This series switches memtable and cache to use a new representation for mutation data,
called `mutation_partition_v2`. In this representation, range tombstone information is stored
in the same tree as rows, attached to row entries. Each entry has a new tombstone field,
which represents range tombstone part which applies to the interval between this entry and
the previous one. See docs/dev/mvcc.md for more details about the format.
The transient mutation object still uses the old model in order to avoid work needed to adapt
old code to the new model. It may also be a good idea to live with two models, since the
transient mutation has different requirements and thus different trade-offs can be made.
Transient mutation doesn't need to support eviction and strong exception guarantees,
so its algorithms and in-memory representation can be simpler.
This allows us to incrementally evict range tombstone information. Before this series,
range tombstones were accumulated and evicted only when the whole partition entry was evicted. This
could lead to inefficient use of cache memory.
Another advantage of the new representation is that reads don't have to lookup
range tombstone information in a different tree while reading. This leads to simpler
and more efficient readers.
There are several disadvantages too. Firstly, rows_entry is now larger by 16 bytes.
Secondly, update algorithms are more complex because they need to deoverlap range tombstone
information. Also, to handle preemption and provide strong exception guarantees, update
algorithms may need to allocate sentinel entries, which adds complexity and reduces performance.
The memtable reader was changed to use the same cursor implementation
which cache uses, for improved code reuse and reducing risk of bugs
due to discrepancy of algorithms which deal with MVCC.
Remaining work:
- performance optimizations to apply_monotonically() to avoid regressions
- performance testing
- preemption support in apply_to_incomplete (cache update from memtable)
Fixes#2578Fixes#3288Fixes#10587Closes#12048
* github.com:scylladb/scylladb:
test: mvcc: Extend some scenarios with exhaustive consistency checks on eviction
test: mvcc: Extract mvcc_container::allocate_in_region()
row_cache, lru: Introduce evict_shallow()
test: mvcc: Avoid copies of mutation under failure injection
test: mvcc: Add missing logalloc::reclaim_lock to test_apply_is_atomic
mutation_partition_v2: Avoid full scan when applying mutation to non-evictable
Pass is_evictable to apply()
tests: mutation_partition_v2: Introduce test_external_memory_usage_v2 mirroring the test for v1
tests: mutation: Fix test_external_memory_usage() to not measure mutation object footprint
tests: mutation_partition_v2: Add test for exception safety of mutation merging
tests: Add tests for the mutation_partition_v2 model
mutation_partition_v2: Implement compact()
cache_tracker: Extract insert(mutation_partition_v2&)
mvcc, mutation_partition: Document guarantees in case merging succeeds
mutation_partition_v2: Accept arbitrary preemption source in apply_monotonically()
mutation_partition_v2: Simplify get_continuity()
row_cache: Distinguish dummy insertion site in trace log
db: Use mutation_partition_v2 in mvcc
range_tombstone_change_merger: Introduce peek()
readers: Extract range_tombstone_change_merger
mvcc: partition_snapshot_row_cursor: Handle non-evictable snapshots
mvcc: partition_snapshot_row_cursor: Support digest calculation
mutation_partition_v2: Store range tombstones together with rows
db: Introduce mutation_partition_v2
doc: Introduce docs/dev/mvcc.md
db: cache_tracker: Introduce insert() variant which positions before existing entry in the LRU
db: Print range_tombstone bounds as position_in_partition
test: memtable_test: Relax test_segment_migration_during_flush
test: cache_flat_mutation_reader: Avoid timestamp clash
test: cache_flat_mutation_reader_test: Use monotonic timestamps when inserting rows
test: mvcc: Fix sporadic failures due to compact_for_compaction()
test: lib: random_mutation_generator: Produce partition tombstone less often
test: lib: random_utils: Introduce with_probability()
test: lib: Improve error message in has_same_continuity()
test: mvcc: mvcc_container: Avoid UB in tracker() getter when there is no tracker
test: mvcc: Insert entries in the tracker
test: mvcc_test: Do not set dummy::no on non-clustering rows
mutation_partition: Print full position in error report in append_clustered_row()
db: mutation_cleaner: Extract make_region_space_guard()
position_in_partition: Optimize equality check
mvcc: Fix version merging state resetting
mutation_partition: apply_resume: Mark operator bool() as explicit
This PR extends the description of using `nodetool removenode `to remove an unavailable node, as requested in https://github.com/scylladb/scylla-enterprise/issues/2338.
