The function underlying_type() returns an data_type by value,
but the code assigned it to a reference.
At first I was sure this is an error
(assigning temporary value to a reference), but it turns out
that this is most likely correct due to C++ lifetime
extension rules.
I think it's better to avoid such unituitive tricks.
Assigning to value makes it clearer that the code
is correct and there are no dangling references.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Closes#12485
With sufficiently many test cases we would eventually run out of IP
addresses, because IPs (which are leased from a global host registry)
would only be released at the end of an entire test suite.
In fact we already hit this during next promotions, causing much pain
indeed.
Release IPs when a cluster, after being marked dirty, is stopped and
thrown away.
Closes#12482
Introduce a new "script" operation, which loads a script from the specified path, then feeds the mutation fragment stream to it. The script can then extract, process and present information from the sstable as it wishes.
For now only Lua scripts are supported for the simple reason that Lua is easy to write bindings for, it is simple and lightweight and more importantly we already have Lua included in the Scylla binary as it is used as the implementation language for UDF/UDA. We might consider WASM support in the future, but for now we don't have any language support in WASM available.
Example:
```lua
function new_stats(key)
return {
partition_key = key,
total = 0,
partition = 0,
static_row = 0,
clustering_row = 0,
range_tombstone_change = 0,
};
end
total_stats = new_stats(nil);
function inc_stat(stats, field)
stats[field] = stats[field] + 1;
stats.total = stats.total + 1;
total_stats[field] = total_stats[field] + 1;
total_stats.total = total_stats.total + 1;
end
function on_new_sstable(sst)
max_partition_stats = new_stats(nil);
if sst then
current_sst_filename = sst.filename;
else
current_sst_filename = nil;
end
end
function consume_partition_start(ps)
current_partition_stats = new_stats(ps.key);
inc_stat(current_partition_stats, "partition");
end
function consume_static_row(sr)
inc_stat(current_partition_stats, "static_row");
end
function consume_clustering_row(cr)
inc_stat(current_partition_stats, "clustering_row");
end
function consume_range_tombstone_change(crt)
inc_stat(current_partition_stats, "range_tombstone_change");
end
function consume_partition_end()
if current_partition_stats.total > max_partition_stats.total then
max_partition_stats = current_partition_stats;
end
end
function on_end_of_sstable()
if current_sst_filename then
print(string.format("Stats for sstable %s:", current_sst_filename));
else
print("Stats for stream:");
end
print(string.format("\t%d fragments in %d partitions - %d static rows, %d clustering rows and %d range tombstone changes",
total_stats.total,
total_stats.partition,
total_stats.static_row,
total_stats.clustering_row,
total_stats.range_tombstone_change));
print(string.format("\tPartition with max number of fragments (%d): %s - %d static rows, %d clustering rows and %d range tombstone changes",
max_partition_stats.total,
max_partition_stats.partition_key,
max_partition_stats.static_row,
max_partition_stats.clustering_row,
max_partition_stats.range_tombstone_change));
end
```
Running this script wilt yield the following:
```
$ scylla sstable script --script-file fragment-stats.lua --system-schema system_schema.columns /var/lib/scylla/data/system_schema/columns-24101c25a2ae3af787c1b40ee1aca33f/me-1-big-Data.db
Stats for sstable /var/lib/scylla/data/system_schema/columns-24101c25a2ae3af787c1b40ee1aca33f//me-1-big-Data.db:
397 fragments in 7 partitions - 0 static rows, 362 clustering rows and 28 range tombstone changes
Partition with max number of fragments (180): system - 0 static rows, 179 clustering rows and 0 range tombstone changes
```
Fixes: https://github.com/scylladb/scylladb/issues/9679Closes#11649
* github.com:scylladb/scylladb:
tools/scylla-sstable: consume_reader(): improve pause heuristincs
test/cql-pytest/test_tools.py: add test for scylla-sstable script
tools: add scylla-sstable-scripts directory
tools/scylla-sstable: remove custom operation
tools/scylla-sstable: add script operation
tools/sstable: introduce the Lua sstable consumer
dht/i_partitioner.hh: ring_position_ext: add weight() accessor
lang/lua: export Scylla <-> lua type conversion methods
lang/lua: use correct lib name for string lib
lang/lua: fix type in aligned_used_data (meant to be user_data)
