# ElasticSearch + Cassandra **URL:** \ **Category:** Elasticsearch\ **Created:** [April 4, 2011, 5:12pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188 "2011-04-04T17:12:28Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Drew\_Kutcharian](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/drew_kutcharian/32/742_2.png) [@Drew\_Kutcharian](https://discuss.elastic.co/u/Drew_Kutcharian)\ **Post date:** [April 4, 2011, 5:12pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/1 "2011-04-04T17:12:28Z")
Hi Everyone, Has anyone done/attempted to integrate ElasticSearch with Cassandra like was described at [http://www.elasticsearch.org/blog/2010/02/25/nosql\_yessearch.html](http://www.elasticsearch.org/blog/2010/02/25/nosql_yessearch.html) ? I don't mean using Cassandra as a Gateway for ES, but using ES to query the data in Cassandra automatically. Thanks, Drew ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [April 5, 2011, 10:44am UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/2 "2011-04-05T10:44:36Z")
Not that I am aware... . On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > Hi Everyone, > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > like was described at [Elasticsearch Platform — Find real-time answers at scale | Elastic](http://www.elasticsearch.org/blog/2010/02/25/nosql_yessearch.html) > ? > > I don't mean using Cassandra as a Gateway for ES, but using ES to > query the data in Cassandra automatically. > > Thanks, > > Drew ---
**Author:** ![Paul\_Smith](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/paul_smith/32/1323_2.png) [@Paul\_Smith](https://discuss.elastic.co/u/Paul_Smith)\ **Post date:** [April 6, 2011, 3:41am UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/3 "2011-04-06T03:41:33Z")
It's not based on Elasticsearch, but tjake has the Solandra integration: > **[GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra)** > > Solandra = Solr + Cassandra. Contribute to tjake/Solandra development by creating an account on GitHub. On 5 April 2011 20:44, Shay Banon [shay.banon@elasticsearch.com](mailto:shay.banon@elasticsearch.com) wrote: > Not that I am aware... . > > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > Hi Everyone, > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > like was described at > [Elasticsearch Platform — Find real-time answers at scale | Elastic](http://www.elasticsearch.org/blog/2010/02/25/nosql_yessearch.html) > ? > > I don't mean using Cassandra as a Gateway for ES, but using ES to > query the data in Cassandra automatically. > > Thanks, > > Drew ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [April 6, 2011, 9:08am UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/4 "2011-04-06T09:08:26Z")
Its not what was asked for. The question was for something to automatically index changes done to cassandra. Solandra tries to build solr on top of cassandra to make it better distributed, but it combines then two problems instead of one: using solr (distributed execution) and trying to hack Lucene to work on top of cassandra which is problematic and probably bad in most cases. On Wednesday, April 6, 2011 at 6:41 AM, Paul Smith wrote: > It's not based on Elasticsearch, but tjake has the Solandra integration: > > [GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra) > > On 5 April 2011 20:44, Shay Banon [shay.banon@elasticsearch.com](mailto:shay.banon@elasticsearch.com) wrote: > > > Not that I am aware... . > > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > > > > Hi Everyone, > > > > > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > > > like was described at [Elasticsearch Platform — Find real-time answers at scale | Elastic](http://www.elasticsearch.org/blog/2010/02/25/nosql_yessearch.html) > > > ? > > > > > > I don't mean using Cassandra as a Gateway for ES, but using ES to > > > query the data in Cassandra automatically. > > > > > > Thanks, > > > > > > Drew ---
**Author:** ![Karussell1](https://avatars.discourse-cdn.com/v4/letter/k/50afbb/32.png) [@Karussell1](https://discuss.elastic.co/u/Karussell1)\ **Post date:** [April 6, 2011, 12:14pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/5 "2011-04-06T12:14:13Z")
Just as a side note. Maybe it is a bit unfair to compare Solandra with Elasticsearch. Solandra looks pretty cool and interesting. 