Strengthened isolation to Read Committed level while maintaining high availability. This eliminates dirty reads while keeping the system partition tolerant.
Read Committed isolation across distributed nodes
No dirty reads (only see committed values)
Still available during network partitions
Stronger consistency than Read Uncommitted
No Dirty Reads: Never read uncommitted changes
Committed Values Only: Always read the latest committed version
Non-Repeatable Reads: Same query might return different results
Phantom Reads: New rows might appear between reads
Version Control: Track committed vs uncommitted versions
Read Filtering: Only return committed values on reads
Write Buffers: Stage writes until commit
Distributed Commit: Coordinate commits across nodes
Over Read Uncommitted:
Eliminates dirty reads
Provides better data integrity
Reduces inconsistent application state
Still maintains high availability
Gained:
No dirty reads
Better data integrity
More predictable behavior
Lost:
Slightly more coordination overhead
Potential for blocked reads during commits
More complex implementation
Read Committed is the default isolation level for:
PostgreSQL
SQL Server
Oracle
Most web applications
It hits the sweet spot between consistency and performance for many workloads.
From weakest to strongest isolation levels we've built:
Read Uncommitted: Maximum availability, dirty reads allowed
Read Committed: No dirty reads, still highly available
Next would be Repeatable Read and Serializable...
Each level trades some availability for stronger consistency guarantees. The key is picking the right level for your use case.