lang/lua: use lua_State* in Scylla type <-> Lua type conversions
tools/sstable_consumer: more consistent method naming
tools/scylla-sstable: extract sstable_consumer interface into own header
tools/json_writer: add accessor to underlying writer
tools/scylla-sstable: fix indentation
tools/scylla-sstable: export mutation_fragment_json_writer declaration
tools/scylla-sstable: mutation_fragment_json_writer un-implement sstable_consumer
tools/scylla-sstable: extract json writing logic from json_dumper
tools/scylla-sstable: extract json_writer into its own header
tools/scylla-sstable: use json_writer::DataKey() to write all keys
tools/scylla-types: fix use-after-free on main lambda captures
Inferring shard from generation is long gone. We still use it in
some scripts, but that's no longer needed in Scylla, when loading
the SSTables, and it also conflicts with ongoing work of UUID-based
generations.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closes#12476
The CQL binary protocol version 3 was introduced in 2014. All Scylla
version support it, and Cassandra versions 2.1 and newer.
Versions 1 and 2 have 16-bit collection sizes, while protocol 3 and newer
use 32-bit collection sizes.
Unfortunately, we implemented support for multiple serialization formats
very intrusively, by pushing the format everywhere. This avoids the need
to re-serialize (sometimes) but is quite obnoxious. It's also likely to be
broken, since it's almost untested and it's too easy to write
cql_serialization_format::internal() instead of propagating the client
specified value.
Since protocols 1 and 2 are obsolete for 9 years, just drop them. It's
easy to verify that they are no longer in use on a running system by
examining the `system.clients` table before upgrade.
Fixes#10607Closes#12432
* github.com:scylladb/scylladb:
treewide: drop cql_serialization_format
cql: modification_statement: drop protocol check for LWT
transport: drop cql protocol versions 1 and 2
The consume loop had some heuristics in place to determine whether after
pausing, the consumer wishes to skip just the partition or the remaining
content of the sstable. This heuristics was flawed so replace it with a
non-heuristic method: track the last consumed fragment and look at this
to determine what should be done.
To test the script operation, we use some of the example scripts from
the example directory. Namely, dump.lua and slice.lua. These two scripts
together have a very good coverage of the entire script API. Testing
their functionality therefore also provides a good coverage of the lua
bindings. A further advantage is that since both scripts dump output in
identical format to that of the data-dump operation, it is trivial to do
a comparison against this already tested operation.
A targeted test is written for the sstable skip functionality of the
consumer API.
To be the home of example scripts for scylla-sstable. For now only a
README.md is added describing the directory's purpose and with links to
useful resources.
One example script is added in this patch, more will come later.
Loads the script from the specified path, then feeds the mutation
fragment stream to it. For now only Lua scripts are supported for the
simple reason that Lua is easy to write bindings for, it is simple and
lightweight and more importantly we already have Lua included in the
Scylla binary as it is used as the implementation language for UDF/UDA.
We might consider WASM support in the future, but for now we don't have
any language support in WASM available.
The Lua sstable consumer loads a script from the specified path then
feeds the mutation fragment stream to the script via the
sstable_consumer methods, each method of which the script is allowed to
define, effectively overloading the virtual method in Lua.
This allows for very wide and flexible customization opportunities for
what to extract from sstables and how to process and present them,
without the need to recompile the scylla-sstable tool.
Instead of the lua_slice_state which is local to this file. We want to
reuse the Scylla type <-> Lua type conversion functions but for that
they have to use the more generic lua_State*. No functionality or
convenience is lost with the switch, the code didn't make use of the
other fields bundled in lua_slice_state.
So it can be used in code outside scylla-sstable.cc. This source file is
quite large already, and as we have yet another large chunk of code to
add, we want to add it in a separate file.