3 months ago I did a minor evaluation for my project and Solandra was in a useful state. BUT as it turns out performance and memory usage of ES (or pure solr) was far better on a single machine than Solandra. Also Solandra had some bugs (jvm crashed, facets didn't work) which then were fixed I think. Also ES is a lot cleaner. In terms of technologies involved and in terms of written unit tests. If you look into the test folder of solandra it is pretty much empty. Then Solandra is 1 year old, where Elasticsearch is built from an author with concepts of the well known, several years old project 'Compass' in mind 🙂 Regards, Peter. On 6 Apr., 11:08, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > Its not what was asked for. The question was for something to automatically index changes done to cassandra. Solandra tries to build solr on top of cassandra to make it better distributed, but it combines then two problems instead of one: using solr (distributed execution) and trying to hack Lucene to work on top of cassandra which is problematic and probably bad in most cases. > > On Wednesday, April 6, 2011 at 6:41 AM, Paul Smith wrote: > > > It's not based on Elasticsearch, but tjake has the Solandra integration: > > > [GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra) > > > On 5 April 2011 20:44, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > Not that I am aware... . > > > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > > > > > > Hi Everyone, > > > > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > > > > like was described athttp://www.elasticsearch.org/blog/2010/02/25/nosql\_yessearch.html > > > > ? > > > > > I don't mean using Cassandra as a Gateway for ES, but using ES to > > > > query the data in Cassandra automatically. > > > > > Thanks, > > > > > Drew ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [April 6, 2011, 12:21pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/6 "2011-04-06T12:21:38Z")
Yes, agreed, Solandra and Lucandra are pretty cool in terms of concepts, but I think they lack when it comes to how they use Lucene (putting the solr aspect aside). The problem (and its based on my last check in how the Lucene on top of Cassandra implementation was done) is how the reader/searcher works on top of Cassandra. First, it bypass a lot of optimizations lucene has in terms of how it stores/fetches data in its reader/searcher implementation, and uses Cassandra to load that info. The more problematic nature is how lucene uses things like FieldCache and caches based on readers, which is problematic when using the reader/searcher based on Lucandra (sorting and facets for example). This can cause very severe performance/memory problems. Again, this is based on my overview of the code. If I am missing something, I would love to be corrected. Not here to spread FUD or anything. -shay.banon On Wednesday, April 6, 2011 at 3:14 PM, Karussell wrote: > Just as a side note. > > Maybe it is a bit unfair to compare Solandra with Elasticsearch. > Solandra looks pretty cool and interesting. > > 3 months ago I did a minor evaluation for my project and Solandra was > in a useful state. > BUT as it turns out performance and memory usage of ES (or pure solr) > was far better on a single machine than Solandra. > Also Solandra had some bugs (jvm crashed, facets didn't work) which > then were fixed I think. > > Also ES is a lot cleaner. In terms of technologies involved and in > terms of written unit tests. If you look into the test folder of > solandra it is pretty much empty. > > Then Solandra is 1 year old, where Elasticsearch is built from an > author with concepts of the well known, several years old project > 'Compass' in mind 🙂 > > Regards, > Peter. > > On 6 Apr., 11:08, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > Its not what was asked for. The question was for something to automatically index changes done to cassandra. Solandra tries to build solr on top of cassandra to make it better distributed, but it combines then two problems instead of one: using solr (distributed execution) and trying to hack Lucene to work on top of cassandra which is problematic and probably bad in most cases. > > > > On Wednesday, April 6, 2011 at 6:41 AM, Paul Smith wrote: > > > > > It's not based on Elasticsearch, but tjake has the Solandra integration: > > > > > [GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra) > > > > > On 5 April 2011 20:44, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > > > Not that I am aware... . > > > > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > > > > > > > > Hi Everyone, > > > > > > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > > > > > like was described athttp://www.elasticsearch.org/blog/2010/02/25/nosql\_yessearch.html > > > > > ? > > > > > > > I don't mean using Cassandra as a Gateway for ES, but using ES to > > > > > query the data in Cassandra automatically. > > > > > > > Thanks, > > > > > > > Drew ---
