This commit removes the information about the recommended way of upgrading
ScyllaDB images - by updating ScyllaDB and OS packages in one step. This upgrade
procedure is not supported (it was implemented, but then reverted).
Refs https://github.com/scylladb/scylladb/issues/15733Closesscylladb/scylladb#21876
Currently truncating a table works by issuing an RPC to all the nodes which call `database::truncate_table_on_all_shards()`, which makes sure that older writes are dropped.
It works with tablets, but is not safe. A concurrent replication process may bring back old data.
This change makes makes TRUNCATE TABLE a topology operation, so that it excludes with other processes in the system which could interfere with it. More specifically, it makes TRUNCATE a global topology request.
Backporting is not needed.
Fixes#16411Closesscylladb/scylladb#19789
* github.com:scylladb/scylladb:
docs: docs: topology-over-raft: Document truncate_table request
storage_proxy: fix indentation and remove empty catch/rethrow
test: add tests for truncate with tablets
storage_proxy: use new TRUNCATE for tablets
truncate: make TRUNCATE a global topology operation
storage_service: move logic of wait_for_topology_request_completion()
RPC: add truncate_with_tablets RPC with frozen_topology_guard
feature_service: added cluster feature for system.topology schema change
system.topology_requests: change schema
storage_proxy: propagate group0 client and TSM dependency
The goal of merge is to reduce the tablet count for a shrinking table. Similar to how split increases the count while the table is growing. The load balancer decision to merge is implemented today (came with infrastructure introduced for split), but it wasn't handled until now.
Initial tablet count is respected while the table is in "growing mode". For example, the table leaves it if there was a need to split above the initial tablet count. After the table leaves the mode, the average size can be trusted to determine that the table is shrinking. Merge decision is emitted if the average tablet size is 50% of the target. Hysteresis is applied to avoid oscillations between split and merges.
Similar to split, the decision to merge is recorded in tablet map's resize_type field with the string "merge". This is important in case of coordinator failover, so new coordinator continues from where the old left off.
Unlike split, the preparation phase during merge is not done by the replica (with split compactions), but rather by the coordinator by co-locating sibling tablets in the same node's shard. We can define sibling tablets as tablets that have contiguous range and will become one after merge. The concept is based on the power-of-two constraint and token contiguity. For example, in a table with 4 tablets, tablets of ids 0 and 1 are siblings, 2 and 3 are also siblings.
The algorithm for co-locating sibling tablets is very simple. The balancer is responsible for it, and it will emit migrations so that "odd" tablet will follow the "even" one. For example, tablet 1 will be migrated to where tablet 0 lives. Co-location is low in priority, it's not the end of the world to delay merge, but it's not ideal to delay e.g. decommission or even regular load balancing as that can translate into temporary unbalancing, impacting the user activities. So co-location migrations will happen when there is no more important work to do.
While regular balancing is higher in priority, it will not undo the co-location work done so far. It does that by treating co-located tablets as if they were already merged. The load inversion convergence check was adjusted so balancer understand when two tablets are being migrated instead of one, to avoid oscillations.
When balancer completes co-location work for a table undergoing merge, it will put the id of the table into the resize_plan, which is about communicating with the topology coordinator that a table is ready for it. With all sibling tablets co-located, the coordinator can resize the tablet map (reduce it by a factor of 2) and record the new map into group0. All the replicas will react to it (on token metadata update) by merging the storage (memtable(s) + sstables) of sibling tablets into one.
Fixes#18181.
system test details:
test: https://github.com/pehala/scylla-cluster-tests/blob/tablets_split_merge/tablets_split_merge_test.py
yaml file: https://github.com/pehala/scylla-cluster-tests/blob/tablets_split_merge/test-cases/features/tablets/tablets-split-merge-test.yaml
instance type: i3.8xlarge
nodes: 3
target tablet size: 0.5G (scaled down by 10, to make it easier to trigger splits and merges)
description: multiple cycles of growing and shrinking the data set in order to trigger splits and merges.
data_set_size: ~100G
initial_tablets: 64, so it grew to 128 tablets on split, and back to 64 on merge.