There is no point in the former implementing said interface. For one it
is a futurized interface, which is not needed for something writing to
the stdout. Rename the methods to follow the naming convention of rjson
writers more closely.
We want to split this class into two parts: one with the actual logic
converting mutation fragments to json, and a wrapper over this one,
which implements the sstable_consumer interface.
As a first step we extract the class as is (no changes) and just forward
all-calls from now empty wrapper to it.
This method was renamed from its previous name of PartitionKey. Since in
json partition keys and clustering keys look alike, with the only
difference being that the former may also have a token, it makes to have
a single method to write them (with an optional token parameter). This
was the case at some point, json_dumper::write_key() taking this role.
However at a later point, json_writer::PartitionKey() was introduced and
now the code uses both. Standardize on the latter and give it a more
generic name.
The main lambda of scylla-types, the one passed to app_template::run()
was recently made a coroytine. app_template::run() however doesn't keep
this lambda alive and hence after the first suspention point, accessing
the lambda's captures triggers use-after-free.
The simple fix is to convert the coroutine into continuation chain.
Consider the following MVCC state of a partition:
v2: ==== <7> [entry2] ==== <9> ===== <last dummy>
v1: ================================ <last dummy> [entry1]
Where === means a continuous range and --- means a discontinuous range.
After two LRU items are evicted (entry1 and entry2), we will end up with:
v2: ---------------------- <9> ===== <last dummy>
v1: ================================ <last dummy> [entry1]
This will cause readers to incorrectly think there are no rows before
entry <9>, because the range is continuous in v1, and continuity of a
snapshot is a union of continuous intervals in all versions. The
cursor will see the interval before <9> as continuous and the reader
will produce no rows.
This is only temporary, because current MVCC merging rules are such
that the flag on the latest entry wins, so we'll end up with this once
v1 is no longer needed:
v2: ---------------------- <9> ===== <last dummy>
...and the reader will go to sstables to fetch the evicted rows before
entry <9>, as expected.
The bug is in rows_entry::on_evicted(), which treats the last dummy
entry in a special way, and doesn't evict it, and doesn't clear the
continuity by omission.
The situation is not easy to trigger because it requires certain
eviction pattern concurrent with multiple reads of the same partition
in different versions, so across memtable flushes.
Closes#12452
Sstable read related metrics are broken for a long time now. First, the introduction of inactive reads (https://github.com/scylladb/scylladb/issues/1865) diluted this metric, as it now also contained inactive reads (contrary to the metric's name). Then, after moving the semaphore in front of the cache (3d816b7c1) this metric became completely broken as this metric now contains all kinds of reads: disk, in-memory and inactive ones too.
This series aims to remedy this:
* `scylla_database_active_reads` is fixed to only include active reads.
* `scylla_database_active_reads_memory_consumption` is renamed to `scylla_database_reads_memory_consumption` and its description is brought up-to-date.
* `scylla_database_disk_reads` is added to track current reads that are gone to disk.
* `scylla_database_sstables_read` is added to track the number of sstables read currently.
Fixes: https://github.com/scylladb/scylladb/issues/10065Closes#12437
* github.com:scylladb/scylladb:
replica/database: add disk_reads and sstables_read metrics
sstables: wire in the reader_permit's sstable read count tracking
reader_concurrency_semaphore: add disk_reads and sstables_read stats
replica/database: fix active_reads_memory_consumption_metric
replica/database: fix active_reads metric
Azure metadata API may return empty zone sometimes. If that happens
shard-0 gets empty string as its rack, but propagates UNKNOWN_RACK to
other shards.
Empty zones response should be handled regardless.
refs: #12185
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closes#12274
Cassandra refuses a request with more than one equality relation to the
same column, for example
DELETE FROM tbl WHERE partitionKey = ? AND partitionKey = ?
It complains that
partitionkey cannot be restricted by more than one relation if it
includes an Equal
Currently, Scylla doesn't consider such requests an error. Whether or
not we should be compatible with Cassandra here is discussed in
issue #12472. But as long as we do accept this query, we should be
sure we do the right thing: "WHERE p = 1 AND p = 2" should match
nothing (not the first, or last, value being tested..), and "WHERE p = 1
AND p = 1" should match the matches of p = 1. This patch adds a test
for verify that these requests indeed yield correct results. The
test is scylla_only because, as explained above, Cassandra doesn't
support this feature at all.
