All Errors

This error occurs in Express.js when middleware or a route handler calls the next() function more than once during a single request cycle. Calling next() twice causes Express to attempt to send the response multiple times, leading to unexpected behavior and cryptic errors.

CR_UNKNOWN_ERROR (2000) is a catch-all MySQL client error that fires before the connector can deliver a more specific message. It usually appears when the connection or authentication handshake is aborted early—for example, when TLS is required but the client and server cannot agree on a cipher stack or when an authentication plugin terminates the session without reporting a normal SQLSTATE. Because no additional diagnostics are printed, the client sees only "Unknown MySQL error" and the server log typically contains nothing more than a brief warning or a reverse DNS lookup entry.

This error occurs when attempting to execute write operations (INSERT, UPDATE, DELETE) on a read-only transaction. Common causes include connecting to a read-only replica, hot standby server, or default_transaction_read_only setting enabled.

DynamoDB returns TableInUseException when you try to modify a table while another operation is already in progress on that table. This error occurs during concurrent CreateTable, UpdateTable, or DeleteTable operations on the same DynamoDB table.

Supabase returns 'bad_oauth_callback: OAuth callback contains an error' when the OAuth provider redirects back with an error parameter in the URL. This typically happens when the user denies permission, the OAuth flow times out, or there's a configuration mismatch between your Supabase project and the OAuth provider.

PostgreSQL error 25001 occurs when a transaction is already active and prevents certain operations like DROP DATABASE or ALTER TYPE from executing. Commit or rollback the current transaction first to resolve this.

This error occurs when AWS DynamoDB encounters conflicts while exporting table data to Amazon S3. Conflicts typically arise from concurrent export jobs, S3 bucket permission issues, or existing files in the target location. The export operation fails, preventing data backup or migration.

Error 1179 occurs when you attempt to run DDL (ALTER TABLE, LOCK TABLES) or administrative commands inside an active transaction. MySQL blocks these operations to maintain transaction integrity and prevent deadlocks.

MySQL Error 1177 occurs when the database engine cannot find, access, or open a table referenced in a CHECK or FOREIGN KEY constraint. Common causes include non-existent tables, case sensitivity mismatches, corrupted files, or insufficient permissions.

This error occurs when you try to reference a non-existent index or key in your MySQL table. It's commonly caused by using FORCE INDEX, USE INDEX, or DROP KEY commands with an index name that doesn't exist, or by typos in index names. The error can also occur when trying to drop a foreign key that has been corrupted or already removed.

This MySQL client error occurs when trying to fetch rows from a prepared statement that doesn't return a result set. It typically happens in C/C++ applications using the MySQL C API when calling mysql_stmt_fetch() on statements that execute non-SELECT queries like INSERT, UPDATE, or DELETE.

DynamoDB returns ItemCollectionSizeLimitExceededException when an item collection exceeds the 10 GB size limit. This occurs when too much data accumulates under a single partition key value, requiring data redistribution, archival, or partition key redesign to resolve.

Supabase returns 'identity_not_found: Identity does not exist' when attempting to link, unlink, or reference an identity that has been deleted or doesn't exist in the auth.identities table. This typically occurs during OAuth linking operations, user merging, or when identities are manually removed from the database. The fix involves verifying the identity exists, recreating it if needed, and ensuring proper linking procedures.

This Firebase Cloud Messaging error occurs when a registration token (FCM token) is being used with a different sender ID than the one it was originally created for. The token is permanently tied to its original sender ID and cannot be used with other Firebase projects.

PostgreSQL aborts transactions when errors occur, preventing further queries until explicitly rolled back. This happens because PostgreSQL enters an aborted state rather than continuing execution like some other databases.

This error occurs when Elasticsearch nodes cannot discover or elect a master node, preventing cluster formation. Usually caused by discovery misconfiguration, network issues, or insufficient master-eligible nodes to form a quorum.

Test summary

PostgreSQL collation mismatch errors occur when database collation settings no longer match the OS locale, typically after system upgrades. Fix by refreshing collation versions and reindexing affected databases.

This error occurs when attempting to authenticate or perform actions with a Supabase user whose phone number has not been verified via OTP. Users must complete SMS verification before proceeding.

Spreading props from untrusted sources can introduce XSS vulnerabilities when malicious attributes like dangerouslySetInnerHTML are injected. This security risk occurs when user-provided data is spread directly onto components without validation.