More specifically, return a future which is equivalent to the original
future (when the original future resolves, this future will contain its
result).
Thus we don't discard the future, the user gets it back.
Let them decide what to do with it.
"
Currently we `assert(_stopped)` in the destructor, but this is too
harsh, especially on freshly created semaphore instances that weren't
even used yet. This basically mandates semaphores to be initialized at
the end of the constructor body, which is very cumbersome.
Further to that, this series relaxes the checks on destroying an
unstopped previously (but not currently) used semaphore. As destroying
such a semaphore without stop is risky an error is still logged.
Tests: unit(dev)
"
* 'reader-concurrency-semaphore-relax-stop-check/v1' of https://github.com/denesb/scylla:
reader_concurrency_semaphore: relax _stopped check when destroying a used semaphore
reader_concurrency_semaphore: allow destroying without stop() when not used yet
reader_concurrency_semaphore: add permit-stats
To make it easier to construct objects with semaphore members. When the
construction of such object fails, they can now just destroy their
semaphore member as usual, without having to employ tricks to make sure
its is stopped before.
We have been seeing rare failures of the cql-pytest (translated from
Cassandra's unit tests) for testing TTL in secondary indexes:
cassandra_tests/validation/entities/secondary_index_test.py::testIndexOnRegularColumnInsertExpiringColumn
The problem is that the test writes an item with 1 second TTL, and then
sleeps *exactly* 1.0 seconds, and expects to see the item disappear
by that time. Which doesn't always happen:
The problem with that assumption stems from Scylla's TTL clock ("gc_clock")
being based on Seastar's lowres clock. lowres_clock only has a 10ms
"granularity": The time Scylla sees when deciding whether an item expires
may be up to 10ms in the past - the arbitrary point when the lowres timer
happened to last run. In rare overload cases, the inaccuracy may be even
grater than 10ms (if the timer got delayed by other things running).
So when Scylla is asked to expire an item in 1 second - we cannot be
sure it will be expired in exactly 1 second or less - the expiration
can be also around 10ms later.
So in this patch we change the test to sleep with more than enough
margin - 1.1 seconds (i.e., 100ms more than 1 second). By that time
we're sure the item must have expired.
Before this patch, I saw the test failing once every few hundred runs,
after this patch I ran if 2,000 times without a single failure.
Fixes#9008
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210712100655.953969-1-nyh@scylladb.com>
When a table with compact storage has no regular column (only primary
key columns), an artificial column of type empty is added. Such column
type can't be returned via CQL so CDC Log shouldn't contain a column
that reflects this artificial column.
This patch does two things:
1. Make sure that CDC Log schema does not contain columns that reflect
the artificial column from a base table.
2. When composing mutation to CDC Log, ommit the artificial column.
Fixes#8410
Test: unit(dev)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Closes#8988
This series fixes some issues that gcc 11 complains about. I believe all
are correct errors from the standard's view. Clang accepts the changed code.
Note that this is not enough to build with gcc 11, but it's a start.
Closes#9007
* github.com:scylladb/scylla:
utils: compact-radix-tree: detemplate array_of<>
utils: compact-radix-tree: don't redefine type as member
raft: avoid changing meaning of a symbol inside a class
cql3: lists: catch polymorphic exceptions by reference
The construct
struct q {
a a;
};
Changes the meaning of `a` from a type to a data member. gcc dislikes
it and I agree. Fully qualify the type name to avoid an error.
Returning a function parameter guarantees copy elision and does not
require a std::move(). Enable -Wredundant-move to warn us that the
move is unneeded, and gain slightly more readable code. A few violations
are trivially adjusted.
Closes#9004
This warning prevents using std::move() where it can hurt
- on an unnamed temporary or a named automatic variable being
returned from a function. In both cases the value could be
constructed directly in its final destination, but std::move()
prevents it.
Fix the handful of cases (all trivial), and enable the warning.
