ron
Member
I've been collecting statistics using VST's for a few weeks. I'm curious about what's happening with AI and BI writes ... and thought someone might care to comment.
During a particular 15 minute period when batch processing was done last night:
AI: Partial Writes.... 17,785
AI: Total Writes...... 17,785
AI: AIW Writes....... 17,467
AI: Busy Buff Waits.. 167
BI: Partial Writes.... 8,768
BI: Total Writes...... 26,281
BI: BIW Writes....... 14,128
BI: Busy Buff Waits. 10,940
I've noticed that whether the system load is heavy or light, the exact same pattern persists:
(1) For AI the three "write" figures are very close. In particular: partial and total writes are nearly always identical and AIW writes is always 95% or more of all writes. Busy Buffer Waits is always very small.
(2) For BI, partial writes is always about 1/3rd of total writes. BIW writes is always about 50% of total writes. Busy Buffer Waits is always very high.
Why is there such a difference between the figures for AI and BI?
(I appreciate that the high incidence of partial writes is exacerbated by having the AI and BI block size set to 16K ... and in the near future we will be seeing what happens if that is reduced to 8K.)
Environment:
Sun V480 + Solaris 8 + Progress 9.1D06 + 16 GB memory.
DB: Striped across 8 x 36 GB discs; 8K block size. (3 x APW)
AI: Dedicated 36 GB disc; 16K block size. (AIW + 30 aibufs)
BI: Dedicated 36 GB disc; 16K block size. (BIW + 30 bibufs)
-B 27500
During a particular 15 minute period when batch processing was done last night:
AI: Partial Writes.... 17,785
AI: Total Writes...... 17,785
AI: AIW Writes....... 17,467
AI: Busy Buff Waits.. 167
BI: Partial Writes.... 8,768
BI: Total Writes...... 26,281
BI: BIW Writes....... 14,128
BI: Busy Buff Waits. 10,940
I've noticed that whether the system load is heavy or light, the exact same pattern persists:
(1) For AI the three "write" figures are very close. In particular: partial and total writes are nearly always identical and AIW writes is always 95% or more of all writes. Busy Buffer Waits is always very small.
(2) For BI, partial writes is always about 1/3rd of total writes. BIW writes is always about 50% of total writes. Busy Buffer Waits is always very high.
Why is there such a difference between the figures for AI and BI?
(I appreciate that the high incidence of partial writes is exacerbated by having the AI and BI block size set to 16K ... and in the near future we will be seeing what happens if that is reduced to 8K.)
Environment:
Sun V480 + Solaris 8 + Progress 9.1D06 + 16 GB memory.
DB: Striped across 8 x 36 GB discs; 8K block size. (3 x APW)
AI: Dedicated 36 GB disc; 16K block size. (AIW + 30 aibufs)
BI: Dedicated 36 GB disc; 16K block size. (BIW + 30 bibufs)
-B 27500