Reval on 4.0 with Segmented tables

[sujoy]

Hi All,

On segmented Tables , eg:

/.../1
    /2021.01.01/tab/
    ...
/.../2
    /2021.01.02/tab/
    ...

When I load my process from root:

/.../db
   sym
   par.txt


# cat par.txt
# /.../1
# /.../2

If I add reval on 4.0, which default to having -u 1 , I am getting access error as -u 1 does not allow read above current directory over IPC

// Server
.z.pg:{reval(value;enlist x)}

// Client
q)h"select from tab where date=.z.d-1"
'access: /.../2/2021.12.09/tab/sym
  [0]  h"select from tab where date=.z.d-1"

The only workaround I could think of is to move to root directory under which the segments exists :

\cd ..

Now it starts working over IPC.

1. Is this done for a reason in 4.0?

2. Is there any other way?

[LeahS]

Very interesting observation here @sujoy13

Thanks for sharing with the community. Looking forward to learning from the feedback received 🙌

[LeahS]

In fact, we have some internal feedback to share: 

A FIX from 4.0 README.txt (attached) is a likely explanation here. 

Hope this is satisfactory for you.

Kind regards,

Leah 

[sujoy]

Thanks for this @leah_marie_s , I get the idea why this was done.

However, doesn't this defeat the purpose of having segmented tables while using reval on 4.0? 

If you check here on kx website segment  the design of par.txt, this will not allow access to run select on HDB's on 4.0 and if reval is enabled. 

[LeahS · Accepted solution]

For the purpose of this topic thread and our fellow community members, the internal advice shared was a workaround by creating symlinks under the main hdb dir, pointing to the relevant directories above. 

Thanks again for sharing with the community,

Leah 

[matt_moore]

Are there any better suggestions? just encountered this problem and this work around doesn't seem feasible for a structure like this

/.../SYM1
    /2021.01.01/tab/
    ...
/.../SYM2
    /2021.01.01/tab/
    ...

[sujoy]

Thanks Matt, did not think of this scenario.

I really hope we have a more permanent fix for this in future release.