66 articles
RSSHow to fix ClickHouse errors — table engine choice, ORDER BY for primary key, INSERT too many small parts, LowCardinality types, Nullable performance, ZooKeeper for Replicated tables, and HTTP vs Native client.
How to fix Mongoose errors — useNewUrlParser removed, strictQuery default flip, populate returning null, lean() losing methods, discriminator setup, transaction sessions, and TypeScript Document types.
How to fix Prisma Postgres (managed) errors — prisma+postgres:// connection string, DIRECT_URL for migrations, edge runtime via Accelerate, schema drift, Prisma Studio access, and tiering limits.
How to fix Peewee errors — OperationalError database is locked, connection already open, field type mismatch, model meta database missing, N+1 queries, and peewee-migrate setup.
How to fix Tortoise ORM errors — Tortoise.init not called, no module imported model, fetch_related missing, aerich migration setup, FastAPI integration patterns, and ConfigurationError missing connection.
How to fix psycopg errors — psycopg2 to psycopg 3 import migration, connection pool setup, row factory tuple vs dict, COPY protocol changes, async psycopg pool, server-side cursor confusion, and binary mode performance.
How to fix asyncpg errors — connection refused localhost 5432, pool exhausted timeout, prepared statement does not exist, type codec not registered, JSON automatic conversion, and transaction rollback on exception.
How to fix SQLAlchemy 2.x errors — DetachedInstanceError from lazy loading, QueuePool limit exceeded, MissingGreenlet in async context, N+1 queries, IntegrityError rollback, and Alembic migration failures.
How to fix PocketBase issues — authentication, collection access rules, real-time subscriptions, file uploads, relations, and self-hosted deployment.
How to fix Astro DB issues — schema definition, seed data, queries with drizzle, local development, remote database sync, and Astro Studio integration.
How to fix ElectricSQL issues — Postgres setup with logical replication, shape definitions, real-time sync to the client, React hooks, write-path through the server, and deployment configuration.
How to fix PowerSync issues — SQLite local database, sync rules configuration, backend connector setup, watched queries, offline-first patterns, and React and React Native integration.
How to fix Neon Postgres issues — connection string setup, serverless HTTP driver vs TCP, database branching, connection pooling, Drizzle and Prisma integration, and cold start optimization.
How to fix Turso database issues — libsql client setup, connection URLs and auth tokens, embedded replicas for local-first apps, schema migrations, Drizzle ORM integration, and edge deployment.
How to fix Upstash issues — Redis REST client setup, rate limiting with @upstash/ratelimit, QStash message queues, Kafka topics, Vector search, and edge runtime integration.
How to fix Convex backend issues — query/mutation/action patterns, schema validation, real-time reactivity, file storage, auth integration, and common TypeScript type errors.
How to fix Kysely query builder issues — database interface definition, dialect setup, type-safe joins and subqueries, migration runner, kysely-codegen for generated types, and common TypeScript errors.
How to fix Supabase issues — Row Level Security policies, realtime subscriptions, storage permissions, auth session with Next.js, edge functions, and common client configuration mistakes.
How to fix Drizzle ORM issues — schema definition, drizzle-kit push vs migrate, relation queries with, transactions, type inference, and common PostgreSQL/MySQL configuration problems.
How to fix MySQL replication issues — SHOW REPLICA STATUS errors, relay log corruption, GTID configuration, replication lag, skipping errors, and replica promotion.
How to fix PostgreSQL JSONB query issues — -> vs ->> operators, @> containment, GIN indexes, type casting, array queries, and indexing strategies for JSONB columns.
How to fix PostgreSQL Row Level Security (RLS) issues — enabling RLS, policy expressions, BYPASSRLS role, SET ROLE, current_user vs session_user, and Supabase auth.uid() patterns.
How to fix Redis Cluster errors — MOVED redirects, CROSSSLOT multi-key operations, cluster-aware client setup, hash tags for key grouping, and failover handling.
How to fix MongoDB aggregation pipeline issues — $lookup field matching, $unwind on missing fields, $match placement, $group _id, type mismatches, and pipeline debugging.
How to fix Prisma enum errors — schema definition, database sync, TypeScript enum type mismatch, filtering by enum, and migrating existing enum values.
How to fix Spring Data JPA query issues — JPQL vs native SQL, derived method naming, @Modifying for updates, pagination, projections, and LazyInitializationException.
How to fix MongoDB schema validation errors — $jsonSchema rules, required fields, type mismatches, enum constraints, bypassing validation for migrations, and Mongoose schema conflicts.
How to fix MySQL full-text search issues — FULLTEXT index creation, minimum word length, stopwords, boolean mode vs natural language mode, InnoDB vs MyISAM, and LIKE fallback.
How to fix PostgreSQL indexes not being used — EXPLAIN ANALYZE output, function on indexed column, type mismatches, statistics staleness, partial indexes, and query planner costs.
How to fix Prisma connection pool errors — pool size configuration, connection leaks, serverless deployments, singleton pattern, query timeout, and pgBouncer integration.
How to fix Rails N+1 queries — includes vs joins vs preload vs eager_load, Bullet gem detection, avoiding N+1 in serializers and views, and counter caches.
How to fix Spring @Transactional not rolling back — checked vs unchecked exceptions, self-invocation proxy bypass, rollbackFor, transaction propagation, and nested transactions.
How to fix MySQL indexes not being used by the query optimizer — EXPLAIN output, implicit conversions, function on columns, composite index order, cardinality issues, and forcing indexes.
