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Mark Miller commented on LUCENE-1458: ------------------------------------- Hmm - I must have something off then. I've never been into this stuff much before. on a cache hit, I'm still calling docs.readTerm(entry.freq, entry.isIndex) - I'm just caching the freq, isIndex, and the positions with a CurrentState object. The captureCurrentState now telescopes down capturing the state of each object Perhaps I'm off there - because if I do that, it seems I have to capture the state right before the call to readTerm in next() - otherwise readTerm will move everything forward before I can grab it when I actually put the state into the cache - when its FOUND. I may be all wet though - no worries - I'm really just playing around trying to learn some of this - only way I learn to is to code. bq. Hmm I wonder whether we should also cache the seek(ord) calls? I was wondering about that, but hand't even got to thinking about it :) > Further steps towards flexible indexing > --------------------------------------- > > Key: LUCENE-1458 > URL: https://issues.apache.org/jira/browse/LUCENE-1458 > Project: Lucene - Java > Issue Type: New Feature > Components: Index > Affects Versions: 2.9 > Reporter: Michael McCandless > Assignee: Michael McCandless > Priority: Minor > Attachments: LUCENE-1458-back-compat.patch, > LUCENE-1458-back-compat.patch, LUCENE-1458-back-compat.patch, > LUCENE-1458-back-compat.patch, LUCENE-1458-back-compat.patch, > LUCENE-1458-back-compat.patch, LUCENE-1458.patch, LUCENE-1458.patch, > LUCENE-1458.patch, LUCENE-1458.patch, LUCENE-1458.patch, LUCENE-1458.patch, > LUCENE-1458.patch, LUCENE-1458.patch, LUCENE-1458.patch, LUCENE-1458.patch, > LUCENE-1458.tar.bz2, LUCENE-1458.tar.bz2, LUCENE-1458.tar.bz2, > LUCENE-1458.tar.bz2, LUCENE-1458.tar.bz2, LUCENE-1458.tar.bz2, > LUCENE-1458.tar.bz2 > > > I attached a very rough checkpoint of my current patch, to get early > feedback. All tests pass, though back compat tests don't pass due to > changes to package-private APIs plus certain bugs in tests that > happened to work (eg call TermPostions.nextPosition() too many times, > which the new API asserts against). > [Aside: I think, when we commit changes to package-private APIs such > that back-compat tests don't pass, we could go back, make a branch on > the back-compat tag, commit changes to the tests to use the new > package private APIs on that branch, then fix nightly build to use the > tip of that branch?o] > There's still plenty to do before this is committable! This is a > rather large change: > * Switches to a new more efficient terms dict format. This still > uses tii/tis files, but the tii only stores term & long offset > (not a TermInfo). At seek points, tis encodes term & freq/prox > offsets absolutely instead of with deltas delta. Also, tis/tii > are structured by field, so we don't have to record field number > in every term. > . > On first 1 M docs of Wikipedia, tii file is 36% smaller (0.99 MB > -> 0.64 MB) and tis file is 9% smaller (75.5 MB -> 68.5 MB). > . > RAM usage when loading terms dict index is significantly less > since we only load an array of offsets and an array of String (no > more TermInfo array). It should be faster to init too. > . > This part is basically done. > * Introduces modular reader codec that strongly decouples terms dict > from docs/positions readers. EG there is no more TermInfo used > when reading the new format. > . > There's nice symmetry now between reading & writing in the codec > chain -- the current docs/prox format is captured in: > {code} > FormatPostingsTermsDictWriter/Reader > FormatPostingsDocsWriter/Reader (.frq file) and > FormatPostingsPositionsWriter/Reader (.prx file). > {code} > This part is basically done. > * Introduces a new "flex" API for iterating through the fields, > terms, docs and positions: > {code} > FieldProducer -> TermsEnum -> DocsEnum -> PostingsEnum > {code} > This replaces TermEnum/Docs/Positions. SegmentReader emulates the > old API on top of the new API to keep back-compat. > > Next steps: > * Plug in new codecs (pulsing, pfor) to exercise the modularity / > fix any hidden assumptions. > * Expose new API out of IndexReader, deprecate old API but emulate > old API on top of new one, switch all core/contrib users to the > new API. > * Maybe switch to AttributeSources as the base class for TermsEnum, > DocsEnum, PostingsEnum -- this would give readers API flexibility > (not just index-file-format flexibility). EG if someone wanted > to store payload at the term-doc level instead of > term-doc-position level, you could just add a new attribute. > * Test performance & iterate. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online. --------------------------------------------------------------------- To unsubscribe, e-mail: java-dev-unsubscr...@lucene.apache.org For additional commands, e-mail: java-dev-h...@lucene.apache.org