Performance - Page Management Statistics

The following page management statistics are displayed in the Performance output window:

Statistics	Description
Page buffers per sorter	This is the total number of Mimer SQL pages that a sorting thread may utilize.
Remaining sorters	The initial value is the maximum number of concurrent sorters that are permitted. The current value reflects the number of additional sorters that may be started before no further parallel sorts are allowed. The value will increase if the size of the bufferpool is increased but will never be greater than the number of request threads allowed.
Pages written to disk	This is the number of Mimer SQL pages written to disk and is an indication of the frequency of disk update operations.
Number of file extend operations	This is the number of times databank files have been dynamically extended since the database was last started. For performance reasons, this value should be as low as possible. A databank can be extended manually by using the SQL command ALTER DATABANK.

For each of the buffer sizes (4K, 32K, 128K) the following is displayed:

Statistics	Description
Page buffers	This is the number of page buffers allocated to the relevant bufferpool region.
Page partitions	The buffer pool is divided into separate partitions. Each partition can be accessed concurrently by the request threads. In a tightly-coupled multi-processor system it is desirable, for performance reasons, to have at least as many partitions as there are threads. The number of partitions may be increased by increasing the buffer pool size.
Page requests	This is the total number of times access was required to the buffer pool pages since the database was started.
Page faults	This is the number of page requests that resulted in disk access operations. If this value is more than 5-10% of the total number of page requests, performance can be improved significantly by increasing the buffer pool size.
Pages swapped out	This is the total number of pages which were written to disk when they were swapped out of the buffer pool.