The test test/cluster/test_ttl_row.py::test_row_ttl_scheduling_group wants to
verify that the new CQL per-row TTL feature does all its work (expiration
scanning, deletion of expired items) on all nodes in the "streaming"
scheduling group, not in the statement scheduling group.
As originally written, the test couldn't require that it uses exactly zero
time in the statement scheduling group - because some things do happen
there - specifically the ALTER TABLE request we use to enable TTL.
So the test checked that the time in the "wrong" group is less than 0.2
of the total time, not zero.
But in one CI run, we got to exactly 0.2 and the test failed. Running
this test locally, I see the margin is pretty narrow: The test almost
always fails if I set the threshold ratio to 0.1.
The solution in this patch is to move the ALTER TABLE work to a different
scheduling group (by using an additional service level). After doing that
the CPU usage in sl:default goes down to exactly zero - not close to zero
but exactly zero.
However, it seems that there is always some rare background work in
sl:default and debug builds it can come out more than 0ms (e.g., in
one test we saw 1ms), so we keep checking that sl:default is much
lower than sl:stream - not exactly zero.
Incidentally, I converted the serial loop adding the 200 rows in the
test's setup to a parallel loop, to make the test setup slightly faster.
I also added to the test a sanity check that the scheduling group sl:default
that we are measuring that TTL does zero work in, is actually the scheduling
group that normal writes work in (to avoid the risk of having a test that
verifies that some irrelevant scheduling group is unsurprisingly getting
zero usage...).
Fixes SCYLLADB-1495.
Closesscylladb/scylladb#29447
We only assume that new tablets share boundaries with some old tablets.
In preparation for supporting arbitrary merge plan, where any replica
can be isolated (not merged with siblings) by the merge plan.
There are several reasons we want to do that.
One is that it will give us more flexibility in distributing the
load. We can subdivide tablets at any points, and achieve more
evenly-sized tablets. In particular, we can isolate large partitions
into separate tablets.
Another reason is vnode-to-tablet migration. We could construct a
tablet map which matches exactly the vnode boundaries, so migration
can happen transparently from the CQL-coordinator's point of view.
Implementation details:
We store a vector of tokens which represent tablet boundaries in the
tablet_id_map. tablet_id keeps its meaning, it's an index into vector
of tablets. To avoid logarithmic lookup of tablet_id from the token,
we introduce a lookup structure with power-of-two aligned buckets, and
store the tablet_id of the tablet which owns the first token in the
bucket. This way, lookup needs to consider tablet id range which
overlaps with one bucket. If boundaries are more or less aligned,
there are around 1-2 tablets overlapping with a bucket, and the lookup
is still O(1).
Amount of memory used increased, but not significantly relative to old
size (because tablet_info is currently fat):
For 131'072 tablets:
Before:
Size of tablet_metadata in memory: 57456 KiB
After:
Size of tablet_metadata in memory: 59504 KiB
And reimplement existing split-related methods around it.
This way we avoid calling dht::compaction_group_of(), and
assuming anything about tablet boundaries or tablet count
being a power of two.
This will make later refactoring easier.
Currently, hints that are sent to tablet replicas which are leaving due to RF-- can be lost, because `hint_sender` only checks if the destination host is leaving. To avoid this, we add a new method `effective_replication_map::is_leaving(host, token)` which checks if the tablet identified by the given token is leaving the host. This method is called by the `hint_sender` to check if the hint should be sent only to the destination host, or to all the replicas. This way, we increase consistency. For v-node based ERPs, `is_leaving()` calls `token_metadata::is_leaving(host)`.
Fixes: SCYLLADB-287
This is an improvement, and backport is not needed.
Closesscylladb/scylladb#28770
* github.com:scylladb/scylladb:
test: verify hints are delivered during tablet RF reduction
hint_sender: use per-tablet is_leaving() to avoid losing hints on RF reduction
erm: add is_leaving() to effective_replication_map
Fixes a race condition where tablet split can crash the server during truncation.
