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
To reduce dependency load, use std ranges instead of boost ranges.
The std::ranges::{lower,upper}_bound don't support heterogeneous lookup,
but a more natural solution is to use a projection to search for the name,
so we use that and the custom comparator is removed.
Many callers are converted as well due to poor interoperability between
boost ranges and std ranges.
This is optimization.
Example:
block0: start=aaa, end=aaA
block1: start=bbb, end=bbB
block2: whatever
Before the patch, advance_to("aAA") would skip to block0, and upper
bound probe would skip to block1. This way, the reader would read the
range of block0 from the data file.
After the patch, "end" position is taken into account, so
advance_to("aAA") will notice that block0 doesn't contain the position
and will skip to block1. This is especially important for dense
indexes, as it allows us to skip accessing data file if the search key
is missing.
It also solves the edge case problem related to the fact that single
row reads are using a range which with positions which are not equal
to the key, but are before(key) and after(key) for the lower bound and
upper bound respectively. Before the patch, advance_to(before("bbb"))
would skip to block0, before the position is before the block1's
start. And upper bound probe for after("bbb") would point to
block2. This way the read would scan block0 needlessly. After the
patch, advance_to(before("bbb")) will skip to block1 because we notice
based on "end" that block0 doesn't contain the position.
This change also ensures that the start position of the upper bound
entry of the after_key(pos), where pos is the last advance_to()
position, is warm in cache. This is needed to optimize single-row
reads with a dense index so that they always read exactly one promoted
index block. For this to work, probe_upper_bound() for the
after_key(row) always needs to find the upper bound block in
cache.
It was unnecessary to emit a skip info for the first block since it
follows immediately the partition start, but it is relevant to the
optimization of avoiding data reads for missing keys. This
optimization relies on the fact that lower bound position equals upper
bound position. If the reader's key is before the first key in the
partition and we don't arm the skip info for the first block, lower
bound would be equal to the partition start, and upper bound would be
equal to the first row's position, which are not equal.
Currently, it may happen that the last promoted index block includes
the partition_end marker. That's because we first write the partition
end marker and then emit the unclosed block. This behavior matches
Cassandra (checked in 3.x and 5.0.1).
This is problematic for ruling out data file reads based on index.
The width field is currently unused, but it will be used later where
the width of the last block is used to compute the skip position past
the last block for lookups which land after all keys in the
partition. If width includes the marker then such a skip would land in
the next partition, which is incorrect, as the reader context expects
a cell element. Even if that was recognized, it's wrong - if this is
not a single partition read (so upper bound is not at the next
partition too), then we would read from the wrong (next) partition.
We want to be able to make such skips in order to avoid unnecessary
data file IO for reads of missing rows. Currently, we would always
read the last block even if the key is past its "end" position.
Another way to solve this would be to propagate the "past the last
block" condition from the index cursor to the reader and let it deal
with it, but the logic for that would be complicated. With this fix,
there is no special logic required.
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 reduce 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, 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 reads two rows from the middle of a large partition (1M
rows), of subsequent keys. 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%
(cherry picked from commit dfb339376aff1ed961b26c4759b1604f7df35e54)
Will be needed by the reader to jump to the current block even if we
already advanced to it before, when setting up the reader context.
We want to advance to lower bound earlier, before the praser skips to
the lower bound. We want that in order to set input stream data file
range based on index. If we didn't have access to the current block
and used the result from advance_to(), the parser will think we're
already in the block which has lower_bound when it attempts to skip,
and will not skip, falling back to scanning.
In order to later use the formatter for the inner class
promoted_index_block, which is defined out of line after
cached_promoted_index class definition.
This fixes a use-after-free bug when parsing clustering key across
pages.
Clustering key index lookup is based on the index file page cache. We
do a binary search within the index, which involves parsing index
blocks touched by the algorithm. Index file pages are 4 KB chunks
which are stored in LSA.