latency of reads and writes that happened in parallel to split and merge:
```
$ for i in scylla-bench*; do cat $i | grep "Mode\|99th:\|99\.9th:"; done
Mode: write
99.9th: 3.145727ms
99th: 1.998847ms
99.9th: 3.145727ms
99th: 2.031615ms
Mode: read
99.9th: 3.145727ms
99th: 2.031615ms
99.9th: 3.145727ms
99th: 2.031615ms
Mode: write
99.9th: 3.047423ms
99th: 1.933311ms
99.9th: 3.047423ms
99th: 1.933311ms
Mode: read
99.9th: 3.145727ms
99th: 1.900543ms
99.9th: 3.145727ms
99th: 1.900543ms
Mode: write
99.9th: 5.079039ms
99th: 3.604479ms
99.9th: 35.389439ms
99th: 25.624575ms
Mode: write
99.9th: 3.047423ms
99th: 1.998847ms
99.9th: 3.047423ms
99th: 1.998847ms
Mode: read
99.9th: 3.080191ms
99th: 2.031615ms
99.9th: 3.112959ms
99th: 2.031615ms
```
Closesscylladb/scylladb#20572
* github.com:scylladb/scylladb:
docs: Document tablet merging
tests/boost: Add test to verify correctness of balancer decisions during merge
tests/topology_experimental_raft: Add tablet merge test
service: Handle exception when retrying split
service: Co-locate sibling tablets for a table undergoing merge
gms: Add cluster feature for tablet merge
service: Make merge of resize plan commutative
replica: Implement merging of compaction groups on merge completion
replica: Handle tablet merge completion
service: Implement tablet map resize for merge
locator: Introduce merge_tablet_info()
service: Rename topology::transition_state::tablet_split_finalization
service: Respect initial_tablet_count if table is in growing mode
service: Wire migration_tablet_set into the load balancer
locator: Add tablet_map::sibling_tablets()
service: Introduce sorted_replicas_for_tablet_load()
locator/tablets: Extend tablet_replica equality comparator to three-way
service: Introduce alias to per-table candidate map type
service: Add replication constraint check variant for migration_tablet_set
service: Add convergence check variant for migration_tablet_set
service: Add migration helpers for migration_tablet_set
service/tablet_allocator: Introduce migration_tablet_set
service: Introduce migration_plan::add(migrations_vector)
locator/tablets: Introduce tablet_map::for_each_sibling_tablets()
locator/tablets: Introduce tablet_map::needs_merge()
locator/tablets: Introduce resize_decision::initial_decision()
locator/tablets: Fix return type of three-way comparison operators
service: Extract update of node load on migrations
service: Extract converge check for intra-node migration
service: Extract erase of tablet replicas from candidate list
scripts/tablet-mon: Allow visualization of tablet id
Although `crc_check_chance` is accepted as a configuration option in ScyllaDB,
the value is currently ignored during runtime. This change makes this behavior
explicit in the documentation to prevent potential user misunderstandings.
Changes:
- Explicitly document that the option is currently a no-op
- Provide clear guidance on the current implementation
- Prevent confusion about the option's actual functionality
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21794
Small adjustments and improvements to the documentation in the raft
section.
Fixing Markdown lint warnings:
- MD004/ul-style: Unordered list style [Expected: dash; Actual: asterisk]
- MD007/ul-indent: Unordered list indentation [Expected: 0; Actual: 2]
- MD032/blanks-around-lists: Lists should be surrounded by blank lines
- MD036/no-emphasis-as-heading: Emphasis used instead of a heading
- MD046/code-block-style: Code block style [Expected: fenced; Actual: indented]
Closesscylladb/scylladb#21780
With commits ed7d352e7d and bb1867c7c7, we now have input streams for both compressed and uncompressed SSTables that provide seamless checksum and digest checking. The code for these was based on `validate_checksums()`, which implements its own validation logic over raw streams. This has led to some duplicate code.