Refs #12472
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#12473
* seastar ca586cfb8d...8889cbc198 (14):
> http: request_parser: fix grammar ambiguity in field_content
Fixes#12468
> sstring: use fold expression to simply copy_str_to()
> sstring: use fold expression to simply str_len()
> metrics: capture by move in make_function()
> metrics: replace homebrew is_callable<> with is_invocable_v<>
> reactor: use std::move() to avoid copy.
> reactor: remove redundant semicolon.
> reactor: use mutable to make std::move() work.
> build: install liburing explicitly on ArchLinux.
> reactor: use a for loop for submitting ios
> metrics: add spaces around '='
> parallel utils: align concept with implementation
> reactor: s/resize(0)/clear()/
> reactor: fix a typo in comment
Closes#12469
This commit removes consume_in_reverse::legacy_half_reverse, an option
once used to indicate that the given key ranges are sorted descending,
based on the clustering key of the start of the range, and that the
range tombstones inside partition would be sorted (descending, as all
the mutation fragments would) according to their end (but range
tombstone would still be stored according to their start bound).
As it turns out, mutation::consume, when called with legacy_half_reverse
option produces invalid fragment stream, one where all the row
tombstone changes come after all the clustering rows. This was not an
issue, since when constructing results from the query, Scylla would not
pass the tombstones to the client, but instead compact data beforehand.
In this commit, the consume_in_reverse::legacy_half_reverse is removed,
along with all the uses.
As for the swap out in mutation_partition.cc in query_mutation and
to_data_query_result:
The downstream was not prepared to deal with legacy_half_reverse.
mutation::consume contains
```
if (reverse == consume_in_reverse::yes) {
while (!(stop_opt = consume_clustering_fragments<consume_in_reverse::yes>(_ptr->_schema, partition, consumer, cookie, is_preemptible::yes))) {
co_await yield();
}
} else {
while (!(stop_opt = consume_clustering_fragments<consume_in_reverse::no>(_ptr->_schema, partition, consumer, cookie, is_preemptible::yes))) {
co_await yield();
}
}
```
So why did it work at all? to_data_query_result deals with a single slice.
The used consumer (compact_for_query_v2) compacts-away the range tombstone
changes, and thus the only difference between the consume_in_reverse::no
and consume_in_reverse::yes was that one was ordered increasing wrt. ckeys
and the second one was ordered decreasing. This property is maintained if
we swap out for the consume_in_reverse::yes format.
Refs: #12353Closes#12453
* github.com:scylladb/scylladb:
mutation{,_consumer,_partition}: remove consume_in_reverse::legacy_half_reverse
mutation_partition_view: treat query::partition_slice::option::reversed in to_data_query_result as consume_in_reverse::yes
mutation: move consume_in_reverse def to mutation_consumer.hh
Convert decompressed temporary buffers into tracked buffers just before
returning them to the upper layer. This ensures these buffers are known
to the reader concurrency semaphore and it has an accurate view of the
actual memory consumption of reads.
Fixes: #12448Closes#12454
The test would use a trick to start a separate Scylla cluster from the
one provided originally by the test framework. This is not supported by
the test framework and may cause unexpected problems.
Change the test to perform regular node operations. Instead of starting
a fresh cluster of 3 nodes, we join the first of these nodes to the
original framework-provided cluster, then decommission the original
nodes, then bootstrap the other 2 fresh nodes.
Also add some logging to the test.
Refs: #12438, #12442Closes#12457
This series adds the implementation and usage of rust wasmtime bindings.
The WASM UDFs introduced by this patch are interruptable and use memory allocated using the seastar allocator.
This series includes #11102 (the first two commits) because #11102 required disabling wasm UDFs completely. This patch disables them in the middle of the series, and enables them again at the end.
