Abstract: A shared memory device called the Coupling Facility (CF) is used to record the indoubt transaction entries for each member of the database cluster, avoiding the CPU cost and elapsed time impact of persisting this information to disk (either via a log write or a relational table I/O). The CF provides full read/write access and data coherency for concurrent access by all the members in the database cluster. At any given point in time, the CF will contain the full list of indoubt transactions for the entire database cluster. CF duplexing is used to guarantee the integrity of the CF structure used for the indoubt list. In the event of complete loss of both CF structures (which will not happen except in major disaster situations), data sharing group restart processing can reconstruct the CF structures from the individual member logs.

Abstract: A partial index availability system places, in a restricted state, all pages in the index associated with a structure modification, when an error occurs in processing a log of the said structure modification. This maintains traversability of the rest of the index that is not in restricted state. The system locates and marks a left sentinel and a right sentinel associated with a non-leaf page that is in a restricted state preventing an undo of a transaction. The sentinels prevent a transaction from accessing an uncommitted change associated with the non-leaf page. After a recovery procedure is run the entire index is made available. During the period between the placement of the index pages in LPL or rebuild pending to the time of final removal of these pages from their restrictive states as a result of a recovery procedure being run, the users are given access to the non-restricted portion of the index.

Abstract: A system, method and a computer usable medium tangibly embodying a program of instructions executable by the computer to perform a computer-based method for restoration of a database from a failed data recovery. For each failed data recovery the method generates a log error data set having log records of a faulty transaction unapplied to data due to inconsistency. Log error data set is directly useable by a log analysis tool to regenerate and redo the unapplied faulty transaction to recover the data and by a print log tool to diagnose the faulty transaction. Log records mimic format of records of an archive log data set and identify data objects, faulty transactions on the data objects and a range of the unapplied data objects' updates.

Abstract: A shared memory device called the Coupling Facility (CF) is used to record the indoubt transaction entries for each member of the database cluster, avoiding the CPU cost and elapsed time impact of persisting this information to disk (either via a log write or a relational table I/O). The CF provides full read/write access and data coherency for concurrent access by all the members in the database cluster. At any given point in time, the CF will contain the full list of indoubt transactions for the entire database cluster. CF duplexing is used to guarantee the integrity of the CF structure used for the indoubt list. In the event of complete loss of both CF structures (which will not happen except in major disaster situations), data sharing group restart processing can reconstruct the CF structures from the individual member logs.