Measures reported by ProBILogActTest
The Before Image file(s) stores information about every transaction which makes a change to the database. If the transaction is aborted / undone, this information will be read back from the BI file to restore original values of the database back into the database if necessary.
In addition when a database goes down unexpectedly, the crash recovery process reads back and undo any transaction that was not completed.
Output of the test : One set of results for every user accessing the locks on the target Progress database server being monitored.
The measures made by this test are as follows:
| Measurement |
Description |
Measurement Unit |
Interpretation |
| Total_writes |
Indicates the total number of writes to the before-image file during the last measurement period. |
Writes/Sec |
The value of this measure includes the value of the BIW_writes measure too. |
| BIW_writes |
Indicates the total number of writes performed by the Before-Image writer during the last measurement period. |
Writes/Sec |
The BIW is a background process that continually writes filled BI buffers to disk. Since writes to the BI file occur in the background, client and server processes rarely have to wait for a filled buffer to be written to disk. BIWs are optional, but highly recommended for improving I/O performance. |
| BIW_writes_hit_ratio |
Indicates the ratio between the writes performed by the before-Image writer and the total writes to the Before image file during the last measurement period. |
Percent |
|
| Buffer_busy_waits |
Indicates the number of times Buffer_busy_waits have occurred on the before image file when a block in the buffer cache was being held by the Before image writer during the last measurement period. |
Number |
|
| Force_wait |
Indicates the rate at which commit waits have occurred on the before image file when a block in the buffer cache was being held by the Before image writer during the last measurement period. |
Records/sec |
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