Closes#8992
"
After this series one can use perf_fast_forward to generate the data set.
It takes a lot less time this way than to use scylla-bench.
"
* 'perf-fast-forward-scylla-bench-dataset' of github.com:tgrabiec/scylla:
tests: perf_fast_forward: Use data_source::make_ck()
tests: perf_fast_forward: Move declaration of clustered_ds up
tests: perf_fast_forward: Make scylla_bench_small_part_ds1 not included by default
tests: perf_fast_forward: Add data sets which conform to scylla-bench schema
This patch adds to cql-pytest/README.md a paragraph on where run /
run-cassandra expect to find Scylla or Cassandra, and how to override
that choice.
Also make a couple of trivial formatting changes.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210708142730.813660-1-nyh@scylladb.com>
"
When obtaining a valid permit was made mandatory, code which now had to
create reader permits but didn't have a semaphore handy suddenly found
itself in a difficult situation. Many places and most prominently tests
solved the problem by creating a thread-local semaphore to source
permits from. This was fine at the time but as usual, globals came back
to haunt us when `reader_concurrency_semaphore::stop()` was
introduced, as these global semaphores had no easy way to be stopped
before being destroyed. This patch-set cleans up this wart, by getting
rid of all global semaphores, replacing them with appropriately scoped
local semaphores, that are stopped after being used. With that, the
FIXME in `~reader_concurrency_semaphore()` can be resolved and we an
finally `assert()` that the semaphore was stopped before being
destroyed.
This series is another preparatory one for the series which moves the
semaphore in front of the cache.
tests: unit(dev)
"
* 'reader-concurrency-semaphore-mandatory-stop/v2' of https://github.com/denesb/scylla: (26 commits)
reader_concurrency_semaphore: assert(_stopped) in the destructor
test/lib: remove now unused reader_permit.{hh,cc}
test/boost: migrate off the global test reader semaphore
test/manual: migrate off the global test reader semaphore
test/unit: migrate off the global test reader semaphore
test/perf: migrate off the global test reader semaphore
test/perf: perf.hh: add reader_concurrency_semaphore_wrapper
test/lib: migrate off the global test reader semaphore
test/lib/simple_schema: migrate off the global test reader semaphore
test/lib/sstable_utils: migrate off the global test reader semaphore
test/lib/test_services: migrate off the global test reader semaphore
test/lib/sstable_test_env: add reader_concurrency_semaphore member
test/lib/cql_test_env: add make_reader_permit()
test/lib: add reader_concurrency_semaphore.hh
test/boost/sstable_test: migrate row counting tests to seastar thread
test/boost/sstable_test: test_using_reusable_sst(): pass env to func
test/lib/reader_lifecycle_policy: add permit parameter to factory function
test/boost/mutation_reader_test: share permit between readers in a read
memtable: migrate off the global reader concurrency semaphore
mutation_writer: multishard_writer: migrate off the global reader concurrency semaphore
...
After commit 76227fa ("cql-pytest: use NetworkTopologyStrategy, not
SimpleStrategy"), the cql-pytest tests now NetworkTopologyStrategy instead
of SimpleStrategy in the test keyspaces. The tests continued to use the
"replication_factor" option. The support for this option is a relatively
recent, and was only added to Cassandra in the 4.0 release series
(see https://issues.apache.org/jira/browse/CASSANDRA-14303). So users
who happen to have Cassandra 3 installed and want to run a cql-pytest
against it will see the test failing when it can't create a keyspace.
This patch trivially fixes the problem by using the name of the current
DC (automatically determined) instead of the word 'replication_factor'.
Almost all tests are fixed by a single fix to the test_keyspace fixture
which creates one keyspace used by most tests. Additional changes were
needed in test_keyspace.py, for tests which explicitly create keyspaces.
I tested the result on Cassandra 3.11.10, Cassandra 4 (git master) and
Scylla.
