4d9271df98
This is yet another part in the BTI index project. Overarching issue: https://github.com/scylladb/scylladb/issues/19191 Previous part: https://github.com/scylladb/scylladb/pull/25626 Next parts: make `ms` the default. Then, general tweaks and improvements. Later, potentially a full `da` format implementation. This patch series introduces a new, Scylla-only sstable format version `ms`, which is like `me`, but with the index components (Summary.db and Index.db) replaced with BTI index components (Partitions.db and Rows.db), as they are in Cassandra 5.0's `da` format version. (Eventually we want to just implement `da`, but there are several other changes (unrelated to the index files) between `me` and `da`. By adding this `ms` as an intermediate step we can adapt the new index formats without dragging all the other changes into the mix (and raising the risk of regressions, which is already high)). The high-level structure of the PR is: 1. Introduce new component types — `Partitions` and `Rows`. 2. Teach `class sstable` to open them when they exist. 3. Teach the sstable writer how to write index data to them. 4. Teach `class sstable` and unit tests how to deal with sstables that have no `Index` or `Summary` (but have `Partitions` and `Rows` instead). 5. Introduce the new sstable version `ms`, specify that it has `Partitions` and `Rows` instead of `Index` and `Summary`. 6. Prepare unit tests for the appearance of `ms`. 7. Enable `ms` in unit tests. 8. Make `ms` enablable via db::config (with a silent fall back to `me` until the new `MS_SSTABLE_FORMAT` cluster feature is enabled). 9. Prepare integration tests for the appearance of `ms`. 10. Enable both `ms` and `me` in tests where we want both versions to be tested. This series doesn't make `ms` the default yet, because that requires teaching Scylla Manager and a few dtests about the new format first. It can be enabled by setting `sstable_format: ms` in the config. Per a review request, here is an example from `perf_fast_forward`, demonstrating some motivation for a new format. (Although not the main one. The main motivations are getting rid of restrictions on the RAM:disk ratio, and index read throughput for datasets with tiny partitions). The dataset was populated with `build/release/scylla perf-fast-forward --smp=1 --sstable-format=$VERSION --data-directory=data.$VERSION --column-index-size-in-kb=1 --populate --random-seed=0`. This test involves a partition with 1000000 clustering rows (with 32-bit keys and 100-byte values) and ~500 index blocks, and queries a few particular rows from the partition. Since the branching factor for the BIG promoted index is 2 (it's a binary search), the lookup involves ~11.2 sequential page reads per row. The BTI format has a more reasonable branching factor, so it involves ~2.3 page reads per row. `build/release/scylla perf-fast-forward --smp=1 --data-directory=perf_fast_forward_data/me --run-tests=large-partition-select-few-rows`: ``` offset stride rows iterations avg aio aio (KiB) 500000 1 1 70 18.0 18 128 500001 1 1 647 19.0 19 132 0 1000000 1 748 15.0 15 116 0 500000 2 372 29.0 29 284 0 250000 4 227 56.0 56 504 0 125000 8 116 106.0 106 928 0 62500 16 67 195.0 195 1732 ``` `build/release/scylla perf-fast-forward --smp=1 --data-directory=perf_fast_forward_data/ms --run-tests=large-partition-select-few-rows`: ``` offset stride rows iterations avg aio aio (KiB) 500000 1 1 51 5.1 5 20 500001 1 1 64 5.3 5 20 0 1000000 1 679 4.0 4 16 0 500000 2 492 8.0 8 88 0 250000 4 804 16.0 16 232 0 125000 8 409 31.0 31 516 0 62500 16 97 54.0 54 1056 ``` Index file size comparison for the default `perf_fast_forward` tables with `--random-seed=0`: Large partition table (dominated by intra-partition index): 2.4 MB with `me`, 732 kB with `ms`. For the small partitions table (dominated by inter-partition index): 11 MB with `me`, 8.4 MB with `ms`. External tests: I ran SCT test `longevity-mv-si-4days-streaming-test` test on 6 nodes with 30 shards each for 8 hours. No anomalies were observed. New functionality, no backport needed. Closes scylladb/scylladb#26215 * github.com:scylladb/scylladb: test/boost/bloom_filter_test: add test_rebuild_from_temporary_hashes test/cluster: add test_bti_index.py test: prepare bypass_cache_test.py for `ms` sstables sstables/trie/bti_index_reader: add a failure injection in advance_lower_and_check_if_present test/cqlpy/test_sstable_validation.py: prepare the test for `ms` sstables tools/scylla-sstable: add `--sstable-version=?` to `scylla sstable write` db/config: expose "ms" format to the users via database config test: in Python tests, prepare some sstable filename regexes for `ms` sstables: add `ms` to `all_sstable_versions` test/boost/sstable_3_x_test: add `ms` sstables to multi-version tests test/lib/index_reader_assertions: skip some row index checks for BTI indexes test/boost/sstable_inexact_index_test: explicitly use a `me` sstable test/boost/sstable_datafile_test: skip test_broken_promoted_index_is_skipped for `ms` sstables test/resource: add `ms` sample sstable files for relevant tests test/boost/sstable_compaction_test: prepare for `ms` sstables. test/boost/index_reader_test: prepare for `ms` sstables test/boost/bloom_filter_tests: prepare for `ms` sstables test/boost/sstable_datafile_test: prepare for `ms` sstables test/boost/sstable_test: prepare for `ms` sstables. sstables: introduce `ms` sstable format version tools/scylla-sstable: default to "preferred" sstable version, not "highest" sstables/mx/reader: use the same hashed_key for the bloom filter and the index reader sstables/trie/bti_index_reader: allow the caller to passing a precalculated murmur hash sstables/trie/bti_partition_index_writer: in add(), get the key hash from the caller sstables/mx: make Index and Summary components optional sstables: open Partitions.db early when it's needed to populate key range for sharding metadata sstables: adapt sstable::set_first_and_last_keys to sstables without Summary sstables: implement an alternative way to rebuild bloom filters for sstables without Index utils/bloom_filter: add `add(const hashed_key&)` sstables: adapt estimated_keys_for_range to sstables without Summary sstables: make `sstable::estimated_keys_for_range` asynchronous sstables/sstable: compute get_estimated_key_count() from Statistics instead of Summary replica/database: add table::estimated_partitions_in_range() sstables/mx: implement sstable::has_partition_key using a regular read sstables: use BTI index for queries, when present and enabled sstables/mx/writer: populate BTI index files sstables: create and open BTI index files, when enabled sstables: introduce Partition and Rows component types sstables/mx/writer: make `_pi_write_m.partition_tombstone` a `sstables::deletion_time`
ScyllaDB Documentation
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---------------------- Prerequisites ----------------------
Building User Documentation
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