Opened 8 years ago

Closed 7 years ago

#418 closed enhancement (fixed)

wildcard search in omega

Reported by: do Owned by: olly
Priority: normal Milestone: 1.2.5
Component: Omega Version: 1.0.17
Severity: normal Keywords:
Cc: Blocked By:
Blocking: Operating System: All

Description

It seems Omega doesn't support wildcard search. So I feature request to add it.

ps. Or it is unusable/not effective to be used? As I understand wildcarded word searched not by prefix, but first searched in (other) database by prefix, then query expanded to 23456 words which are ORed and searched again in main database. (This to my ignorant non-IR-scientific view looks strange. Why not just search by prefix in the first place?)

Change History (2)

comment:1 Changed 8 years ago by olly

  • Milestone set to 1.2.x

Omega really needs a generic way to set (or clear) QueryParser flags. We can cleanly add that in 1.2.x without breaking compatibility, so setting the milestone.

We can't "just search by prefix" as we don't have an index which tells us all the documents which match a given term prefix. So we have to merge the posting lists for all the terms that the wildcard expands to.

It is possible to keep an index for term prefixes to accelerate wildcard expansions (see #207), but that will take significantly more space. For most users that probably isn't worthwhile so it's likely to be an index-time choice.

comment:2 Changed 7 years ago by olly

  • Milestone changed from 1.2.x to 1.2.5
  • Resolution set to fixed
  • Status changed from new to closed

Implemented in r15323 - now any QueryParser flags can be set from omegascript.

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