@TwitchiH & @fredbrancz Prometheus Deep Dive Introduction Intro 2.0 to 2.2.1 2.4 - 2.6 Beyond Outro ACID ACID databases... Atomicity - since 1.x Consistency - since 1.x Isolation - will happen within 2 @TwitchiH & @fredbrancz Prometheus Deep Dive Introduction Intro 2.0 to 2.2.1 2.4 - 2.6 Beyond Outro ACID Isolation Each append action gets a write ID (64 bit monotonic counter) Every sample’s write ID

2 Distributed Transaction 3.2.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity guarantees that each transaction database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations transactions based on XA standard just as local transactions. XA standard can strictly guarantee ACID features of transactions. That guarantee can be a double‐edged sword. It is more proper in the implementation

3 Distributed Transaction 4.3.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity guarantees that each transaction database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations transactions based on XA standard just as local transactions. XA standard can strictly guarantee ACID features of transactions. That guarantee can be a double‐edged sword. It is more proper in the implementation

. MySQL Wire Protocol heartbeat meta TiDB is not a database middleware Sharding middleware TiDB ACID Transaction Support Mostly Elastic Scaling Complex Query (Join, Sub query, GROUP BY) Failover Manual specifying sharding rules ● Full-featured SQL layer which is designed for distributed computing ● ACID sementics, transaparent to application layer ● MySQL compatiblity Cons: ● Not 100% MySQL compatibility

4 Distributed Transaction 4.4.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity guarantees that each transaction database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations transactions based on XA standard just as local transactions. XA standard can strictly guarantee ACID features of transactions. That guarantee can be a double‐edged sword. It is more proper in the implementation

2 Distributed Transaction 3.2.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity: transactions are executed as database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations impact on performance in concurrent sce‐ narios. BASE Transaction If a transaction that implements ACID is called a rigid transaction, then a transaction based on a BASE transaction element is called a

2 Distributed Transaction 3.2.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity: transactions are executed as database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations impact on performance in concurrent sce‐ narios. BASE Transaction If a transaction that implements ACID is called a rigid transaction, then a transaction based on a BASE transaction element is called a

4 Distributed Transaction 4.4.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity guarantees that each transaction database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations transactions based on XA standard just as local transactions. XA standard can strictly guarantee ACID features of transactions. That guarantee can be a double‐edged sword. It is more proper in the implementation

2 Distributed Transaction 8.2.1 Background Database transactions should satisfy the features of ACID (atomicity, consistency, isolation and dura‐ bility). • Atomicity: transactions are executed as database has provided perfect native ACID support, it can become an obstacle to the system performance under distributed situations. How to make databases satisfy ACID features un‐ der distributed situations impact on performance in concurrent sce‐ narios. BASE Transaction If a transaction that implements ACID is called a rigid transaction, then a transaction based on a BASE transaction element is called a

Transaction save points (nested transactions) are also supported. All Firebird transactions are ACID compliant. ACID is explained below: Atomicity ensures that transactions either complete in their entirety