After this patch, `libwasmtime.a` can be removed from the toolchain.
This patch also removes the workaround for #https://github.com/scylladb/scylladb/issues/9387 but it hasn't been tested with ARM yet - if the ARM test causes issues I'll revert this part of the change.
Closes#11351
* github.com:scylladb/scylladb:
build: remove references to unused c bindings of wasmtime
test: assert that WASM allocations can fail without crashing
wasm: limit memory allocated using mmap
wasm: add configuration options for instance cache and udf execution
test: check that wasmtime functions yield
wasm: use the new rust bindings of wasmtime
rust: add Wasmtime bindings
rust: add build profiles more aligned with ninja modes
rust: adjust build according to cxxbridge's recommendations
tools: toolchain: dbuild: prepare for sharing cargo cache
In issue #3668, a discussion spanning several years theorized that several
things are wrong with the "timestamp" type. This patch begins by adding
several tests that demonstrate that Scylla is in fact behaving correctly,
and mostly identically to Cassandra except one esoteric error handling
case.
However, after eliminating the red herrings, we are left for the real
issue that prompted opening #3668, which is a duplicate of issues #2693
and #2694, and this patch also adds a reproducer for that. The issue is
that Cassandra 4 added support for arithmetic expressions on values,
and timestamps can be added durations, for example:
'2011-02-03 04:05:12.345+0000' - 1d
is a valid timestamp - and we don't currently support this syntax.
So the new test - which passes on Cassandra 4 and fails on Scylla
(or Cassandra 3) is marked xfail.
Refs #2693
Refs #2694
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#12436
The line modified in this patch was supposed to increase the
optimization levels of parsers in debug mode to 1, because they
were too slow otherwise. But as a side effect, it also reduced the
optimization level in release mode to 1. This is not a problem
for the CQL frontend, because statement preparation is not
performance-sensitive, but it is a serious performance problem
for Alternator, where it lies in the hot path.
Fix this by only applying the -O1 to debug modes.
Fixes#12463Closes#12460
Before the changes intorducing the new wasmtime bindings we relied
on an downloaded static library libwasmtime.a. Now that the bindings
are introduced, we do not rely on it anymore, so all references to
it can be removed.
The main source of big allocations in the WASM UDF implementation
is the WASM Linear Memory. We do not want Scylla to crash even if
a memory allocation for the WASM Memory fails, so we assert that
an exception is thrown instead.
The wasmtime runtime does not actually fail on an allocation failure
(assuming the memory allocator does not abort and returns nullptr
instead - which our seastar allocator does). What happens then
depends on the failed allocation handling of the code that was
compiled to WASM. If the original code threw an exception or aborted,
the resulting WASM code will trap. To make sure that we can handle
the trap, we need to allow wasmtime to handle SIGILL signals, because
that what is used to carry information about WASM traps.
The new test uses a special WASM Memory allocator that fails after
n allocations, and the allocations include both memory growth
instructions in WASM, as well as growing memory manually using the
wasmtime API.
Signed-off-by: Wojciech Mitros <wojciech.mitros@scylladb.com>
The wasmtime runtime allocates memory for the executable code of
the WASM programs using mmap and not the seastar allocator. As
a result, the memory that Scylla actually uses becomes not only
the memory preallocated for the seastar allocator but the sum of
that and the memory allocated for executable codes by the WASM
runtime.
To keep limiting the memory used by Scylla, we measure how much
memory do the WASM programs use and if they use too much, compiled
WASM UDFs (modules) that are currently not in use are evicted to
make room.
To evict a module it is required to evict all instances of this
module (the underlying implementation of modules and instances uses
shared pointers to the executable code). For this reason, we add
reference counts to modules. Each instance using a module is a
reference. When an instance is destroyed, a reference is removed.
If all references to a module are removed, the executable code
for this module is deallocated.
The eviction of a module is actually acheved by eviction of all
its references. When we want to free memory for a new module we
repeatedly evict instances from the wasm_instance_cache using its
LRU strategy until some module loses all its instances. This
process may not succeed if the instances currently in use (so not
in the cache) use too much memory - in this case the query also
fails. Otherwise the new module is added to the tracking system.
