convex-db

Using Convex DB

Convex DB provides SQL access over lattice data. Connect via JDBC, PostgreSQL wire protocol, or the direct lattice API.

Reference: convex-db/README.md for full documentation including replication, PostgreSQL server setup, and architecture details.

Connecting

JDBC (Java)

// In-memory
Connection conn = DriverManager.getConnection("jdbc:convex:mydb");

// Persistent (Etch-backed, survives restarts)
Connection conn = DriverManager.getConnection("jdbc:convex:file:/data/mydb.etch");

Driver auto-registers via ServiceLoader. Class: convex.db.jdbc.ConvexDriver

PostgreSQL Clients (psql, DBeaver, DataGrip, Python, etc.)

# Start the PG server
java -cp convex-db.jar convex.db.psql.PgServer -p 5432 -d mydb

# Then connect with any PG client
psql -h localhost -p 5432 -d mydb

import psycopg2
conn = psycopg2.connect(host="localhost", port=5432, dbname="mydb")

Creating Tables

CREATE TABLE users (id, name, email)

Column 0 (first column) is always the primary key. Types are inferred from inserted data.

Inserting Data

INSERT INTO users VALUES (1, 'Alice', 'alice@example.com')

For bulk loading, use prepared statements with batch:

PreparedStatement ps = conn.prepareStatement("INSERT INTO users VALUES (?, ?, ?)");
for (int i = 0; i < 10000; i++) {
    ps.setLong(1, i);
    ps.setString(2, "Name-" + i);
    ps.setString(3, "email-" + i + "@example.com");
    ps.addBatch();
}
ps.executeBatch();

Querying

-- Point lookup (fast — O(log n) via PK index pushdown)
SELECT * FROM users WHERE id = 1

-- Filtering, sorting, pagination
SELECT name, email FROM users WHERE name LIKE 'A%' ORDER BY name LIMIT 10

-- Joins
SELECT c.name, o.amount
FROM customers c INNER JOIN orders o ON c.id = o.customer_id

-- Aggregations
SELECT department, COUNT(*), AVG(salary)
FROM employees GROUP BY department HAVING COUNT(*) > 5

Supported SQL

• DDL: CREATE TABLE, DROP TABLE
• DML: INSERT, UPDATE, DELETE
• Queries: SELECT, WHERE, ORDER BY, LIMIT, OFFSET
• Joins: INNER JOIN, LEFT JOIN, RIGHT JOIN, CROSS JOIN
• Aggregations: GROUP BY, HAVING, COUNT, SUM, AVG, MIN, MAX
• Expressions: CASE WHEN, COALESCE, CAST, BETWEEN, IN, LIKE, IS NULL
• Functions: ABS, FLOOR, CEIL, SQRT, UPPER, LOWER, TRIM, SUBSTRING, LENGTH, CONCAT

Transactions

conn.setAutoCommit(false);
stmt.execute("INSERT INTO users VALUES (2, 'Bob', 'bob@example.com')");
stmt.execute("UPDATE users SET email = 'new@example.com' WHERE id = 1");
conn.commit();    // atomic merge — all changes become visible
// or conn.rollback() to discard

Column Types

Direct Lattice API

For programmatic access without SQL overhead:

ConvexDB cdb = ConvexDB.create();
SQLDatabase db = cdb.database("mydb");

// Create table
db.tables().createTable("users", new String[]{"id", "name", "email"});

// Insert
db.tables().insert("users", 1, "Alice", "alice@example.com");

// Point lookup
AVector<ACell> row = db.tables().selectByKey("users", 1);

// Scan all
Index<ABlob, AVector<ACell>> all = db.tables().selectAll("users");

// Delete
db.tables().deleteByKey("users", 1);

Performance Tips

• Use PK lookups (WHERE id = ?) for point queries — O(log n) via index pushdown
• Use PreparedStatements — plans compile once, reuse across executions
• Use batch inserts for bulk loading — significantly faster than individual statements
• Full scans are O(n) — filter on PK when possible

Building and Testing

# Build (requires Convex core installed first)
cd convex && mvn clean install -DskipTests -pl convex-db -am

# Run tests
cd convex && mvn test -pl convex-db