`truncate_table_on_all_shards()` disables compaction on all existing compaction groups, then later calls `discard_sstables()` which asserts that compaction is disabled. Between these two points, tablet split can call `set_split_mode()`, which creates new compaction groups via `make_empty_group()` — these start with `compaction_disabled_counter == 0`. When `discard_sstables()` checks its assertion, it finds these new groups and fires `on_internal_error`, aborting the server.
In `storage_group::set_split_mode()`, before creating new compaction groups, check whether the main compaction group has compaction disabled. If it does, bail out early and return `false` (not ready). This is safe because the split will be retried once truncation completes and re-enables compaction.
A new regression test `test_split_emitted_during_truncate` reproduces the
exact interleaving using two error injection points:
- **`database_truncate_wait`** — pauses truncation after compaction is disabled but before `discard_sstables()` runs.
- **`tablet_split_monitor_wait`** (new, in `service/storage_service.cc`) — pauses the split monitor at the start of `process_tablet_split_candidate()`.
The test creates a single-tablet table, triggers both operations, uses the injection points to force the problematic ordering, then verifies that truncation completes successfully and the split finishes afterward.
Fixes: SCYLLADB-1035
This needs to be backported to all currently supported version.
Closesscylladb/scylladb#29250
* github.com:scylladb/scylladb:
test: add test_split_emitted_during_truncate
table: fix race between tablet split and truncate
In partition_snapshot_row_cursor::maybe_refresh(), the !is_in_latest_version()
path calls lower_bound(_position) on the latest version's rows to find the
cursor's position in that version. When lower_bound returns null (the cursor
is positioned above all entries in the latest version in table order), the code
unconditionally sets _background_continuity = true and allows the subsequent
if(!it) block to erase the latest version's entry from the heap.
This is correct for forward traversal: null means there are no more entries
ahead, so removing the version from the heap is safe.
However, in reversed mode, null from lower_bound means the cursor is above
all entries in table order -- those entries are BELOW the cursor in query
order and will be visited LATER during reversed traversal. Erasing the heap
entry permanently loses them, causing live rows to be skipped.
The fix mirrors what prepare_heap() already does correctly: when lower_bound
returns null in reversed mode, use std::prev(rows.end()) to keep the last
entry in the heap instead of erasing it.
Add test_reversed_maybe_refresh_keeps_latest_version_entry to mvcc_test,
alongside the existing reversed cursor tests. The test creates a two-version
partition snapshot (v0 with range tombstones, v1 with a live row positioned
below all v0 entries in table order), and
traverses in reverse calling maybe_refresh() at each step -- directly
exercising the buggy code path. The test fails without the fix.
The bug was introduced by 6b7473be53 ("Handle non-evictable snapshots",
2022-11-21), which added null-iterator handling for non-evictable snapshots
(memtable snapshots lack the trailing dummy entry that evictable snapshots
have). prepare_heap() got correct reversed-mode handling at that time, but
maybe_refresh() received only forward-mode logic.
The bug is intermittent because multiple mechanisms cause iterators_valid()
to return false, forcing maybe_refresh() to take the full rebuild path via
prepare_heap() (which handles reversed mode correctly):
- Mutation cleaner merging versions in the background (changes change_mark)
- LSA segment compaction during reserve() (invalidates references)
- B-tree rebalancing on partition insertion (invalidates references)
- Debug mode's always-true need_preempt() creating many multi-version
partitions via preempted apply_monotonically()
A dtest reproducer confirmed the same root cause: with 100K overlapping range
tombstones creating a massively multi-version memtable partition (287K preemption
events), the reversed scan's latest_iterator was observed jumping discontinuously
during a version transition -- the latest version's heap entry was erased --
causing the query to walk the entire partition without finding the live row.
Fixes: SCYLLADB-1253
Closesscylladb/scylladb#29368
execute_batch_without_checking_exception_message() inserted entries
into the authorized prepared cache before verifying that
check_access() succeeded. A failed BATCH therefore left behind
cached 'authorized' entries that later let a direct EXECUTE of the
same prepared statement skip the authorization check entirely.
