master index

Definition of master index in The Network Encyclopedia.

What is Master Index?

The end product of the indexing process in Microsoft Indexing Service. The process first creates word lists, which are merged into shadow indexes and then become one master index.

Unlike word lists, which reside in volatile memory, the shadow indexes and the master index are persistent indexes that are stored on disk.

The process by which shadow indexes are combined into a master index is called a master merge. A master merge combines multiple shadow indexes with any old master index to create a new master index.

The new master index is the most efficient form for the index of a corpus of documents being indexed by the Indexing Service. The master index stores the indexing data in a highly compressed format in a structure called the catalog.

The compressed nature of the master index provides the most efficient data structure for storing information and for issuing queries against the corpus, but the process of generating a master index is resource intensive and is generally performed by the Indexing Service when load on the server is low.

However, the administrator can also force a merge to update the master index after new documents are added to the corpus being indexed.