**Author:** ![Karussell1](https://avatars.discourse-cdn.com/v4/letter/k/50afbb/32.png) [@Karussell1](https://discuss.elastic.co/u/Karussell1)\ **Post date:** [April 6, 2011, 8:40pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/7 "2011-04-06T20:40:59Z")
On 6 Apr., 14:21, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > Yes, agreed, Solandra and Lucandra are pretty cool in terms of concepts, but I think they lack when it comes to how they use Lucene (putting the solr aspect aside). > > The problem (and its based on my last check in how the Lucene on top of Cassandra implementation was done) @tjake rewrote the integration from scratch for the solandra version, so not sure if this still applies. > Not here to spread FUD or anything. yes, of course. Maybe we should invite him to get a real conversation 🙂 ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [April 6, 2011, 8:48pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/8 "2011-04-06T20:48:17Z")
On Wednesday, April 6, 2011 at 11:40 PM, Karussell wrote: > On 6 Apr., 14:21, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > Yes, agreed, Solandra and Lucandra are pretty cool in terms of concepts, but I think they lack when it comes to how they use Lucene (putting the solr aspect aside). > > > > The problem (and its based on my last check in how the Lucene on top of Cassandra implementation was done) > > @tjake rewrote the integration from scratch for the solandra version, > so not sure if this still applies. As far as I can see it still suffers from the reader problem mentioned: [https://github.com/tjake/Solandra/blob/solandra/src/lucandra/IndexReader.java](https://github.com/tjake/Solandra/blob/solandra/src/lucandra/IndexReader.java). The main problem is that it looses the whole immutable (up to deletes) segment reader based concept in lucene (on top of other low level optimizations in how lucene readers work). Not here to spread FUD or anything. > yes, of course. Maybe we should invite him to get a real > conversation 🙂 ---
**Author:** ![tjake](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tjake/32/3244_2.png) [@tjake](https://discuss.elastic.co/u/tjake)\ **Post date:** [April 6, 2011, 9:02pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/9 "2011-04-06T21:02:13Z")
On Apr 6, 7:21 am, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > Yes, agreed, Solandra and Lucandra are pretty cool in terms of concepts, but I think they lack when it comes to how they use Lucene (putting the solr aspect aside). > > The problem (and its based on my last check in how the Lucene on top of Cassandra implementation was done) is how the reader/searcher works on top of Cassandra. First, it bypass a lot of optimizations lucene has in terms of how it stores/fetches data in its reader/searcher implementation, and uses Cassandra to load that info. You mean in terms of file format correct? It's true Lucene format is much better here but Cassandra will get to this. In the meantime the benefit of the data being truly masterless and scalable (compared to a tech like solr). > The more problematic nature is how lucene uses things like FieldCache and caches based on readers, which is problematic when using the reader/searcher based on Lucandra (sorting and facets for example). This can cause very severe performance/memory problems. Solandra breaks the index into manageable shards so this is less of a problem than it was in Lucandra. The solution for this long term comes when Cassandra trigger support comes in, then it will be able to update the FieldCache's without invalidating them (since Solandra allocates a fixed space of documents that can be filled in over time). I haven't taken a deep look at how ES handles this problem but I'd love a breif description if you have a sec Shay. > Again, this is based on my overview of the code. If I am missing something, I would love to be corrected. Not here to spread FUD or anything. I don't see any FUD here. Simply that Solandra is taking a more fundamental approach to handling distributed search by dealing with it at the file format level... Elasticsearch has build distributed search ontop of Lucene and added a number of great features and service layer. Solandras strongest use case is for those who need potentially millions of smaller indexes since it's not creating a directory per index under the hood but rather using composite keys in Cassandra. -Jake > -shay.banon > > On Wednesday, April 6, 2011 at 3:14 PM, Karussell wrote: > > > Just as a side note. > > > Maybe it is a bit unfair to compare Solandra with Elasticsearch. > > Solandra looks pretty cool and interesting. > > > 3 months ago I did a minor evaluation for my project and Solandra was > > in a useful state. > > BUT as it turns out performance and memory usage of ES (or pure solr) > > was far better on a single machine than Solandra. > > Also Solandra had some bugs (jvm crashed, facets didn't work) which > > then were fixed I think. > > > Also ES is a lot cleaner. In terms of technologies involved and in > > terms of written unit tests. If you look into the test folder of > > solandra it is pretty much empty. > > > Then