This PR deduplicates the uncompressed case by modifying `validate_checksums()` to use a checksummed input stream instead of a raw stream. The same cannot be done for compressed SSTables though. The reason is that `validate_checksums()` needs to examine the whole data file, even if an invalid chunk is encountered. In the checksummed case we support that by offloading the error handling logic from the data source via a function parameter. In the compressed data source we cannot do that because it needs to return decompressed data and decompression may fail if the data are invalid.
This PR also enables `validate_checksums()` to partially verify SSTables with just the per-chunk checksums if the digest is missing.
In more detail, this PR consists of:
* Port of some integrity checks from `do_validate_uncompressed()` to the checksummed data source. It should now be able to detect corruption due to truncated or appended chunks (expected number of chunks is retrieved from the CRC component).
* Introduction of `error_handler` parameter in checksummed data source and `data_stream()`.
* Refactoring of `validate_checksums()`. The JSON response of `sstable validate-checksums` was also modified to report a missing digest.
* Tests for `validate_checksums()` against SSTables with truncated data, appended data, invalid digests, or no digest.
Refs #19058.
This PR is a hybrid of cleanup and feature. No backport is needed.
Closesscylladb/scylladb#20933
* github.com:scylladb/scylladb:
tools/scylla-sstable: Rename valid_checksums -> valid
test: Check validate_checksums() with missing digest
sstables: Allow validate_checksums() to report missing digests
sstables: Refactor validate_checksums() to use checksummed data stream
sstables: Add error_handler parameter to data_stream()
sstables: Add error handler in checksummed data source
sstables: Check for excessive chunks in checksummed data source
sstables: Check for premature EOF in checksummed data source
test: test_validate_checksums: Check SSTable with invalid digest
test: test_validate_checksums: Check SSTable with appended data
test: test_validate_checksums: Complement test for truncated SSTable
This transition state will be reused by merge completion, so let's
rename it to tablet_resize_finalization.
The completion handling path will also be reused, so let's rename
functions involved similarly.
The old name "tablet split finalization" is deprecated but still
recognized and points to the correct transition. Otherwise, the
reverse lookup would fail when populating topology system table
which last state was split finalization.
NOTE:
I thought of adding a new tablet_merge_finalization, but it would
complicate things since more than one table could be ready for
either split or merge, so you need a generic transition state
for handling resize completion.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Task status information from nodetool commands is not retained permanently:
- Status of completed tasks is only kept for `task_ttl_in_seconds`
- Status is removed after being queried, making it a one-time operation
This behavior is important for users to understand since subsequent
queries for the same completed task will not return any information.
Add documentation to make this clear to users.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21386
Demote --scylla-data-dir and --scylla-yaml-file to schema source
helpers, rather than schema source in themselves. This practically means
that when these options are used, they won't define where the tool will
attempt to load the schema from, they will just be helpers to help locate
the schema, for whichever schema source the tool was instructed to use
(or left to choose).
--scylla-data-dir and --scylla-yaml-file being schema sources were
problematic with encryption at rest and for S3 support (not yet
implemented). With encryption, the tool needs access to the
configuration, so --scylla-yaml-file is often used to provide the path
to the configuration file, which contains encryption configuration,
needed for the tool to decrypt the sstable. Currently, using this option
implies forcing the tool to read the schema from the schema tables,
which is a problematic option for tests -- Scylla might be compacting a
schema sstable and this will make the tool fail to load the schema.
Demoting these options the schema helpers, allows providing them, while
at the same time having the option to use a different schema-source.
To allow the user to force the tool to load the schema from the schema
tables, a new --schema-tables option is added. Similarly, a
--sstable-schema option is introduced to force the tool to load the
schema from the sstable itself.
With this, each 4 schema source now has an option to force the use of
said schema source. There are various helper options to be used along
with these.
The documentation as well as the tests are updated with the changes.
The schema related documentation gets an rather extensive facelift
because it was a bit out-of-date and incomplete.
Fixes: scylladb/scylladb#20534Closesscylladb/scylladb#21678
Update the tablestats documentation to correctly describe the "Number of
partitions" metric. The previous documentation incorrectly referred to
"estimated row count" when the command actually shows estimated partition count.