How to fix Prisma transaction errors — interactive transactions vs $transaction array, error handling and rollback, nested transactions, timeout issues, and isolation levels.
How to diagnose and fix slow MySQL queries — enabling the slow query log, reading EXPLAIN output, adding indexes, fixing N+1 queries, and optimizing JOINs and ORDER BY.
How to diagnose and fix slow PostgreSQL queries — reading EXPLAIN ANALYZE output, adding the right indexes, fixing N+1 queries, optimizing joins, and using pg_stat_statements.
How to fix TypeORM QueryFailedError, entity not found errors, relation issues, missing migrations, and connection configuration problems in Node.js and NestJS applications.
How to fix PostgreSQL 'sorry, too many clients already' error — checking active connections, using connection pooling with PgBouncer, tuning max_connections, fixing ORM pool settings, and finding connection leaks.
How to fix Prisma's 'Unique constraint failed on the fields' error — finding which field caused it, handling upserts, race conditions, and bulk insert deduplication.
How to fix MongoDB 'not primary' errors when writing to a replica set, read preference misconfiguration, connecting to a secondary, replica set elections, and write concern settings.
How to fix Django migration conflicts — why multiple leaf migrations conflict, how to merge conflicting migrations, resolve dependency chains, and set up a team workflow to prevent migration conflicts.
How to fix Spring Boot 'Failed to configure a DataSource' errors, missing URL property, driver class not found, connection refused, and how to correctly configure datasource properties for MySQL, PostgreSQL, and H2.
How to fix AWS RDS connection timeout errors from Lambda functions and EC2 instances, security group configuration, VPC settings, connection pooling, and RDS Proxy setup for Lambda.
How to fix Prisma migration errors — migrate dev failing with schema drift, migrate deploy errors in production, database out of sync, and how to safely reset or resolve migration conflicts.
How to fix Redis keys that never expire — why EXPIRE commands are silently overwritten, how SET options replace TTL, how to inspect key TTL, and how to prevent accidental TTL removal in your application.
How to fix Elasticsearch index_not_found_exception errors — why index operations fail with 404, how to create indices correctly, manage index aliases, and handle missing indices in production.
How to fix MySQL 'Deadlock found when trying to get lock; try restarting transaction' — diagnosing deadlock causes, using SHOW ENGINE INNODB STATUS, and preventing deadlocks with consistent lock ordering.
Fix Elasticsearch cluster health red status by resolving unassigned shards, disk watermark issues, node failures, and shard allocation problems.
How to fix the MongoDB E11000 duplicate key error by identifying duplicate fields, fixing index conflicts, using upserts, handling null values, and resolving race conditions.
How to fix the SQLite 'database is locked' error caused by concurrent writes, long-running transactions, missing WAL mode, busy timeout, and unclosed connections.
How to fix MySQL syntax error 1064 caused by typos, reserved words, wrong quotes, missing commas, version-incompatible syntax, and ORM-generated queries.
How to fix MySQL ERROR 1205 Lock wait timeout exceeded caused by long-running transactions, row-level locks, missing indexes, deadlocks, and InnoDB lock contention.
How to fix MySQL error 1146 Table doesn't exist caused by wrong database selection, case sensitivity issues, missing migrations, InnoDB tablespace corruption, and cross-OS imports.
How to fix PostgreSQL deadlock detected error caused by concurrent transactions, conflicting row locks, foreign key locks, and lock ordering issues.
How to fix the PostgreSQL error 'permission denied for table' by granting privileges, fixing default permissions, resolving schema and ownership issues, RLS policies, and role inheritance.
How to fix the PostgreSQL 'relation does not exist' error caused by schema search_path issues, case sensitivity, wrong database connections, missing migrations, and more.
How to fix PostgreSQL FATAL role does not exist error caused by missing database roles, peer authentication, wrong usernames, and platform-specific installation defaults.
How to fix Redis OOM command not allowed when used memory exceeds maxmemory caused by memory limits, missing eviction policies, large keys, and memory fragmentation.
How to fix the PostgreSQL error 'could not connect to server: Connection refused' caused by server not running, wrong host/port, pg_hba.conf, or firewall issues.
How to fix the MySQL error 1040 'Too many connections' by adjusting max_connections, fixing connection leaks, and optimizing connection pooling.
How to fix 'duplicate key value violates unique constraint' in PostgreSQL by resetting sequences, using upserts, fixing bulk imports, and handling concurrent inserts.
How to fix Django's 'OperationalError: no such table' error caused by missing migrations, wrong database configuration, corrupted files, or Docker volume issues.
How to fix MySQL ERROR 2002 (HY000) when the MySQL client can't connect through the Unix socket file on Linux, macOS, Docker, and WSL.
How to fix MongoDB 'MongoServerError: bad auth Authentication failed', 'MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017', and 'MongooseServerSelectionError' connection errors. Covers MongoDB not running, connection string format, Atlas network access, Docker networking, authentication, DNS/SRV issues, TLS/SSL, and Mongoose options.
How to fix Redis errors: WRONGTYPE Operation against a key holding the wrong kind of value, MISCONF Redis is configured to save RDB snapshots, OOM command not allowed, READONLY You can't write against a read only replica, and other common Redis errors. Covers key type mismatches, disk issues, memory limits, eviction policies, connection problems, and serialization.
How to fix MySQL 'ERROR 1045 (28000): Access denied for user root@localhost (using password: YES/NO)' on Linux, macOS, Windows, and Docker. Covers password reset, auth plugin issues, skip-grant-tables recovery, MySQL 8 vs 5.7 differences, and host mismatches.