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Database scaling & optimization

Indexing, connection pooling, read replicas, query tuning, and throughput-aware SQL.

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Database scaling & optimization medium

Composite index leftmost prefix in Python

Simulate a composite index in SQLite and check whether query columns match the leftmost prefix rule for index usage.

sqlite indexes database
Python 
import sqlite3


def get_indexed_columns(table_name):
    """Simulate a composite index by reading column names that start with 'idx_'."""
    conn = sqlite3.connect(":memory:")
    conn.execute(f"CREATE TABLE {table_name} (id INTEGER, idx_col1 TEXT, idx_col2 INTEGER, other TEXT)")
    conn.execute(f"CREATE INDEX idx_…
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