This strategy may evict some instances unnecessarily, but evicting
modules should not happen frequently, and any more efficient
solution requires an even bigger intervention into the code.
Different users may require different limits for their UDFs. This
patch allows them to configure the size of their cache of wasm,
the maximum size of indivitual instances stored in the cache, the
time after which the instances are evicted, the fuel that all wasm
UDFs are allowed to consume before yielding (for the control of
latency), the fuel that wasm UDFs are allowed to consume in total
(to allow performing longer computations in the UDF without
detecting an infinite loop) and the hard limit of the size of UDFs
that are executed (to avoid large allocations)
The new implementation for WASM UDFs allows executing the UDFs
in pieces. This commit adds a test asserting that the UDF is in fact
divided and that each of the execution segments takes no longer than
1ms.
This patch replaces all dependencies on the wasmtime
C++ bindings with our new ones.
The wasmtime.hh and wasm_engine.hh files are deleted.
The libwasmtime.a library is no longer required by
configure.py. The SCYLLA_ENABLE_WASMTIME macro is
removed and wasm udfs are now compiled by default
on all architectures.
In terms of implementation, most of code using
wasmtime was moved to the Rust source files. The
remaining code uses names from the new bindings
(which are mostly unchanged). Most of wasmtime objects
are now stored as a rust::Box<>, to make it compatible
with rust lifetime requirements.
Signed-off-by: Wojciech Mitros <wojciech.mitros@scylladb.com>
The C++ bindings provided by wasmtime are lacking a crucial
capability: asynchronous execution of the wasm functions.
This forces us to stop the execution of the function after
a short time to prevent increasing the latency. Fortunately,
this feature is implemented in the native language
of Wasmtime - Rust. Support for Rust was recently added to
scylla, so we can implement the async bindings ourselves,
which is done in this patch.
The bindings expose all the objects necessary for creating
and calling wasm functions. The majority of code implemented
in Rust is a translation of code that was previously present
in C++.
Types exported from Rust are currently required to be defined
by the same crate that contains the bridge using them, so
wasmtime types can't be exported directly. Instead, for each
class that was supposed to be exported, a wrapper type is
created, where its first member is the wasmtime class. Note
that the members are not visible from C++ anyway, the
difference only applies to Rust code.
Aside from wasmtime types and methods, two additional types
are exported with some associated methods.
- The first one is ValVec, which is a wrapper for a rust Vec
of wasmtime Vals. The underlying vector is required by
wasmtime methods for calling wasm functions. By having it
exported we avoid multiple conversions from a Val wrapper
to a wasmtime Val, as would be required if we exported a
rust Vec of Val wrappers (the rust Vec itself does not
require wrappers if the type it contains is already wrapped)
- The second one is Fut. This class represents an computation
tha may or may not be ready. We're currently using it
to control the execution of wasm functions from C++. This
class exposes one method: resume(), which returns a bool
that signals whether the computation is finished or not.
Signed-off-by: Wojciech Mitros <wojciech.mitros@scylladb.com>
A cargo profile is created for each of build modes: dev, debug,
sanitize, realease and coverage. The names of cargo profiles are
prefixed by "rust-" because cargo does not allow separate "dev"
and "debug" profiles.
The main difference between profiles are their optimization levels,
they correlate to the levels used in configure.py. The debug info
is stripped only in the dev mode, and only this mode uses
"incremental" compilation to speed it up.
Currently, the rust build system in Scylla creates a separate
static library for each incuded rust package. This could cause
duplicate symbol issues when linking against multiple libraries
compiled from rust.
This issue is fixed in this patch by creating a single static library
to link against, which combines all rust packages implemented in
Scylla.
The Cargo.lock for the combined build is now tracked, so that all
users of the same scylla version also use the same versions of
imported rust modules.
Additionally, the rust package implementation and usage
docs are modified to be compatible with the build changes.
This patch also adds a new header file 'rust/cxx.hh' that contains
definitions of additional rust types available in c++.
