在2008-11-12，"Michael Stack" <[EMAIL PROTECTED]> 写道：
>王凯 wrote:
>>
>>
>>
>>
>>
>> 在2008-11-12，"Michael Stack" <[EMAIL PROTECTED]> 写道：
>>
>>> 王凯 wrote:
>>>
>>>> hello, every one. i used to test the performance in PE, but the
>>>> performance is not well enough.
>>>>
>>> Please say more. What kind of numbers were you getting?
>>>
>>>
>>>> especially, the table format is not as what i need. so, i create a table
>>>> and write some string in every cell. then, i use the count , the count
>>>> time is the count_1 time.
>>>> after all, i count all the tables again, the count time is the count_2
>>>> time. count_2 time is almost half of the count_1 time!
>>>>
>>>> i do not know why this happened, perhaps cache?
>>>>
>>>>
>>> Perhaps. If you enable DEBUG and look in the regionserver log, you can
>>> see log of cache hits and misses. Try and get general sense of how
>>> first run compares to second. Are your reads random or serial? If
>>> serial, then yeah, cache is going to help.
>>>
>> thanks, i am a new comer
>> when the data would be in cache? some times , the count time is never change!
>>
>
>Are you using hbase TRUNK? If so, and if your checkout was recent,
>you'll see benefit/disadvantage of cache.
hadoop 0.18.1, hbase 0.18.0. I do not use TRUNK , any useful update?
what do you mean the disadvantage of cache?
>
>
>>>> column row cell write count_1 count_2
>>>> 10 10000 10B 17.2 13.5 7.2
>>>> 10 10000 50B 17 13.1 7.3
>>>> 10 10000 200B 19.7 13.6 7.6
>>>> 10 100000 10B 128.4 131.5 74.7
>>>> 10 100000 50B 134.6 143.1 66.2
>>>> 10 100000 200B 138.1 100.1 77.3
>>>>
>>>>
>>>>
>>> What is above saying? That in column 10, you wrote 1000 items of size
>>> ten bytes? The write took 17.2ms, first read 13.5ms and the second 7.2ms?
>>>
>>>
>>
>> sorry, i did not explain this clearly. there is 10 columns in the table,
>> 10000 rows in a column ,and the 10Bytes in a row
>> the time is 17s, 13.5s, 7.2s
>>
>>
>10000 rows in a column? Do you mean 10000 rows in the table and each row
>has an entry in the column? Or do you mean 10 rows in the table and each
>row has 10000 columns?
>
10000 rows in the table and each row has an entry in the column
>
>17seconds, 13.5seconds and 7.2seconds are not what we usually see. Tell
>us more about your hardware setup.
DELL PowerEdge 430 , P4 2.8G, 1G Memory. Tooooo poor!
>Thanks,
>St.Ack
