for hdb query, why is it fast when including where date>$date$

[renbright]

when I query HDB, it is always faster using date>$date$?  $date$ could be .z.d-10000, which is much larger than my earliest date in KDB.

[rocuinneagain]

Hi renbright - 

There are some posts showing how to embed code which will make your question more clear:

• Adding inline code to your questions & messages
• Creating q code block with syntax highlighting in a message

Can you share more complete example?

The second of these queries is faster because it reads less data:

//Retrieves data from all dates
select from table
//Retrieves only the last 5 days of data
select from table where date>(.z.d-5)

• Historical database
• Partitioned tables
• .z.d