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From "一米阳光" <710339...@qq.com>
Subject re:scan performance super bad
Date Tue, 15 May 2018 02:40:03 GMT
>So it looks like you have a numeric value being stored here in the string >column. Are
you sure that you are properly zero-padding when creating your >key? For example if you
accidentally scan from "50_..." to "80_..." you >will end up scanning a huge portion of
your table.i'm sure they are properly zero-padding.
>What client version are you using? 1.7.0?i used 1.6.0
>Looks like you got the metrics from the kudu master, not a tablet server. >You need
to figure out which tablet server you are scanning and grab the >metrics from that one.oh
i have checked the metrics and find that rows_scanned is not much more than rows_returned.let
me describe the situation. data is like below, i add a column filter on dimension00 with value
'iphone',and the rows_scanned is about 5 times more than the rows_returned, so i think it
is reasonable.key              dimension00000001_time_0    iphone000001_time_1    android000001_time_2
   ipad000001_time_3    windows_phone000001_time_4    unkown
in addition, the leader of the tablet which store the target partition was killed by mistake,
and then a new leader comes up, i found that scan performance was much better. all server
config is same, the slow leader's workload is lower than the new one, but it's performance
is bad...do you have some config suggestions?
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