WORD index and CONTAINS predicate support for character large object (CLOB) columns [CR 415547]

Sybase IQ 12.7 ESD #3 provides support for WORD (WD) indexes on LONG VARCHAR character large object (CLOB) columns and support of the CONTAINS predicate on LONG VARCHAR (CLOB) columns with a WD index.

The following documentation updates will be made to Chapter 6, “Using Sybase IQ Indexes” for this feature.

• In the section “Overview of indexes,” the bullet regarding the WD index in the section “Sybase IQ index types” will be changed to say:

  “WD Used to index keywords by treating the contents of a CHAR, VARCHAR, or LONG VARCHAR column as a delimited list.”

• In the section “Choosing an index type,” the following row will be added to Table 6-2 “Query type/index” in the section “Types of queries”:

  Type of query usage	Recommended index type
  In a CONTAINS predicate	WD

• In the section “Choosing an index type,” the following phrase will be added to the third bullet regarding other factors in the section “Types of queries”:

  LONG VARCHAR data can only be used in the default and WD index types;

• In the section “Choosing an index type,” the following row will be added to Table 6-4 “Indexes supported for data types” in the section “Data types in the index”:

  Data type	Supported indexes	Unsupported indexes
  long varchar	WD	CMP, HG, HNG, LF, DATE, TIME, DTTM

• Several changes will be made to the section “The Containment (WD) index type” in the section “Sybase IQ index types.”

  • The description of the Containment (WD) index will include the LONG VARCHAR data type:

    “The Containment (WD) index allows you to store words from a column string of CHAR, VARCHAR, and LONG VARCHAR data.”

  • Three of the bullets in the “Recommended use” section will be modified as follows:

    • The column-name must identify a CHAR, VARCHAR, or LONG VARCHAR column in a base table.

    • The minimum permitted column width is 3 bytes and the maximum permitted column width is the maximum width for a LOB column. (The maximum length is equal to 4GB multiplied by the database page size.)

    • The sp_iqcheckdb (DBCC consistency checker) allocation, check, verify, and repair modes support the WD index on CHAR, VARCHAR, and LONG VARCHAR columns.

  • The third item in the Disadvantages column of Table 6-9 “WD advantages/disadvantages” will be changed to say:

    “Can only use this index if data in your columns is CHAR, VARCHAR, or LONG VARCHAR.”