In commit c24bc3b we decided that creating a new table in Alternator
will by default use vnodes - not tablets - because of all the missing
features in our tablets implementation that are important for
Alternator, namely - LWT, CDC and Alternator TTL.
We never documented this, or the fact that we support a tag
`experimental:initial_tablets` which allows to override this decision
and create an Alternator table using tablets. We also never documented
what exactly doesn't work when Alternator uses tablet.
This patch adds the missing documentation in docs/alternator/new-apis.md
(which is a good place for describing the `experimental:initial_tablets`
tag). The patch also adds a new test file, test_tablets.py, which
includes tests for all the statements made in the document regarding
how `experimental:initial_tablets` works and what works or doesn't
work when tablets are enabled.
Two existing tests - for TTL and Streams non-support with tablets -
are moved to the new test file.
When the tablets feature will finally be completed, both the document
and the tests will need to be modified (some of the tests should be
outright deleted). But it seems this will not happen for at least
several months, and that is too long to wait without accurate
documentation.
Fixes#21629
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#22462
(cherry picked from commit c0821842de)
Closesscylladb/scylladb#23298
b1cf1890a9