This screen displays one line of information for each DBR process active on the node. (If there is no active DBR process, the screen is empty.) If this screen is not used, the only method available to users to determine if the DBR process is running is to use the RMU Show Users utility. However, the RMU Show Users utility only indicates that the DBR process is running; it does not indicate what type of progress DBR is making in the recovery operation. For each active DBR process, the DBR Activity screen shows the following: o The DBR process ID o The activity being performed. (A list of these activities appears later in this help display.) o The operation being performed. (A list of these operations appears later in this help display.) o The lock ID, if any, being requested Several significant restrictions apply to the DBR Activity screen: o The DBR Activity screen only shows information about DBR processes running on that node. It does not display information about DBR processes running on other nodes. o The DBR Activity screen does not identify which user process is being recovered. This information can be obtained from the Active User Stall Messages screen. o The DBR Activity screen is not logged to the RMU Show Statistics output file, which means that it cannot be replayed. The DBR process currently records the following distinct activities: o Activation The DBR process is being activated by the monitor. o Database Attach The DBR process is attaching to the database. o AIJ Recovery The DBR process is recovering any pending AIJ operations. o Root Update The DBR process is recovering any pending database root information updates. o GB Recovery The DBR process is recovering any pending global buffer transactions. o Recovery Setup The DBR process is initializing its recovery context information. o Transaction Redo The DBR process is redoing committed transactions that have not yet been flushed to the database. o Transaction Undo The DBR process is undoing uncommitted transactions that have already been flushed to the database. o Buffer Flush The DBR process is flushing its cache buffers to the database. o Database Detach The DBR process is detaching from the database and terminating the image. For each activity recorded by the DBR process, a variety of database operations are performed. These operations are identified by the following messages: o Extending storage area n This message is displayed whenever a storage area (identified by its numeric identifier n-see RMU Dump output) file is physically extended. This message should occur only occasionally; this message may occur more frequently when you use WORM areas, as pages cannot be reused once they have been written. o Prepared, waiting to commit distributed transaction This message is displayed whenever a database user participating in a distributed transaction (coordinated by DECdtm) is "Prepared to Commit or Roll Back," but has not received the final transaction outcome from DECdtm. If this message occurs frequently, you should look into the possibility of a distributed deadlock. Distributed deadlock can occur in a distributed transaction involving multiple databases that are on two or more nonclustered machines. o Reading .AIJ file block n This message is displayed whenever AIJ lock information needs to be refreshed; this typically occurs only the first time a user attaches to the database. The .aij file is read to determine the AIJ logical EOF (not to be confused with the OpenVMS logical EOF). This operation also occurs when the DBR process needs REDO information from the .aij file. o Reading ROOT file This message is displayed whenever the in-memory database root information has been determined to be out-of-date and must be re-read from the disk. This message normally occurs only when a database parameter is modified by a user on line, or some information in the database root is modified by the system (such as the AIJ sequence number). o Reading .RUJ file block n This message is displayed whenever an UNDO operation needs to read the next RUJ page to acquire the rollback information necessary to complete the operation. The .ruj file is read one block at a time, backwards. Thus, the identified block number indicates the remaining number of blocks to be processed. o Reading pages n:n to n:n This message is displayed whenever one or more pages is read into either the DBR process local buffer or the global buffer. One full buffer of pages is being read. The format string n:n identifies the physical area and the page number. o Writing .AIJ file block n This message is displayed whenever DBR actually writes commit or rollback information to the .aij file. The write buffer can be as close to 64,000 bytes in length as possible. o Writing ROOT file This message is displayed whenever the in-memory database root information is modified by DBR. o Writing pages back to database This message is displayed whenever one or more data pages is written to the database. This is typically caused by a request to access those pages from another recovery process, or by detaching from the database.