Move the cache insertion after the access check so that entries are
only cached on success. This matches the pattern already used by
do_execute_prepared() for individual EXECUTE requests.
Introduced in 98f5e49ea8
Fixes https://scylladb.atlassian.net/browse/SCYLLADB-1221
Backport: all supported versions
Closesscylladb/scylladb#29432
* github.com:scylladb/scylladb:
test/cqlpy: add reproducer for BATCH prepared auth cache bypass
cql3: fix authorization bypass via BATCH prepared cache poisoning
Add parametrized integration test that verifies DESCRIBE CLUSTER returns correct
values in both normal and maintenance modes:
The parametrization keeps the validation logic (CQL queries and assertions)
identical for both modes, while the setup phase is mode-specific. This ensures
the same assertions apply to both cluster states:
- partitioner is org.apache.cassandra.dht.Murmur3Partitioner
- snitch is org.apache.cassandra.locator.SimpleSnitch
- cluster name matches system.local cluster_name
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Update cluster_describe_statement::describe() to retrieve cluster metadata
from storage_service::describe_cluster() instead of directly from db::config
or gossiper.
The storage_service provides a centralized API for accessing cluster metadata
(cluster_name, partitioner, snitch_name) that works in both normal and
maintenance modes, improving separation of concerns.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Add cluster_info struct containing cluster_name, partitioner, and snitch_name.
Implement describe_cluster() method to provide cluster metadata by combining
data from gossiper (cluster_name, partitioner) and snitch (snitch_name).
It will be used by next patch
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Previously Alternator, when emit Amazon's ARN would not stick to the
standard. After our attempt to run KCL with scylla we discovered few
issues.
Amazon's ARN looks like this:
arn:partition:service:region:account-id:resource-type/resource-id
for example:
arn:aws:dynamodb:us-west-2:111122223333:table/TestTable/stream/2015-05-11T21:21:33.291
KCL checks for:
- ARN provided from Alternator calls must fit with basic Amazon's ARN
pattern shown above,
- region constisting only of lower letter alphabets and `-`, no
underscore character
- account-id being only digits (exactly 12)
- service being `dynamodb`
- partition starting with `aws`
The patch updates our code handling ARNs to match those findings.
1. Split `stream_arn` object into `stream_arn` - ARN for streams only and
`stream_shard_id` - id value for stream shards. The latter receives original
implementation. The former emits and parses ARN in a Amazon style.
for example:
2. Update new `stream_arn` class to encode keyspace and table together
separating them by `@`. New ARN looks like this:
arn:aws:dynamodb:us-east-1:000000000000:table/TestKeyspace@TestTable/stream/2015-05-11T21:21:33.291
3. hardcode `dynamodb` as service, `aws` as partition, `us-east-1` as
region and `000000000000` as account-id (must have 12 digits)
4. Update code handling ARNs for tags manipulation to be able to parse
Amazon's style ARNs. Emiting code is left intact - the parser is now
capable of parsing both styles.
5. Added unit tests.
Fixes#28350
Fixes: SCYLLADB-539
Fixes: #28142Closesscylladb/scylladb#28187
This series makes result metadata handling for auth LIST statements consistent and adds coverage for the driver-visible behavior.
The first patch makes the result-column metadata construction shared across the affected statements, so the metadata shape used for PREPARE and EXECUTE stays uniform and easier to reason about.
The second patch adds regression coverage for both sides of the metadata-id flow:
- a Python auth-cluster test verifies that prepared LIST ROLES OF returns a non-empty result metadata id and that a later EXECUTE reuses it without METADATA_CHANGED
- a Boost transport test covers the recovery path where the client sends an empty request metadata id and the server responds with METADATA_CHANGED and the full metadata
Together these patches tighten the implementation and protect the prepared-metadata-id behavior exposed to drivers.
Fixes: https://scylladb.atlassian.net/browse/SCYLLADB-1218
backport: this change should be backported to all active branches to help the driver operation
Closesscylladb/scylladb#29347
Add a boost test that verifies commitlog segments are replayed in
ascending segment ID order within each shard. The test creates
multiple segments, triggers replay via commitlog_replayer, and
captures the "Replaying" debug log messages to verify the order.
