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Rtrader
Rtrader

Reputation: 947

Saving all tables,variables, and functions of a KDB+ instance and then reloading

Is there a simple way to save all tables,variables and fucntions and then reload them into another kdb+ instance? For example, lets say my machine is set to restart weekly but I want reload everything that was in my kdb+ session before the restart.

Thanks.

Upvotes: 2

Views: 1362

Answers (2)

Connor Gervin
Connor Gervin

Reputation: 946

If you want something out of the box for maintaining variable state(tables/dicts/lists/atom), then have a look at http://code.kx.com/q/cookbook/logging/

/cmdline startup
q db_main -l -p 8090

/To store state before the restart, modify .z.exit to flush to the qdb file 
.z.exit:{value"\\l"}

This will not cover functions however, but ideally these shouldn't be changing anyway.

If you really need to save these you can look at saving all namespaces to disk.

.z.exit:{`:/tmp/ns set get each {x!x}`$".",/:string key`}

/on startup
{{y set x[y]}[x;]each key x} `.q`.Q _ get `:/tmp/ns

Regards,

Connor

Upvotes: 2

Ryan Hamilton
Ryan Hamilton

Reputation: 2605

Save the state to file using set/get. This is limited to small workspaces.

>q
KDB+ 3.4 2016.06.14 Copyright (C) 1993-2016 Kx Systems

q)a:1
q)t:([] b:til 100)
q)s:select from t where b<5
q)`:session.bin set get `.
`:session.bin
q)\\

>q
KDB+ 3.4 2016.06.14 Copyright (C) 1993-2016 Kx Systems

q)`. set get `:session.bin
`.
q)a
1
q)s
b
-
0
1
2
3
4

Logging and snapshots is an alternative: http://www.timestored.com/kdb-guides/kdb-command-line-options#kdb-logging-replication

Upvotes: 1

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