Secondary tracing sessions used to compute the execution time
from the point of their `begin()`-ning, not the parent session's
`begin()`. As a result, replica reported a slow query if it
exceeded the entire threshold *on that replica* too.
This change augments `trace_info` with the TS of parent's session
starting point, to be used as a reference on replicas.
Fixes#9403Closes#10005
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
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.
Enable creating shared_ptr<BaseClass> in nonstatic_class_registry
using BaseClass::ptr_type and use that for
abstract_replication_strategy.
While at it, also clean up compressor with that respect
to define compressor::ptr_type as shared_ptr<compressor>
thus simplifying compressor_registry.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
The tracing code assumes that query_option_names and query_option_values
vectors always have the same length as the prepared_statements vector,
but it's not true. E.g. if one of the statements in a batch is
incorrect, it will create a discrepancy between the number of prepared
statements and the number of bound names and values, which currently
leads to a segmentation fault.
To overcome the problem, all three vectors are integrated into a single
vector, which makes size mismatches impossible.
Tested manually with code that triggers a failure while executing
a batch statement, because the Python driver performs driver-side
validation and thus it's hard to create a test case which triggers
the problem.
closes: #9221
The write paths in storage_proxy pass replica sets as
std::unordered_set<gms::inet_address>. This is a complex type, with
N+1 allocations for N members, so we change it to a small_vector (via
inet_address_vector_replica_set) which requires just one allocation, and
even zero when up to three replicas are used.
This change is more nuanced than the corresponding change to the read path
abe3d7d7 ("Merge 'storage_proxy: use small_vector for vectors of
inet_address' from Avi Kivity"), for two reasons:
- there is a quadratic algorithm in
abstract_write_response_handler::response(): it searches for a replica
and erases it. Since this happens for every replica, it happens N^2/2
times.
- replica sets for writes always include all datacenters, while reads
usually involve just one datacenter.
So, a write to a keyspace that has 5 datacenters will invoke 15*(15-1)/2
=105 compares.
We could remove this by sending the index of the replica in the replica
set to the replica and ask it to include the index in the response, but
I think that this is unnecessary. Those 105 compares need to be only
105/15 = 7 times cheaper than the corresponding unordered_set operation,
which they surely will. Handling a response after a cross-datacenter round
trip surely involves L3 cache misses, and a small_vector reduces these
to a minimum compared to an unordered_set with its bucket table, linked
list walking and managent, and table rehashing.
Tests using perf_simple_query --write --smp 1 --operations-per-shard 1000000
--task-quota-ms show two allocations removed (as expected) and a nice
reduction in instructions executed.
before: median 204842.54 tps ( 54.2 allocs/op, 13.2 tasks/op, 49890 insns/op)
after: median 206077.65 tps ( 52.2 allocs/op, 13.2 tasks/op, 49138 insns/op)
Closes#8847
Eliminate not used includes and replace some more includes
with forward declarations where appropriate.
Signed-off-by: Pavel Solodovnikov <pa.solodovnikov@scylladb.com>
storage_proxy.hh is huge and includes many headers itself, so
remove its inclusions from headers and re-add smaller headers
where needed (and storage_proxy.hh itself in source files that
need it).
Ref #1.
fixes AddressSanitizer: stack-buffer-underflow on address 0x7ffd9a375820 at pc 0x555ac9721b4e bp 0x7ffd9a374e70 sp 0x7ffd9a374620
Backend registry holds a unique pointer to the backend implementation
that must outlive the whole tracing lifetime until the shutdown call.
So it must be catched/moved before the program exits its scope by
passing out the lambda chain.
Regarding deletion of the default destructor: moving object requires
a move constructor (for do_with) that is not implicitly provided if
there is a user-defined object destructor defined even tho its impl
is default.
Signed-off-by: Ivan Prisyazhnyy <ivan@scylladb.com>
Closes#8461
We want to change the internals of cql3::raw_value{_view}.
However, users of cql3::raw_value and cql3::raw_value_view often
use them by extracting the internal representation, which will be different
after the planned change.
This commit prepares us for the change by making all accesses to the value
inside cql3::raw_value(_view) be done through helper methods which don't expose
the internal representation publicly.
After this commit we are free to change the internal representation of
raw_value_{view} without messing up their users.
Tracing is created in two steps and is destroyed in two too.
The 2nd step doesn't have the corresponding stop part, so here
it is -- defer tracing stop after it was started.
