Request

What the server does

"What is there at all in this database?"

list_tables — tables, sizes, estimated row counts

"How is the orders table structured?"

describe_table — columns, indexes, foreign keys both ways

"How many orders were placed in July, and for how much?"

query — SELECT with aggregation

"Why is this query slow?"

explain — plan, indexes, row estimate

"Who am I connected as and what am I allowed to do?"

server_info — database, user, GRANT, server limits

"Set the status of the canceled orders."

execute — only when ALLOW_UPDATE_OPERATION=true

What

Why

DDL

CREATE, ALTER, DROP, TRUNCATE, RENAME — under no settings.

Switching databases, SET, CALL, PREPARE, LOAD DATA, locks, and GRANT

Changes the meaning of the next query or executes untrusted text.

SELECT ... INTO OUTFILE

Writing a file on the database server.

UPDATE and DELETE without WHERE

Requires explicit allow_full_table=true in the call.

Multiple statements in one call

Executes exactly one.

Variable

Default

Purpose

MYSQL_HOST

127.0.0.1

Database server host

MYSQL_PORT

3306

Port

MYSQL_SOCKET_PATH

—

Unix socket instead of host/port

MYSQL_USER

—

User (required)

MYSQL_PASS

—

Password (alias of MYSQL_PASSWORD)

MYSQL_PASS_FILE

—

Read the password from a file instead of a variable

MYSQL_DB

—

Database (required, alias of MYSQL_DATABASE)

MYSQL_SSL

false

Require TLS

MYSQL_SSL_CA

—

Path to the root certificate; it alone enables TLS

MYSQL_SSL_REJECT_UNAUTHORIZED

true

Verify the server certificate

ALLOW_INSERT_OPERATION

false

Allow INSERT

ALLOW_UPDATE_OPERATION

false

Allow UPDATE

ALLOW_DELETE_OPERATION

false

Allow DELETE

MYSQL_MAX_ROWS

1000

Maximum rows in one response

MYSQL_TIMEOUT_MS

30000

Query timeout

MYSQL_CONNECT_TIMEOUT_MS

10000

Connection timeout

MYSQL_POOL_SIZE

3

Connections in the pool

MYSQL_MAX_RETRIES

2

Retries on connection loss or deadlocks

MYSQL_READ_ONLY_TX

true

Run reads in a read-only transaction

ASKADS_TELEMETRY

—

0 turns off anonymous launch statistics

Behavior

Change

MYSQL_DB is mandatory

The server is always bound to one database.

Responses are limited by MYSQL_MAX_ROWS

Answers are marked as truncated.

DDL is unavailable

Even if write permissions are enabled.

UPDATE/DELETE without WHERE

They require explicit confirmation in the call.

The toolset is different

query, execute, explain, list_tables, describe_table, server_info.

Symptom

Cause

errno 1045

Invalid MYSQL_USER / MYSQL_PASS

errno 1044

The user exists, but has no access to the database.

errno 1142

Missing GRANT for the operation or table. ALLOW_* does not help here.

errno 3159

The server requires TLS: set MYSQL_SSL=true.

ECONNREFUSED / ETIMEDOUT

Host, port, firewall, or a VPN that isn’t up.

ER_NOT_SUPPORTED_AUTH_MODE

TLS is required for caching_sha2_password.

Server doesn’t connect

The configuration error is visible directly in the dialog: the server starts without credentials and explains what is missing.