Fixes#8990
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210708123428.811184-1-nyh@scylladb.com>
We know that today in Scylla concurrent schema changes done on different
coordinators are not safe - and we plan to address this problem with Raft.
However, the test in this patch - reproducing issue #8968 - demonstrates
that even on a single node concurrent schema changes are not safe:
The test involves one thread which constantly creates a keyspace and
then a table in it - and a second thread which constantly deletes this
keyspace. After doing this for a while, the schema reaches an inconsistent
state: The keyspace is at a state of limbo where it cannot be dropped
(dropping it succeeds, but doesn't actually drop it), and a new keyspace
cannot be created under the same name).
Note that to reproduce this bug, it was important that the test create
both a keyspace and a table. Were the test to just create an empty keyspace,
without a table in it, the bug would not be reproduced.
Refs #8968.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210704121049.662169-1-nyh@scylladb.com>
Supplying a convenience semaphore wrapper, which stops the contained
semaphore when destroyed. It also provides a more convenient
`make_permit()`. This class is intended to make the migration to local
semaphores less painful.
In older versions of Cassandra (such as 3.11.10 which I tried), the
CQL server is not turned on by default, unless the configuration file
explicitly has "start_native_transport: true" - without it only the
Thrift server is started.
So fix the cql-pytest/run-cassandra to pass this option. It also
works correctly in Cassandra 4.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210708113423.804980-1-nyh@scylladb.com>
The test case checks that deleting a base table clustering range
works fine. This operation is potentially heavy, as it involves
generating a view update for every row. With large enough ranges,
the number can reach millions and beyond.
The test case checks that deleting a whole base table partition
works fine. This operation is potentially heavy, as it involves
generating a view update for every row. With large enough partitions,
the number can reach millions and beyond.
The factory method doesn't match the signature of
`reader_lifecycle_policy::make_reader()`, notably the permit is missing.
Add it as it is important that the wrapping evictable reader and
underlying reader share the permits.
Permits were designed such that there is one permit per read, being
shared by all readers in that read. Make sure readers created by tests
adhere to this.
Naming the concurrency semaphore is currently optional, unnamed
semaphores defaulting to "Unnamed semaphore". Although the most
important semaphores are named, many still aren't, which makes for a
poor debugging experience when one of these times out.
To prevent this, remove the name parameter defaults from those
constructors that have it and require a unique name to be passed in.
Also update all sites creating a semaphore and make sure they use a
unique name.
Since compaction is layered on top of sstables, let's move all compaction code
into a new top-level directory.
This change will give me extra motivation to remove all layer violations, like
sstable calling compaction-specific code, and compaction entanglement with
other components like table and storage service.
Next steps:
- remove all layer violations
- move compaction code in sstables namespace into a new one for compaction.
- move compaction unit tests into its own file
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210707194058.87060-1-raphaelsc@scylladb.com>
This dataset exists for convenience, to be able to run scylla-bench
against the data set generated by perf_fast_forward. It doesn't
increase coverage. So do not include it by default to not waste
resources on it.
Cassandra 3.0 deprecated the 'sstable_compression' attribute and added
'class' as a replacement. Follow by supporting both.
The SSTABLE_COMPRESSION variable is renamed to SSTABLE_COMPRESSION_DEPRECATED
to detect all uses and prevent future misuse.
To prevent old-version nodes from seeing the new name, the
compression_parameters class preserves the key name when it is
constructed from an options map, and emits the same key name when
asked to generate an options map.
Existing unit tests are modified to use the new name, and a test
is added to ensure the old name is still supported.
Fixes#8948.
Closes#8949
"
The main goal of this series is to improve efficiency of reads from large partitions by
reducing amount of I/O needed to read the sstable index. This is achieved by caching
index file pages and partition index entries in memory.
Currently, the pages are cached by individual reads only for the duration of the read.
This was done to facilitate binary search in the promoted index (intra-partition index).