Solandra is 1 year old, where Elasticsearch is built from an > > author with concepts of the well known, several years old project > > 'Compass' in mind 🙂 > > > Regards, > > Peter. > > > On 6 Apr., 11:08, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > Its not what was asked for. The question was for something to automatically index changes done to cassandra. Solandra tries to build solr on top of cassandra to make it better distributed, but it combines then two problems instead of one: using solr (distributed execution) and trying to hack Lucene to work on top of cassandra which is problematic and probably bad in most cases. > > > > On Wednesday, April 6, 2011 at 6:41 AM, Paul Smith wrote: > > > > > > > It's not based on Elasticsearch, but tjake has the Solandra integration: > > > > > [GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra) > > > > > On 5 April 2011 20:44, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > > > > > Not that I am aware... . > > > > > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > > > > > > > > > > Hi Everyone, > > > > > > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > > > > > > like was described athttp://www.elasticsearch.org/blog/2010/02/25/nosql\_yessearch.html > > > > > > ? > > > > > > > I don't mean using Cassandra as a Gateway for ES, but using ES to > > > > > > query the data in Cassandra automatically. > > > > > > > Thanks, > > > > > > > Drew ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [April 6, 2011, 9:43pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/10 "2011-04-06T21:43:00Z")
Heya, great you jumped in :), answers below: On Thursday, April 7, 2011 at 12:02 AM, tjake wrote: > On Apr 6, 7:21 am, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > Yes, agreed, Solandra and Lucandra are pretty cool in terms of concepts, but I think they lack when it comes to how they use Lucene (putting the solr aspect aside). > > > > The problem (and its based on my last check in how the Lucene on top of Cassandra implementation was done) is how the reader/searcher works on top of Cassandra. First, it bypass a lot of optimizations lucene has in terms of how it stores/fetches data in its reader/searcher implementation, and uses Cassandra to load that info. > > You mean in terms of file format correct? It's true Lucene format is > much better here but Cassandra will get to this. > Yes, the intimacy with how Lucene works with the data structures it generates and then searches on is a great boon for performance. Cassandra is blazing fast, but its hard to believe it can catch up to a system that creates the data structures it knows it is going to consume. > In the meantime the > benefit of the data being truly masterless and scalable (compared to a > tech like solr). > Agreed, thats a real benefit. The main problem here though is that Solandra still needs to work with solr distributed search support 🙂 > > > The more problematic nature is how lucene uses things like FieldCache and caches based on readers, which is problematic when using the reader/searcher based on Lucandra (sorting and facets for example). This can cause very severe performance/memory problems. > > Solandra breaks the index into manageable shards so this is less of a > problem than it was in Lucandra. > Right, but how big can a single shard be? The more you have, the more problems you run into with how Solr executes distributed search (blocking IO, http, and all the other bits). And with big shards, having to reload all the caches once you want to see changes is very costly. > The solution for this long term > comes when Cassandra trigger support comes in, then it will be able to > update the FieldCache's without invalidating them (since Solandra > allocates a fixed space of documents that can be filled in over > time). > FieldCache is one (very good) example. Other includes filter caching, or any reader cache base constructs. Those are used heavily in advance search systems and become harder to solve with trigger based approach. > I haven't taken a deep look at how ES handles this problem but > I'd love a breif description if you have a sec Shay. > Sure, no secret sauce here, it basically uses the same logic as Lucene FIeldCache, using the segment cache key to cache the data (like field level cache). Those are immutable (not evicted because of deletes, mind you). > > > Again, this is based on my overview of the code. If I am missing something, I would love to be corrected. Not here to spread FUD or anything. > > I don't see any FUD here. Simply that Solandra is taking a more > fundamental approach to handling distributed search by dealing with it > at the file format level... Elasticsearch has build distributed search > ontop of Lucene and added a number of great features and service > layer. > Its