Before:
```
Number of keys (estimate) | The estimated row count
```
After:
```
Number of partitions (estimate) | The estimated partition count
```
This distinction is important since a partition (identified by its partition
key) can contain multiple rows in ScyllaDB. The updated format also matches
Cassandra's nodetool output for better compatibility.
Fixesscylladb/scylladb#21586
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21598
When users start an operation asynchronously with API, they are expected to check the operation's status. Hence, the status should be kept in task manager for reasonable time after the operation is done. The operations that are started internally usually don't need to stay in task manager for that long.
Add api_task_ttl that will be used for tasks started with API. By default it's 1 hour. The time for which non-API tasks stay in task manager isn't changed.
Fixes: #21499.
Refs: #21425.
No backport needed - previous versions may use task_ttl
Closesscylladb/scylladb#21505
* github.com:scylladb/scylladb:
test: add test to check user_task_ttl
tasks: api: move make_task method
docs: nodetool: update backup and restore commands docs
docs: update task manager docs
nodetool: add nodetool tasks user-ttl command
node_ops: use user task ttl for node ops virtual task
tasks: use user_task_ttl for tasks started by user
api: task_manager: add /task_manager/user_ttl to get and set user task ttl
tasks: add task_manager::task::is_user_task method
tasks: keep updateable_value of task_ttl in task manager
db: config: add user_task_ttl_seconds named value
Java tools are deprecated and slated for removal in the next ScyllaDB release.
Update the admin-tools docs and make sure all java tool documentation pages have a notice reflecting this fact.
Fixes: https://github.com/scylladb/scylladb/issues/21149
Should be backported to 6.2, so users of the latest stable version can see the notice.
Closesscylladb/scylladb#21522
* github.com:scylladb/scylladb:
docs: sstableloader.rst: add deprecation notice
docs: admin-tools: update deprecation notice for sstable{dump,metadata}
docs: tools_index.rst: remove deprecated sstablereset and sstablerepairedset tools
Stop taking snapshots of MVs and allow taking snapshot of individual tables, now one can take a snapshot of any base table, any view or index. Also add tests to cover new cases both boost test (using cc code) and pytest (using the API)
Also, update documentation to reflect the change
fixes: #21339fixes: #20760Closesscylladb/scylladb#21433
The `sstable validate-checksums` tool provides the validation result
via the `valid_checksums` key in its JSON response.
The name can be misleading as it refers to both the per-chunk checksums
and the digest (full checksum). We use the terms "digest" and
"full checksum" interchangeably.
Replace with the word "valid" to avoid confusion.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Currently, `validate_checksums()` expects the SSTable to have a digest
component and fails immediately otherwise. This is suboptimal since data
integrity verification could still be carried out partially via checksum
checking.
Lift this restriction by allowing the function to perform checksum
checking in any case, and treat digest checking as best effort. Add a
separate boolean flag in the response to indicate the presence or
absence of the digest component, so that the user can deduce if a valid
result involved digest checking or not.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
I reread the "ScyllaDB Alternator for DynamoDB users" document
(alternator/compatibility.md) and improved various places that I thought
needed improvement.
Two of the more significant changes is moving the not-really-important
"Scan ordering" section much lower in the document and explaining it
better, and improving the "provisioning" section to focus on the available
and missing functionality, and not on minor API details.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#21605
Schema of system tables is defined statically and table_schema_version needs to be explicitly set in code like this:
```
builder.with_version(system_keyspace::generate_schema_version(table_id, version_offset));
```
Whenever schema is changed, the schema version needs to change, otherwise we hit undefined behavior when trying to interpret mutation data created with the old schema using the new schema.
It's not obvious that one needs to do that and developers often forget to do that. There were several instances of mistakes of omission, some caught during review, some not, e.g.: 31ea74b96e.
This patch changes definitions to call the new `schema_builder::with_hash_version()`, which will make the schema builder compute version from schema definition so that changes of the schema will automatically change the version. This way we no longer rely on the developer to remember to bump the version offset.
All nodes should arrive at the same version, which is verified by existing `test_group0_schema_versioning` and a new unit test: `test_system_schema_version_is_stable`.