Closes#12410
* github.com:scylladb/scylladb:
docs: improve the warning and add a comment to update/remove the information in the future
doc: extend the information on removing an unavailable node
docs: extend the warning on the Remove a Node page
Related https://github.com/scylladb/scylladb/issues/12658.
This issue fixes the bug in the upgrade guides for the released versions.
Closes#12679
* github.com:scylladb/scylladb:
doc: fix the service name in the upgrade guide for patch releases versions 2022
doc: fix the service name in the upgrade guide from 2021.1 to 2022.1
This extracts information which was there in row_cache.md, but is
relevant to MVCC in general.
It also makes adaptations and reflects the upcoming changes in this
series related to switching to the new mutation_partition_v2 model:
- continuity in evictable snapshots can now overlap. This is needed
to represent range tombstone information, which is linked to
continuity information.
- description of range tombstone representation was added
The docs/alternator/compatibility.md file links to various open issues
on unimplemented features. One of the links was to an already-closed
issue. Replace it by a link to an open issue that was missing.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#12649
New clusters that use a fresh conf/scylla.yaml will have `consistent_cluster_management: true`, which will enable Raft, unless the user explicitly turns it off before booting the cluster.
People using existing yaml files will continue without Raft, unless consistent_cluster_management is explicitly requested during/after upgrade.
Also update the docs: cluster creation and node addition procedures.
Fixes#12572.
Closes#12585
* github.com:scylladb/scylladb:
docs: mention `consistent_cluster_management` for creating cluster and adding node procedures
conf: enable `consistent_cluster_management` by default
add Make variable named `PREVIEW_HOST` so it can be overriden like
```
make preview PREVIEW_HOST=$(hostname -I | cut -d' ' -f 1)
```
it allows developer to preview the document if the host buiding the
document is not localhost.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#12589
Fix https://github.com/scylladb/scylla-docs/issues/3968
This PR adds the information that an upgrade to each successive major version is required to upgrade from an old ScyllaDB version.
Closes#12586
* github.com:scylladb/scylladb:
docs: remove repetition
doc: add the general upgrade policy to the uprage page
This PR is not related to any reported issue in the repo.
I've just discovered a broken link in the university caused by a
missing redirection.
Closes#12567
Allow replacing a node given its Host ID rather than its ip address.
This series adds a replace_node_first_boot option to db/config
and makes use of it in storage_service.
The new option takes priority over the legacy replace_address* options.
When the latter are used, a deprecation warning is printed.
Documentation updated respectively.
And a cql unit_test is added.
Ref #12277Closes#12316
* github.com:scylladb/scylladb:
docs: document the new replace_node_first_boot option
dist/docker: support --replace-node-first-boot
db: config: describe replace_address* options as deprecated
test: test_topology: test replace using host_id
test: pylib: ServerInfo: add host_id
storage_service: get rid of get_replace_address
storage_service: is_replacing: rely directly on config options
storage_service: pass replacement_info to run_replace_ops
storage_service: pass replacement_info to booststrap
storage_service: join_token_ring: reuse replacement_info.address
storage_service: replacement_info: add replace address
init: do not allow cfg.replace_node_first_boot of seed node
db: config: add replace_node_first_boot option
Rename `system.raft_config` to `system.raft_snapshot_config` to make it clearer
what the table stores.
Remove the `my_server_id` partition key column from
`system.raft_snapshot_config` and a corresponding column from
`system.raft_snapshots` which would store the Raft server ID of the local node.
It's unnecessary, all servers running on a given node in different groups will
use the same ID - the Raft ID of the node which is equal to its Host ID. There
will be no multiple servers running in a single Raft group on the same node.
Closes#12513
* github.com:scylladb/scylladb:
db: system_keyspace: remove (my_)server_id column from RAFT_SNAPSHOTS and RAFT_SNAPSHOT_CONFIG
db: system_keyspace: rename 'raft_config' to 'raft_snapshot_config'
Leave the guide for manual opening in though, the script might not work
in all cases.
