Hi Walter, I used to have larger settings on our caches but it seemed like I had to make the caches that small to reduce memory usage to keep from getting the dreaded OOM exceptions. Also our search is behind Akamai with a one hour TTL. Our slave farm has a load balancer in front of twelve slave servers and our index is being updated constantly, pretty much 24/7.
So my question would be how do you run with such big caches without going into the OOM zone? Was the Netflix index only updated based upon the release schedules of the studios, like once a week? Our entertainment stores used to be like that before we turned into a marketplace based e-tailer, but now we get new listings from merchants all the time and so have a constant churn of additions and deletions in our index. I feel like at 32GB our heap is really huge, but we seem to use almost all of it with these settings. I am trying out the G1GC on one slave to see if that gets memory usage lower but while it has a different collection pattern in the various spaces it seems like the total memory usage peaks out at about the same level. Thanks Robi -----Original Message----- From: Walter Underwood [mailto:wun...@wunderwood.org] Sent: Tuesday, June 18, 2013 6:57 PM To: solr-user@lucene.apache.org Subject: Re: yet another optimize question Your query cache is far too small. Most of the default caches are too small. We run with 10K entries and get a hit rate around 0.30 across four servers. This rate goes up with more queries, down with less, but try a bigger cache, especially if you are updating the index infrequently, like once per day. At Netflix, we had a 0.12 hit rate on the query cache, even with an HTTP cache in front of it. The HTTP cache had an 80% hit rate. I'd increase your document cache, too. I usually see about 0.75 or better on that. wunder On Jun 18, 2013, at 10:22 AM, Petersen, Robert wrote: > Hi Otis, > > Yes the query results cache is just about worthless. I guess we have too > diverse of a set of user queries. The business unit has decided to let bots > crawl our search pages too so that doesn't help either. I turned it way down > but decided to keep it because my understanding was that it would still help > for users going from page 1 to page 2 in a search. Is that true? > > Thanks > Robi > > -----Original Message----- > From: Otis Gospodnetic [mailto:otis.gospodne...@gmail.com] > Sent: Monday, June 17, 2013 6:39 PM > To: solr-user@lucene.apache.org > Subject: Re: yet another optimize question > > Hi Robi, > > This goes against the original problem of getting OOMEs, but it looks like > each of your Solr caches could be a little bigger if you want to eliminate > evictions, with the query results one possibly not being worth keeping if you > can't get the hit % up enough. > > Otis > -- > Solr & ElasticSearch Support -- http://sematext.com/ > > > On Mon, Jun 17, 2013 at 2:21 PM, Petersen, Robert > <robert.peter...@mail.rakuten.com> wrote: >> Hi Otis, >> >> Right I didn't restart the JVMs except on the one slave where I was >> experimenting with using G1GC on the 1.7.0_21 JRE. Also some time ago I >> made all our caches small enough to keep us from getting OOMs while still >> having a good hit rate. Our index has about 50 fields which are mostly >> int IDs and there are some dynamic fields also. These dynamic fields can be >> used for custom faceting. We have some standard facets we always facet on >> and other dynamic facets which are only used if the query is filtering on a >> particular category. There are hundreds of these fields but since they are >> only for a small subset of the overall index they are very sparsely >> populated with regard to the overall index. With CMS GC we get a sawtooth >> on the old generation (I guess every replication and commit causes it's >> usage to drop down to 10GB or so) and it seems to be the old generation >> which is the main space consumer. With the G1GC, the memory map looked >> totally different! I was a little lost looking at memory consumption with >> that GC. Maybe I'll try it again now that the index is a bit smaller than >> it was last time I tried it. After four days without running an optimize >> now it is 21GB. BTW our indexing speed is mostly bound by the DB so >> reducing the segments might be ok... >> >> Here is a quick snapshot of one slaves memory map as reported by PSI-Probe, >> but unfortunately I guess I can't send the history graphics to the solr-user >> list to show their changes over time: >> Name Used Committed Max >> Initial Group >> Par Survivor Space 20.02 MB 108.13 MB 108.13 MB >> 108.13 MB HEAP >> CMS Perm Gen 42.29 MB 70.66 MB 82.00 MB 20.75 >> MB NON_HEAP >> Code Cache 9.73 MB 9.88 MB 48.00 MB 2.44 MB >> NON_HEAP >> CMS Old Gen 20.22 GB 30.94 GB 30.94 GB >> 30.94 GB HEAP >> Par Eden Space 42.20 MB 865.31 MB 865.31 MB >> 865.31 MB HEAP >> Total 20.33 GB 31.97 GB 32.02 GB >> 31.92 GB TOTAL >> >> And here's our current cache stats from a random slave: >> >> name: queryResultCache >> class: org.apache.solr.search.LRUCache >> version: 1.0 >> description: LRU