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Blocking API based on the Unix module.
Warning: This module is not well tested. Please report any issues.
This module implements a blocking API. It is not designed for preemptive threading. That is, connections and connection pools must be created and used within a single thread, and any limitation on multithreading from the driver or client library applies.
You can use a connection pool to cache a single DB connection, additional connections will not be allocated, since usage is serial.
connect uri locates and loads a driver which can handle uri, passes uri to the driver, which establish a connection and returns a first-class module implementing Caqti_connection_sig.S.
If you use preemptive threading, note that the connection must only be used from the thread where it was created.
with_connection uri f calls connect on uri. If connect evaluates to Ok connection, with_connection passes the connection to f. Once f either evaluates to a result, or raises an exception, with_connection closes the database connection.
connect_pool uri is a pool of database connections constructed by connect uri.
Do not use pooling for connections to volatile resources like sqlite3::memory: and beware of temporary tables or other objects which may not be shared across connections to the same URI.
If you use preemptive threading, note that the connection pool must only be used from the thread where it was created. Use thread local storage to create a separate pool per thread if necessary.
parametermax_size
The maximum number of open connections. Must be at least 1. For drivers which does not support concurrent connections, this will be ignored and the value 1 used instead.
parametermax_idle_size
The maximum number of idle connections to put into the pool for reuse. Defaults to max_size. Must be between 0 and max_size. If you set this, you must also set max_size. For drivers which does not support pooling, this will be ignored and the value 0 used instead. For drivers which does not support concurrent connections, but supports pooling, the value will clipped to a maximum of 1.