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 >>
