Function set_meta_value

pub async fn set_meta_value(
    pool: &Pool<MySql>,
    key: &str,
    value: &str,
) -> Result<()>

Sets a metadata value for a specific key.

This function stores a key-value pair in the metadata table. If the key already exists, its value is updated. The operation is performed atomically within a transaction and is protected by a mutex to prevent concurrent modifications.

Arguments

• pool - Database connection pool for executing the query
• key - The unique key to associate with the value
• value - The value to store

Returns

• Ok(()) - Successfully stored the key-value pair
• Err(anyhow::Error) - Failed to store the key-value pair

Concurrency

This function acquires the global metadata mutex to ensure thread safety when multiple threads attempt to modify the same key.

Transaction Handling

This function uses a database transaction that:

1. Deletes any existing entries with the same key
2. Inserts the new key-value pair

If any part of this operation fails, the entire transaction is rolled back, preserving data consistency.