# Which Problems Are Solved
Streams allow differentiating logs produced by different components of
Zitadel.
# How the Problems Are Solved
The `backend/v3/instrumentation/logging` package now exposes convenience
function for setting and getting a logger from the context. As well as
high-level functions to emit log records at various levels. When
constructing a new logger a "stream" needs to be specified:
- **runtime**: General runtime logs, such as startup and shutdown
messages. Default for logs that do not belong to the other categories.
- **request**: Logs for incoming API and HTTP requests.
- **event_handler**: Logs for event handling in projections.
- **queue**: Logs for the job queue processing.
- **event_pusher**: Logs for event pushing to the database. Disabled by
default, contains sensitive information.
Each line from the returned logger contains a `stream` field as well as
a `version` field with the current Zitadel version.
## Runtime config
Streams can be enabled by passing an array of stream names in the
runtime config. Because some log streams may contain sensitive data
(especially events), it is now also possible to mask values by their
key.
# Additional Changes
- Wrap `slogctx` in the `logging` package. (Except API error converter
packages, because of import cycle)
- Add some docs to `logging` package so other devs understand how to add
logging to Zitadel
- Add `logging.OnError` and `logging.WithError` helper functions with
`Panic()` and `Fatal()` methods, to preserve current calls in the `cmd`
packages.
- Add instance context extractor.
- Only output request details in the request info log. Request ID
remains propagated through context.
- Moved middleware functionality into protocol specific packages.
- Removed setting of URI to context in metric middleware. There were ony
setters and no getters. (Unused value)
- Reuse a single statusWriter in the middleware package for middlewares
that need to know the response status.
# Additional Context
- Closes#11333
- Closes#11331
- Partly #11330
---------
Co-authored-by: Silvan <[email protected]>
# Which Problems Are Solved
Optimize the query that checks for terminated sessions in the access
token verifier. The verifier is used in auth middleware, userinfo and
introspection.
# How the Problems Are Solved
The previous implementation built a query for certain events and then
appended a single `PositionAfter` clause. This caused the postgreSQL
planner to use indexes only for the instance ID, aggregate IDs,
aggregate types and event types. Followed by an expensive sequential
scan for the position. This resulting in internal over-fetching of rows
before the final filter was applied.

Furthermore, the query was searching for events which are not always
applicable. For example, there was always a session ID search and if
there was a user ID, we would also search for a browser fingerprint in
event payload (expensive). Even if those argument string would be empty.
This PR changes:
1. Nest the position query, so that a full `instance_id, aggregate_id,
aggregate_type, event_type, "position"` index can be matched.
2. Redefine the `es_wm` index to include the `position` column.
3. Only search for events for the IDs that actually have a value. Do not
search (noop) if none of session ID, user ID or fingerpint ID are set.
New query plan:

# Additional Changes
- cleanup how we load multi-statement migrations and make that a bit
more reusable.
# Additional Context
- Related to https://github.com/zitadel/zitadel/issues/7639