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Description

MySQL Error 3614 occurs when an optimizer hint within a SQL query is provided with an incorrect number of arguments. This error indicates a syntax mismatch between the hint's definition and its usage, preventing the MySQL server from correctly applying the intended optimization strategy.

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Error Message

Invalid number of arguments for hint %s

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Known Causes

3 known causes

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Incorrect Argument Count

Providing more or fewer arguments than a specific MySQL optimizer hint expects is a primary cause of this error.

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Misunderstood Hint Syntax

Users might misunderstand the exact syntax or required parameters for a particular optimizer hint, leading to incorrect argument specifications.

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Typographical Errors

Simple typos, missing commas, or extra characters in the argument list of a hint can cause the server to misinterpret the number of arguments.

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Solutions

4 solutions available

1. Correct Hint Syntax and Arguments easy

Verify and adjust the syntax and number of arguments for the hint being used in your SQL query.

1

Identify the specific hint causing the error. The error message `Invalid number of arguments for hint %s` will usually show the name of the hint.

2

Consult the MySQL documentation for the correct syntax and expected number of arguments for that specific hint.

e.g., For `/*+ INDEX(table_name index_name) */`, ensure you provide both the table name and the index name.

3

Modify your SQL query to use the hint with the correct number and type of arguments.

Example of a correct index hint:
SELECT /*+ INDEX(users user_email_idx) */ * FROM users WHERE email = 'test@example.com';

2. Remove or Comment Out Problematic Hints easy

Temporarily disable hints to isolate the issue or if they are not essential for query execution.

1

Locate the hint within your SQL query that is causing the error.

2

Comment out the hint by enclosing it in `/* */` or by removing it entirely.

Example of commenting out a hint:
SELECT * FROM orders WHERE order_date > '2023-01-01'; -- /*+ HINT_NAME(arguments) */

3

Re-execute the query to confirm if the error is resolved. If it is, you can either leave the hint commented out or investigate its correct usage.

3. Check MySQL Version Compatibility for Hints medium

Ensure the hints you are using are supported by your MySQL version and that their syntax hasn't changed.

1

Determine your current MySQL server version. You can do this by running the following command:

SELECT VERSION();

2

Refer to the official MySQL documentation for your specific version and review the section on optimizer hints. Pay close attention to any changes or deprecations in hint syntax or functionality.

For example, search for 'MySQL [your_version] optimizer hints'.

3

If a hint is deprecated or its syntax has changed, update your query accordingly based on the documentation.

If `/*+ USE_FRM(table_name) */` was used in an older version but is now `/*+ DERIVED_PRUNING(table_name) */`, update your query.

4. Review Application Code for Dynamic Hint Generation advanced

If hints are being generated dynamically by application code, inspect that code for errors in hint construction.

1

Identify the part of your application code that constructs SQL queries containing optimizer hints.

2

Debug the code that generates the hint string. Ensure that variables used to construct the hint are correctly populated and that the overall string adheres to valid MySQL hint syntax.

Example (Python pseudocode):
if condition:
    hint = f"/*+ INDEX({table_name} {index_name}) */"
else:
    hint = ""
sql_query = f"SELECT {hint} * FROM {table_name} WHERE ..."

Check if `table_name` or `index_name` are empty or contain invalid characters.

3

Log the generated SQL query before it's executed to verify the hint's structure and arguments.

Example: `logger.debug(f'Executing SQL: {generated_sql_query}')`

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Related Errors

5 related errors

MySQL Error 3614: Invalid Hint Arguments