To parse the first key of the block, we reuse clustering_parser, which
is also used when parsing the data file. The parser is stateful and
accepts consecutive chunks as temporary_buffers. The parser is
supposed to keep its state across chunks.
In b1b5bda, the parser was changed to keep shared fragments of the
buffer passed to the parser in its internal state (across pages)
rather than copy the fragments into a new buffer. This is problematic
when buffers come from page cache because LSA buffers may be moved
around or evicted. So the temporary_buffer which is a view on the LSA
buffer is valid only around the duration of a single consume() call to
the parser.
If the blob which is parsed (e.g. variable-length clustering key
component) spans pages, the fragments stored in the parser may be
invalidated before the component is fully parsed. As a result, the
parsed clustering key may have incorrect component values. This never
causes parsing errors because the "length" field is always parsed from
the current buffer, which is valid, and component parsing will end at
the right place in the next (valid) buffer.
The problematic path for clustering_key parsing is the one which calls
primitive_consumer::read_bytes(), which is called for example for text
components. Fixed-size components are not parsed like this, they store
the intermediate state by copying data.
This may cause incorrect clustering keys to be parsed when doing
binary search in the index, diverting the search to an incorrect
block.
The solution is to use page_view instead of temporary_buffer, which
can be safely shared via share() and stored across allocating
section. The page_view maintains its hold to the LSA buffer even
across allocating sections.
Fixes#20766
When reset() is done due to allocating section retry, it can be
theoretically in an arbitrary point. So we should not assume that it
finished parsing and state was reset by previous parsing. We should
reset all the fields.
Parser's state was not reset when allocating section was retried.
This doesn't cause problems in practice, because reserves are enough
to cover allocation demands of parsing clustering keys, which are at
most 64K in size. But it's still potentially unsafe and needs fixing.
"crawling" is a little bit obscure in this context. so let's rename this
class to reflect the fact that this reader only reads the entire content
of the sstable.
both crawling reader for kl and mx formats are renamed. also, in order
to be consistent, all "crawling reader" in variable names are updated
as well.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
When purging regular tombstone consult the min_live_timestamp, if available.
This is safe since we don't need to protect dead data from resurrection, as it is already dead.
For shadowable_tombstones, consult the min_memtable_live_row_marker_timestamp,
if available, otherwise fallback to the min_live_timestamp.
If we see in a view table a shadowable tombstone with time T, then in any row where the row marker's timestamp is higher than T the shadowable tombstone is completely ignored and it doesn't hide any data in any column, so the shadowable tombstone can be safely purged without any effect or risk resurrecting any deleted data.
In other words, rows which might cause problems for purging a shadowable tombstone with time T are rows with row markers older or equal T. So to know if a whole sstable can cause problems for shadowable tombstone of time T, we need to check if the sstable's oldest row marker (and not oldest column) is older or equal T. And the same check applies similarly to the memtable.
If both extended timestamp statistics are missing, fallback to the legacy (and inaccurate) min_timestamp.
Fixesscylladb/scylladb#20423Fixesscylladb/scylladb#20424
> [!NOTE]
> no backport needed at this time
> We may consider backport later on after given some soak time in master/enterprise
> since we do see tombstone accumulation in the field under some materialized views workloads
Closesscylladb/scylladb#20446
* github.com:scylladb/scylladb:
cql-pytest: add test_compaction_tombstone_gc
sstable_compaction_test: add mv_tombstone_purge_test
sstable_compaction_test: tombstone_purge_test: test that old deleted data do not inhibit tombstone garbage collection
sstable_compaction_test: tombstone_purge_test: add testlog debugging
sstable_compaction_test: tombstone_purge_test: make_expiring: use next_timestamp
sstable, compaction: add debug logging for extended min timestamp stats
compaction: get_max_purgeable_timestamp: use memtable and sstable extended timestamp stats
compaction: define max_purgeable_fn
tombstone: can_gc_fn: move declaration to compaction_garbage_collector.hh
sstables: scylla_metadata: add ext_timestamp_stats
compaction_group, storage_group, table_state: add extended timestamp stats getters
sstables, memtable: track live timestamps
memtable_encoding_stats_collector: update row_marker: do nothing if missing
before this change, we rely on `using namespace seastar` to use
`seastar::format()` without qualifying the `format()` with its
namespace. this works fine until we changed the parameter type
of format string `seastar::format()` from `const char*` to
`fmt::format_string<...>`. this change practically invited
`seastar::format()` to the club of `std::format()` and `fmt::format()`,
where all members accept a templated parameter as its `fmt`
parameter. and `seastar::format()` is not the best candidate anymore.
