Almost all callers call new_keyspace with durable writes ON, so it's
worth having default value for it
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The object in question fully describes the keyspace to be created and,
among other things, contains replication strategy options. Next patches
move the "initial_tablets" option out of those options and keep it
separately, so the ks metadata should also carry this option separately.
This patch is _just_ extending the metadata creation API, in fact the
new field is unused (write-only) so all the places that need to provide
this data keep it disengaged and are explicitly marked with FIXME
comment. Next patches will fix that.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Currently, table_helper::setup_keyspace is used only for starting
the system_traces keyspace. We need to handle concurrent group 0
operations possible during concurrent bootstrap in the Raft-based
topology.
We refactor table_helper::setup_keyspace so that it calls
migration_manager::announce at most twice. We achieve it by
announcing all tables at once.
The number of announcements should further be reduced to one, but
it requires a big refactor. The CQL code used in
parse_new_cf_statement assumes the keyspace has already been
created. We cannot have such an assumption if we want to announce
a keyspace and its tables together. However, we shouldn't touch
the CQL code as it would impact user requests, too.
One solution is using schema_builder instead of the CQL statements
to create tables in table_helper.
Another approach is removing table_helper completely. It is used
only for the system_traces keyspace, which Scylla creates
automatically. We could refactor the way Scylla handles this
keyspace and make table_helper unneeded.
In the following commit, we reduce migration_manager::announce
calls in table_helper::setup_keyspace by announcing all tables
together. To do it, we cannot use table_helper::setup_table
anymore, which announces a single table itself. However, the new
code still has to translate CQL statements, so we extract it to the
new parse_new_cf_statement function to avoid duplication.
This reverts commit 4b80130b0b, reversing
changes made to a5519c7c1f. It's suspected
of causing dtest failures due to a bug in coroutine::parallel_for_each.
We refactor table_helper::setup_keyspace so that it calls
migration_manager::announce at most twice. We achieve it by
announcing all tables at once.
The number of announcements should further be reduced to one, but
it requires a big refactor. The CQL code used in
parse_new_cf_statement assumes the keyspace has already been
created. We cannot have such an assumption if we want to announce
a keyspace and its tables together. However, we shouldn't touch
the CQL code as it would impact user requests, too.
One solution is using schema_builder instead of the CQL statements
to create tables in table_helper.
Another approach is removing table_helper completely. It is used
only for the system_traces keyspace, which Scylla creates
automatically. We could refactor the way Scylla handles this
keyspace and make table_helper unneeded.
In the following commit, we reduce migration_manager::announce
calls in table_helper::setup_keyspace by announcing all tables
together. To do it, we cannot use table_helper::setup_table
anymore, which announces a single table itself. However, the new
code still has to translate CQL statements, so we extract it to the
new parse_new_cf_statement function to avoid duplication.
Currently we hold group0_guard only during DDL statement's execute()
function, but unfortunately some statements access underlying schema
state also during check_access() and validate() calls which are called
by the query_processor before it calls execute. We need to cover those
calls with group0_guard as well and also move retry loop up. This patch
does it by introducing new function to cql_statement class take_guard().
Schema altering statements return group0 guard while others do not
return any guard. Query processor takes this guard at the beginning of a
statement execution and retries if service::group0_concurrent_modification
is thrown. The guard is passed to the execute in query_state structure.
Fixes: #13942
Message-ID: <ZNsynXayKim2XAFr@scylladb.com>
This reverts commit 70b5360a73. It generates
a failure in group0_test .test_concurrent_group0_modifications in debug
mode with about 4% probability.
Fixes#15050
Currently we hold group0_guard only during DDL statement's execute()
function, but unfortunately some statements access underlying schema
state also during check_access() and validate() calls which are called
by the query_processor before it calls execute. We need to cover those
calls with group0_guard as well and also move retry loop up. This patch
does it by introducing new function to cql_statement class take_guard().
