The onstat -g rah command displays the read-ahead request statistics. For more details about the Read Ahead changes read this PDF
Read Ahead # threads 4 # Requests 34679 # Continued 2048 # Memory Failures 0 Q depth 0 Last Thread Add 05/17/2013.14:50 Partition ReadAhead Statistics Buffer Disk Hit Data Index Idx/Dat Partnum Reads Reads Ratio # Reqs Eff # Reqs Eff # Reqs Eff 0x200003 2412176 587381 75 0 0 150499 67 0 0
Option | Description |
---|---|
# threads | Number of read-ahead threads |
# Requests | Number of read-ahead requests |
# Continued | Number of times a read-ahead request continued to occur |
# Memory Failures | Number of failed requests because of insufficient memory |
Q Depth | Depth of request queue |
Last Thread Add | Date and time when the last read-ahead thread was added |
Partnum | Partition number |
Buffer reads | Number of bufferpool and disk pages that were read |
Disk Reads | Number of pages that were read from disk |
Hit Ratio | Cache hit ratio for the partition |
# Reqs | Number of data page read ahead requests. |
Eff | Efficiency of the read-ahead requests. This is the ratio been the number of pages requested by read-ahead operations to the number of pages that were already cached and for which a read-ahead operations was not needed. Values are between 0 and 100. A higher number means that read ahead is beneficial. |
To discuss how Oninit ® can assist please call on +1-913-674-0360 or alternatively just send an email specifying your requirements.