Preface

TideSQL is a pluggable storage engine for MariaDB, built on the TidesDB library. It lets a MariaDB table keep its data in a TidesDB log-structured merge tree instead of InnoDB, reachable through ordinary SQL. Switching a table from InnoDB to TidesDB is a change to the ENGINE clause and nothing more.

This is the TideSQL 5.x manual, the storage engine for TidesDB v10.x.x, and the companion to the TidesDB library manual. It tracks the 5.x line as a whole, so a minor or patch release extends this manual rather than starting a separate one. Where this book says “the library” it means TidesDB, and where it needs to explain a storage behavior in depth it points at the library manual rather than repeating it.

What it is

Transactional, through the library’s multi-version concurrency control, so readers proceed without blocking writers.
A full SQL engine surface, with primary keys, secondary indexes, foreign keys, auto-increment, virtual and stored generated columns, savepoints, TTL expiration, data-at-rest encryption, full-text, vector and spatial indexes, online DDL, partitioning, and online backup, all reached through standard SQL.
Log-structured, so it favors write throughput, with compaction keeping read cost bounded.

What it is not

Not a fork of InnoDB. The concurrency model is optimistic MVCC from the library rather than InnoDB’s pessimistic row locks, which changes how write contention behaves. The Transactions chapter is the one to read before porting a contention-heavy workload.
Not a distributed system on its own. The engine stores data on one node, and clustering comes from the layers above it. Within those layers TideSQL is a first-class participant in both MariaDB replication and Galera, with engine-level write-set certification and cross-node conflict resolution rather than a generic pass-through. See Replication and High Availability.
Not a place to relearn the library. The on-disk format, compaction, and recovery all belong to TidesDB and are documented in its manual.

Who this manual is for

If you are putting tables on TideSQL, read Getting Started, then Concepts, and keep the SQL Reference nearby.

If you are operating a server that uses it, Administration covers monitoring, backup, maintenance, online DDL, and partitioning.

If you want to know how a row becomes bytes on disk, Internals covers the storage layout, the optimizer integration, and the write-path optimizations the engine layers over the library.

Where the engine keeps its data

TidesDB data files live in a sibling directory of the MariaDB data directory named tidesdb_data, and the engine manages that layout itself. The location can be overridden with the read-only tidesdb_data_home_dir system variable.