This check is already in place, but isn't fully working, i.e.
switching from a vnode KS to a tablets KS is not allowed, but
this check doesn't work in the other direction. To fix the
latter, `ks_prop_defs::get_initial_tablets()` has been changed
to handle 3 states: (1) init_tablets is set, (2) it was skipped,
(3) tablets are disabled. These couldn't fit into std::optional,
so a new local struct to hold these states has been introduced.
Callers of this function have been adjusted to set init_tablets
to an appropriate value according to the circumstances, i.e. if
tablets are globally enabled, but have been skipped in the CQL,
init_tablets is automatically set to 0, but if someone executes
ALTER KS and doesn't provide tablets options, they're inherited
from the old KS.
I tried various approaches and this one resulted in the least
lines of code changed. I also provided testcases to explain how
the code behaves.
Fixes: #18795
(cherry picked from commit 758139c8b2)
Closesscylladb/scylladb#19540
This commit adds support for executing ALTER KS for keyspaces with
tablets and utilizes all the previous commits.
The ALTER KS is handled in alter_keyspace_statement, where a global
topology request in generated with data attached to system.topology
table. Then, once topology state machine is ready, it starts to handle
this global topology event, which results in producing mutations
required to change the schema of the keyspace, delete the
system.topology's global req, produce tablets mutations and additional
mutations for a table tracking the lifetime of the whole req. Tracking
the lifetime is necessary to not return the control to the user too
early, so the query processor only returns the response while the
mutations are sent.
There's a test that checks how ALTER changes the initial tablets value,
but it equips the statement with `replication` parameters because of
limitations that parser used to impose. Now the `tablets` parameters can
come on their own, so add a new test. The old one is kept from
compatibility considerations.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
(cherry picked from commit 1003391ed6)
Currently, LWT is not supported with tablets.
In particular the interaction between paxos and tablet
migration is not handled yet.
Therefore, it is better to outright reject LWT queries
for tablets-enabled tables rather than support them
in a flaky way.
This commit also marks tests that depend on LWT
as expeced to fail.
Fixesscylladb/scylladb#18066
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#18103
Call the before_drop_column_family notifications
before dropping the views to allow the tablet_allocator
to delete the view's tablets.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
When tablets are enabled and a keyspace being described has them
explicitly disabled or non-automatic initial value of zero, include this
into the returned describe statement too
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Recently, in commit 49026dc319, the
way to choose the number of tablets in a new keyspace changed.
This broke the test we had for a memory leak when many tablets were
used, which saw the old syntax wasn't recognized and assumed Scylla
is running without tablet support - so the test was skipped.
Let's fix the syntax. After this patch the test passes if the tablets
experimental feature is enabled, and only skipped if it isn't.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch adds a reproducer test for the memory leak described in
issue #16493: If a table is repeatedly created and dropped, memory
is leaked by task tracking. Although this "leak" can be temporary
if task_ttl_in_seconds is properly configured, it may still use too
much memory if tables are too frequently created and dropped.
The test here shows that (before #16493 was fixed) as little as
100 tables created and deleted can cause Scylla to run out of
memory.
The problem is severely exacerbated when tablets are used which is
why the test here uses tablets. Before the fix for #16493 (a Seastar
patch, scylladb/seastar#2023), this test of 100 iterations always
failed (with test/cql-pytest/run's default memory allowance).
After the fix, the test doesn't fail in 100 iterations - and even
if increased manually to 10,000 iterations it doesn't fail.
The new test uses the initial_tablets feature, so requires Scylla to be
run with the "tablets" experimental option turned on. This is not
currently the default of test.py or test/cql-pytest/run, so I turned
it on manually to check this test. I also checked that the test is
correctly skipped if tablets are not turned on.
Refs #16493
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#16717