Closesscylladb/scylladb#21602
* github.com:scylladb/scylladb:
system_tables: Compute schema version automatically
schema_builder: Introduce with_hash_version()
schema: Store raw_view_info in schema::raw_schema
schema: Remove dead comment
hashing: Add hasher for unordered_map
hashing: Add hasher for unique_ptr
hashing: Add hasher for double
[avi: add missing include <memory> to hashing.hh]
The java tools (including sstableloader) are deprecated and slated for
removal in the next ScyllaDB release. Add a notice about this to the
sstableloader page.
These two tools already have a deprecation notice, since ScyllaDB 5.4.
Now we have a target release for the actual removal of these tools, so
update the deprecation notice to reflect that.
Theset tools were unused and one of them doesn't even work, as ScyllaDB
doesn't have incremental repair implemented.
We are deprecating the java tools in the next release so drop these from
the list. Since they don't even have a page of their own, they don't get
a deprecation notice like the other tools in this PR.
This depends on the previous change to the schema_builder
which makes version computation depend on definition only
instead of being new time uuid.
This way we avoid the possibility for a common mistake
when schema of a system table is extended but we forget
to bump up its version passed to .with_version().
Separate the configuration for enabling the tablets feature from the enablement of tablets when creating new keyspaces.
This change always enables the TABLETS cluster feature and the tablets logic respectively.
The `enable_tablets` config option just controls whether tablets are enabled or disabled by default for new keyspaces.
If `enable_tablets` is set to `true`, tablets can be disabled using `CREATE KEYSPACE WITH tablets = { 'enabled': false }` as it is today.
If `enable_tablets` is set to `false`, tablets can be enabled using `CREATE KEYSPACE WITH tablets = { 'enabled': true }`.
The motivation for this change is to simplify the user experience of using tablets by setting the default for new keyspaces to false amd allowing the user to simply opt-in by using tablets = {enabled: true }.
This is not pissible today.
The user has to enable tablets by default for all new keyspaces (that use the NetworkTopologyStrategy) and then actively opt-out to use vnodes.
* Not required to be backported to OSS versions. May be backported to specific enterprise versions
* This PR resubmits https://github.com/scylladb/scylladb/pull/20729 that was reverted in 73b1f66b70 due to https://github.com/scylladb/scylladb/issues/21159 which is now fixed
Closesscylladb/scylladb#21451
* github.com:scylladb/scylladb:
data_dictionary: keyspace_metadata::describe: print tablets enabled also when defaulted
tablets_test: test enable/disable tablets when creating a new keyspace
treewide: always allow tablets keyspaces
feature_service: prevent enabling both tablets and gossip topology changes
alternator: create_keyspace_metadata: enable tablets using feature_service
Python and Python developers don't like directory names to include a minus sign, like "cql-pytest". In this patch we rename test/cql-pytest to test/cqlpy, and also change a few references in other code (e.g., code that used test/cql-pytest/run.py) and also references to this test suite in documentation and comments.
Arguably, the word "test" was always redundant in test/cql-pytest, and I want to leave the "py" in test/cqlpy to emphasize that it's Python-based tests, contrasting with test/cql which are CQL-request-only approval tests.
The second patch in the series fixes a small regression in the test/cqlpy/run script.
Fixes#20846
Test organization only, so backports not strictly necessary, but let's do them anyway because otherwise it will make any future backporting of tests in the cqlpy directory more messy than it needs to be.
Closesscylladb/scylladb#21446
* github.com:scylladb/scylladb:
test/cqlpy: fix "run" script without any parameters
test: rename "cql-pytest" to "cqlpy"
With the tablets feature always enabled (Unless gossip toopology
changes are forced), the enable_tablets option now controls only
the default for newly created keyspaces.
Even when set to `false`, tablets are still enabled as a
feature and the user may explicitly enable tablets
using `CREATE KEYSPACE <name> WITH tablets = {'enabled': true}`
Note: best viewed with `git show -w`
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Python and Python developers don't like directory names to include a
minus sign, like "cql-pytest". In this patch we rename test/cql-pytest
to test/cqlpy, and also change a few references in other code (e.g., code
that used test/cql-pytest/run.py) and also references to this test suite
in documentation and comments.
