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Avoiding buffer manager thrashing
Example of -threads
option
Options string for Main cache: "-threads -file_suffix threads-iqmon -append
-interval 10"
CPUs
Limit NTeams MaxTms NThrds
10
100
10
100
10
100
10
100
10
100
10
100
10
100
Avoiding buffer manager thrashing
476
2
0
137
0
22
0
203
3
The results of the
-threads
2000-01-24 10:59:24
4
12
100
6
12
100
6
12
100
7
12
100
7
12
100
7
12
100
7
12
100
Operating system paging affects queries that need buffers which exceed the
free memory available. Some of this paging is necessary, especially as you
allocate more and more physical memory to your buffer caches. However, if
you overallocate the physical memory to your buffer caches, the operating
system paging occurs much more frequently, and it can cause your entire
system to thrash. The reverse is true as well: IQ thrashes if you do not allocate
enough memory to your buffer caches.
option look like the following:
Threads
Resrvd Free
Locks Waits
13
68
106
12
63
4
12
63
0
12
62
1
12
62
0
12
58
1
12
58
0
590
6
0
1
0
5
0
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