FlexMeasures · Flix6x · Aug 3, 2026 · Jul 28, 2026 · Jul 28, 2026 · Jul 28, 2026
diff --git a/documentation/changelog.rst b/documentation/changelog.rst
@@ -51,6 +51,7 @@ Infrastructure / Support
 ----------------------
 * The database migration for this release splits each stored flex-context's ``inflexible-device-sensors`` field into ``inflexible-consumption``/``inflexible-production`` sensor references, classifying each sensor by its ``consumption_is_positive`` attribute (behavior-preserving; sensor attributes themselves are kept). Downgrading merges them back into bare sensor IDs, dropping any source filters added in the meantime [see `PR #2358 <https://www.github.com/FlexMeasures/flexmeasures/pull/2358>`_]
 * Speed up listing assets: eager-load each asset's sensors instead of lazy-loading them one query per asset during serialization, and skip loading sensors entirely for field-filtered responses that do not include them [see `PR #2363 <https://www.github.com/FlexMeasures/flexmeasures/pull/2363>`_]
+* Speed up scheduling jobs by building the scheduling problem directly with the HiGHS Python API (``highspy``), bypassing Pyomo's model construction and solution-ingestion overhead (roughly a second for a single-device job, and several seconds for multi-device jobs); this direct backend is the new default for the ``FLEXMEASURES_LP_SOLVER`` setting (``"highspy"``), while any Pyomo-based solver (e.g. the previous default ``"appsi_highs"``, or ``"cbc"``) remains available as before [see `PR #2364 <https://www.github.com/FlexMeasures/flexmeasures/pull/2364>`_]
 * Price fields in the flex-context (including nested commitment prices, which are now also held to the flex-context's shared currency) are selected for currency validation by field type (``PriceField``) instead of by name suffix [see `PR #2311 <https://www.github.com/FlexMeasures/flexmeasures/pull/2311>`_]
 * Document ``SECURITY_TWO_FACTOR`` and related 2FA configuration settings [see `PR #2340 <https://www.github.com/FlexMeasures/flexmeasures/pull/2340>`_]
 * ``flexmeasures db upgrade`` now runs ``VACUUM ANALYZE`` after upgrading by default, so Postgres has fresh planner statistics right after a migration; opt out with ``--no-vacuum`` [see `PR #2333 <https://www.github.com/FlexMeasures/flexmeasures/pull/2333>`_]

diff --git a/documentation/configuration.rst b/documentation/configuration.rst
@@ -55,11 +55,17 @@ Default: ``False``
 FLEXMEASURES_LP_SOLVER
 ^^^^^^^^^^^^^^^^^^^^^^
 
-The command to run the scheduling solver. This is the executable command which FlexMeasures calls via the `pyomo library <http://www.pyomo.org/>`_. Potential values might be ``cbc``, ``cplex``, ``glpk`` or ``appsi_highs``. Consult `their documentation <https://pyomo.readthedocs.io/en/stable/solving_pyomo_models.html#supported-solvers>`_ to learn more. 
-We have tested FlexMeasures with `HiGHS <https://highs.dev/>`_ and `Cbc <https://coin-or.github.io/Cbc/intro>`_.
-Note that you need to install the solver, read more at :ref:`installing-a-solver`.
+The scheduling solver backend.
 
-Default: ``"appsi_highs"``
+The default, ``"highspy"``, builds the scheduling problem directly with the `HiGHS <https://highs.dev/>`_ Python API (``highspy``, which is installed with FlexMeasures).
+This bypasses the `pyomo library <http://www.pyomo.org/>`_ and is much faster to construct, while solving the exact same problem.
+
+Any other value is interpreted as the name of a Pyomo solver interface (the model is then built with Pyomo, which calls the solver).
+Potential values might be ``cbc``, ``cplex``, ``glpk`` or ``appsi_highs``. Consult `the Pyomo documentation <https://pyomo.readthedocs.io/en/stable/solving_pyomo_models.html#supported-solvers>`_ to learn more.
+We have tested FlexMeasures with `HiGHS <https://highs.dev/>`_ (both via ``highspy`` and via ``appsi_highs``) and `Cbc <https://coin-or.github.io/Cbc/intro>`_.
+Note that a separate solver installation is only needed for external solvers such as ``cbc`` — both HiGHS-based choices (``highspy`` and ``appsi_highs``) rely on the ``highspy`` package that is installed together with FlexMeasures. Read more at :ref:`installing-a-solver`.
+
+Default: ``"highspy"``
 
 
 FLEXMEASURES_LP_SOLVER_OPTIONS

diff --git a/documentation/host/deployment.rst b/documentation/host/deployment.rst
@@ -89,25 +89,19 @@ Install the linear solver on the server
 ---------------------------------------
 
 To compute schedules, FlexMeasures uses the `HiGHS <https://highs.dev/>`_ mixed integer linear optimization solver (FlexMeasures solver by default) or `Cbc <https://github.com/coin-or/Cbc>`_.
-Solvers are used through `Pyomo <http://www.pyomo.org>`_\ , so in principle supporting a `different solver <https://pyomo.readthedocs.io/en/stable/solving_pyomo_models.html#supported-solvers>`_ would be possible.
+By default, HiGHS is used directly through its Python API (``highspy``, which is installed together with FlexMeasures), so no extra installation is needed.
+Solvers can also be used through `Pyomo <http://www.pyomo.org>`_\ , so in principle supporting a `different solver <https://pyomo.readthedocs.io/en/stable/solving_pyomo_models.html#supported-solvers>`_ would be possible.
 
 You tell FlexMeasures with the config setting :ref:`solver-config` which solver to use.
 
-However, the solver also needs to be installed - in addition to FlexMeasures (the Docker image already has it). Here is advice on how to install the two solvers we test internally:
-
-
 .. note:: We default to HiGHS, as it seems more powerful
 
 
-HiGHS can be installed using pip:
-
-.. code-block:: bash
-
-   $ pip install highspy
-
+Both HiGHS-based solver choices (``highspy`` and ``appsi_highs``) rely on the ``highspy`` package, which is installed together with FlexMeasures — nothing more to do.
 More information on `the HiGHS website <https://highs.dev/>`_.
 
-Cbc needs to be present on the server where FlexMeasures runs, under the ``cbc`` command.
+An external solver, on the other hand, needs to be installed in addition to FlexMeasures (the Docker image already has it).
+For example, Cbc needs to be present on the server where FlexMeasures runs, under the ``cbc`` command.
 
 You can install it on Debian like this:
 

diff --git a/documentation/host/installation.rst b/documentation/host/installation.rst
@@ -360,13 +360,9 @@ Install an LP solver
 
 For computing schedules, the FlexMeasures platform uses a linear program solver. Currently that is the HiGHS or CBC solvers.
 
-It's already installed in the Docker image. For yourself, you can simply install it like this:
+The default solver (HiGHS, used directly via its Python API) is installed together with FlexMeasures, so there is nothing to do here.
 
-.. code-block:: bash
-
-   $ pip install highspy
-
-Read more on solvers (e.g. how to install a different one) at :ref:`installing-a-solver`.
+Read more on solvers (e.g. how to install a different one, such as CBC) at :ref:`installing-a-solver`.