Arguably, the word "test" was always redundant in test/cql-pytest, and
I want to leave the "py" in test/cqlpy to emphasize that it's Python-based
tests, contrasting with test/cql which are CQL-request-only approval
tests.
Fixes#20846
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Updates the theme to the latest version to enable tooltips and modifies the db_options.tmpl to show the new role in action.
Closesscylladb/scylladb#21324
Cassandra 4.1 announced a new option to create a role with:
`HASHED PASSWORD`. Example:
```
CREATE ROLE bob WITH HASHED PASSWORD = 'hashed_password';
```
We've already introduced another option following the same
semantics: `SALTED HASH`; example:
```
CREATE ROLE bob WITH SALTED HASH = 'salted_hash';
```
The change hasn't made it to any release yet, so in this commit
we rename it to `HASHED PASSWORD` to be compatible with Cassandra.
Additionally, we adjust existing tests to work against Cassandra too.
Fixesscylladb/scylladb#21350Closesscylladb/scylladb#21352
This reverts commit c286434e4c, reversing
changes made to 6712fcc316.
The commit causes memtable_test to be very flaky in debug mode.
Specifically, subtests test_exceptions_in_flush_on_sstable_open
and test_exceptions_in_flush_on_sstable_write).
Separate the configuration for enabling the tablets feature from the enablement of tablets when creating new keyspaces.
This change always enables the TABLETS cluster feature and the tablets logic respectively.
The `enable_tablets` config option just controls whether tablets are enabled or disabled by default for new keyspaces.
If `enable_tablets` is set to `true`, tablets can be disabled using `CREATE KEYSPACE WITH tablets = { 'enabled': false }` as it is today.
If `enable_tablets` is set to `false`, tablets can be enabled using `CREATE KEYSPACE WITH tablets = { 'enabled': true }`.
The motivation for this change is to simplify the user experience of using tablets by setting the default for new keyspaces to false amd allowing the user to simply opt-in by using tablets = {enabled: true }.
This is not pissible today.
The user has to enable tablets by default for all new keyspaces (that use the NetworkTopologyStrategy) and then actively opt-out to use vnodes.
* Not required to be backported to OSS versions. May be backported to specific enterprise versions
Closesscylladb/scylladb#20729
* github.com:scylladb/scylladb:
data_dictionary: keyspace_metadata::describe: print tablets enabled also when defaulted
tablets_test: test enable/disable tablets when creating a new keyspace
treewide: always allow tablets keyspaces
feature_service: prevent enabling both tablets and gossip topology changes
alternator: create_keyspace_metadata: enable tablets using feature_service
Single-row reads from large partition issue 64 KiB reads to the data file,
which is equal to the default span of the promoted index block in the data file.
If users would want to increase selectivity of the index to speed up single-row reads,
this won't be effective. The reason is that the reader uses promoted index
to look up the start position in the data file of the read, but end position
will in practice extend to the next partition, and amount of I/O will be
determined by the underlying file input stream implementation and its
read-ahead heuristics. By default, that results in at least 2 IOs 32KB each.
There is already infrastructure to lookup end position based on upper
bound of the read, in anticipation for sharing the promoted index cache,
but it's not effective becasue it's a non-populating lookup and the upper
bound cursor has its own private cached_promoted_index, which is cold
when positions are computed. It's non-populating on purpose, to avoid
extra index file IO to read upper bound. In case upper bound is far-enough
from the lower bound, this will only increase the cost of the read.
The solution employed here is to warm up the lower bound cursor's
cache before positions are computed, and use that cursor for
non-populating lookup of the upper bound.
We use the lower bound cursor and the slice's lower bound so that we
read the same blocks as later lower-bound slicing would, so that we
don't incur extra IO for cases where looking up upper bound is not
worth it, that is when upper bound is far from the lower bound. If
upper bound is near lower bound, then warming up using lower bound
will populate cached_promoted_index with blocks which will allow us to
locate the upper bound block accurately. This is especially important
for single-row reads, where the bounds are around the same key. In
this case we want to read the data file range which belongs to a
single promoted index block. It doesn't matter that the upper bound
is not exactly the same. They both will likely lie in the same block,
and if not, binary search will bring adjacent blocks into cache. Even
if upper bound is not near, the binary search will populate the cache
with blocks which can be used to narrow down the data file range
somewhat.