certainly a cool way to try and solve it. I have been there, trying to do the same starting from custom Directory implementations to custom readers mainly optimized to use Data Grids (with collocation), elasticsearch, at least for me, is the next step that I took from there, mainly letting Lucene do what it does best, and try and wrap it in the best way possible :). Term based Vs. Document based partitioning has been a great question to ask when trying to build distributed search engines. I think that is has basically been proven, at least from the practical sense, that document based partitioning is the way to go (watch this on google doing it: [Challenges in Building Large-Scale Information Retrieval Systems - VideoLectures.NET](http://videolectures.net/wsdm09_dean_cblirs/), at 9:44 mark). This is, by the way, why riak search, though another really cool technology, is very very problematic. They do term based partitioning, and its a slippery road from there (think of implementing something like facets in a collocated manner with term based partitioning, something called by doc data). Though Solandra does not strictly use term based partitioning, it still replicate based on terms (I think?). > Solandras strongest use case is for those who need potentially > millions of smaller indexes since it's not creating a directory per > index under the hood but rather using composite keys in Cassandra. > Agreed, thats a boon. In elasticsearch there is no reason why you could not create million of indices, but the overhead of each shard Lucene wise is substantial (starting with file handles...). At least for those cases, elasticsearch wise, the idea that you can control routing when indexing and searching allows you to create index with N number of shards, and index all those docs with the a qualifier (that also controls routing) and be able to filter only the ones you want out. > -Jake > > > -shay.banon > > > > On Wednesday, April 6, 2011 at 3:14 PM, Karussell wrote: > > > > > Just as a side note. > > > > > Maybe it is a bit unfair to compare Solandra with Elasticsearch. > > > Solandra looks pretty cool and interesting. > > > > > 3 months ago I did a minor evaluation for my project and Solandra was > > > in a useful state. > > > BUT as it turns out performance and memory usage of ES (or pure solr) > > > was far better on a single machine than Solandra. > > > Also Solandra had some bugs (jvm crashed, facets didn't work) which > > > then were fixed I think. > > > > > Also ES is a lot cleaner. In terms of technologies involved and in > > > terms of written unit tests. If you look into the test folder of > > > solandra it is pretty much empty. > > > > > Then Solandra is 1 year old, where Elasticsearch is built from an > > > author with concepts of the well known, several years old project > > > 'Compass' in mind 🙂 > > > > > Regards, > > > Peter. > > > > > On 6 Apr., 11:08, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > > > Its not what was asked for. The question was for something to automatically index changes done to cassandra. Solandra tries to build solr on top of cassandra to make it better distributed, but it combines then two problems instead of one: using solr (distributed execution) and trying to hack Lucene to work on top of cassandra which is problematic and probably bad in most cases. > > > > > > On Wednesday, April 6, 2011 at 6:41 AM, Paul Smith wrote: > > > > > > > > > It's not based on Elasticsearch, but tjake has the Solandra integration: > > > > > > > [GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra) > > > > > > > On 5 April 2011 20:44, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > > > > > > > Not that I am aware... . > > > > > > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > > > > > > > > > > > > Hi Everyone, > > > > > > > > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > > > > > > > like was described athttp://www.elasticsearch.org/blog/2010/02/25/nosql\_yessearch.html > > > > > > > ? > > > > > > > > > I don't mean using Cassandra as a Gateway for ES, but using ES to > > > > > > > query the data in Cassandra automatically. > > > > > > > > > Thanks, > > > > > > > > > Drew ---
