A Practical Hardware Sizing Guide for Sybase IQ

These properties can be queried using the SQL Anywhere property() function. Since these
properties represent instantaneous values, they need be queried frequently while evaluating the
workload to capture the worst case values.
The following SQL will take 100 samples at 5 second intervals and calculate the maximum cache
usage:
begin
end;
declare c1 int;
declare local temporary table #tmp1(ar bigint, lp bigint) in SYSTEM;
set c1 = 0;
lp: loop
set c1 = c1 + 1;
if c1 > 100 then
leave lp
end if;
insert #tmp1 select property('ActiveReq'), property('LockedHeapPages');
waitfor delay ‟00:00:05‟;
end loop;
select max(lp) as MaxLockedHeapPages,
max(ar) as MaxActiveReq ,
max(lp)/max(ar) as AvgPagesPerRequest
from #tmp1;
The maximum number of requests that can be executed concurrently can now be calculated
using the cache size and request size as follows:
MaxActiveReq = CurrentCacheSizeKB / PageSizeKB / AvgPagesPerRequest
Assuming that the current cache is set to 256 MB, the catalog page size is 4 KB, and the average
pages per request is 500, the total number of concurrent active requests would be:
Versioning
MaxActiveReq = ( 256 * 1024) / 4 / 500
MaxActiveReq = 131.072 rounded down to 131
Version memory is allocated during runtime of the Sybase IQ engine. Generally, this is a very
small amount of RAM (1K-3K per version being tracked). Typically, the total version memory
used is measured in KB or single digit MB sizes. On systems with hundreds of thousands or
millions of versions currently active, this can become significant.
Load Memory
Beginning with IQ 15.0 most load memory requirements for bulk load operations were
eliminated.
With IQ 15.2 all load memory requirements were removed.
Load memory in IQ 15.0 and 15.1 was reduced to only being used for fixed width data loads. All
delimited and binary data load operations use IQ temporary cache for load memory.
The fixed width data loads continue to adhere to the following algorithms and guidelines for
sizing load memory.
Final
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