despite that argument-dependent lookup (ADT for short) favors the
function which is in the same namespace as its parameter, but
`using namespace` makes `seastar::format()` more competitive,
so both `std::format()` and `seastar::format()` are considered
as the condidates.
that is what is happening scylladb in quite a few caller sites of
`format()`, hence ADT is not able to tell which function the winner
in the name lookup:
```
/__w/scylladb/scylladb/mutation/mutation_fragment_stream_validator.cc:265:12: error: call to 'format' is ambiguous
265 | return format("{} ({}.{} {})", _name_view, s.ks_name(), s.cf_name(), s.id());
| ^~~~~~
/usr/bin/../lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/format:4290:5: note: candidate function [with _Args = <const std::basic_string_view<char> &, const seastar::basic_sstring<char, unsigned int, 15> &, const seastar::basic_sstring<char, unsigned int, 15> &, const utils::tagged_uuid<table_id_tag> &>]
4290 | format(format_string<_Args...> __fmt, _Args&&... __args)
| ^
/__w/scylladb/scylladb/seastar/include/seastar/core/print.hh:143:1: note: candidate function [with A = <const std::basic_string_view<char> &, const seastar::basic_sstring<char, unsigned int, 15> &, const seastar::basic_sstring<char, unsigned int, 15> &, const utils::tagged_uuid<table_id_tag> &>]
143 | format(fmt::format_string<A...> fmt, A&&... a) {
| ^
```
in this change, we
change all `format()` to either `fmt::format()` or `seastar::format()`
with following rules:
- if the caller expects an `sstring` or `std::string_view`, change to
`seastar::format()`
- if the caller expects an `std::string`, change to `fmt::format()`.
because, `sstring::operator std::basic_string` would incur a deep
copy.
we will need another change to enable scylladb to compile with the
latest seastar. namely, to pass the format string as a templated
parameter down to helper functions which format their parameters.
to miminize the scope of this change, let's include that change when
bumping up the seastar submodule. as that change will depend on
the seastar change.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Extend the `sstable::validate()` to validate the checksums of
uncompressed SSTables. Given that this is already supported for
compressed SSTables, this allows us to provide consistent behavior
across any type of SSTable, be it either compressed or uncompressed.
The most prominent use case for this is scrub/validate, which is now
able to detect file-level corruption in uncompressed SSTables as
well.
Note that this change will not affect normal user reads which skip
checksum validation altogether.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Store and retrieve the optional extended timestamp statistics
(min_live_timestamp and min_live_row_marker_timestamp)
in the scylla_metadata component.
Note that there is no need for a cluster feature to
store those attributes since the scylla_metadata
on-disk format is extensible so that old sstables
can be read by new versions, seeing the extra stats
is missing, and new sstables can be read by old
versions that ignore unknown scylla metadata section types.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
When garbage collecting tombstones, we care only
about shadowing of live data. However, currently
we track min/max timestamp of both live and dead
data, but there is no problem with purging tombstones
that shadow dead data (expired or shdowed by other
tombstones in the sstable/memtable).
