The JusDB Database Engineering Blog

TiDB 8.0 is the most production-ready version of the distributed SQL database yet. With improved HTAP, stronger MySQL compatibility, and Resource Groups, it's compelling for teams outgrowing single-node MySQL.

pg_stat_statements tracks every query's total time, call count, and cache hit ratio. Learn to enable it, find your highest-cost queries, hunt for cache misses, and measure the impact of every optimization.

EXPLAIN ANALYZE tells you exactly why your PostgreSQL query is slow, but reading its output is a skill most developers never learn. Learn every node type, identify the five worst plan patterns, and fix them.

MongoDB's flexible schema allows fields to be null, explicitly set to null, or simply absent — and these three states behave differently in queries, aggregations, and indexes.

MySQL 8.0 introduced EXPLAIN FORMAT=TREE — a hierarchical, human-readable query plan format that reveals join order, access methods, and cost estimates in a way that the traditional tabular EXPLAIN cannot.

Compare CockroachDB, Google Spanner, and YugabyteDB — consistency models, PostgreSQL compatibility, and operational costs

Understand Google Spanner's architecture — TrueTime, interleaved tables, schema design, and cost model

PostgreSQL views historically executed with the owner's privileges, bypassing row-level security policies. PostgreSQL 15 fixed this with security_invoker views — here's why it matters and how to use it in multi-tenant schemas.

A complete guide to MySQL JSON functions — JSON column type, JSON_EXTRACT and arrow operators, JSON_SET vs JSON_INSERT vs JSON_REPLACE vs JSON_MERGE_PATCH, functional indexes, and multi-valued indexes for arrays.

Use PostgreSQL FDW to query MySQL, S3, MongoDB, and other databases from within PostgreSQL — setup and performance tips

A production guide to PostgreSQL full-text search — building tsvector generated columns, GIN indexes, multi-column search with setweight, ts_rank scoring, websearch_to_tsquery, and comparison against Elasticsearch.

A production guide to MySQL full-text search — FULLTEXT index creation, MATCH AGAINST in natural language and boolean modes, the 50% rule, InnoDB vs MyISAM FTS, combining with B-tree indexes, and comparison against Elasticsearch.