[20190219]xargs -P实现并行执行.txt
[20190219]xargs -P实现并行执行.txt
--//上午做测试,链接http://blog.itpub.net/267265/viewspace-2636342/,我的执行脚本,使用host read -p 'wait finish...'.
--//这样很蛮烦,因为许多测试需要5分钟完成,我必须时不时看看脚本完成是否完成,非常繁琐,是否可以通过shell内部的wait等后台
--//任务完成,自动下一步操作.
--//google : xargs wait ,发现如下链接:
https://stackoverflow.com/questions/51410472/bash-wait-for-process-substitution-subshell-to-finish
https://serverfault.com/questions/819028/bash-script-wait-for-all-xargs-processes-to-be-finished
https://stackoverflow.com/questions/30924350/use-xargs-to-wait-for-enter-key
https://unix.stackexchange.com/questions/477971/call-a-command-wait-then-execute-another-command
--//看了许多链接感觉都不是很好,都需要写shell脚本.我仔细看了xargs文档,发现都忘了xargs支持-P参数可以实现并行操作.
$ time seq 10 | xargs -I{} -n1 bash -c "sleep {} "
real 0m55.040s
user 0m0.010s
sys 0m0.026s
--//这样脚本需要55秒完成.
$ echo {1..10} | sed -e 's/ /+/g' | bc -l
55
$ time seq 10 | xargs -I{} -n1 -P10 bash -c "sleep {} "
real 0m10.008s
user 0m0.010s
sys 0m0.026s
--//如果并行,这样就需要10秒完成.
--//修改脚本如下:
$ cat cc.txt
delete from job_times;
commit ;
drop table t purge;
create table t as select rownum id from dual ;
execute sys.dbms_stats.gather_table_stats ( OwnName => user,TabName => 't',Estimate_Percent => NULL,Method_Opt => 'FOR ALL COLUMNS SIZE 1 ',Cascade => True ,No_Invalidate => false);
alter procedure do_work compile ;
alter procedure do_work1 compile ;
host sleep 3
host seq &&1 | xargs -I{} -n1 -P &&1 bash -c "sqlplus -s -l scott/&&2 <<< \"execute do_work(&&3,'null')\" " > /dev/null 2>&1
host sleep 1
create unique index pk_t on t(id);
alter table t modify (id not null);
host seq &&1 | xargs -I{} -n1 -P &&1 bash -c "sqlplus -s -l scott/&&2 <<< \"execute do_work(&&3,'notnull')\" " > /dev/null 2>&1
host sleep 1
host seq &&1 | xargs -I{} -n1 -P &&1 bash -c "sqlplus -s -l scott/&&2 <<< \"execute do_work1(&&3,'id=1_unique_index')\" " > /dev/null 2>&1
host sleep 1
drop index pk_t ;
create index pk_t on t(id);
host seq &&1 | xargs -I{} -n1 -P &&1 bash -c "sqlplus -s -l scott/&&2 <<< \"execute do_work1(&&3,'id=1_index')\" " > /dev/null 2>&1
host sleep 1
alter table t result_cache (mode force);
host seq &&1 | xargs -I{} -n1 -P &&1 bash -c "sqlplus -s -l scott/&&2 <<< \"execute do_work(&&3,'result_cache')\" " > /dev/null 2>&1
host sleep 1
--//因为这样完成在启动新的任务,不用时不时查看.
--//重复测试看看:
SCOTT@book> @ cc.txt 50 book 1e6
....
--//测试结果如下:
SCOTT@book> select method,count(*),round(avg(TIME_ELA),0),sum(TIME_ELA) from job_times group by method order by 3 ;
METHOD COUNT(*) ROUND(AVG(TIME_ELA),0) SUM(TIME_ELA)
-------------------- ---------- ---------------------- -------------
result_cache 50 8542 427111
id=1_unique_index 50 9526 476293
null 50 10761 538056
id=1_index 50 29453 1472659
notnull 50 30639 1531925
--//10g下的测试结果:
SCOTT@test> select method,count(*),round(avg(TIME_ELA),0),sum(TIME_ELA) from job_times group by method order by 3 ;
METHOD COUNT(*) ROUND(AVG(TIME_ELA),0) SUM(TIME_ELA)
-------------------- ---------- ---------------------- -------------
id=1_unique_index 50 4829 241474
notnull 50 33711 1685566
id=1_index 50 34647 1732330
null 50 38203 1910151
--//细节就不再说明了.
来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/267265/viewspace-2636382/，如需转载，请注明出处，否则将追究法律责任。
转载于:http://blog.itpub.net/267265/viewspace-2636382/