). I would say this is expected because in such case if the number of expansions for "se*" is big then you would have to check the positions for a significant words. I don't know if there is a limitation in the number of expansions for a prefix query contained into a phrase query but I would look at this parameter first (limit the number of expansion per prefix search, let's say the N most significant words based on the frequency of the words for instance).
2015-11-02 13:36 GMT+01:00 jim ferenczi <jim.feren...@gmail.com>: > > > > *I am not able to get the above point. So when I start Solr with 28g RAM, > for all the activities related to Solr it should not go beyond 28g. And the > remaining heap will be used for activities other than Solr. Please help me > understand.* > > Well those 28GB of heap are the memory "reserved" for your Solr > application, though some parts of the index (not to say all) are retrieved > via MMap (if you use the default MMapDirectory) which do not use the heap > at all. This is a very important part of Lucene/Solr, the heap should be > sized in a way that let a significant amount of RAM available for the > index. If not then you rely on the speed of your disk, if you have SSDs > it's better but reads are still significantly slower with SSDs than with > direct RAM access. Another thing to keep in mind is that mmap will always > tries to put things in RAM, this is why I suspect that you swap activity is > killing your performance. > > 2015-11-02 11:55 GMT+01:00 Modassar Ather <modather1...@gmail.com>: > >> Thanks Jim for your response. >> >> The remaining size after you removed the heap usage should be reserved for >> the index (not only the other system activities). >> I am not able to get the above point. So when I start Solr with 28g RAM, >> for all the activities related to Solr it should not go beyond 28g. And >> the >> remaining heap will be used for activities other than Solr. Please help me >> understand. >> >> *Also the CPU utilization goes upto 400% in few of the nodes:* >> You said that only machine is used so I assumed that 400% cpu is for a >> single process (one solr node), right ? >> Yes you are right that 400% is for single process. >> The disks are SSDs. >> >> Regards, >> Modassar >> >> On Mon, Nov 2, 2015 at 4:09 PM, jim ferenczi <jim.feren...@gmail.com> >> wrote: >> >> > *if it correlates with the bad performance you're seeing. One important >> > thing to notice is that a significant part of your index needs to be in >> RAM >> > (especially if you're using SSDs) in order to achieve good performance.* >> > >> > Especially if you're not using SSDs, sorry ;) >> > >> > 2015-11-02 11:38 GMT+01:00 jim ferenczi <jim.feren...@gmail.com>: >> > >> > > 12 shards with 28GB for the heap and 90GB for each index means that >> you >> > > need at least 336GB for the heap (assuming you're using all of it >> which >> > may >> > > be easily the case considering the way the GC is handling memory) and >> ~= >> > > 1TO for the index. Let's say that you don't need your entire index in >> > RAM, >> > > the problem as I see it is that you don't have enough RAM for your >> index >> > + >> > > heap. Assuming your machine has 370GB of RAM there are only 34GB left >> for >> > > your index, 1TO/34GB means that you can only have 1/30 of your entire >> > index >> > > in RAM. I would advise you to check the swap activity on the machine >> and >> > > see if it correlates with the bad performance you're seeing. One >> > important >> > > thing to notice is that a significant part of your index needs to be >> in >> > RAM >> > > (especially if you're using SSDs) in order to achieve good >> performance: >> > > >> > > >> > > >> > > *As mentioned above this is a big machine with 370+ gb of RAM and Solr >> > (12 >> > > nodes total) is assigned 336 GB. The rest is still a good for other >> > system >> > > activities.* >> > > The remaining size after you removed the heap usage should be reserved >> > for >> > > the index (not only the other system activities). >> > > >> > > >> > > *Also the CPU utilization goes upto 400% in few of the nodes:* >> > > You said that only machine is used so I assumed that 400% cpu is for a >> > > single process (one solr node), right ? >> > > This seems impossible if you are sure that only one query is played >> at a >> > > time and no indexing is performed. Best thing to do is to dump stack >> > trace >> > > of the solr nodes during the query and to check what the threads are >> > doing. >> > > >> > > Jim >> > > >> > > >> > > >> > > 2015-11-02 10:38 GMT+01:00 Modassar Ather <modather1...