You *can use solr as a database, in the same sense that you *can use a chainsaw to remodel your bathroom. Is it the right tool for the job? No. Can you make it work? Yes. As for HA and cluster rdbms gallera cluster works great for Maria db, and is acid compliant. I’m sure any other database has its own cluster like product, or would hope so. Generally it’s best to use the right tool for the job and not force behavior from something it’s not intended to do.
That being said I heavily abuse solr as a data store as pre processing data before it goes into the index is more efficient for me than a bunch of sql joins for the outgoing product, but for actually editing and storing the data a relational db is easier to deal with and easier to find others that can work with it. > On Jun 2, 2019, at 4:33 PM, Ralph Soika <ralph.so...@imixs.com> wrote: > > Thanks Jörn and Erick for your explanations. > > What I do so far is the following: > > * I have a RDBMS with one totally flatten table holding all the data and the > id. > * The data is unstructured. Fields can vary from document to document. I > have no fixed schema. A dataset is represented by a Hashmap. > * Lucene (7.5) is perfect to index the data - with analysed-fulltext and > also with non-analysed-fields. > > The whole system is highly transactional as it runs on Java EE with JPA and > Session EJBs. > I can easily rebuild my index on any time as I have all the data in a RDBMS. > And of course it was necessary in the past to rebuild the index for many > projects after upgrading lucene (e.g. from 4.x to 7.x). > > So, as far as I understand, you recommend to leave the data in the RDBMS? > > The problem with RDBMS is that you can not easily scale over many nodes with > a master less cluster. This was why I thought Solr can solve this problem > easily. On the other hand my Lucene index also did not scale over multiple > nodes. Maybe Solr would be a solution to scale just the index? > > Another solution I am working on is to store all my data in a HA Cassandra > cluster because I do not need the SQL-Core functionallity. But in this case I > only replace the RDBMS with Cassandra and Lucene/Solr holds again only the > index. > > So Solr can't improve my architecture, with the exception of the fact that > the search index could be distributed across multiple nodes with Solr. Did I > get that right? > > > === > Ralph > > >> On 02.06.19 16:35, Erick Erickson wrote: >> You must be able to rebuild your index completely when, at some point, you >> change your schema in incompatible ways. For that reason, either you have to >> play tricks with Solr (i.e. store all fields or the original document or….) >> or somehow have access to the original document. >> >> Furthermore, starting with Lucene 8, Lucene will not even open an index >> _ever_ touched with Lucene 6. In general you can’t even open an index with >> Lucene X that was ever worked on with Lucene X-2 (starting where X = 8). >> >> That said, it’s a common pattern to put enough information into Solr that a >> user can identify documents that they need then go to the system-of-record >> for the full document, whether that is an RDBMS or file system or whatever. >> I’ve seen lots of hybrid systems that store additional data besides the id >> and let the user get to the document she wants and only when she clicks on a >> single document go to the system-of-record and fetch it. Think of a Google >> search where the information you see as the result of a search is stored in >> Solr, but when the user clicks on a link the original doc is fetched from >> someplace other than Solr. >> >> FWIW, >> Erick >> >>> On Jun 2, 2019, at 7:05 AM, Jörn Franke <jornfra...@gmail.com> wrote: >>> >>> It depends what you want to do with it. You can store all fields in Solr >>> and filter on them. However, as soon as it comes to Acid guarantees or if >>> you need to join the data you will be probably needing something else than >>> Solr (or have other workarounds eg flatten the table ). >>> >>> Maybe you can describe more what the users do in Solr or in the database. >>> >>>> Am 02.06.2019 um 15:28 schrieb Ralph Soika <ralph.so...@imixs.com>: >>>> >>>> Inspired by an article in the last german JavaMagazin written by Uwe >>>> Schindler I wonder if Solr can also be used as a database? >>>> >>>> In our open source project Imixs-Workflow we use Lucene >>>> <https://imixs.org/doc/engine/queries.html> since several years with great >>>> success. We have unstructured document-like data generated by the workflow >>>> engine. We store all the data in a transactional RDBMS into a blob column >>>> and index the data with lucene. This works great and is impressive fast >>>> also when we use complex queries. >>>> >>>> The thing is that we do not store any fields into lucene - only the >>>> primary key of our dataset is stored in lucene. The document data is >>>> stored in the SQL database. >>>> >>>> Now as far as I understand is solr a cluster enabled datastore which can >>>> be used to store also all the data form our document. >>>> The problem with relational databases was always the lack of cloud/cluster >>>> support to get more stable data by using redundancy over serveral nodes. >>>> >>>> What do you think? Is solr an alternative to store and index data instead >>>> of useing Lucene in combination with RDBMS? >>>> >>>> >>>> === >>>> Ralph >>>> >
