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https://issues.apache.org/jira/browse/SOLR-3173?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13219175#comment-13219175
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Yonik Seeley commented on SOLR-3173:
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bq. I belive you are already commenting on the related Jira issue that I havnt
created yet
Optimistic locking as a superset to insert/update:
What I already had in mind:
- update only a specific version of the document by specifying it's exact
version: _version_=12345
- add a document only if it doesn't already exist (i.e. insert): _version_=-1
- add a document regardless: don't specify a version
So now that I look at it again, it looks like what's missing is your "UPDATE"
semantics which would only replace the record if it already existed (a weaker
form of the first case... any positive version is OK). But I really wonder how
useful those semantics are (only add a doc if it's overwriting an existing doc,
regardless of what version or what data it contains?)
If there are usecases, we certainly should be able to do it.
As far as what \_version\_ is, it's new and used for solrcloud to handle
reorders of updates to replicas (among other things).
The leader shard decides what the version of a document should be (versions
only increase), and forwards the doc with the version to the replicas.
If a replica receives the same doc with a lower version, it knows that it can
safely drop it because it already has a newer version.
> Database semantics - insert and update
> --------------------------------------
>
> Key: SOLR-3173
> URL: https://issues.apache.org/jira/browse/SOLR-3173
> Project: Solr
> Issue Type: New Feature
> Components: update
> Affects Versions: 3.5
> Environment: All
> Reporter: Per Steffensen
> Assignee: Per Steffensen
> Labels: RDBMS, insert, nosql, uniqueKey, update
> Fix For: 4.0
>
> Original Estimate: 168h
> Remaining Estimate: 168h
>
> In order increase the ability of Solr to be used as a NoSql database (lots of
> concurrent inserts, updates, deletes and queries in the entire lifetime of
> the index) instead of just a search index (first: everything indexed (in one
> thread), after: only queries), I would like Solr to support the following
> features inspired by RDBMSs and other NoSql databases.
> * Given a solr-core with a schema containing a uniqueKey-field "uniqueField"
> and a document Dold, when trying to INSERT a new document Dnew where
> Dold.uniqueField is equal to Dnew.uniqueField, then I want a
> DocumentAlredyExists error. If no such document Dold exists I want Dnew
> indexed into the solr-core.
> * Given a solr-core with a schema containing a uniqueKey-field "uniqueField"
> and a document Dold, when trying to UPDATE a document Dnew where
> Dold.uniqueField is equal to Dnew.uniqueField I want Dold deleted from and
> Dnew added to the index (just as it is today).If no such document Dold exists
> I want nothing to happen (Dnew is not added to the index)
> The essence of this issue is to be able to state your intent (insert or
> update) and have slightly different semantics (from each other and the
> existing update) depending on you intent.
> The functionality provided by this issue is only really meaningfull when you
> run with "updateLog" activated.
> This issue might be solved more or less at the same time as SOLR-3178, and
> only one single SVN patch might be given to cover both issues.
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