Fixes#10030.
The change was tested with perf-fast-forward.
I populated the data set with `column_index_size_in_kb` set to 1
scylla perf-fast-forward --populate --run-tests=large-partition-slicing --column-index-size-in-kb=1
Test run:
build/release/scylla perf-fast-forward --run-tests=large-partition-select-few-rows -c1 --keep-cache-across-test-cases --test-case-duration=0
This test issues two reads of subsequent keys from the middle of a large partition (1M rows in total). The first read will miss in the index file page cache, the second read will hit.
Notice that before the change, the second read issued 2 aio requests worth of 64KiB in total.
After the change, the second read issued 1 aio worth of 2 KiB. That's because promoted index block is larger than 1 KiB.
I verified using logging that the data file range matches a single promoted index block.
Also, the first read which misses in cache is still faster after the change.
Before:
```
running: large-partition-select-few-rows on dataset large-part-ds1
Testing selecting few rows from a large partition:
stride rows time (s) iterations frags frag/s mad f/s max f/s min f/s avg aio aio (KiB) blocked dropped idx hit idx miss idx blk c hit c miss c blk allocs tasks insns/f cpu
500000 1 0.009802 1 1 102 0 102 102 21.0 21 196 2 1 0 1 1 0 0 0 568 269 4716050 53.4%
500001 1 0.000321 1 1 3113 0 3113 3113 2.0 2 64 1 0 1 0 0 0 0 0 116 26 555110 45.0%
```
After:
```
running: large-partition-select-few-rows on dataset large-part-ds1
Testing selecting few rows from a large partition:
stride rows time (s) iterations frags frag/s mad f/s max f/s min f/s avg aio aio (KiB) blocked dropped idx hit idx miss idx blk c hit c miss c blk allocs tasks insns/f cpu
500000 1 0.009609 1 1 104 0 104 104 20.0 20 137 2 1 0 1 1 0 0 0 561 268 4633407 43.1%
500001 1 0.000217 1 1 4602 0 4602 4602 1.0 1 2 1 0 1 0 0 0 0 0 110 26 313882 64.1%
```
Backports: none, not a regression
Closesscylladb/scylladb#20522
* github.com:scylladb/scylladb:
perf: perf_fast_forward: Add test case for querying missing rows
perf-fast-forward: Allow overriding promoted index block size
perf-fast-forward: Test subsequent key reads from the middle in test_large_partition_select_few_rows
perf-fast-forward: Allow adding key offset in test_large_partition_select_few_rows
perf-fast-forward: Use single-partition reads in test_large_partition_select_few_rows
sstables: bsearch_clustered_cursor: Add more tracing points
sstables: reader: Log data file range
sstables: bsearch_clustered_cursor: Unify skip_info logging
sstables: bsearch_clustered_cursor: Narrow down range using "end" position of the block
sstables: bsearch_clustered_cursor: Skip even to the first block
test: sstables: sstable_3_x_test: Improve failure message
sstables: mx: writer: Never include partition_end marker in promoted index block width
sstables: Reduce amount of I/O for clustering-key-bounded reads from large partitions
sstables: clustered_cursor: Track current block
This commit improves the README file so that it's more helpful
to documentation contributors. Especially, it:
- Adds the link to the prerequisites.
- Add information on troubleshooting (checking the links, headings, etc.)
- Removes the section on creating a knowledge base article, as we no longer
promote adding KBs in favor of creating a coherent documentation set.
Fixes https://github.com/scylladb/scylladb/issues/21257Closesscylladb/scylladb#21262
This commit updates the configuration for ScyllaDB documentation so that:
- 6.2 is the latest version.
- 6.2 is removed from the list of unstable versions.
It must be merged when ScyllaDB 6.2 is released.
In addition, this commit uncomments the redirections that should be applied
when version 6.2 is the latest stable version (which will happen when this commit
is merged).
No backport is required.
Closesscylladb/scylladb#21133