Schema altering statements return group0 guard while others do not
return any guard. Query processor takes this guard at the beginning of a
statement execution and retries if service::group0_concurrent_modification
is thrown. The guard is passed to the execute in query_state structure.
Fixes: #13942
Message-ID: <ZNSWF/cHuvcd+g1t@scylladb.com>
The system.group0_history table provides useful descriptions
for each command committed to Raft group 0. One way of applying
a command to group 0 is by calling migration_manager::announce.
This function has the description parameter set to empty string
by default. Some calls to announce use this default value which
causes null values in system.group0_history. We want
system.group0_history to have an actual description for every
command, so we change all default descriptions to reasonable ones.
We can't provide a reasonable description to announce in
query_processor::execute_thrift_schema_command because this
function is called in multiple situations. To solve this issue,
we add the description parameter to this function and to
handler::execute_schema_command that calls it.
The migration_manager service is responsible for schema convergence
in the cluster - pushing schema changes to other nodes and pulling
schema when a version mismatch is observed. However, there is also
a part of migration_manager that doesn't really belong there -
creating mutations for schema updates. These are the functions with
prepare_ prefix. They don't modify any state and don't exchange any
messages. They only need to read the local database.
We take these functions out of migration_manager and make them
separate functions to reduce the dependency of other modules
(especially query_processor and CQL statements) on
migration_manager. Since all of these functions only need access
to storage_proxy (or even only replica::database), doing such a
refactor is not complicated. We just have to add one parameter,
either storage_proxy or database and both of them are easily
accessible in the places where these functions are called.
Push those calls up the call stack, to `trace_keyspace_helper` module.
Pass `migration_manager` reference around together with
`query_processor` reference.
coroutine::parallel_for_each avoids an allocation and is therefore preferred. The lifetime
of the function object is less ambiguous, and so it is safer. Replace all eligible
occurences (i.e. caller is a coroutine).
One case (storage_service::node_ops_cmd_heartbeat_updater()) needed a little extra
attention since there was a handle_exception() continuation attached. It is converted
to a try/catch.
Closes#10699
`announce` now takes a `group0_guard` by value. `group0_guard` can only
be obtained through `migration_manager::start_group0_operation` and
moved, it cannot be constructed outside `migration_manager`.
The guard will be a method of ensuring linearizability for group 0
operations.
1. Generalize the name so it mentions group 0, which schema will be a
strict subset of.
2. Remove the fact that it performs a "read barrier" from the name. The
function will be used in general to ensure linearizability of group0
operations - both reads and writes. "Read barrier" is Raft-specific
terminology, so it can be thought of as an implementation detail.
The functions which prepare schema change mutations (such as
`prepare_new_column_family_announcement`) would use internally
generated timestamps for these mutations. When schema changes are
managed by group 0 we want to ensure that timestamps of mutations
applied through Raft are monotonic. We will generate these timestamps at
call sites and pass them into the `prepare_` functions. This commit
prepares the APIs.
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
This was needed to fix issue #2129 which was only manifest itself with
auto_bootstrap set to false. The option is ignored now and we always
wait for schema to synch during boot.
Static constructors (specifically for the `system_keyspaces` global variable)
need their dependencies to be already constructed when their own
construction begins. Because tracing uses seastar::sstring, which is not
constexpr, we must change it to std::string_view (which is). Change
the type and perform the required adjustments. The definition is moved
to the header file for simplicity.
The database, keyspace, and table classes represent the replica-only
part of the objects after which they are named. Reading from a table
doesn't give you the full data, just the replica's view, and it is not
consistent since reconciliation is applied on the coordinator.
As a first step in acknowledging this, move the related files to
a replica/ subdirectory.
Stop using database (and including database.hh) for schema related
purposes and use data_dictionary instead.
data_dictionary::database::real_database() is called from several
places, for these reasons:
- calling yet-to-be-converted code
- callers with a legitimate need to access data (e.g. system_keyspace)
but with the ::database accessor removed from query_processor.
