Problem: It is not documented what these operations do in terms of maintaining a database, knowing what these operation do will help efficiently administer the database. Solution: A backup and restore will do the following: - The pages in the database used by tables and indexes are allocated contiguously. - Indexes are computed. And index tree is rebuilt. - The index selectivity is recomputed for all indexes. - The TIP (transaction information pages) pages containing old transactions and current transactions are discarded and the transaction numbers are set to the beginning. - All metadata versions are reset to 0 (some objects may start with a version of 1 0r 2). InterBase allows only 255 versions of a record in a system table. - All unused data pages are discarded. - No back versions or deltas or records are present. - No garbage index pages are present. - All tasks that are performed by a sweep with a single connection. A sweep does the following tasks: - Brings forward the oldest interesting transaction (OIT) as much as possible. If there is exclusive access the OIT number will be one less than the Next Transaction number. - Touches every record in every table in the database that is accessible to the transaction that is being used. This is similar to how a SELECT touches a record, triggering the garbage collection mechanism. Garbage collection does the following: - Deletes all versions of a record older than the version of the OIT, and all delta records older than the version of the OIT. - In InterBase v5.0.0 garbage collection of index pages also occurs. A reindex (making an index inactive, then active) does the following: - Rebuilds the index tree. - The selectivity is recomputed for the index.
Last Modified: 26-OCT-00