kdb+ and q
Q+A on all things kdb+ database and the q language
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Heap is a lot larger than used, how to find the cause?

I've got a process doing some calculations on a timer and sending updated table to another process. Its heap is more than 3x of used even after manual trigger of .Q.gc. key value used 567774096 heap 1946157056 peak 2617245696 I'm using KDB+ 4.0 2021....

In-place attribute removal

Is there any way to do this? `# looks to always be creating a copy of the original list for `g/`u, whether it's applied on a list reference or value. I wrote a C function to set the list object's u member (x->u) to 0, and from within q called this fu...

Changing column type fails

Hello, I have a table that's loaded by some data from an odbc call and the structure is as follows: q)meta res c | t f a ----------| ----- id | C first_name| C last_name | C email | C Updating the column type for "id" to a symbol using the following ...

smdesai by New Contributor II
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Parallelising .Q.dpft with default compression enabled

.Q.dpft and why to parallelise it .Q.dpft can be split into 4 steps Find the index ordering of the table with iasc Enumerate table against sym file Save down table 1 column at a time, reordering and applying attributes as it goes Set .d file down Sin...