Currently, the next start of a scheduled background job is
calculated by adding the `schedule_interval` to its finish
time. This does not allow scheduling jobs to execute at fixed
times, as the next execution is "shifted" by the job duration.
This commit introduces the option to execute a job on a fixed
schedule instead. Users are expected to provide an initial_start
parameter on which subsequent job executions are aligned. The next
start is calculated by computing the next time_bucket of the finish
time with initial_start origin.
An `initial_start` parameter is added to the compression, retention,
reorder and continuous aggregate `add_policy` signatures. By passing
that upon policy creation users indicate the policy will execute on
a fixed schedule, or drifting schedule if `initial_start` is not
provided.
To allow users to pick a drifting schedule when registering a UDA,
an additional parameter `fixed_schedule` is added to `add_job`
to allow users to specify the old behavior by setting it to false.
Additionally, an optional TEXT parameter, `timezone`, is added to both
add_job and add_policy signatures, to address the 1-hour shift in
execution time caused by DST switches. As internally the next start of
a fixed schedule job is calculated using time_bucket, the timezone
parameter allows using timezone-aware buckets to calculate
the next start.
Add option `USE_TELEMETRY` that can be used to exclude telemetry from
the compile.
Telemetry-specific SQL is moved, which is only included when extension
is compiled with telemetry and the notice is changed so that the
message about telemetry is not printed when Telemetry is not compiled
in.
The following code is not compiled in when telemetry is not used:
- Cross-module functions for telemetry.
- Checks for telemetry job in job execution.
- GUC variables `telemetry_level` and `telemetry_cloud`.
Telemetry subsystem is not included when compiling without telemetry,
which requires some functions to be moved out of the telemetry
subsystem:
- Metadata handling is moved out of the telemetry module since it is
used not only with telemetry.
- UUID functions are moved into a separate module instead of being
part of the telemetry subsystem.
- Telemetry functions are either added or removed when updating from a
previous version.
Tests are updated to:
- Not use telemetry functions to get UUID or Metadata and instead use
the moved UUID and metadata functions.
- Not include telemetry information in tests that do not require it.
- Configuration files do not set telemetry variables when telemetry is
not compiled in.
- Replaced usage of telemetry functions in non-telemetry tests with
other sources of same information.
Fixes#3931
