Developer Tools
Questions related to KX Developer Tooling
cancel
Showing results for 
Search instead for 
Did you mean: 

Forum Posts

how to append a new column to hdb file?

hi, I have stored some hdb files, but, now, I have to modify the table schema, so the hdb data need to be modified too. Is there a function for me to add a new column to the hdb files directly?

Isaac by New Contributor
  • 574 Views
  • 2 replies
  • 0 kudos

RE: [personal kdb+] unique index

X-Originating-IP: 174.7.132.159User-Agent: Workspace Webmail 5.16.0Message-Id: <20160101200302.85f80dae80d1d2f2e266ec6278e6cbe8.4a08ca37d3.wbe@email07.europe.secureserver.net>From: "David Demner \(AquaQ\)" To: personal-kdbplus@googlegroups.comSubject...

unique index

Why is unique index not improving performance in this case? Furthermore, applying group attribute on cust column in table a surprising makes this 10x slower. Why? n:1300000a:([]cust:n?`8; v1:n?100; v2:n?100; v3:n?100)/ with unique indexb1:`u#exec dis...

Sam1 by New Contributor
  • 301 Views
  • 0 replies
  • 0 kudos

optimize ungroup columns operation in kdb

I am trying to flatten some columns of a table into a single column. My current approach is to enlist those columns into a single column and then use ungroup on table to flatten it. But this approach is very inefficient, takes more than 2 seconds on ...

Sam1 by New Contributor
  • 256 Views
  • 0 replies
  • 0 kudos