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Storage engines | Tarantool
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Storage engines

Storage engines

A storage engine is a set of low-level routines which actually store and retrieve tuple values. Tarantool offers a choice of two storage engines:

  • memtx is the in-memory storage engine used by default.
  • vinyl is the on-disk storage engine.

Below you can find comparing of the two engines in brief. All the details on how each engine works you can find in the dedicated sections:

The primary difference between memtx and vinyl is that memtx is an in-memory engine while vinyl is an on-disk engine. An in-memory storage engine is generally faster (each query is usually run under 1 ms), and the memtx engine is justifiably the default for Tarantool. But on-disk engine such as vinyl is preferable when the database is larger than the available memory, and adding more memory is not a realistic option.

Option memtx vinyl
Supported index type TREE, HASH, RTREE or BITSET TREE
Temporary spaces Supported Not supported
random() function Supported Not supported
alter() function Supported Supported starting from the 1.10.2 release (the primary index cannot be modified)
len() function Returns the number of tuples in the space Returns the maximum approximate number of tuples in the space
count() function Takes a constant amount of time Takes a variable amount of time depending on a state of a DB
delete() function Returns the deleted tuple, if any Always returns nil
yield Does not yield on the select requests unless the transaction is committed to WAL Yields on the select requests or on its equivalents: get() or pairs()