Error map
HikariCP timeout HikariPool-1 - Connection is not available, request timed out after 30000ms
Java · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
PDOException: could not find driver
The PDO driver for your database (pdo_mysql, pdo_pgsql, pdo_sqlite) isn’t installed or enabled.
Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. All pooled connections were in use and max pool size was reached.
The application’s connection pool was exhausted — all connections busy or leaked.
MySQL ERROR 2003 (HY000): Can't connect to MySQL server on 'host:3306' (111)
The client couldn’t reach MySQL over TCP — server down, wrong host/port, firewall, or MySQL bound to localhost only.
Lock wait timeout exceeded; try restarting transaction (MySQL 1205)
A query waited too long for a row lock held by another transaction and gave up.
server closed the connection unexpectedly — This probably means the server terminated abnormally before or while processing the request.
The connection to PostgreSQL dropped — the server restarted/crashed, a proxy/firewall killed an idle connection, or the backend w…
ERROR: prepared statement "s1" already exists (PgBouncer transaction mode)
Named prepared statements collided — typically because PgBouncer in transaction pooling mode hands connections between clients.
MySQL ERROR 1049 (42000): Unknown database 'x'
The database named in the connection doesn’t exist on that server.
PDOException: SQLSTATE[HY000] [2002] Connection refused
PHP couldn’t reach the database server at the host/port in your DSN.
MySQL ERROR 2002 (HY000): Can't connect to local MySQL server through socket
The client couldn’t reach the MySQL server — it isn’t running, or the client is looking for the socket/port in the wrong place.
MySQL ERROR 1040 (08004): Too many connections
MySQL reached `max_connections` and refuses new clients.
Error: P1001: Can't reach database server at `host`:`5432`
Prisma couldn’t connect to the database in DATABASE_URL.
MySQL ERROR 2006 (HY000): MySQL server has gone away
The connection to MySQL was closed — usually by a timeout or a packet larger than `max_allowed_packet`.
Two steps away (33)
PHP Fatal error: Uncaught Error: Call to undefined function
PHP can’t find the function you called — usually a missing extension, missing include, or namespace issue.
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The MySQL JDBC driver couldn’t reach the database (or the connection dropped).
Fatal error: Uncaught Error: Call to undefined function imagecreatefromjpeg()
The GD extension (or its JPEG/WebP support) isn’t installed for the PHP version serving the site.
HTTP 504 Gateway Timeout
A proxy or gateway waited too long for the upstream server to respond and gave up.
Cloudflare Error 524: A Timeout Occurred
Cloudflare connected to the origin, but the origin didn’t send an HTTP response within 100 seconds.
HTTP 304 Not Modified
The cached copy is still valid, so the server sends no body and the client reuses its cache.
Error: socket hang up / read ECONNRESET
The other side closed the TCP connection abruptly while your client was still using it.
MySQL ERROR 1130 (HY000): Host 'x' is not allowed to connect to this MySQL server
No MySQL account exists for the host you’re connecting from.
MySQL ERROR 2013 (HY000): Lost connection to MySQL server during query
The connection dropped mid-query — server crash/restart, timeouts, or a proxy cutting long queries.
Deadlock found when trying to get lock; try restarting transaction
Two transactions waited on each other’s locks; the database killed one so the other could continue.
MySQL ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction
MySQL detected a deadlock between two transactions and rolled one back.
ERROR: canceling statement due to statement timeout
A query ran longer than statement_timeout and PostgreSQL cancelled it.
PostgreSQL: could not connect to server / connection refused — Is the server running on host and accepting TCP/IP connections?
The client reached no PostgreSQL listener at that host/port — the server is down, listening elsewhere, or not accepting remote co…
FATAL: database "x" does not exist
The connection names a database that isn’t on that server.
FATAL: sorry, too many clients already / remaining connection slots are reserved for non-replication superuser connections
PostgreSQL reached max_connections.
PostgreSQL: ERROR: column "x" does not exist
PostgreSQL can’t find the column — a missing migration, a case-sensitive quoted name, or a string literal written in double quote…
ERROR: column "x" of relation "y" already exists
ALTER TABLE ADD COLUMN for a column that’s already there.
ERROR: cannot drop table x because other objects depend on it
Views, foreign keys or other objects depend on what you’re dropping.
MySQL ERROR 1045 (28000): Access denied for user
MySQL rejected the login — wrong password, wrong user/host combination, or the user doesn’t exist.
WordPress: Error Establishing a Database Connection
WordPress can’t connect to its MySQL/MariaDB database with the credentials in wp-config.php, or the database server is down.
MySQL ERROR 1046 (3D000): No database selected
A query referenced tables without a database selected (no USE and no db in the connection).
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
Job for mysql.service failed because the control process exited with error code
The MySQL/MariaDB service failed to start — the real reason is in the MySQL error log.
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
The docker CLI can’t talk to the Docker engine — it isn’t running, or your user can’t access the socket.
Too many open files (EMFILE)
The process hit its file-descriptor limit — sockets, files and pipes all count.
MySQL ERROR 1114 (HY000): The table 'x' is full
MySQL couldn’t extend the table — disk full, a size limit, or a MEMORY table hitting max_heap_table_size.
MySQL ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled
Creating a stored function failed because binary logging requires it to declare its data access characteristics.
MongooseError: Operation `users.find()` buffering timed out after 10000ms
Mongoose queued a query waiting for a connection that never opened.
MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
The MongoDB driver couldn’t find a reachable server for the connection string.
PrismaClientKnownRequestError P2002: Unique constraint failed on the fields: (`email`)
A Prisma create/update violated a unique constraint.
MySQL ERROR 1153 (08S01): Got a packet bigger than 'max_allowed_packet' bytes
A single statement or row exceeded max_allowed_packet — big BLOBs, huge INSERTs or large dump lines.
sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) connection to server … failed
SQLAlchemy’s DB driver raised an operational error — connection failures, lost connections or locked SQLite databases.
API Gateway: {"message": "Endpoint request timed out"} (504 after 29 seconds)
The backend (usually Lambda) didn’t respond within API Gateway’s integration timeout (29 seconds by default for REST APIs).
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