Also update the version example, we changed how development versions
look like.
Closes#12511
Make it clear that the table stores the snapshot configuration, which is
not necessarily the currently operating configuration (the last one
appended to the log).
In the future we plan to have a separate virtual table for showing the
currently operating configuration, perhaps we will call it
`system.raft_config`.
Currently, we call cargo build every time we build scylla, even
when no rust files have been changed.
This is avoided by adding a depfile to the ninja rule for the rust
library.
The rust file is generated by default during cargo build,
but it uses the full paths of all depenencies that it includes,
and we use relative paths. This is fixed by specifying
CARGO_BUILD_DEP_INFO_BASEDIR='.', which makes it so the current
path is subtracted from all generated paths.
Instead of using 'always' when specifying when to run the cargo
build, a dependency on Cargo.lock is added additionally to the
depfile. As a result, the rust files are recompiled not only
when the source files included in the depfile are modified,
but also when some rust dependency is updated.
Cargo may put an old cached file as a result of the build even
when the Cargo.lock was recently updated. Because of that, the
the build result may be older than the Cargo.lock file even
if the build was just performed. This may cause ninja to rebuilt
the file every following time. To avoid this, we 'touch' the
build result, so that its last modification time is up to date.
Because the dependency on Cargo.lock was added, the new command
for the build does not modify it. Instead, the developer must
update it when modifying the dependencies - the docs are updated
to reflect that.
Closes#12489Fixes#12508
Our handling of NULLs in expressions is different from Cassandra's,
and more uniform. For example, the filter "WHERE x = NULL" is an
error in Cassandra, but supported in Scylla. Let's explain how and why.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#12494
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
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.
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
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++.
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.
Fixes https://github.com/scylladb/scylladb/issues/12314
This PR adds the upgrade guide for ScyllaDB Enterprise - from version
2022.1 to 2022.2. Using this opportunity, I've replaced "Scylla" with
"ScyllaDB" in the upgrade-enterprise index file.
In previous releases, we added several upgrade guides - one per platform
(and version). In this PR, I've merged the information for different
platforms to create one generic upgrade guide. It is similar to what
@kbr- added for the Open Source upgrade guide from 5.0 to 5.1. See
https://docs.scylladb.com/stable/upgrade/upgrade-opensource/upgrade-guide-from-5.0-to-5.1/.
Closes#12339
* github.com:scylladb/scylladb:
docs: add the info about minor release
docs: add the new upgade guide 2022.1 to 2022.2 to the index and the toctree
docs: add the index file for the new upgrage guide from 2022.1 to 2022.2
docs: add the metrics update file to the upgrade guide 2022.1 to 2022.2
docs: add the upgrade guide for ScyllaDB Enterprise from 2022.1 to 2022.2
The alternator compatibility.md document mentions the missing ACL
(access control) feature, but unlike other missing features we
forgot to link to the open issue about this missing feature.
So let's add that link.
Refs #5047.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closes#12399
Fixes https://github.com/scylladb/scylladb/issues/12318
This PR removes all occurrences of the `auto_bootstrap` option in the docs.
In most cases, I've simply removed the option name and its definition, but sometimes additional changes were necessary:
- In node-joined-without-any-data.rst, I removed the `auto_bootstrap `option as one of the causes of the problem.
- In rebuild-node.rst, I removed the first step in the procedure (enabling the `auto_bootstrap `option).
- In admin. rst, I removed the section about manual bootstrapping - it's based on setting `auto_bootstrap` to false, which is not possible now.
Closes#12419
* github.com:scylladb/scylladb:
docs: remove the auto_bootstrap option from the admin procedures - involves removing the Manual Bootstraping section
docs: remove the auto_bootstrap option from the procedure to replace a dead node
docs: remove the auto_bootstrap option from the Troubleshooting article about a node joining with no data
docs: remove the auto_bootstrap option from the procedure to rebuild a node after losing the data volume
docs: remove the auto_bootstrap option from the procedures to create a cluster or add a DC
