package pgx_unix

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PGX using the standard library's Unix module for IO (synchronous)


Dune Dependency





2.3 (unreleased)

2.2 (2022-10-26)

  • Support ocaml 5.0 deprecations (

2.1 (2022-05-31)

Breaking changes

  • Missing SASL authentication impl provides an error instead of hanging (

  • pgx_lwt_mirage now requires conduit 2.3 instead of 2.2 (

2.0 (2021-05-12)

Breaking changes

  • The Pgx module is now wrapped, which means Pgx_aux, Types, Access, etc. aren't added to the global scope. The main result of this is that Pgx_value now needs to be accessed as Pgx.Value. (

  • Pgx_async.connect and with_conn now have an additional optional ?ssl argument (see below).


  • Pgx_async now supports TLS connections using Conduit_async. This is enabled by default and can be controlled with the new ?ssl argument to connect and with_conn. (


  • Improved message for authentication errors. Previously these raised Pgx_eof, and now they raise PostgreSQL_Error("Failed to authenticate with postgres server", additional details ...). (


  • Support new Mirage-conduit timeout argument (

1.0 (2020-05-08)

Breaking changes

  • Pgx_value.t is an opaque type now. Use Pgx_value.of/to converters. Note that these converters are not equivalent to the OCaml functions like bool_of_string or float_of_string, and that for bytea data, you need to use Pgx_value.of/to_binary, not Pgx_value.of/to_string.

  • Pgx_lwt has been renamed Pgx_lwt_unix.

  • Pgx.execute now uses the unnamed prepare statement. In most cases this should not affect anything, but if you were relying on Pgx not internally using the unnamed prepared statement, you will need to fix your code. If you run into this, the fix is to use Pgx.with_prepared and name your prepared statement.

  • Pgx_value.of_inet/to_inet now use Ipaddr.t from the ipaddr library instead of Unix.inet_addr.


  • Pgx_value.of_binary and Pgx_value.to_binary added for bytea data.

  • Add execute_map helper to Pgx

  • Add execute_pipe helper to Pgx_async

  • Add execute_unit helper to Pgx

  • Break out Pgx_value_core library, which will allow users of Pgx_unix and Pgx_lwt to use the Core_kernel.Tim and Date types. This is still included by default in Pgx_async.

  • Added Pgx_lwt_mirage

  • Pgx_value types now all implement compare and sexp_of


  • Pgx no longer assumes all strings are binary data. Strings must be valid varchar data in the database's encoding. Use Pgx_value.of/to_binary with bytea columns if you want binary.

  • Use a tail-recursive implementation

  • Use Unix.getuid + Lwt_unix.getpwuid instead of Lwt.getlogin for the default username, since getlogin fails in some cases.

  • Use int64 to keep track of prepared statements just in case someone prepares several million statements in one program


  • Re-raise exceptions with backtraces if possible.

  • Pgx_async uses Async.Log for logging instead of printing directly to stderr

  • Use Sexplib0 instead of Sexplib

  • Use the Query protocol for parameterless execute instead of Prepare + Bind

  • Use the unnamed prepared statement for execute

  • Use ipaddr library instead of Unix.inet_addr

  • Split Pgx_lwt into Pgx_lwt_unix and Pgx_lwt_mirage

0.1 (2018-05-31)

Initial release since fork from PG'OCaml.

  • More tests

  • More consistent use of async API's

  • Addition of Pgx.Value for hopefully easier conversion to and from DB types

  • Safe handling of concurrent queries (not any faster, but they won't crash)

  • Improved interface for prepared statements to make it harder to execute non-existent ones


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