Pros of CockroachDB

• Better support for geo-distributed deployments and multi-region setups
• Stronger consistency guarantees with serializable isolation by default
• More mature cloud-native architecture and Kubernetes integration

Cons of CockroachDB

• Higher resource consumption, especially for smaller workloads
• Less flexible storage engine options compared to TiDB's pluggable architecture
• Steeper learning curve for SQL dialect and configuration options

Code Comparison

TiDB SQL syntax:

CREATE TABLE users (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(255),
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

CockroachDB SQL syntax:

CREATE TABLE users (
  id INT PRIMARY KEY DEFAULT unique_rowid(),
  name STRING,
  created_at TIMESTAMP DEFAULT current_timestamp()
);

Both databases support standard SQL syntax, but CockroachDB uses STRING instead of VARCHAR and unique_rowid() instead of AUTO_INCREMENT. TiDB's syntax is more similar to MySQL, while CockroachDB's is closer to PostgreSQL.

TiDB and CockroachDB are both distributed SQL databases designed for horizontal scalability and high availability. TiDB offers better compatibility with MySQL ecosystems, while CockroachDB excels in geo-distributed deployments. The choice between them depends on specific use cases, existing infrastructure, and scalability requirements.

Pros of YugabyteDB

• Better support for geo-distributed deployments and multi-region setups
• Native support for both SQL (PostgreSQL-compatible) and NoSQL APIs
• Stronger consistency guarantees with linearizable ACID transactions

Cons of YugabyteDB

• Smaller community and ecosystem compared to TiDB
• Less mature and battle-tested in large-scale production environments
• Limited support for advanced features like distributed transactions across shards

Code Comparison

YugabyteDB (C++):

Status YBClient::CreateTable(const string& table_name,
                             const Schema& schema,
                             const CreateTableOptions& options) {
  // Implementation details
}

TiDB (Go):

func (s *session) CreateTable(ctx context.Context, stmt *ast.CreateTableStmt) error {
    // Implementation details
}

Both projects use different programming languages for their core implementations. YugabyteDB primarily uses C++ for its storage engine and query processing, while TiDB is written in Go. This difference affects performance characteristics and development workflows.

YugabyteDB focuses on providing a unified platform for both SQL and NoSQL workloads, making it suitable for applications requiring flexible data models. TiDB, on the other hand, emphasizes compatibility with MySQL and excels in handling large-scale OLTP workloads.

Pros of Vitess

• More mature project with longer history and wider adoption
• Better suited for horizontal scaling of MySQL databases
• Stronger support for sharding and multi-tenancy

Cons of Vitess

• Less flexible query processing capabilities
• More complex setup and configuration
• Limited support for advanced SQL features compared to TiDB

Code Comparison

Vitess query execution:

func (vtg *VTGate) Execute(ctx context.Context, session *vtgatepb.Session, sql string, bindVariables map[string]*querypb.BindVariable) (*vtgatepb.Session, *sqltypes.Result, error) {
    // Query execution logic
}

TiDB query execution:

func (e *Execute) Next(ctx context.Context, req *chunk.Chunk) error {
    // Query execution logic
}

Both projects use Go for their core implementations, but TiDB's query execution is more tightly integrated with its storage engine, while Vitess acts as a proxy layer on top of MySQL.

Vitess is better suited for scaling existing MySQL deployments, while TiDB offers a more comprehensive distributed database solution with advanced SQL features. The choice between them depends on specific use cases and requirements.

Pros of HBase

• Mature and battle-tested system with a large user base
• Strong support for very large datasets and high write throughput
• Tight integration with the Hadoop ecosystem

Cons of HBase

• Steeper learning curve and more complex setup compared to TiDB
• Less SQL-like query language, which may require more specialized knowledge
• Generally slower for complex analytical queries

Code Comparison

HBase (Java):

Put put = new Put(Bytes.toBytes("row1"));
put.addColumn(Bytes.toBytes("cf"), Bytes.toBytes("qual1"), Bytes.toBytes("value1"));
table.put(put);

TiDB (SQL):

INSERT INTO table_name (column1, column2)
VALUES ('value1', 'value2');

Key Differences

• TiDB offers a more familiar SQL interface, while HBase uses a NoSQL model
• TiDB provides built-in distributed transactions, which HBase lacks natively
• HBase is better suited for write-heavy workloads, while TiDB offers better support for complex queries and OLTP scenarios

Use Cases

• HBase: Large-scale data storage, real-time data processing, and time-series data
• TiDB: Hybrid transactional and analytical processing (HTAP), scaling out MySQL applications, and distributed OLTP systems

Both systems have their strengths, and the choice between them depends on specific requirements, existing infrastructure, and team expertise.

Pros of Cassandra

• Highly scalable and distributed architecture, designed for large-scale deployments
• Strong support for multi-datacenter replication and high availability
• Mature project with a large community and extensive ecosystem

Cons of Cassandra

• Limited support for complex queries and joins compared to TiDB's SQL capabilities
• Less flexible schema changes, as altering existing tables can be challenging
• Steeper learning curve for developers unfamiliar with the CQL query language

Code Comparison

Cassandra (CQL):

CREATE TABLE users (
  id UUID PRIMARY KEY,
  name TEXT,
  email TEXT
);

TiDB (SQL):

CREATE TABLE users (
  id UUID PRIMARY KEY,
  name VARCHAR(255),
  email VARCHAR(255)
);

Both databases support creating tables, but TiDB uses standard SQL syntax, while Cassandra uses its own CQL language. TiDB offers more traditional relational database features, including support for complex queries and transactions, making it easier for developers familiar with SQL to work with. Cassandra, on the other hand, is optimized for high-throughput, low-latency operations on large-scale distributed systems, sacrificing some flexibility in query capabilities for improved scalability and performance in specific use cases.