We'll need to find another way to supply system_keyspace with
data access.
- to gain access to the wasm engine for testing whether used
defined functions compile. We'll have to find another way to
do this as well.
The change is a straightforward replacement. One case in
modification_statement had to change a capture, but everything else
was just a search-and-replace.
Some files that lost "database.hh" gained "mutation.hh", which they
previously had access to through "database.hh".
After the migration manager can be obtained from the query
processor the table heler can also benefit from it and not
call for global migration manager instance any longer.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Currently the statement's execute() method accepts storage
proxy as the first argument. This is enough for all of them
but schema altering ones, because the latter need to call
migration manager's announce.
To provide the migration manager to those who need it it's
needed to have some higher-level service that the proxy. The
query processor seems to be good candidate for it.
Said that -- all the .execute()s now accept the querty
processor instead of the proxy and get the proxy itself from
the query processor.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
It looks like the history of the flag begins in Cassandra's
https://issues.apache.org/jira/browse/CASSANDRA-7327 where it is
introduced to speedup tests by not needing to start the gossiper.
The thing is we always start gossiper in our cql tests, so the flag only
introduce noise. And, of course, since we want to move schema to use raft
it goes against the nature of the raft to be able to apply modification only
locally, so we better get rid of the capability ASAP.
Tests: units(dev, debug)
Message-Id: <20201230111101.4037543-2-gleb@scylladb.com>
Keeping the query processor reference on the table_helper in raii manner
seems waistful, the only user of it -- the trace_keyspace_helper -- has
a bunch of helpers on board, each would then keep its own copy for no
gain.
At the same time the trace_keyspace_helper already gets the query processor
for its needs, so it can share one with table_helper-s.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The goal is to make table_helper API require the query_processor
reference and use it where needed. The .setup_table() is private
method, and still grabs the query processor reference itself. Since
its futures do noth reshard, it's safe to carry the query processor
reference through.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
In order to improve observability, add a username field to the the
system_traces.sessions table. The system table should be change
while upgrading by running the fix_system_distributed_tables.py
script. Until the table is updated, the old behaviour is preserved.
Fixes#6737.
Change CQL parsing routine to return std::unique_ptr
instead of seastar::shared_ptr.
This can help reduce redundant shared_ptr copies even further.
Make some supplementary changes necessary for this transition:
* Remove enabled_shared_from_this base class from the following
classes: truncate_statement, authorization_statement,
authentication_statement: these were previously constructing
prepared_statement instance in `prepare` method using
`shared_from_this`.
Make `prepare` methods implementation of inheriting classes
mirror implementation from other statements (i.e.
create a shallow copy of the object when prepairing into
`prepared_statement`; this could be further refactored
to avoid copies as much as possible).
* Remove unused fields in create_role_statement which led to
error while using compiler-generated copy ctor (copying
uninitialied bool values via ctor).
Signed-off-by: Pavel Solodovnikov <pa.solodovnikov@scylladb.com>
This patches silences the remaining discarded future warnings, those
where it cannot be determined with reasonable confidence that this was
indeed the actual intent of the author, or that the discarding of the
future could lead to problems. For all those places a FIXME is added,
with the intent that these will be soon followed-up with an actual fix.
I deliberately haven't fixed any of these, even if the fix seems
trivial. It is too easy to overlook a bad fix mixed in with so many
mechanical changes.
query_processor uses storage_proxy to access data, and the local
database object to access replicated metadata. While it seems strange
that the database object is not used to access data, it is logical
when you consider that a sharded<database> only contain's this node's
data, not the cluster data.
Take advantage of this to replace sharded<database> with a single database
shard.
Automatically accept registered schema extensions into the properties
set, and when building, generate the corresponding extension object into
the resulting schema.
This reverts commit db5bf363d0. Causes
errors of the sort
Exiting on unhandled exception: exceptions::invalid_request_exception
(Keyspace 'system_traces' does not exist)