Correct segment ordering is required by the strongly consistent
tables feature, particularly commitlog-based storage that relies
on replayed raft items being stored in order.
Ref SCYLLADB-1411.
The commitlog replayer groups segments by shard using a
std::unordered_multimap, then iterates per-shard segments via
equal_range(). However, equal_range() does not guarantee iteration
order for elements with the same key, so segments could be replayed
out of order within a shard. This can increase memory and disk
consumption during fragmented entry reconstruction, which accumulates
fragments across segments and benefits from ascending ID order.
This is also required by the strongly consistent tables feature,
particularly commitlog-based storage that relies on replayed raft
items being stored in order.
Fix by changing the data structure from
std::unordered_multimap<unsigned, commitlog::descriptor>
to
std::unordered_map<unsigned, utils::chunked_vector<commitlog::descriptor>>
Since the descriptors are inserted from a std::set ordered by ID, the
vector preserves insertion (and thus ID) order. The per-shard iteration
now simply iterates the vector, guaranteeing correct replay order.
Fixes SCYLLADB-1411.
Add a GitHub Actions workflow that runs scripts/compare_build_systems.py
on PRs touching build system files (configure.py, **/CMakeLists.txt,
cmake/**).
This prevents future deviations between the two build systems by
catching mismatches early in the CI pipeline.
Closesscylladb/scylladb#29426
The CMake build had -fsanitize-address-use-after-scope (enable) when
it should have been -fno-sanitize-address-use-after-scope (disable).
The comment on lines 24-25 of cql3/CMakeLists.txt explains the intent:
the use-after-scope sanitizer uses too much stack space on CqlParser
and overflows the stack. The Python-ninja path in configure.py:2801-2802
correctly had -fno-sanitize-address-use-after-scope.
Found by black-box comparison of compiler flags between the Python-ninja
and CMake build paths (ninja -nv output, debug mode, CqlParser.o):
Python-ninja: -fno-sanitize-address-use-after-scope (correct: disable)
CMake: -fsanitize-address-use-after-scope (wrong: enable)
Closesscylladb/scylladb#29439
The test waited for two "Finished tablet repair" log messages on the
coordinator, expecting one per tablet. But there are two log sources
that emit messages matching this pattern:
repair module (repair/repair.cc:2329):
"Finished tablet repair for table=..."
topology coordinator (topology_coordinator.cc:2083):
"Finished tablet repair host=..."
When the coordinator is also a repair replica (always the case with
RF=3 and 3 nodes), both messages appear in the coordinator log for the
same tablet within 1ms of each other. The test consumed both, thinking
both tablets were done, while the second tablet repair was still running.
From the CI failure logs:
04:08:09.658 Found: repair[...]: Finished tablet repair for table=...
global_tablet_id=e42fd650-3542-11f1-9756-85403784a622:0
04:08:09.660 Found: raft_topology - Finished tablet repair host=...
tablet=e42fd650-3542-11f1-9756-85403784a622:0
Both messages are for tablet :0. Tablet :1 repair had not finished yet.
The test then wrote keys 20-29 while the second tablet repair was still
in progress. That repair flushed the memtable (via
prepare_sstables_for_incremental_repair), including keys 20-29 in the
repair scan, and mark_sstable_as_repaired set repaired_at=2 on the
resulting sstable. This caused the assertion failure on servers[0]:
"should not have post-repair keys in repaired sstables, got:
{20, 21, 22, 23, 24, 25, 26, 27, 28, 29}"
Fix by matching "Finished tablet repair host=" which is unique to the
topology coordinator message and avoids the ambiguity.
Also fix an incorrect comment that said being_repaired=null when at that
point in the test being_repaired is still set to the session_id (the
delay_end_repair_update injection prevents end_repair from running).
Fixes: SCYLLADB-1478
Closesscylladb/scylladb#29444
In commit 727f68e0f5 we added the ability to SELECT:
* Individual elements of a map: `SELECT map_col[key]`.