Also, for shadowable tombstones, we track live row marker timestamps
separately since, if the live row marker timestamp is greater than
a shadowable tombstone timestamp, then the row marker
would shadow the shadowable tombstone thus exposing the cells
in that row, even if their timestasmp may be smaller
than the shadow tombstone's.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
The reconcilable_result is built as it would be constructed for
forward read queries for tables with reversed order.
Mutations constructed for reversed queries are consumed forward.
Drop overloaded reversed functions that reverse read_command and
reconcilable_result directly and keep only those requiring smart
pointers. They are not used any more.
assert() is traditionally disabled in release builds, but not in
scylladb. This hasn't caused problems so far, but the latest abseil
release includes a commit [1] that causes a 1000 insn/op regression when
NDEBUG is not defined.
Clearly, we must move towards a build system where NDEBUG is defined in
release builds. But we can't just define it blindly without vetting
all the assert() calls, as some were written with the expectation that
they are enabled in release mode.
To solve the conundrum, change all assert() calls to a new SCYLLA_ASSERT()
macro in utils/assert.hh. This macro is always defined and is not conditional
on NDEBUG, so we can later (after vetting Seastar) enable NDEBUG in release
mode.
[1] 66ef711d68Closesscylladb/scylladb#20006
Now that the origin is available inside the sstable object, no need to
pass it to the methods called in the write path.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Pass origin when opening the sstable from the writer and store it in the
sstable object. This will make the origin available for the entire write
path.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
There are two schema's associated with a sstable writer:
the sstable's schema (i.e. the schema of the table at the time when the
sstable object was created), and the writer's schema (equal to the schema
of the reader which is feeding into the writer).
It's easy to mix up the two and break something as a result.
The writer's schema is needed to correctly interpret and serialize the data
passing through the writer, and to populate the on-disk metadata about the
on-disk schema.
The sstables's schema is used to configure some parameters for newly created
sstable, such as bloom filter false positive ratio, or compression.
The problem fixed by this patch is that the writer was wrongly creating
the compressor objects based on its own schema, but using them based
based on the sstable's schema the sstable's schema.
This patch forces the writer to use the sstable's schema for both.
There are two schema's associated with a sstable writer:
the sstable's schema (i.e. the schema of the table at the time when the
sstable object was created), and the writer's schema (equal to the schema
of the reader which is feeding into the writer).
It's easy to mix up the two and break something as a result.
The writer's schema is needed to correctly interpret and serialize the data
passing through the writer, and to populate the on-disk metadata about the
on-disk schema.
The sstables's schema is used to configure some parameters for newly created
sstable, such as bloom filter false positive ratio, or compression.
The problem fixed by this patch is that the writer was wrongly creating
the filter based on its own schema, while the layer outside the writer
was interpreting it as if it was created with the sstable's schema.
This patch forces the writer to pick the filter's parameters based on the
sstable's schema instead.
Log the sstable origin when its bloom filter is being rebuilt. The
origin has to be passed to the method by the caller as it is not
available in the sstable object when the filter is rebuilt.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Closesscylladb/scylladb#19601
The bloom filters are built with partition estimates, as the actual
partition count might not be available in all the cases. If the estimate
was bad, the bloom filters might end up too large or too small than
their optimal sizes. Rebuild such bloom filters with actual partition
count before the filter is written to disk and the sstable is sealed.
Fixes#19049
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
flat_mutation_reader_v2 was introduced in a pair of commits in 2021:
e3309322c3 "Clone flat_mutation_reader related classes into v2 variants"
08b5773c12 "Adapt flat_mutation_reader_v2 to the new version of the API"
as a replacement for flat_mutation_reader, using range_tombstone_change
instead of range_tombstone to represent represent range tombstones. See
those commits for more information.
The transition was incremental; the last use of the original
flat_mutation_reader was removed in 2022 in commit
026f8cc1e7 "db: Use mutation_partition_v2 in mvcc"
In turn, flat_mutation_reader was introduced in 2017 in commit
748205ca75 "Introduce flat_mutation_reader"
To transition from a mutation_reader that nested rows within
a partition in a separate stream, to a flat reader that streamed
partitions and rows in the same stream.
