partitioning - How to see which MySQL partitions are chosen? -


i'm running query against partitions table performance terrible. have feeling doing full table scan instead of scan of 2 or 3 partitions. partition key in clause.

is there way can check partitions looked @ answer query? there explain tell me partitions use?

any tips using partitions in joins?

i'm using mysql 5.6.11

thanks

try use

explain partitions  select *  tbl1  inner join tbl2 on tbl1.id=tbl2.id

Comments

Post a Comment

Popular posts from this blog

matlab - Deleting rows with specific rules -

i got 20*3 cell array , need delete rows contains "137", "2" , "n:t" origin data: 't' '' '' 'np(*)' '' '' [ 137] '' '' [ 2] '' '' 'are' 'and' 'np(fcc_a1#1)' '' '' '1:t' [ 1200] [0.7052] '' [1.2051e+03] [0.7076] '' 'are' 'and' 'np(fcc_a1#3)' '' '' '2:t' [ 1200] [0.0673] '' [1.2051e+03] [0.0671] '' 'are' 'and' 'np(m23c6)' '' '' '3:t' [ 1200] [0.227...
Read more

image - ClassNotFoundException when add a prebuilt apk into system.img in android -

i'm in trouble add prebuilt apk system.img based taiwan mtk android phone platform, when push apk onto device,after reboot phone,the apk can installed succecessfully,but if add apk alps/out/target/product/$prj/system/app or vendor/mediatek/$prj/artifacts/out/target/product/$prj/system/app ,and produce system.img,the apk can't installed normally,the logcat say: a.lang.runtimeexception: unable instantiate activity componentinfo{com.sec.android.widgetapp.ap.hero.accuweather.widget/com.sec.android.widgetapp.ap.hero.accuweather.widget.weatherclock}: java.lang.classnotfoundexception: com.sec.android.widgetapp.ap.hero.accuweather.widget.weatherclock. can tell me what's problem ? when package manager installs apps part of system partition different installing apps on data partition. looks app using libraries somewhere else. when install on data lib directory created in apps data directory , symlinked /data/app-lib/. when apps installed on system it's expecte...
Read more