But need to keep in mind, that tracing is also shut down on
drain, so the stopping should handle this.
Fixes#8382
tests: unit(dev), manual(start-stop, aborted-start)
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Message-Id: <20210331092221.1602-1-xemul@scylladb.com>
Constructors of classes inherited from file_impl copy alignment
values by hands, but miss the overwrite one, thus on a new file
it remains default-initialized.
To fix this and not to forget to properly initalize future fields
from file_impl, use the impl's copy constructor.
tests: unit(dev)
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Message-Id: <20210325104830.31923-1-xemul@scylladb.com>
If tracing::tracing::_ignore_trace_events is enabled then
the tracing system must ignore all sessions events
for non full_tracing sessions (probability tracing and
user requested) and creating subsessions with the
make_trace_info.
Patch introduces the slow query tracing fast mode that
omits all events during tracing.
Signed-off-by: Ivan Prisyazhnyy <ivan@scylladb.com>
This series adds slow query logging capability to alternator. Queries which last longer than the specified threshold are logged in `system_traces.node_slow_log` and traced.
In order to be better prepared for https://github.com/scylladb/scylla/issues/2572, this series also expands the tracing API to allow custom key-value params and adds a custom `alternator_op` parameter to the slow node log. This information can also be deduced from the tracing session id by consulting the system_traces.events table, but https://github.com/scylladb/scylla/issues/2572 's assumption is that this tracing might not always be available in the future.
This series comes with a simple test case which checks if operation logs indeed end up in `system_traces.node_slow_log`.
Tests:
unit(dev, alternator pytest)
manual: verified that no operations are logged if slow query logging is disabled; verified that operations that take less time than the threshold are not logged; verified with test_batch.py::test_batch_write_item_large that a large-enough operation is indeed logged and traced.
Fixes#8292
Example trace:
```cql
cqlsh> select parameters, duration from system_traces.node_slow_log where start_time=b7a44589-8711-11eb-8053-14c6c5faf955;
parameters | duration
---------------------------------------------------------------------------------------------+----------
{'alternator_op': 'DeleteTable', 'query': '{"TableName": "alternator_Test_1615979572905"}'} | 75732
```
Closes#8298
* github.com:scylladb/scylla:
alternator: add test for slow query logging
alternator: allow enabling slow query logging
tracing: allow providing a custom session record param
The mechanism of session record params is currently only used
to store query strings and a couple more params like consistency level,
but since we now have more frontends than just CQL and Thrift,
it would be nice to also allow the users to put custom parameters in
there.
An immediate first user of this mechanism would be alternator,
which is going to put the operation type under the "alternator_op" key.
The operation type is not part of the query string due to how DynamoDB's
protocol works - the op type is stored separately in the HTTP header.
While it's possible to extract the operation type from the session_id,
it might not be the case once #2572 is implemented.
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>
Timeout config is now stored in each connection, so there's no point
in tracking it inside each query as well. This patch removes
timeout_config from query_options and follows by removing now
unnecessary parameters of many functions and constructors.
The query processor is required in table_helper's used by tracing. Now
everything is ready to push the query processor reference from main down
to the table helpers.
Because of the current initialization sequence it's only possible to have
the started query processor at the .start_tracing() time. Earlier, when
the sharded<tracing> is started the query processor is not yet started,
so tracing keeps a pointer on local query processor.
When tracing is stopped, the pointer is null-ed. This is safe (but an
assert is put when dereferencing it), because on stop trace writes' gate
is closed and the query processor is only used in them.
Also there's still a chance that tracing remains started in case of start
abort, but this is on-par with the current code -- sharded query processor
is not stopped, so the memory is not freed.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The goal is to make tracing keyspace helper reference query processor, so this
patch adds the needed arguments through the initialization stack.
Signed-off-by: Pavel Emelyanov <xemul@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>
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.
`trace_keyspace_helper::make_slow_query_mutation_data` expected a
"query" key in its parameters, which does not appear in case of
e.g. batches of prepared statements. This is example of failing
`record.parameters`:
```
...{"query[0]" : "INSERT INTO ks.tbl (pk, i) values (?, ?);"},
{"query[1]" : "INSERT INTO ks.tbl (pk, i) values (?, ?);"}...
```
In such case Scylla recorded no trace and said:
```
ERROR 2020-09-28 10:09:36,696 [shard 3] trace_keyspace_helper - No
"query" parameter set for a session requesting a slow_query_log record
```
Fix here is to leave query empty if not found. The users can still
retrieve the query contents from existing info.
