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https://issues.apache.org/jira/browse/SOLR-1709?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13020802#comment-13020802
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Peter Sturge commented on SOLR-1709:
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Updating ResponseBuilder rather than FacetInfo really came from tracing the
references through the hierarchy - so, I don't think anything is missed by
moving this to FacetInfo props, and should provide better encapsulation.
Deprecating data faceting in favour of generic range faceting should be fine,
as long as there exists a clear path to easily move from 'the way we were' with
date facets, to 'the way it will be' (range faceting). It would be a shame to
break clients that rely on the existing date facet parameters/syntax, so I
guess if they're mapped to range (I think some of this is in 3.x already?),
that would be good.
Thanks
> Distributed Date Faceting
> -------------------------
>
> Key: SOLR-1709
> URL: https://issues.apache.org/jira/browse/SOLR-1709
> Project: Solr
> Issue Type: Improvement
> Components: SearchComponents - other
> Affects Versions: 1.4
> Reporter: Peter Sturge
> Assignee: Hoss Man
> Priority: Minor
> Fix For: 4.0
>
> Attachments: FacetComponent.java, FacetComponent.java,
> ResponseBuilder.java, SOLR-1709.patch,
> SOLR-1709_distributed_date_faceting_v3x.patch, solr-1.4.0-solr-1709.patch
>
>
> This patch is for adding support for date facets when using distributed
> searches.
> Date faceting across multiple machines exposes some time-based issues that
> anyone interested in this behaviour should be aware of:
> Any time and/or time-zone differences are not accounted for in the patch
> (i.e. merged date facets are at a time-of-day, not necessarily at a universal
> 'instant-in-time', unless all shards are time-synced to the exact same time).
> The implementation uses the first encountered shard's facet_dates as the
> basis for subsequent shards' data to be merged in.
> This means that if subsequent shards' facet_dates are skewed in relation to
> the first by >1 'gap', these 'earlier' or 'later' facets will not be merged
> in.
> There are several reasons for this:
> * Performance: It's faster to check facet_date lists against a single map's
> data, rather than against each other, particularly if there are many shards
> * If 'earlier' and/or 'later' facet_dates are added in, this will make the
> time range larger than that which was requested
> (e.g. a request for one hour's worth of facets could bring back 2, 3
> or more hours of data)
> This could be dealt with if timezone and skew information was added, and
> the dates were normalized.
> One possibility for adding such support is to [optionally] add 'timezone' and
> 'now' parameters to the 'facet_dates' map. This would tell requesters what
> time and TZ the remote server thinks it is, and so multiple shards' time data
> can be normalized.
> The patch affects 2 files in the Solr core:
> org.apache.solr.handler.component.FacetComponent.java
> org.apache.solr.handler.component.ResponseBuilder.java
> The main changes are in FacetComponent - ResponseBuilder is just to hold the
> completed SimpleOrderedMap until the finishStage.
> One possible enhancement is to perhaps make this an optional parameter, but
> really, if facet.date parameters are specified, it is assumed they are
> desired.
> Comments & suggestions welcome.
> As a favour to ask, if anyone could take my 2 source files and create a PATCH
> file from it, it would be greatly appreciated, as I'm having a bit of trouble
> with svn (don't shoot me, but my environment is a Redmond-based os company).
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