Kevin Watters created SOLR-13749:
------------------------------------
Summary: Implement support for joining across collections with
multiple shards ( XCJF )
Key: SOLR-13749
URL: https://issues.apache.org/jira/browse/SOLR-13749
Project: Solr
Issue Type: New Feature
Security Level: Public (Default Security Level. Issues are Public)
Reporter: Kevin Watters
This ticket includes 2 query parsers.
The first one is the "Cross collection join filter" (XCJF) parser. This is
the "Cross-collection join filter" query parser. It can do a call out to a
remote collection to get a set of join keys to be used as a filter against the
local collection.
The second one is the Hash Range query parser that you can specify a field name
and a hash range, the result is that only the documents that would have hashed
to that range will be returned.
This query parser will do an intersection based on join keys between 2
collections.
The local collection is the collection that you are searching against.
The remote collection is the collection that contains the join keys that you
want to use as a filter.
Each shard participating in the distributed request will execute a query
against the remote collection. If the local collection is setup with the
compositeId router to be routed on the join key field, a hash range query is
applied to the remote collection query to only match the documents that contain
a potential match for the documents that are in the local shard/core.
Here's some vocab to help with the descriptions of the various parameters.
||Term||Description||
|Local Collection|This is the main collection that is being queried.|
|Remote Collection|This is the collection that the XCJFQuery will query to
resolve the join keys.|
|XCJFQuery|The lucene query that executes a search to get back a set of join
keys from a remote collection|
|HashRangeQuery|The lucene query that matches only the documents whose hash
code on a field falls within a specified range.|
||Param||Default||Required||Description||
|collection| |Required|The name of the external Solr collection to be queried
to retrieve the set of join key values ( required )|
|zkHost| |Optional|The connection string to be used to connect to Zookeeper.
zkHost and solrUrl are both optional parameters, and at most one of them should
be specified. If neither of zkHost or solrUrl are specified, the local
Zookeeper cluster will be used. ( optional )|
|solrUrl| |Optional|The URL of the external Solr node to be queried ( optional
)|
|from| |Required|The join key field name in the external collection ( required
)|
|to| |Required|The join key field name in the local collection|
|v| |See Note|The query to be executed against the external Solr collection to
retrieve the set of join key values. Note: The original query can be passed
at the end of the string or as the "v" parameter. It's recommended to use
query parameter substitution with the "v" parameter to ensure no issues arise
with the default query parsers.|
|routed|See Notes| |true / false. If true, the XCJF query will use each
shard's hash range to determine the set of join keys to retrieve for that
shard. This parameter improves the performance of the cross-collection join,
but it depends on the local collection being routed by the toField. If this
parameter is not specified, the XCJF query will try to determine the correct
value automatically.|
|ttl|3600| |The length of time that an XCJF query in the cache will be
considered valid, in seconds. Defaults to 3600 (one hour). The XCJF query
will not be aware of changes to the remote collection, so if the remote
collection is updated, cached XCJF queries may give inaccurate results. After
the ttl period has expired, the XCJF query will re-execute the join against the
remote collection.|
|_All others_| | |Any normal Solr parameter can also be specified as a local
param.|
Example Solr Config.xml changes:
{{<}}{{cache}} {{name}}{{=}}{{"hash_vin"}}
{{ }}{{class}}{{=}}{{"solr.LRUCache"}}
{{ }}{{size}}{{=}}{{"128"}}
{{ }}{{initialSize}}{{=}}{{"0"}}
{{ }}{{regenerator}}{{=}}{{"solr.NoOpRegenerator"}}{{/>}}
{{<}}{{queryParser}} {{name}}{{=}}{{"xcjf"}}
{{class}}{{=}}{{"org.apache.solr.search.join.XCJFQueryParserPlugin"}}{{>}}
{{ }}{{<}}{{str}} {{name}}{{=}}{{"routerField"}}{{>vin</}}{{str}}{{>}}
{{</}}{{queryParser}}{{>}}
{{<}}{{queryParser}} {{name}}{{=}}{{"hash_range"}}
{{class}}{{=}}{{"org.apache.solr.search.join.HashRangeQueryParserPlugin"}}
{{/>}}
Example Usage:
{{{{{!xcjf collection=}}{{"otherCollection"}} {{from=}}{{"fromField"}}
{{to=}}{{"toField"}} {{v=}}{{"*:*"}}{{}}}}}
--
This message was sent by Atlassian Jira
(v8.3.2#803003)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
