Chaining Indexes

With Perceptive Enterprise Search - Local Administration Console, you can create a chained index that links multiple indexes together. That is, you can set up an index which is really a list that points to other indexes. When you run a query on a chained index, it queries all the indexes in the list.

You may have up to 128 indexes in a chain, and you can create nested chains, or chained indexes that point to other chained indexes.

The result of querying an index chain is like performing the same query on each of the indexes in turn. The results list reflects the number of hits from each link in the chain, so it is quite normal to see words repeated on the list.

Chaining indexes can be useful if you want to distribute an index periodically, with incremental revisions. If you chain the original index with each revision, the two indexes are effectively combined. Any query performed on the original index will also be executed against the revisions.

Creating a chained index

Perceptive Enterprise Search - Local Administration Console contains a tool that can be used to create chained indexes. Under the "I'm looking in" panel on the left-hand side of Perceptive Enterprise Search - Local Administration Console, select the indexes that you want to include in the chain, right click and select "Create Index Chain" and follow the prompts.

Manually creating a chained index

Normally when you create an index, Perceptive Enterprise Search - Local Administration Console automatically creates the ISYS.CFG file, which contains all of the indexing rules and index options. In the case of a chained index, you need to create a simple ISYS.CFG file yourself, using a text editor such as Notepad. To create a chained index:

1. Choose or create a folder in which you would like to store your chained index.
2. Launch the text editor that you wish to use to create your own ISYS.CFG file.
3. Type the following information into the file, using the details of your own indexes:

NAME Your index name
INCLUDE Directory of first index
INCLUDE Directory of second index
INCLUDE Directory of third index
INCLUDE Directory of fourth index
INCLUDE Directory of n th index

For example:

NAME Master index
INCLUDE C:\Documents and Settings\User\My Documents
INCLUDE G:\WordDocs
INCLUDE K:\Marketing
INCLUDE P:\Sales

...would create a chained index called Master Index and would include the four indexes located in the directories nominated. The order which the indexes are listed determines the order which Perceptive Enterprise Search - Local Administration Console will search. In this example, Perceptive Enterprise Search - Local Administration Console will first search first in C:\Documents and Settings\User\My Documents, and lastly in P:\Sales.

4. Save your ISYS.CFG as text file to the directory that you have just created, or any other directory you choose which does not already contain an Perceptive Enterprise Search - Local Administration Console index.

Note: you cannot update or Reindex chained indexes; you must Update each index in the chain individually.