* Individual elements of a set: `SELECT set_col[key]` returns key if the key exists in the set, or null if it doesn't, allowing to check if the element exists in the set.
* Individual pieces of a UDT: `SELECT udt_col.field`.
But at the time, we didn't provide any way to retrieve the **meta-data** for this value, namely its timestamp and TTL. We did not support `SELECT TIMESTAMP(collection[key])`, or `SELECT TIMESTAMP(udt.field)`.
Users requested to support such SELECTs in the past (see issue #15427), and Cassandra 5.0 added support for this feature - for both maps and sets and udts - so we also need this feature for compatibility. This feature was also requested recently by vector-search developers, who wanted to read Alternator columns - stored as map elements, not individual columns - with their WRITETIME information.
The first four patches in this series adds the feature (in four smaller patches instead one big one), the fifth and sixth patches add tests (cqlpy and boost tests, respectively). The seventh patch adds documentation.
All the new tests pass on Cassandra 5, failed on Scylla before the present fix, and pass with it.
The fix was surprisingly difficult. Our existing implementation (from 727f68e0f5 building on earlier machinery) doesn't just "read" `map_col[key]` and allow us to return just its timestamp. Rather, the implementation reads the entire map, serializes it in some temporary format that does **not** include the timestamps and ttls, and then takes the subscript key, at which point we no longer have the timestamp or ttl of the element. So the fix had to cross all these layers of the implementation.
While adding support for UDT fields in a pre-existing grammar nonterminal "subscriptExpr", we unintentionally added support for UDT fields also in LWT expressions (which used this nonterminal). LWT missing support for UDT fields was a long-time known compatibility issue (#13624) so we unintentionally fixed it :-) Actually, to completely fix it we needed another small change in the expression implementation, so the eighth patch in this series does this.
Fixes#15427Fixes#13624Closesscylladb/scylladb#29134
* github.com:scylladb/scylladb:
cql3: support UDT fields in LWT expressions
cql3: document WRITETIME() and TTL() for elements of map, set or UDT
test/boost: test WRITETIME() and TTL() on map collection elements
test/cqlpy: test WRITETIME() and TTL() on element of map, set or UDT
cql3: prepare and evaluate WRITETIME/TTL on collection elements and UDT fields
cql3: parse per-element timestamps/TTLs in the selection layer
cql3: add extended wire format for per-element timestamps and TTLs
cql3: extend WRITETIME/TTL grammar to accept collection and UDT elements
Document the new vector index behavior in the user-facing and developer
docs.
Describe `index_version` as a creation timeuuid stored in
`system_schema.indexes`, clarify that recreating an index changes it
while ALTER TABLE does not, and document that Scylla allows multiple
named vector indexes on the same column while still rejecting unnamed
duplicates.
Add cqlpy tests for the current CREATE INDEX behavior of vector indexes.
Cover named and unnamed duplicates, IF NOT EXISTS, coexistence of
multiple named vector indexes on the same column, interactions between
named and unnamed indexes, and the same-name-on-different-table case.
An unprivileged user could bypass authorization checks by exploiting
the BATCH prepared statement cache:
1. Prepare an INSERT on a table the user has no access to
2. Execute it inside a BATCH — gets Unauthorized
3. Execute the same prepared INSERT directly — succeeds
Apply filter_errors() to grep_for_errors() results in
test_split_stopped_on_shutdown and
test_group0_apply_while_node_is_being_shutdown. Without filtering,
benign RPC errors like 'connection dropped: Semaphore broken' that
occur during graceful shutdown cause spurious test failures.
Accept both list[str] (from distinct_errors=True) and
list[list[str]] (from distinct_errors=False) in filter_errors(),
matching against the first line of each error group. This allows
tests that call grep_for_errors() with default arguments to
pipe results directly through filter_errors().
