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CPUSPEEDNW 2894.14695
IOSEEKTIM 10
IOTFRSPEED 4096
SREADTIM
MREADTIM
CPUSPEED
MBRC
MAXTHR
SLAVETHR
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（11）隐含参数：
SQL> @?/rdbms/admin/show_para
Enter value for p: table_scan_cost
old 12: AND upper(i.ksppinm) LIKE upper(‘%&p%‘)
new 12: AND upper(i.ksppinm) LIKE upper(‘%table_scan_cost%‘)
P_NAME P_DESCRIPTION P_VALUE ISDEFAULT ISMODIFIED ISADJ
---------------------------------------- -------------------------------------------------- ------------------------------ --------- ---------- -----
_table_scan_cost_plus_one bump estimated full table scan and index ffs cost TRUE TRUE FALSE FALSE
by one
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（12）IO成本
I/O Cost = 1 + CEIL(#MRds * (mreadtim / sreadtim))
/O Cost = 1 + CEIL(23.125 * ((10+16*8192/4096) / (10+8192/4096)))
SQL> select 1 + CEIL(23.125 * ((10+16*8192/4096) / (10+8192/4096))) from dual;
1+CEIL(23.125*((10+16*8192/4096)/(10+8192/4096)))
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? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?82
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(13)CPU成本
CPU Cost = ROUND(#CPUCycles / cpuspeed / 1000 / sreadtim)
ROUND(17634933/ 2894.14695 / 1000 / (10+8192/4096))=1
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