Comparative Read Performance Analysis of PostgreSQL and MongoDB in E-Commerce: An Empirical Study of Filtering and Analytical Queries

This paper presents a comparative analysis of read performance for PostgreSQL and MongoDB in e-commerce scenarios, using identical datasets in a resource-constrained single-host environment. The results demonstrate that PostgreSQL executes complex analytical queries 1.6–15.1 times faster, depending on the query type and data volume. The study employed synthetic data generation with the Faker library across three stages, processing up to 300,000 products and executing each of 6 query types 15 times. Both filtering and analytical queries were tested on non-indexed data in a controlled localhost environment with PostgreSQL 17.5 and MongoDB 7.0.14, using default configurations. PostgreSQL showed 65–80% shorter execution times for multi-criteria queries, while MongoDB required approximately 33% less disk space. These findings suggest that normalized relational schemas are advantageous for transactional e-commerce systems where analytical queries dominate the workload. The results are directly applicable to small and medium e-commerce developers operating in budget-constrained, single-host deployment environments when choosing between relational and document-oriented databases for structured transactional data with read-heavy analytical workloads. A minimal indexed validation confirms that the baseline trends remain consistent under a simple indexing configuration. Future work will examine broader indexing strategies, write-intensive workloads, and distributed deployment scenarios.