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Database Administration
Reference : Virtual System Tables : Virtual system table summaries : Buffer status (_BuffStatus)
 
Buffer status (_BuffStatus)
The _BuffStatus VST displays the status of buffers, such as the number of buffers that are in the buffer cache, that are currently in use, that are empty, or that are on the LRU chain, page writer queue, or checkpoint queue.1
Field name
Data type
Description
_BfStatus-APWQ
INTEGER
Number of buffers on the page writer queue.
_BfStatus-CKPMarked
INT64
Number of buffers currently marked for checkpoint.
_BfStatus-CKPQ
INTEGER
Number of buffers on the checkpoint queue.
_BfStatus-HashSize
INTEGER
Size of the buffer hash table.
_BfStatus-LastCkpNum
INTEGER
Most recent checkpoint number. As checkpoints begin, they are assigned a sequential number from the start of the session; the number is also the number of checkpoints that have occurred.
_BfStatus-LRU
INTEGER
Number of buffers on the least recently used (LRU) chain for both the primary and Alternate buffer pools.
_BfStatus-LRU2
INTEGER
Number of buffers on the least recently used (LRU) chain for the Alternate buffer pool.
_BfStatus-ModBuffs
INT64
Number of dirty (modified) buffers.
_BfStatus-TotBufs
INTEGER
Number of buffers in the buffer cache.
_BfStatus-UsedBuffs
INTEGER
Number of buffers used.
_BfStatus-LRU-Skips
INTEGER
Number of times a buffer in the buffer pool is accessed before being placed on the end of the LRU chain.
_BfStatus-LRU2-Skips
INTEGER
Number of times a buffer in the alternate buffer pool is accessed before being placed on the end of the LRU chain.
1 Activity and status of ABL temp-tables is available in this virtual system table. The statistics gathered allow you to monitor the operation and performance of deployed client temp-tables. Specify the range of temp-tables to track with the -ttbasetable and -tttablerangesize startup parameters. Specify temp table indexes with -ttbaseindex and -ttindexrangesize startup parameters. For more information monitoring and debugging temp tables with VSTs, see OpenEdge Development: Debugging and Troubleshooting.