I'll answer this since I happen to know, but these settings are not documented nor can they be modified.
Also, just curious why you want to know? Are you trying to maximize IO profiles or something?
PostgreSQL: 8k pages
Extracts: Based on the OS memory mapping settings
Hi Russel , Thank you for answering that . Are you sure about the above answer. I wish I could have some concrete documentation from Tableau on this .
Reason we are looking for this is to plan for our server side build out . What kind of storage requirement ( IOPS) we should expect and how we design it .
When you say - "Extracts: Based on the OS memory mapping settings" can you elaborate a little bit ?
1 of 1 people found this helpful
Yup, I'm sure. However, this stuff is supposed to be transparent, so you're not going to see any documentation on it.
Realistically, the best thing to do is set up a system, put it under load, and make sure your Average Disk sec / Transfer counter isn't getting above 15-20ms very often. Treat us like you would a database in terms of IOPS.
Here's a blog you might find interesting that gets into disk characteristics:
Memory mapping: Operating Systems use memory mapping to "map" a file on the file system and treat it as if it were physical RAM. Tableau takes advantage of this mechanism. The operating system generally has APIs available that allow you to control the page size used for memory mapping. If you know how to find/call/change these settings you could make the OS do what you need to in this regard - at the risk of making the OS perform terribly if you do the wrong thing
Thank you for the input about what you meant by "Based on the OS memory mapping settings" . I understand you are talking about paging ?
I just wish more was documented . Even in terms of DB products most often they document it . Example is Oracle states what block size they read and write and it is customizable .