Here, we reclaim the original name and rename the awkward
flat_mutation_reader_v2 to mutation_reader.
Note that mutation_fragment_v2 remains since we still use the original
for compatibilty, sometimes.
Some notes about the transition:
- files were also renamed. In one case (flat_mutation_reader_test.cc), the
rename target already existed, so we rename to
mutation_reader_another_test.cc.
- a namespace 'mutation_reader' with two definitions existed (in
mutation_reader_fwd.hh). Its contents was folded into the mutation_reader
class. As a result, a few #includes had to be adjusted.
Closesscylladb/scylladb#19356
When issuing warnings about partitions with the number of rows above a configured threshold,
the large partitions handler does not take into consideration the number of range tombstone
markers in the total rows count. This fix adds the number of range tombstone markers to the
total number of rows and saves this total in system.large_partitions.rows (if it is above
the threshold). It also adds a new column range_tombstones to the system.large_partitions
table which only contains the number of range tombstone markers for the given partition.
This PR fixes the first part of issue #13968
It does not cover distinguishing between live and dead rows. A subsequent PR will handle that.
since we do not rely on FMT_DEPRECATED_OSTREAM to define the
fmt::formatter for us anymore, let's stop defining `FMT_DEPRECATED_OSTREAM`.
in this change,
* utils: drop the range formatters in to_string.hh and to_string.c, as
we don't use them anymore. and the tests for them in
test/boost/string_format_test.cc are removed accordingly.
* utils: use fmt to print chunk_vector and small_vector. as
we are not able to print the elements using operator<< anymore
after switching to {fmt} formatters.
* test/boost: specialize fmt::details::is_std_string_like<bytes>
due to a bug in {fmt} v9, {fmt} fails to format a range whose
element type is `basic_sstring<uint8_t>`, as it considers it
as a string-like type, but `basic_sstring<uint8_t>`'s char type
is signed char, not char. this issue does not exist in {fmt} v10,
so, in this change, we add a workaround to explicitly specialize
the type trait to assure that {fmt} format this type using its
`fmt::formatter` specialization instead of trying to format it
as a string. also, {fmt}'s generic ranges formatter calls the
pair formatter's `set_brackets()` and `set_separator()` methods
when printing the range, but operator<< based formatter does not
provide these method, we have to include this change in the change
switching to {fmt}, otherwise the change specializing
`fmt::details::is_std_string_like<bytes>` won't compile.
* test/boost: in tests, we use `BOOST_REQUIRE_EQUAL()` and its friends
for comparing values. but without the operator<< based formatters,
Boost.Test would not be able to print them. after removing
the homebrew formatters, we need to use the generic
`boost_test_print_type()` helper to do this job. so we are
including `test_utils.hh` in tests so that we can print
the formattable types.
* treewide: add "#include "utils/to_string.hh" where
`fmt::formatter<optional<>>` is used.
* configure.py: do not define FMT_DEPRECATED_OSTREAM
* cmake: do not define FMT_DEPRECATED_OSTREAM
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
in in {fmt} before v10, it provides the specialization of `fmt::formatter<..>`
for `std::string_view` as well as the specialization of `fmt::formatter<..>`
for `fmt::string_view` which is an implementation builtin in {fmt} for
compatibility of pre-C++17. and this type is used even if the code is
compiled with C++ stadandard greater or equal to C++17. also, before v10,
the `fmt::formatter<std::string_view>::format()` is defined so it accepts
`std::string_view`. after v10, `fmt::formatter<std::string_view>` still
exists, but it is now defined using `format_as()` machinery, so it's
`format()` method does not actually accept `std::string_view`, it
accepts `fmt::string_view`, as the former can be converted to
`fmt::string_view`.
