boolean_indexer

be indexer implement

ref:Indexing-Boolean-Expressions

terms

• field: a name for every group of attributions eg: user, ip, sex, tag

• Assigns: a field with multi(or just one) value[s] eg: "user": [david, kevin, lisa]

• Attr: a field with a it's value, eg: <user, david>, <ip, localhost>

• BooleanExpr: represent a boolean expression, it contain a Assigns and a boolean flag mean include/exclude

  eg: "user" include [david, kevin, lisa] it can descript as follow: (david, kevin, lisa) any of them for this expression will be true, false for any other user in this expression

• Conjunction: contain many BooleanExpr with a id and size the size mean the count of BooleanExpr with flag "include"

  eg:
    id: 10,
    size: 2,
    Expressions: [
      "os" exclude [linux, windows] # size 0 bz of flag exclude
      "tag"  include [male, rich]   # size 1
      "user" include [david, lisa]  # size 1
    ]

• Document: contain one or more conjunction

  doc: 1
    {
       id: 10,
       size: 2,
       Expressions: [
         "os" exclude [linux]
         "tag"  include [male, rich]
         "user" include [david, lisa]
       ]
    }, # or logic between many conjunctions
    {
       id: 11,
       size: 1,
       Expressions: [
         "os" include [ios]
         "ip"  exclude [127.0.0.1, 192.168.*.*]
       ]
    }

• EntryId: a unique id can represent doc + conj + size + flag

• PostingList:

  map<Attr, EntryIdList>
eg:
  <age, 15>: [entry_id_01, entry_id_11, entry_id_15]
  <tag, 11>: [entry_id_02, entry_id_09, entry_id_11]
  ...

• EntriesCursor a cursor walk on matched entries pick from PostingList(PostEntries)

EntriesCursor:
  attr    eg: <age, 15>
  index   // current cursor pos
  entries // a point to specific entry id list

• FieldCursor:

FieldCursor include multi EntriesCursor group by field, based on
this, BEIndex can support multi value queries
  eg:
    ip:
    <ip, 127.0.0.1>: [entry_id_11, entry_id_15]
    <ip, 192.168.28.1>: [entry_id_01, entry_id_11, entry_id_15]