[MonetDB-users] time for ssbm
hi, my query schema is SSBM.My database size is 65G.There are five tables :
lineorder 600038145 rows part 1400000 date 2556 supplier 1000000 customer 3000000 and my host have enough memory space up to 500G when i run query
select sum(lo_extendedprice*lo_discount) as revenue from voc.lineorder, voc.dates where lo_orderdate = d_datekey and d_weeknuminyear = 6 and d_year = 1994 and lo_discount between 5 and 7 and lo_quantity between 26 and 35;
the result is below
| revenue | +===============+ | 2605756481323 | +---------------+ 1 tuple (6.2s)
but if i delete the condition of " lo_discount between 5 and 7"
the run result is more faster than the original one.
query
select sum(lo_extendedprice*lo_discount) as revenue from voc.lineorder, voc.dates where lo_orderdate = d_datekey and d_weeknuminyear = 6 and d_year = 1994 and lo_quantity between 26 and 35;
+---------------+ | revenue | +===============+ | 7990711777299 | +---------------+ 1 tuple (410.451ms)
at the same time ,if i delete the condition of "lo_quantity between 26 and 35" the run result is more faster than the original one too.
query
select sum(lo_extendedprice*lo_discount) as revenue from voc.lineorder, voc.dates where lo_orderdate = d_datekey and d_weeknuminyear = 6 and d_year = 1994 and lo_quantity between 26 and 35;
+---------------+ | revenue | +===============+ | 7990711777299 | +---------------+ 1 tuple (463.617ms)
i am confused and if the semijoin costs a lot of execution time ? Thank you for your help.
best reguards,
guangliang peng
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guangliang peng