Isolation Levels

Read Committed

InfiniDB adopts Read Committed isolation level which means that only committed data can be read by users. Every operation in InfiniDB only runs on a snapshot of the system, which achieves a Read Committed Snapshot behavior. It guarantees that reads are not blocked by writes because it works on a snapshot version.

Views

Virtual Views

Since InfiniDB's columnar storage model and range-partitioned storage of each column, each table is already column-wise and row-wise partitioned. Thus, InfiniDB does not store any materialized views to save space and reduce maintenance difficulty. However, it still supports virtual views to be consistent with MySQL syntax.

System Architecture

Shared-Nothing Shared-Disk

InfiniDB suppports two architectures, shared-disk or shared nothing. It can be configured by the administrator while setuping the system.

Storage Architecture

Disk-oriented

Logging

Command Logging

InfiniDB stores all DDL and DML statements as transaction log, which is essentially command logging.

Foreign Keys

Supported

InfiniDB uses MySQL as its front-end and supports all MySQL syntaxes, including foreign keys.

Query Interface

SQL

InfiniDB uses MySQL syntax, which is a SQL interface.

Query Execution

Tuple-at-a-Time Model

In InfiniDB, every job step of the execution plan has a input data list and output data list. Data list has defined iterator and next method, which allows the system to process one tuple at a time.

Joins

Hash Join Sort-Merge Join Semi Join

Concurrency Control

Multi-version Concurrency Control (MVCC) Two-Phase Locking (Deadlock Detection)

InfiniDB applies MVCC to do concurrency control. It uses term System Change Number (SCN) to indicate a version of the system. In its Block Resolution Manager (BRM), it utilizes three structures, Version Buffer, Version Substitution Structure (VSS), and Version Buffer Block Manager, to manage multiple versions. InfiniDB applies deadlock detection to resolve conflicts.

Storage Model

Decomposition Storage Model (Columnar)

Since InfiniDB is an analytic database optimized for OLTP workloads, columnar storage model is a better choice. In this way, I/O activities for selective queries can be reduced as it only needs to fetch relevant columns.

Data Model

Relational

Indexes

Not Supported

InfiniDB is a columnar DBMS. For each column, InfiniDB applies range partitioning and stores the minimum and maximum value of each partition in a small structure called Extent Map. In InfiniDB, Extent Map is only updated when the first query happens after data manipulation. rather than at the point of data manipulation.