Forum: Building VoltDB Applications

Post: Changing the data structure

Changing the data structure
henning
Feb 8, 2010
How much effort will it be, say arround version 1.0, to change the database structure?

Namely adding fields, renaming fields? Will that work on-the-fly or would the system have to be halted?


Thanks,
Henning
Changing the database structure
bheath
Feb 8, 2010
In version 1.0 you will be able to change your stored procedures while the database is running. To change the schema, you will need to do a save of the database, recompile your catalog with the desired schema changes, and reload your database with the new catalog. Shortly after V1 we will begin adding the ability to change the schema while the database is running.

- Bobbi
Timeline
henning
Feb 8, 2010
In version 1.0 you will be able to change your stored procedures while the database is running. To change the schema, you will need to do a save of the database, recompile your catalog with the desired schema changes, and reload your database with the new catalog. Shortly after V1 we will begin adding the ability to change the schema while the database is running.

- Bobbi

Is there a rough prediction when V1 and shortly after may be?
re: Timeline
bheath
Feb 8, 2010
Is there a rough prediction when V1 and shortly after may be?

Version 1 will ship in late Q2, and we will have to weigh the feature requests that come in to decide which to work on first in the next release. This one is likely to be widely requested!

- Bobb
Two ways to change the table structure and content?
chbussler
Apr 6, 2010
Version 1 will ship in late Q2, and we will have to weigh the feature requests that come in to decide which to work on first in the next release. This one is likely to be widely requested!

- Bobb

Hi,

let's assume that after V1 I can dynamically change the table structure. I assume that I can still do it the current way, i.e, shutting down, changing the definition, and starting up again?

Thanks,
Christoph
Changing schema
tcallaghan
Apr 6, 2010
Hi,

let's assume that after V1 I can dynamically change the table structure. I assume that I can still do it the current way, i.e, shutting down, changing the definition, and starting up again?

Thanks,
Christoph

Christoph,

In the post V1 version where we support changing the schema on a running system you will still be able to modify the schema when VoltDB is shut down.

In the current version you can create a snapshot, shut down, modify schema, start up, and restore the snapshot. If you added columns to a table in the snapshot the column will assume its default value on snapshot restore. If you removed columns the snapshot will still restore the table data (minus the removed column(s), of course).

-Tim
Sql ddl
chbussler
Apr 3, 2010
Hi,

how do I delete a table?

Thanks,
Christoph
Changing the data structure
bheath
Apr 3, 2010
Henning and Christoph,

In version 1.0 in order to change the schema, you will need to stop data input, do a save of the database, recompile your catalog with the desired schema changes, and reload your database with the new catalog. Shortly after V1 we will begin adding the ability to add/remove/modify attributes and tables while the database is running.

Bobbi