How to set max bucket in canvas?

[Yungyoung_Ok (ooyy)]

I want to count the number every second to get the maximum count.
So i'm trying to group by my_date_field.

SELECT SUBSTR(CONCAT(TO_CHAR(my_date_field)),4), COUNT(*) FROM "my_index_name" GROUP BY SUBSTR(CONCAT(TO_CHAR(my_date_field)),4)

but TO_CHAR is unknown function...
and i show like this..

Date format parsing exception

I have create_date column as timestamp in database and need create_date value in elastic as "MM/DD/YYYY" or "yyyy-MM-dd" . I am getting below error exception while loading data from oracle database using logstash 2.4. SQL: select to_date(to_char(cast(create_date as date),'MM/DD/YYYY') ,'MM/DD/YYYY') from table X. exception. "error"=>{"type"=>"mapper_parsing_exception", "reason"=>"failed to parse [create_date]", "caused_by"=>{"type"=>"illegal_argument_exception", "reason"=>"In…

my_date_field format is strict_date_time(yyy-MM-dd'T'HH:mm:ss.SSSZZ).

how can i set to get max records?