1 – process_attaches_field
This field displays the total number of database attaches on the current node. If a single process attaches to the database multiple times, this statistic is incremented by the actual number of attaches.
2 – process_failures_field
This field displays the total number of processes that abnormally terminated and required database recovery. In the case of some other node failure, this statistic might indicate process failure on the other node that was actually recovered on this node.
3 – DB freeze len x100 field
This field displays the total database freeze duration, expressed in hundredths of a second. During the database freeze, no database activity is permitted; the database is "frozen". The longer the duration, the more database performance bottlenecks may result.
4 – Tx REDO count field
This field displays the total number of transactions that needed to be "redone". Transaction redo occurs when fast commit transaction processing is enabled. The fast commit feature contains several parameters that can be modified to control the overall redo duration, but at the expense of runtime performance. Transaction redo requires reading the AIJ journal from the failed process' checkpoint location and re-applying all subsequent committed database modifications for that process. This usually involves re-applying many committed transactions. The number of transactions redone is not as important as the amount of work required per transaction. In other words, a single long transaction requires the same redo processing as many short transactions. Transactions that are densely packed into a minimum AIJ interval are more efficiently redone than a transaction whose data spans a long range of AIJ blocks. In other words, long-running transactions that do only occasional infrequent database updates may be redone more efficiently as several short transactions. This is an application issue. However, total application throughput also affects this redo performance. Transaction redo is normally the longest portion of the process recovery operation.
5 – __redo_time_x100_field
This field displays the total time (in hundredths of a second) required for transactions that needed to be "redone".
6 – Tx UNDO count field
This field displays the total number of transactions that needed to be "undone". Transaction undo requires reading the RUJ journal approximately twice, once forwards to determine the end of the current transaction, and then backwards from that location to the beginning of the RUJ file. Transaction undo is performed only on the transaction that was currently active, if any, at the time of process failure.
7 – __undo_time_x100_field
This field displays the total time (in hundredths of a second) required for transactions that needed to be "undone".
8 – no_undo_needed_field
This field displays the total number of transactions that did not need to be "undone". Occasionally, the failed process did not have any active transactions, thereby allowing the database recovery (DBR) process to avoid having to manually determine if a transaction needs being "undone".
9 – Tx committed field
This field displays the total number of transactions that were committed during the transaction undo phase. This normally occurs during the resolution phase of an in-progress distributed transaction. However, this event can also occur if an optimistic commit record was found in the AIJ journal that was not yet recorded in the process' recovery information.
10 – Tx rolled back field
This field displays the total number of transactions that were rolled back during the transaction undo phase. This is the normal result of transaction undo.
11 – No resolve needed field
This field displays the total number of transactions that did not need to be either committed or rolled back during the transaction undo phase. This normally occurs when fast commit transaction processing is enabled, where the RUJ file is examined to locate an active transaction, but none can be found.
12 – AIJ recover x100 field
This field displays the total time (in hundredths of a second) required to recover the in-progress AIJ flush operation, if any. This is normally a very fast operation.
13 – GB recover x100 field
This field displays the total time (in hundredths of a second) required to recover the global buffer information, if applicable. This is normally a very fast operation.
14 – Cache recover x100 field
This field displays the total time (in hundredths of a second) required to recover the row cache following RCS failure or node failure. Depending on the number and sizes of the active row caches, this can be a lengthy operation.
15 – RUJ file reads field
This field displays the total number of read I/O operations performed on the RUJ journal during the transaction undo phase. The RUJ file is never written by the database recovery (DBR) process.
16 – AIJ file reads field
This field displays the total number of read I/O operations performed on the AIJ journal during both the transaction redo and undo phases. If, during the transaction undo phase, the in- progress transaction is rolled back, a rollback record will be written to the AIJ journal.