Document Crate's Features & Storage Details

[robertjpayne]

Crate looks extremely exciting! While evaluating it, and I'm sure others too, there is little information provided on some of the following:

• ACID Properties
• Consistency Guarantees (How is replication done…)
• Transactional Support (If any…)
• Storage Durability (In what scenarios could data loss occur due…)
• Index Types (Geo, Full Text, Composite etc…)

I've tried to find any of the above through the web docs or the Github repo but have not found much other than Full Text support.

[dobe]

hi @robertjpayne thanks for looking at crate - see my answers inline. we hope to get everything into the main documentation as soon as possible.

Consistency Guarantees (How is replication done…)
replication is done synchronously. which means that a write only succeeds if all replicas of a given shard are written successfully

Transactional Support (If any…)
crate has no transaction support, however OCC is supported, see https://crate.io/docs/current/sql/occ.html

Storage Durability (In what scenarios could data loss occur due…)
with replication turned on, data loss can only occur if all replicas and the primary shard dies at the same time.

currently crate supports to do an off site dump via the copy/from/to statement, see https://crate.io/docs/current/sql/dml.html#importing-data but we also have PITR like features on our backlog.

Index Types (Geo, Full Text, Composite etc…)
we use elasticsearch libraries and lucene under the hood, so there are a lot of possibilities here, see https://crate.io/docs/current/sql/ddl.html#indices-and-fulltext-search

hope this, helps

[chaudum]

this information can be found in the latest documentation: https://crate.io/docs/en/latest/storage_consistency.html (will be in the stable section as soon as 0.46 is stable)