Ignite Facts
This is a legacy Apache Ignite documentation
The new documentation is hosted here: https://ignite.apache.org/docs/latest/
Is Ignite a persistent or pure in-memory storage?
Both. Native persistence in Ignite can be turned on and off. This allows Ignite to store data sets bigger than can fit in the available memory. Essentially, the smaller operational data sets can be stored in-memory only, and larger data sets that do not fit in memory can be stored on disk, using memory as a caching layer for better performance.
Is Ignite a distributed database?
Yes. Data in Ignite is either partitioned or replicated across a cluster of multiple nodes. This provides scalability and adds resilience to the system. Ignite automatically controls how data is partitioned, however, users can plug in their own distribution (affinity) functions and collocate various pieces of data together for efficiency.
Is Ignite a relational SQL database?
Not fully. Although Ignite aims to behave like any other relational SQL database, there are differences in how Ignite handles constraints and indexes. Ignite supports primary and secondary indexes, however, the uniqueness can only be enforced for the primary indexes. Ignite also does not support foreign key constraints.
Essentially, Ignite purposely does not support any constraints that would entail a cluster broadcast message for each update and significantly hurt performance and scalability of the system.
Is Ignite an in-memory database?
Yes. Even though Ignite durable memory works well in-memory and on-disk, the disk persistence can be disabled and Ignite can act as a pure in-memory database.
Is Ignite a transactional database?
Not fully. ACID Transactions are supported at the key-value API level. Ignite also supports cross-partition transactions, which means that transactions can span keys residing in different partitions on different servers.
Ignite 2.7 introduces support for SQL transactions based on the MVCC implementation. The SQL transaction support is currently in beta.
Is Ignite a key-value store?
Yes. Ignite provides a feature rich key-value API, that is JCache (JSR-107) compliant and supports Java, C++, and .NET.
Is Ignite an in-memory data grid?
Yes. Ignite is a full-featured data grid, which can be used either in pure in-memory mode or with Ignite native persistence. It can also integrate with any 3rd party database, including any RDBMS or NoSQL store.
What is durable memory?
Ignite durable memory architecture allows Ignite to extend in-memory computing to disk. It is based on a paged-based off-heap memory allocator which becomes durable by persisting to the write-ahead-log (WAL) and, then, to main Ignite persistent storage. When persistence is disabled, durable memory acts like a pure in-memory storage.
What is collocated processing?
Ignite is a distributed system and, therefore, it is important to be able to collocate data with data and compute with data to avoid distributed data noise. Data collocation becomes especially important when performing distributed SQL joins. Ignite also supports sending user logic (functions, lambdas, etc.) directly to the nodes where the data resides and computing on the data locally.
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Updated almost 6 years ago