Concurrency Control

Multi-version Concurrency Control (MVCC)

GridDB adopts MVCC to realize READ_COMMITTED. It improves throughput as multiple transactions can access data that is prior to the update concurrently.

Views

Not Supported

System Architecture

Shared-Nothing

GridDB has a master-slave architecture. All nodes in the cluster contain partitioned data and one node acts as the master. If the master node fails, an election is held quickly and another node is promoted to be the master.

Query Interface

Custom API SQL HTTP / REST Command-line / Shell

GridDB has a Web-application GUI (gs_admin) and command line tool (gs_sh) that integrates cluster operations. GridDB also provides official C and Java based custom API for management operations and basic data extraction. For more complicated queries, GridDB supports TQL, which is a small subset of SQL including search and aggregation.

Indexes

B+Tree Hash Table

GridDB has three types of index: hash index (HASH), tree index (TREE) and space index (SPATIAL). Hash index is used in equivalent-value search and tree index is used in comparison such as range search. The data structure of tree index is B+Tree.

Joins

Not Supported

GridDB does not support JOIN operation, you have to take effort to implement your own comparable operation.

Data Model

Key/Value

The data model of GridDB is key-container model which extends typical NoSQL Key-Value store. Containers are comparable to tables in Relational Database and consist of two types: Collection Container for general purpose; and TimeSeries Container for time series data where each tuple in the container is associated with a timestamp as ROWKEY.

Storage Architecture

Hybrid

GridDB has "Memory first, Storage second" structure where frequently accessed data is stored in memory and the rest is passed on to disks (SSD and HDD).

Stored Procedures

Not Supported

Isolation Levels

Read Committed

GridDB supports READ_COMMITTED as transaction isolation level.