ThumbBase

An in-memory key/value store with support for transaction blocks, rollbacks, and commits.

Installation:

npm install

To start:

npm start

Run tests:

npm test

Performance:

The app uses Javascript Objects {} in place of re-implementing hash tables.

In constant time O(1), Thumbase can set, get, and unset keys, as well as retrieve a count NUMEQUALTO for the number of currently stored instances of a value.

At the expense of space, NUMEQUALTO maintains constant time access to value counts by storing the values in a separate hash table.

Thumbase maintains a stack for a transaction block that becomes active on the BEGIN command. When COMMIT is called, the stack is purged and the changes remain written. If ROLLBACK is called before COMMIT, the changes are undone in linear time 0(n). (n === number of transaction commands in the stack, NOT the number of keys/values stored).

Thumbase handles nested transaction blocks. A new block is instantiated on every BEGIN command. This allows for a ROLLBACK to a previous block that is in-progress and not yet committed.

API:

The command line interface will prompt a user for a command. Simply use any of the valid commands, as indicated below:

> SET a 10

> GET a
  10
 
> SET a 20
> NUMEQUALTO 10
  0
 
> NUMEQUALTO 20
  1
 
> BEGIN
 
> SET a 30
 
> GET a
  30
 
> ROLLBACK
 
> GET a
  20
 
> unset a
 
> COMMIT
 
> GET a
  null

Contact:

Adam D. Richman 
1271 McAllister St. San Francisco, CA 94115
ar@adamrichman.com | www.adamrichman.com | 212-417-0714