Re: Postgresql Sort cost Poor performance?

Thank you for your reply. 

qis3_dp2=>  SHOW lc_collate;
 lc_collate  
-------------
 en_US.UTF-8
(1 row)

Time: 0.311 ms
qis3_dp2=> 

qis3_dp2=> SELECT COUNT(DISTINCT SVIN) AS CHECKCARNUM ,SMTOC FROM
QIS_CARPASSEDSTATION A WHERE 1=1 AND A.SSTATIONCD = 'VQ3_LYG' AND
A.SLINYYY-MM-DD') AND A.DWORKDATE <= TO_DATE('2019-03-11','YYYY-MM-DD')
group by  SMTOC
;
 checkcarnum |         smtoc         
-------------+-----------------------
          90 | HT6LHD700 NH731P    A
         690 | HT6LHD700 NH788P    A
          90 | HT6LHD700 R550P     A
          30 | HT6LHD700 YR615M    A
        1141 | HT6MHB700 NH731P    A



Is there any possibility of optimization?





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