This is an automated email from the ASF dual-hosted git repository.
pierrejeambrun pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/airflow.git
The following commit(s) were added to refs/heads/main by this push:
new 671be47b20e Note that the API server uses a second database connection
pool (#76430)
671be47b20e is described below
commit 671be47b20e5d38b02847e06a31e455064081fe0
Author: Jason(Zhe-You) Liu <[email protected]>
AuthorDate: Wed Nov 4 19:39:11 2026 +0800
Note that the API server uses a second database connection pool (#76430)
The per-worker connection limit doubles in 3.4.0, and the release notes
did not say so, so deployments sizing PgBouncer or max_connections would
not know to account for it.
---
airflow-core/newsfragments/76430.significant.rst | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/airflow-core/newsfragments/76430.significant.rst
b/airflow-core/newsfragments/76430.significant.rst
new file mode 100644
index 00000000000..9a3fde4900b
--- /dev/null
+++ b/airflow-core/newsfragments/76430.significant.rst
@@ -0,0 +1,11 @@
+The API server uses a second database connection pool
+
+API server workers now run some database work on the async engine as well as
the sync one, and each engine has its own connection pool, sized by the same
``[database] sql_alchemy_pool_size`` and ``[database]
sql_alchemy_max_overflow`` settings. What uses the async pool depends on the
``--apps`` option of ``airflow api-server``:
+
+- ``execution``: task heartbeats and several Execution API reads.
+- ``core``: the audit log entry recorded for each write request through the
REST API or the UI.
+- ``all`` (the default): both of the above.
+
+In every mode a worker can therefore open up to twice ``sql_alchemy_pool_size
+ sql_alchemy_max_overflow`` connections (30 with the defaults) and keep up to
twice ``sql_alchemy_pool_size`` of them idle. Account for this, per ``[api]
workers``, when sizing PgBouncer or the database's ``max_connections``.
+
+The async pool is used since #67800, #73403, #73407 and #76416.