**Author:** ![tjake](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tjake/32/3244_2.png) [@tjake](https://discuss.elastic.co/u/tjake)\ **Post date:** [April 6, 2011, 10:17pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/11 "2011-04-06T22:17:25Z")
Thanks, updated below... On Wed, Apr 6, 2011 at 9:43 PM, Shay Banon [shay.banon@elasticsearch.com](mailto:shay.banon@elasticsearch.com)wrote: > Heya, great you jumped in :), answers below: > > On Thursday, April 7, 2011 at 12:02 AM, tjake wrote: > > On Apr 6, 7:21 am, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > Yes, agreed, Solandra and Lucandra are pretty cool in terms of concepts, > but I think they lack when it comes to how they use Lucene (putting the solr > aspect aside). > > The problem (and its based on my last check in how the Lucene on top of > Cassandra implementation was done) is how the reader/searcher works on top > of Cassandra. First, it bypass a lot of optimizations lucene has in terms of > how it stores/fetches data in its reader/searcher implementation, and uses > Cassandra to load that info. > > You mean in terms of file format correct? It's true Lucene format is > much better here but Cassandra will get to this. > > Yes, the intimacy with how Lucene works with the data structures it > generates and then searches on is a great boon for performance. Cassandra is > blazing fast, but its hard to believe it can catch up to a system that > creates the data structures it knows it is going to consume. I guess the limitation is if you can't represent the data in a column family style. I don't see anything in the lucene file format that isn't equally representable. With Solandra on a single node is basically the same search performance for solr with facets and sorting. > In the meantime the > benefit of the data being truly masterless and scalable (compared to a > tech like solr). > > Agreed, thats a real benefit. The main problem here though is that Solandra > still needs to work with solr distributed search support 🙂 It's not _that_ bad the binary format is ok, the only problem is when you want to jump to result 100k it resends all that results. (not sure if 3.1 has addressed this...) Also there is no reason why Solandra has to only use Solr only. I could picture a ES service layer on Cassandra as well 🙂 It seems much of what you've built is similar to cassandra in many ways with write consistency and live scaling, replication. But my goal right now is to provide true distributed to all the solr users out there... The more problematic nature is how lucene uses things like FieldCache and > caches based on readers, which is problematic when using the reader/searcher > based on Lucandra (sorting and facets for example). This can cause very > severe performance/memory problems. > > Solandra breaks the index into manageable shards so this is less of a > problem than it was in Lucandra. > > Right, but how big can a single shard be? The more you have, the more > problems you run into with how Solr executes distributed search (blocking > IO, http, and all the other bits). And with big shards, having to reload all > the caches once you want to see changes is very costly. > The solution for this long term > comes when Cassandra trigger support comes in, then it will be able to > update the FieldCache's without invalidating them (since Solandra > allocates a fixed space of documents that can be filled in over > time). > > FieldCache is one (very good) example. Other includes filter caching, or > any reader cache base constructs. Those are used heavily in advance search > systems and become harder to solve with trigger based approach. Right, but this is the plan of attack to handle not needing to invalidate the caches as often. > I haven't taken a deep look at how ES handles this problem but > I'd love a breif description if you have a sec Shay. > > Sure, no secret sauce here, it basically uses the same logic as Lucene > FIeldCache, using the segment cache key to cache the data (like field level > cache). Those are immutable (not evicted because of deletes, mind you). > > Again, this is based on my overview of the code. If I am missing something, > I would love to be corrected. Not here to spread FUD or anything. > > I don't see any FUD here. Simply that Solandra is taking a more > fundamental approach to handling distributed search by dealing with it > at the file format level... Elasticsearch has build distributed search > ontop of Lucene and added a number of great features and service > layer. > > Its certainly a cool way to try and solve it. I have been there, trying to > do the same starting from custom Directory implementations to custom readers > mainly optimized to use Data Grids (with collocation), elasticsearch, at > least for me, is the next step that I took from there, mainly letting Lucene > do what it does best, and try and wrap it in the best way possible :). > > Term based Vs. Document based partitioning has been a great question to ask > when trying to build distributed search engines. I think that is has > basically been proven, at least from the practical sense, that document > based partitioning is the way to go (watch this on google doing it: > [Challenges in Building Large-Scale Information Retrieval Systems - VideoLectures.NET](http://videolectures.net/wsdm09_dean_cblirs/), at 9:44 mark). > > This is, by the way, why riak search, though another really cool > technology, is very very problematic. They do term based partitioning, and > its a slippery road from there (think of implementing something like facets > in a collocated manner with term based partitioning, something called by doc > data). > > Though Solandra does not strictly use term based partitioning, it still > replicate based on terms (I think?). Lucandra partitioned on terms and this was flawed. Solandra uses Document partitions so a chunk of documents are available locally to search from this minimized the cross node IO. A later feature will be partitioned indexes based on a field like time windows... > Solandras strongest use case is for those who need potentially > millions of smaller indexes since it's not creating a directory per > index under the hood but rather using composite keys in Cassandra. > > Agreed, thats a boon. In elasticsearch there is no reason why you could not > create million of indices, but the overhead of each shard Lucene wise is > substantial (starting with file handles...). > > At least for those cases, elasticsearch wise, the idea that you can control > routing when indexing and searching allows you to create index with N number > of shards, and index all those docs with the a qualifier (that also controls > routing) and be able to filter only the ones you want out. > > -Jake > > -shay.banon > > On Wednesday, April 6, 2011 at 3:14 PM, Karussell wrote: > > Just as a side note. > > Maybe it is a bit unfair to compare Solandra with Elasticsearch. > Solandra looks pretty cool and interesting. > > 3 months ago I did a minor evaluation for my project and Solandra was > in a useful state. > BUT as it turns out performance and memory usage of ES (or pure solr) > was far better on a single machine than Solandra. > Also Solandra had some bugs (jvm crashed, facets didn't work) which > then were fixed I think. > > Also ES is a lot cleaner. In terms of technologies involved and in > terms of written unit tests. If you look into the test folder of > solandra it is pretty much empty. > > Then Solandra is 1 year old, where Elasticsearch is built from an > author with concepts of the well known, several years old project > 'Compass' in mind 🙂 > > Regards, > Peter. > > On 6 Apr., 11:08, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > Its not what was asked for. The question was for something to automatically > index changes done to cassandra. Solandra tries to build solr on top of > cassandra to make it better distributed, but it combines then two problems > instead of one: using solr (distributed execution) and trying to hack Lucene > to work on top of cassandra which is problematic and probably bad in most > cases. > > On Wednesday, April 6, 2011 at 6:41 AM, Paul Smith wrote: > > It's not based on Elasticsearch, but tjake has the Solandra integration: > > [GitHub - tjake/Solandra: Solandra = Solr + Cassandra](https://github.com/tjake/Solandra) > > On 5 April 2011 20:44, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > Not that I am aware... . > On Monday, April 4, 2011 at 8:12 PM, Drew wrote: > > Hi Everyone, > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > like was described athttp:// > [Elasticsearch Platform — Find real-time answers at scale | Elastic](http://www.elasticsearch.org/blog/2010/02/25/nosql_yessearch.html) > ? > > I don't mean using Cassandra as a Gateway for ES, but using ES to > query the data in Cassandra automatically. > > Thanks, > > Drew -- [http://twitter.com/tjake](http://twitter.com/tjake) ---
**Author:** ![massi](https://avatars.discourse-cdn.com/v4/letter/m/b9e5f3/32.png) [@massi](https://discuss.elastic.co/u/massi)\ **Post date:** [April 6, 2011, 11:42pm UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/12 "2011-04-06T23:42:07Z")
Drew, I'm also looking for something similar. Using cassandra as the DB and Elasticsearch as the index to search through this DB. I'm planning to explore the use of an "ORM"-like for cassandra coupled with Elasticsearch. Because I'm programming in Ruby, I'll probably use Escargot for ES ([GitHub - angelf/escargot: ElasticSearch connector for Rails - Abandoned!](https://github.com/angelf/escargot)) and extend/wrap fauna (https:// [github.com/fauna/cassandra](http://github.com/fauna/cassandra)) for Cassandra. M. On Apr 4, 1:12 pm, Drew [d...@venarc.com](mailto:d...@venarc.com) wrote: > Hi Everyone, > > Has anyone done/attempted to integrate Elasticsearch with Cassandra > like was described athttp://www.elasticsearch.org/blog/2010/02/25/nosql\_yessearch.html > ? > > I don't mean using Cassandra as a Gateway for ES, but using ES to > query the data in Cassandra automatically. > > Thanks, > > Drew ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 4:08am UTC](https://discuss.elastic.co/t/elasticsearch-cassandra/4188/13 "2017-07-06T04:08:44Z")