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https://issues.apache.org/jira/browse/LUCENE-3108?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13036284#comment-13036284
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Michael McCandless commented on LUCENE-3108:
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{quote}
bq. How come codecID changed from String to int on the branch?
due to DocValues I need to compare the ID to certain fields to see for
what field I stored and need to open docValues. I always had to parse
the given string which is kind of odd. I think its more natural to
have the same datatype on FieldInfo, SegmentCodecs and eventually in
the Codec#files() method. Making a string out of it is way simpler /
less risky than parsing IMO.
{quote}
OK that sounds great.
{quote}
bq. Can SortField somehow detect whether the needed field was stored in FC vs DV
This is tricky though. You can have a DV field that is indexed too so its hard
to tell if we can reliably do it. If we can't make it reliable I think we
should not do it at all.
{quote}
It is tricky... but, eg, when someone does SortField("title",
SortField.STRING), which cache (DV or FC) should we populate?
{quote}
bq. Should we rename oal.index.values.Type -> .ValueType?
agreed. I also think we should rename Source but I don't have a good name yet.
Any idea?
{quote}
ValueSource? (conflicts w/ FQs though) Though, maybe we can just
refer to it as DocValues.Source, then it's clear?
{quote}
bq. Since we dynamically reserve a value to mean "unset", does that mean there
are some datasets we cannot index?
Again, tricky! The quick answer is yes, but we can't do that anyway since I
have not normalize the range to be 0 based since PackedInts doesn't allow
negative values. so the range we can store is (2^63) -1. So essentially with
the current impl we can store (2^63)-2 and the max value is Long#MAX_VALUE-1.
Currently there is no assert for this which is needed I think but to get around
this we need to have a different impl I think or do I miss something?
{quote}
OK, but I think if we make a "straight longs" impl (ie no packed ints at all)
then we can handle all long values? But in that case we'd require the app to
pick a sentinel to mean "unset"?
> Land DocValues on trunk
> -----------------------
>
> Key: LUCENE-3108
> URL: https://issues.apache.org/jira/browse/LUCENE-3108
> Project: Lucene - Java
> Issue Type: Task
> Components: core/index, core/search, core/store
> Affects Versions: CSF branch, 4.0
> Reporter: Simon Willnauer
> Assignee: Simon Willnauer
> Fix For: 4.0
>
> Attachments: LUCENE-3108.patch
>
>
> Its time to move another feature from branch to trunk. I want to start this
> process now while still a couple of issues remain on the branch. Currently I
> am down to a single nocommit (javadocs on DocValues.java) and a couple of
> testing TODOs (explicit multithreaded tests and unoptimized with deletions)
> but I think those are not worth separate issues so we can resolve them as we
> go.
> The already created issues (LUCENE-3075 and LUCENE-3074) should not block
> this process here IMO, we can fix them once we are on trunk.
> Here is a quick feature overview of what has been implemented:
> * DocValues implementations for Ints (based on PackedInts), Float 32 / 64,
> Bytes (fixed / variable size each in sorted, straight and deref variations)
> * Integration into Flex-API, Codec provides a
> PerDocConsumer->DocValuesConsumer (write) / PerDocValues->DocValues (read)
> * By-Default enabled in all codecs except of PreFlex
> * Follows other flex-API patterns like non-segment reader throw UOE forcing
> MultiPerDocValues if on DirReader etc.
> * Integration into IndexWriter, FieldInfos etc.
> * Random-testing enabled via RandomIW - injecting random DocValues into
> documents
> * Basic checks in CheckIndex (which runs after each test)
> * FieldComparator for int and float variants (Sorting, currently directly
> integrated into SortField, this might go into a separate DocValuesSortField
> eventually)
> * Extended TestSort for DocValues
> * RAM-Resident random access API plus on-disk DocValuesEnum (currently only
> sequential access) -> Source.java / DocValuesEnum.java
> * Extensible Cache implementation for RAM-Resident DocValues (by-default
> loaded into RAM only once and freed once IR is closed) -> SourceCache.java
>
> PS: Currently the RAM resident API is named Source (Source.java) which seems
> too generic. I think we should rename it into RamDocValues or something like
> that, suggestion welcome!
> Any comments, questions (rants :)) are very much appreciated.
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