Fixes#5843Closes#7293
The schema_tables.hh -> migration_manager.hh couple seems to work as one
of "single header for everyhing" creating big blot for many seemingly
unrelated .hh's.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
seastar::apply() is deprecated in recent versions of seastar in favor
of std::apply(), so stop including its header. Calls to unqualified
apply(..., std::tuple<>) are resolved to std::apply() by argument
dependent lookup, so no changes to call sites are necessary.
This avoids a huge number of deprecation warnings with latest seastar.
Message-Id: <20200526090552.1969633-1-avi@scylladb.com>
std::memory_order is an unscoped enum, and so does not need its
members to be prefixed with std::memory_order::, just std::.
This used to work, but in C++20 it no longer does. Use the
standard way to name these constants, which works in both C++17
and C++20.
Reviewed-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Message-Id: <20200512092408.115649-1-avi@scylladb.com>
query_processor is a central class, so reducing its includes
can reduce dependencies treewite. This patch removes includes
for parsed_statement, cf_statement, and untyped_result_set and
fixes up the rest of the tree to include what it lacks as a result
of these removals.
Currently query_options objects is passed to a trace stopping function
which makes it mandatory to make them alive until the end of the
query. The reason for that is to add prepared statement parameters to
the trace. All other query options that we want to put in the trace are
copied into trace_state::params_values, so lets copy prepared statement
parameters there too. Trace enabled case will become a little bit more
expensive but on the other hand we can drop a continuation that holds
query_options object alive from a fast path. It is safe to drop the call
to stop_foreground_prepared() here since The tracing will be stopped
in process_request_one().
Message-Id: <20191205102026.GJ9084@scylladb.com>
Similar to trace_state keep shared_ptr<tracing> _local_tracing_ptr
in one_session_records when constructed so it can be used
during shutdown.
Fixes#5243
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Commit 7e3805ed3d removed the load balancing code from cql
server, but it did not remove most of the craft that load balancing
introduced. The most of the complexity (and probably the main reason the
code never worked properly) is around service::client_state class which
is copied before been passed to the request processor (because in the past
the processing could have happened on another shard) and then merged back
into the "master copy" because a request processing may have changed it.
This commit remove all this copying. The client_request is passed as a
reference all the way to the lowest layer that needs it and it copy
construction is removed to make sure nobody copies it by mistake.
tests: dev, default c-s load of 3 node cluster
Message-Id: <20190906083050.GA21796@scylladb.com>
This patch silences those future discard warnings where it is clear that
discarding the future was actually the intent of the original author,
*and* they did the necessary precautions (handling errors). The patch
also adds some trivial error handling (logging the error) in some
places, which were lacking this, but otherwise look ok. No functional
changes.
We need a way to configure the cql interpreter and runtime. So far we relied
on accessing the configuration class via various backdoors, but that causes
its own problems around initialization order and testability. To avoid that,
this patch adds an empty cql_config class and propagates it from main.cc
(and from tests) to the cql interpreter via the query_options class, which is
already passed everywhere.
Later patches will fill it with contents.
Current cql transport code acquire a permit before processing a query and
release it when the query gets a reply, but some quires leave work behind.
If the work is allowed to accumulate without any limit a server may
eventually run out of memory. To prevent that the permit system should
account for the background work as well. The patch is a first step in
this direction. It passes a permit down to storage proxy where it will
be later hold by background work.
Replace stdx::optional and stdx::string_view with the C++ std
counterparts.
Some instances of boost::variant were also replaced with std::variant,
namely those that called seastar::visit.
Scylla now requires GCC 8 to compile.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20190108111141.5369-1-duarte@scylladb.com>
Static class_registries hinder librarification by requiring linking with
all object files (instead of a library from which objects are linked on
demand) and reduce readability by hiding dependencies and by their
horrible syntax. Hide them behind a non-static, non-template tracing
backend registry.
Message-Id: <20181229121000.7885-1-avi@scylladb.com>
Many headers don't really need to include database.hh, the include can
be replaced by forward declarations and/or including the actually needed
headers directly. Some headers don't need this include at all.
Each header was verified to be compilable on its own after the change,
by including it into an empty `.cc` file and compiling it. `.cc` files
that used to get `database.hh` through headers that no longer include it
were changed to include it themselves.
sprint() recently became more strict, throwing on sprint("%s", 5). Replace
with the more modern format().
Mechanically converted with https://github.com/avikivity/unsprint.