@gmail.com>: >> > > >> > >> Just to add one more point that one external Zookeeper instance is >> also >> > >> running on this particular machine. >> > >> >> > >> Regards, >> > >> Modassar >> > >> >> > >> On Mon, Nov 2, 2015 at 2:34 PM, Modassar Ather < >> modather1...@gmail.com> >> > >> wrote: >> > >> >> > >> > Hi Toke, >> > >> > Thanks for your response. My comments in-line. >> > >> > >> > >> > That is 12 machines, running a shard each? >> > >> > No! This is a single big machine with 12 shards on it. >> > >> > >> > >> > What is the total amount of physical memory on each machine? >> > >> > Around 370 gb on the single machine. >> > >> > >> > >> > Well, se* probably expands to a great deal of documents, but a huge >> > bump >> > >> > in memory utilization and 3 minutes+ sounds strange. >> > >> > >> > >> > - What are your normal query times? >> > >> > Few simple queries are returned with in a couple of seconds. But >> the >> > >> more >> > >> > complex queries with proximity and wild cards have taken more than >> 3-4 >> > >> > minutes and some times some queries have timed out too where time >> out >> > is >> > >> > set to 5 minutes. >> > >> > - How many hits do you get from 'network se*'? >> > >> > More than a million records. >> > >> > - How many results do you return (the rows-parameter)? >> > >> > It is the default one 10. Grouping is enabled on a field. >> > >> > - If you issue a query without wildcards, but with approximately >> the >> > >> > same amount of hits as 'network se*', how long does it take? >> > >> > A query resulting in around half a million record return within a >> > couple >> > >> > of seconds. >> > >> > >> > >> > That is strange, yes. Have you checked the logs to see if something >> > >> > unexpected is going on while you test? >> > >> > Have not seen anything particularly. Will try to check again. >> > >> > >> > >> > If you are using spinning drives and only have 32GB of RAM in >> total in >> > >> > each machine, you are probably struggling just to keep things >> running. >> > >> > As mentioned above this is a big machine with 370+ gb of RAM and >> Solr >> > >> (12 >> > >> > nodes total) is assigned 336 GB. The rest is still a good for other >> > >> system >> > >> > activities. >> > >> > >> > >> > Thanks, >> > >> > Modassar >> > >> > >> > >> > On Mon, Nov 2, 2015 at 1:30 PM, Toke Eskildsen < >> > t...@statsbiblioteket.dk> >> > >> > wrote: >> > >> > >> > >> >> On Mon, 2015-11-02 at 12:00 +0530, Modassar Ather wrote: >> > >> >> > I have a setup of 12 shard cluster started with 28gb memory each >> > on a >> > >> >> > single server. There are no replica. The size of index is around >> > >> 90gb on >> > >> >> > each shard. The Solr version is 5.2.1. >> > >> >> >> > >> >> That is 12 machines, running a shard each? >> > >> >> >> > >> >> What is the total amount of physical memory on each machine? >> > >> >> >> > >> >> > When I query "network se*", the memory utilization goes upto >> 24-26 >> > gb >> > >> >> and >> > >> >> > the query takes around 3+ minutes to execute. Also the CPU >> > >> utilization >> > >> >> goes >> > >> >> > upto 400% in few of the nodes. >> > >> >> >> > >> >> Well, se* probably expands to a great deal of documents, but a >> huge >> > >> bump >> > >> >> in memory utilization and 3 minutes+ sounds strange. >> > >> >> >> > >> >> - What are your normal query times? >> > >> >> - How many hits do you get from 'network se*'? >> > >> >> - How many results do you return (the rows-parameter)? >> > >> >> - If you issue a query without wildcards, but with approximately >> the >> > >> >> same amount of hits as 'network se*', how long does it take? >> > >> >> >> > >> >> > Why the CPU utilization is so high and more than one core is >> used. >> > >> >> > As far as I understand querying is single threaded. >> > >> >> >> > >> >> That is strange, yes. Have you checked the logs to see if >> something >> > >> >> unexpected is going on while you test? >> > >> >> >> > >> >> > How can I disable replication(as it is implicitly enabled) >> > >> permanently >> > >> >> as >> > >> >> > in our case we are not using it but can see warnings related to >> > >> leader >> > >> >> > election? >> > >> >> >> > >> >> If you are using spinning drives and only have 32GB of RAM in >> total >> > in >> > >> >> each machine, you are probably struggling just to keep things >> > running. >> > >> >> >> > >> >> >> > >> >> - Toke Eskildsen, State and University Library, Denmark >> > >> >> >> > >> >> >> > >> >> >> > >> > >> > >> >> > > >> > > >> > >> > >