Cache(maxSize=488, initialSize=6, autowarmCount=6, >> regenerator=org.apache.solr.search.SolrIndexSearcher$3@461ff4c3) >> stats: lookups : 619 >> hits : 36 >> hitratio : 0.05 >> inserts : 592 >> evictions : 101 >> size : 488 >> warmupTime : 2949 >> cumulative_lookups : 681225 >> cumulative_hits : 73126 >> cumulative_hitratio : 0.10 >> cumulative_inserts : 602396 >> cumulative_evictions : 428868 >> >> >> name: fieldCache >> class: org.apache.solr.search.SolrFieldCacheMBean >> version: 1.0 >> description: Provides introspection of the Lucene FieldCache, this is >> **NOT** a cache that is managed by Solr. >> stats: entries_count : 359 >> >> >> name: documentCache >> class: org.apache.solr.search.LRUCache >> version: 1.0 >> description: LRU Cache(maxSize=2048, initialSize=512, autowarmCount=10, >> regenerator=null) >> stats: lookups : 12710 >> hits : 7160 >> hitratio : 0.56 >> inserts : 5636 >> evictions : 3588 >> size : 2048 >> warmupTime : 0 >> cumulative_lookups : 10590054 >> cumulative_hits : 6166913 >> cumulative_hitratio : 0.58 >> cumulative_inserts : 4423141 >> cumulative_evictions : 3714653 >> >> >> name: fieldValueCache >> class: org.apache.solr.search.FastLRUCache >> version: 1.0 >> description: Concurrent LRU Cache(maxSize=280, initialSize=280, >> minSize=252, acceptableSize=266, cleanupThread=false, autowarmCount=6, >> regenerator=org.apache.solr.search.SolrIndexSearcher$1@143eb77a) >> stats: lookups : 1725 >> hits : 1481 >> hitratio : 0.85 >> inserts : 122 >> evictions : 0 >> size : 128 >> warmupTime : 4426 >> cumulative_lookups : 3449712 >> cumulative_hits : 3281805 >> cumulative_hitratio : 0.95 >> cumulative_inserts : 83261 >> cumulative_evictions : 3479 >> >> >> name: filterCache >> class: org.apache.solr.search.FastLRUCache >> version: 1.0 >> description: Concurrent LRU Cache(maxSize=248, initialSize=12, >> minSize=223, acceptableSize=235, cleanupThread=false, autowarmCount=10, >> regenerator=org.apache.solr.search.SolrIndexSearcher$2@36e831d6) >> stats: lookups : 3990 >> hits : 3831 >> hitratio : 0.96 >> inserts : 239 >> evictions : 26 >> size : 244 >> warmupTime : 1 >> cumulative_lookups : 5745011 >> cumulative_hits : 5496150 >> cumulative_hitratio : 0.95 >> cumulative_inserts : 351485 >> cumulative_evictions : 276308 >> >> -----Original Message----- >> From: Otis Gospodnetic [mailto:otis.gospodne...@gmail.com] >> Sent: Saturday, June 15, 2013 5:52 AM >> To: solr-user@lucene.apache.org >> Subject: Re: yet another optimize question >> >> Hi Robi, >> >> I'm going to guess you are seeing smaller heap also simply because you >> restarted the JVM recently (hm, you don't say you restarted, maybe I'm >> making this up). If you are indeed indexing continuously then you shouldn't >> optimize. Lucene will merge segments itself. Lower mergeFactor will force it >> to do it more often (it means slower indexing, bigger IO hit when segments >> are merged, more per-segment data that Lucene/Solr need to read from the >> segment for faceting and such, etc.) so maybe you shouldn't mess with that. >> Do you know what your caches are like in terms of size, hit %, evictions? >> We've recently seen people set those to a few hundred K or even higher, >> which can eat a lot of heap. We have had luck with G1 recently, too. >> Maybe you can run jstat and see which of the memory pools get filled up and >> change/increase appropriate JVM param based on that? How many fields do you >> index, facet, or group on? >> >> Otis >> -- >> Performance Monitoring - http://sematext.com/spm/index.html >> Solr & ElasticSearch Support -- http://sematext.com/ >> >> >> >> >> >> On Fri, Jun 14, 2013 at 8:04 PM, Petersen, Robert >> <robert.peter...@mail.rakuten.com> wrote: >>> Hi guys, >>> >>> We're on solr 3.6.1 and I've read the discussions about whether to optimize >>> or not to optimize. I decided to try not optimizing our index as was >>> recommended. We have a little over 15 million docs in our biggest index >>> and a 32gb heap for our jvm. So without the optimizes the index folder >>> seemed to grow in size and quantity of files. There seemed to be an upper >>> limit but eventually it hit 300 files consuming 26gb of space and that >>> seemed to push our slave farm over the edge and we started getting the >>> dreaded OOMs. We have continuous indexing activity, so I stopped the >>> indexer and manually ran an optimize which made the index become 9 files >>> consuming 15gb of space and our slave farm started having acceptable memory >>> usage. Our merge factor is 10, we're on java 7. Before optimizing, I >>> tried on one slave machine to go with the latest JVM and tried switching >>> from the CMS GC to the G1GC but it hit OOM condition even faster. So it >>> seems like I have to continue to schedule a regular optimize. Right now it >>> has been a couple of days since running the optimize and the index is >>> slowly growing bigger, now up to a bit over 19gb. What do you guys think? >>> Did I miss something that would make us able to run without doing an >>> optimize? >>> >>> Robert (Robi) Petersen >>> Senior Software Engineer >>> Search Department >> >> > > -- Walter Underwood wun...@wunderwood.org