this is why we can inherit from `fmt::formatter<std::string_view>` and
use `formatter<std::string_view>::format(foo, ctx);` to implement the
`format()` method with {fmt} v9, but we cannot do this with {fmt} v10,
and we would have following compilation failure:
```
FAILED: service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o
/home/kefu/.local/bin/clang++ -DFMT_DEPRECATED_OSTREAM -DFMT_SHARED -DSCYLLA_BUILD_MODE=release -DSEASTAR_API_LEVEL=7 -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SSTRING -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"RelWithDebInfo\" -I/home/kefu/dev/scylladb -I/home/kefu/dev/scylladb/build/gen -I/home/kefu/dev/scylladb/seastar/include -I/home/kefu/dev/scylladb/build/seastar/gen/include -I/home/kefu/dev/scylladb/build/seastar/gen/src -ffunction-sections -fdata-sections -O3 -g -gz -std=gnu++20 -fvisibility=hidden -Wall -Werror -Wextra -Wno-error=deprecated-declarations -Wimplicit-fallthrough -Wno-c++11-narrowing -Wno-deprecated-copy -Wno-mismatched-tags -Wno-missing-field-initializers -Wno-overloaded-virtual -Wno-unsupported-friend -Wno-enum-constexpr-conversion -Wno-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb=. -march=westmere -mllvm -inline-threshold=2500 -fno-slp-vectorize -U_FORTIFY_SOURCE -Werror=unused-result -MD -MT service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -MF service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o.d -o service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -c /home/kefu/dev/scylladb/service/topology_state_machine.cc
/home/kefu/dev/scylladb/service/topology_state_machine.cc:254:41: error: no matching member function for call to 'format'
254 | return formatter<std::string_view>::format(it->second, ctx);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
/usr/include/fmt/core.h:2759:22: note: candidate function template not viable: no known conversion from 'seastar::basic_sstring<char, unsigned int, 15>' to 'const fmt::basic_string_view<char>' for 1st argument
2759 | FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
| ^ ~~~~~~~~~~~~
```
because the inherited `format()` method actually comes from
`fmt::formatter<fmt::string_view>`. to reduce the confusion, in this
change, we just inherit from `fmt::format<string_view>`, where
`string_view` is actually `fmt::string_view`. this follows
the document at
https://fmt.dev/latest/api.html#formatting-user-defined-types,
and since there is less indirection under the hood -- we do not
use the specialization created by `FMT_FORMAT_AS` which inherit
from `formatter<fmt::string_view>`, hopefully this can improve
the compilation speed a little bit. also, this change addresses
the build failure with {fmt} v10.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18299
The message says "index-data" but when printing the position, the data
position is printed first, causing confusion. Fix this and while at it,
also print the position of the partition start.
The validate() consumes the content of partitions in a consume-loop.
Every time the consumer asks for a "break", the next PI block is loaded
and set on the validator, so it can validate that further clustering
elements are indeed from this block.
This loop assumed the consumer would only request interruption when the
current clustering block is finished. This is wrong, the consumer can
also request interruption when yielding is needed. When this is the
case, the next PI block doesn't have to be loaded yet, the current one
is not exhausted yet. Check this condition, before loading the next PI
block, to prevent false positive errors, due to mismatched PI block
and clustering elements from the sstable.
It is possible that the next partition has no PI and thus there won't be
a new PI block to overwrite the old one. This will result in
false-positive messages about rows being outside of the finished PI
block.
Promoted index entries can be written on any clustering elements,
icluding range tombstones. So the validating consumer also has the check
whether the current expected clustering block is finished, when
consuming a range tombstone. If it is, consumption has to be
interrupted, so that the outer-loop can load up the next promoted index
block, before moving on to the next clustering element.
For range tombstone end-bounds, the validate_fragment_order() should be
passed a null tombstone, not a disengaged optional. The latter means no
change in the current tombstone. This caused the end bound of range
tombstones to not make it to the validator and the latter complained
later on partition-end that the partition has unclosed range tombstone.