Precompute the expected metadata-id hashes for the prepared LIST auth and
service-level statements and verify that PREPARE returns them while EXECUTE
reuses the prepared metadata without METADATA_CHANGED. Run all cases in a
single auth-cluster test after preparing the cluster, role, and service level
once through the regular manager fixture.
execute_batch_without_checking_exception_message() inserted entries
into the authorized prepared cache before verifying that
check_access() succeeded. A failed BATCH therefore left behind
cached 'authorized' entries that later let a direct EXECUTE of the
same prepared statement skip the authorization check entirely.
Move the cache insertion after the access check so that entries are
only cached on success. This matches the pattern already used by
do_execute_prepared() for individual EXECUTE requests.
Introduced in 98f5e49ea8
Fixes https://scylladb.atlassian.net/browse/SCYLLADB-1221
Prepared LIST statements were not calculating metadata in PREPARE path, and sent empty string hash to client causing problematic behaviour where metadat_id was not recalculated correctly.
This patch moves metadata construction into get_result_metadata() for the affected LIST statements and reuse that metadata when building the result set.
This gives PREPARE a stable metadata id for LIST ROLES, LIST USERS, LIST PERMISSIONS and the service-level variants.
This patch also adds a new boost test that verifies that when an EXECUTE request carries an empty result metadata id while the server has a real metadata id for the result set, the response is marked METADATA_CHANGED and includes the full result metadata plus the server metadata id.
This covers the recovery path for clients that send an empty or otherwise unusable metadata id instead of a matching cached one.
Allow creating multiple named vector indexes on the same column while
still rejecting duplicate unnamed ones.
`index_metadata::equals_noname()` now ignores `index_version`,
which is unique for every vector index creation, so duplicate detection
keeps working for unnamed vector indexes.
CREATE INDEX keeps using structural duplicate detection for regular
indexes and unnamed vector indexes, but named vector indexes are checked
by name only.
The explicit name check is also needed for IF NOT EXISTS when the same
index name already exists on a different table in the same keyspace,
because vector indexes have no backing view table to catch that case.
Add a regression test that reproduces the race between tablet split and
truncation. The test:
1. Creates a single-tablet table and inserts data.
2. Triggers truncation and pauses it (via database_truncate_wait) after
compaction is disabled but before discard_sstables() runs.
3. Triggers tablet split and pauses it (via tablet_split_monitor_wait)
at the start of process_tablet_split_candidate().
4. Releases split so set_split_mode() creates new compaction groups.
5. Waits for the set_split_mode log confirming the groups exist.
6. Releases truncation so discard_sstables() encounters the new groups.
7. Verifies truncation completes and split finishes.
Adds a tablet_split_monitor_wait error injection point in
process_tablet_split_candidate() to allow pausing the split monitor
before it enters the split loop.
Tablet split can call set_split_mode() between the point where
truncate_table_on_all_shards() disables compaction on all existing
compaction groups and the point where discard_sstables() checks that
compaction is disabled. The new split-ready compaction groups created
by set_split_mode() won't have compaction disabled, causing
discard_sstables() to fire on_internal_error.
Fix by preventing set_split_mode() from creating new compaction groups
when compaction is disabled on the main group. If truncation has
already disabled compaction, split will simply report not-ready rather
than creating groups which have compaction enabled.
This is safe because split will be retried once truncation completes
and re-enables compaction.
implement tablet split, tablet merge and tablet migration for tables that use the experimental logstor storage engine.
* tablet merge simply merges the histograms of segments of one compaction group with another.
* for tablet split we take the segments from the source compaction group, read them and write all live records to separate segments according to the split classifier, and move separated segments to the target compaction groups.
* for tablet migration we use stream_blob, similarly to file streaming of sstables. we add a new op type for streaming a logstor segment. on the source we take a snapshot of the segments with an input stream that reads the segment, and on the target we create a sink that allocates a new segment on the target shard and writes to it.
* we also do some improvements for recovery and loading of segments. we add a segment header that contains useful information for non-mixed segments, such as the table and token range.
Refs SCYLLADB-770
no backport - still a new and experimental feature
Closesscylladb/scylladb#29207
* github.com:scylladb/scylladb:
test: logstor: additional logstor tests
docs/dev: add logstor on-disk format section
logstor: add version and crc to buffer header
test: logstor: tablet split/merge and migration
logstor: enable tablet balancing
logstor: streaming of logstor segments using stream_blob
logstor: add take_logstor_snapshot
logstor: segment input/output stream
logstor: implement compaction_group::cleanup
logstor: tablet split
logstor: tablet merge
logstor: add compaction reenabler
logstor: add segment header
logstor: serialize writes to active segment
replica: extend compaction_group functions for logstor
replica: add compaction_group_for_logstor_segment
logstor: code cleanup
In an earlier patch, we used the CQL grammar's "subscriptExpr" in
the rule for WRITETIME() and TTL(). But since we also wanted these
to support UDT fields (x.a), not just collection subscripts (x[3]),
we expanded subscriptExpr to also support the field syntax.
But LWT expressions already used this subscriptExpr, which meant
that LWT expressions unintentionally gained support for UDT fields.
Missing support for UDT fields in LWT is a long-standing known
Cassandra-compatibility bug (#13624), and now our grammar finally
supports the missing syntax.
But supporting the syntax is not enough for correct implementation
of this feature - we also need to fix the expression handling:
Two bugs prevented expressions like `v.a = 0` from working in LWT IF
clauses, where `v` is a column of user-defined type.
The first bug was in get_lhs_receiver() in prepare_expr.cc: it lacked
a handler for field_selection nodes, causing an "unexpected expression"
internal error when preparing a condition like `IF v.a = 0`. The fix
adds a handler that returns a column_specification whose type is taken
from the prepared field_selection's type field.
The second bug was in search_and_replace() in expression.cc: when
recursing into a field_selection node it reconstructed it with only
`structure` and `field`, silently dropping the `field_idx` and `type`
fields that are set during preparation. As a result, any transformation
that uses search_and_replace() on a prepared expression containing a
field_selection — such as adjust_for_collection_as_maps() called from
column_condition_prepare() — would zero out those fields. At evaluation
time, type_of() on the field_selection returned a null data_type
pointer, causing a segmentation fault when the comparison operator tried
to call ->equal() through it. The fix preserves field_idx and type when
reconstructing the node.
Fixes#13624.
Add to the SELECT documentation (docs/cql/dml/select.rst) documentation
of the new ability to select WRITETIME() and TTL() of a single element
of map, set or UDT.
Also in the TTL documentation (docs/cql/time-to-live.rst), which already
had a section on "TTL for a collection", add a mention of the ability
to read a single element's TTL(), and an example.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Add tests in test/boost/expr_test.cc for the low-level implementation
of writetime() and ttl() on a map element.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
This patch adds many tests verifying the behavior of WRITETIME() and
TTL() on individual elements of maps, sets and UDTs, serving as a
regression test for issue #15427. We also add tests verifying our
understanding of related issues like WRITETIME() and TTL() of entire
collections and of individual elements of *frozen* collections.
All new tests pass on Cassandra 5.0, helping to verify that our
implementation is compatible with Cassandra. They also pass on
ScyllaDB after the previous patch (most didn't before that patch).
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Complete the implementation of SELECT WRITETIME(col[key])/TTL(col[key])
and WRITETIME(col.field)/TTL(col.field), building on the grammar (commit 1),
wire format (commit 2), and selection-layer (commit 3) changes in the
preceding patches.
* prepare_column_mutation_attribute() (prepare_expr.cc) now handles the
subscript and field_selection nodes that the grammar produces:
- For subscripts, it validates that the inner column is a non-frozen
map or set and checks the 'writetime_ttl_individual_element' feature
flag so the feature is rejected during rolling upgrades.
- For field selections, it validates that the inner column is a
non-frozen UDT, with the same feature-flag check.
* do_evaluate(column_mutation_attribute) (expression.cc) handles the
same two cases. For a field selection it serializes the field index as
a key and looks it up in collection_element_metadata; for a subscript
it evaluates the subscript key and looks it up in the same map.
A missing key (element not found or expired) returns NULL, matching
Cassandra behavior.
Together with the preceding three patches, this finally fixes#15427.
The next three patches will add tests and documentation for the new
feature, and the final eighth patch will fix the implementation of
UDT fields in LWT expressions - which the first patch made the grammar
allow but is still not implemented correctly.
Wire up the selection and result-set infrastructure to consume the
extended collection wire format introduced in the previous patch and
expose per-element timestamps and TTLs to the expression evaluator.
* Add collection_cell_metadata: maps from raw element-key bytes to
timestamp and remaining TTL, one entry per collection or UDT cell.
Add a corresponding collection_element_metadata span to
evaluation_inputs so that evaluators can access it.
* Add a flag _collect_collection_timestamps to selection (selection.hh/cc).
When any selected expression contains a WRITETIME(col[key])/TTL(col[key])
or WRITETIME(col.field)/TTL(col.field) attribute, the flag is set and
the send_collection_timestamps partition-slice option is enabled,
causing storage nodes to use the extended wire format from the
previous patch.
* Implement result_set_builder::add_collection() (selection.cc): when
_collect_collection_timestamps is set, parse the extended format,
decode per-element timestamps and remaining TTLs (computed from the
stored expiry time and the query time), and store them in
_collection_element_metadata indexed by column position. When the
flag is not set, the existing plain-bytes path is unchanged.
After this patch, the new selection feature is still not available to
the end-user because the prepare step still forbids it. The next patch
will finally complete the expression preparation and evaluation.
It will read the new collection_element_metadata and return the correct
timestamp or TTL value.
Introduce the infrastructure needed to transport per-element timestamps
and TTL expiry times from replicas to coordinators, required for
WRITETIME(col[key]) / TTL(col[key]) and WRITETIME(col.field) /
TTL(col.field).
* Add a 'writetime_ttl_individual_element' cluster feature flag that
guards usage of the new wire format during rolling upgrades: the
extended format is only emitted and consumed when every node in the
cluster supports it.
* Implement serialize_for_cql_with_timestamps() (types/types.cc), a
variant of serialize_for_cql() that appends a per-element section to
the regular CQL bytes, listing each live element's serialized key,
timestamp, and expiry. The format is:
[uint32 cql_len][cql bytes]
[int32 entry_count]
[per entry: (int32 key_len)(key bytes)(int64 timestamp)(int64 expiry)]
expiry is -1 when the element has no TTL.
* Add partition_slice::option::send_collection_timestamps and modify
write_cell() (mutation_partition.cc) to use the new function
serialize_for_cql_with_timestamps() when this option is available.
This commit stands alone with no user-visible effect: nothing yet sets
the new partition-slice option. The next patch adds the selection-layer
code that sets the option and parses the extended response.
Previously, WRITETIME() and TTL() only accepted a simple column name
(cident), so WRITETIME(m['key']) or WRITETIME(x.a) was a syntax error.
This patch begins to implements support for applying WRITETIME() and
TTL() to individual elements of a non-frozen map, set or UDT, as
requested in issue #15427.
On its own this commit only changes the parser (Cql.g). The prepare
step still rejects subscript and field-selection nodes with an
invalid_request_exception, so there is no user-visible behavior change
yet - just that a syntax error is replaced by a different error.
Upcoming patches add the extended wire format for per-element timestamps
(commit 2), the selection layer that consumes it (commit 3), and the
prepare/evaluate logic that ties everything together (commit 4), after
which WRITETIME() and TTL(col[key]) for collection or UDT elements
will finally be fully functional.
The parser change in this patch expands the subscriptExpr rule to
support the col.field syntax, not only col[key]. This change also
allows the UDT field syntax to be used in LWT conditions, which is
another long-standing missing feature (#13624); But to correctly
support this feature we'll need an additional patch to fix a couple
of remaining bugs - this will be the eighth commit in this series.
Remove const specifier from result_set_row._cells member to make
the class nothrow_move_constructible and nothrow_move_assignable
To be used later in query result_set and friends.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