After this series, all reads share the index file page cache, which stays around even after reads stop.
The page cache is subject to eviction. It uses the same region as the current row cache and shares
the LRU with row cache entries. This means that LRU objects need to be virtualized. This series takes
an easy approach and does this by introducing a virtual base class. This adds an overhead to row cache
entry to store the vtable pointer.
SStable indexes have a hierarchy. There is a summary, which is a sparse partition key index into the
full partition index. This one is already kept in memory. The partition index is divided by the summary
into pages. Each entry in the partition index contains promoted index, which is a sparse index into atoms
identified by the clustering key (rows, tombstones).
In order to read the promoted index, the reader needs to read the partition index entry first.
To speed this up, this series also adds caching of partition index entries. This cache survives
reads and is subject to eviction, just like the index file page cache. The unit of caching is
the partition index page. Without this cache, each access to promoted index would have to be
preceded with the parsing of the partition index page containing the partition key.
Performance testing results follow.
1) scylla-bench large partition reads
Populated with:
perf_fast_forward --run-tests=large-partition-skips --datasets=sb-large-part-ds1 \
-c1 -m1G --populate --value-size=1024 --rows=10000000
Single partition, 9G data file, 4MB index file
Test execution:
build/release/scylla -c1 -m4G
scylla-bench -workload uniform -mode read -limit 1 -concurrency 100 -partition-count 1 \
-clustering-row-count 10000000 -duration 60m
TL;DR: after: 2x throughput, 0.5 median latency
Before (c1daf2bb24):
Results
Time (avg): 5m21.033180213s
Total ops: 966951
Total rows: 966951
Operations/s: 3011.997048812112
Rows/s: 3011.997048812112
Latency:
max: 74.055679ms
99.9th: 63.569919ms
99th: 41.320447ms
95th: 38.076415ms
90th: 37.158911ms
median: 34.537471ms
mean: 33.195994ms
After:
Results
Time (avg): 5m14.706669345s
Total ops: 2042831
Total rows: 2042831
Operations/s: 6491.22243800942
Rows/s: 6491.22243800942
Latency:
max: 60.096511ms
99.9th: 35.520511ms
99th: 27.000831ms
95th: 23.986175ms
90th: 21.659647ms
median: 15.040511ms
mean: 15.402076ms
2) scylla-bench small partitions
I tested several scenarios with a varying data set size, e.g. data fully fitting in memory,
half fitting, and being much larger. The improvement varied a bit but in all cases the "after"
code performed slightly better.
Below is a representative run over data set which does not fit in memory.
scylla -c1 -m4G
scylla-bench -workload uniform -mode read -concurrency 400 -partition-count 10000000 \
-clustering-row-count 1 -duration 60m -no-lower-bound
Before:
Time (avg): 51.072411913s
Total ops: 3165885
Total rows: 3165885
Operations/s: 61988.164024260645
Rows/s: 61988.164024260645
Latency:
max: 34.045951ms
99.9th: 25.985023ms
99th: 23.298047ms
95th: 19.070975ms
90th: 17.530879ms
median: 3.899391ms
mean: 6.450616ms
After:
Time (avg): 50.232410679s
Total ops: 3778863
Total rows: 3778863
Operations/s: 75227.58014424688
Rows/s: 75227.58014424688
Latency:
max: 37.027839ms
99.9th: 24.805375ms
99th: 18.219007ms
95th: 14.090239ms
90th: 12.124159ms
median: 4.030463ms
mean: 5.315111ms
The results include the warmup phase which populates the partition index cache, so the hot-cache effect
is dampened in the statistics. See the 99th percentile. Latency gets better after the cache warms up which
moves it lower.
3) perf_fast_forward --run-tests=large-partition-skips
Caching is not used here, included to show there are no regressions for the cold cache case.
TL;DR: No significant change
perf_fast_forward --run-tests=large-partition-skips --datasets=large-part-ds1 -c1 -m1G
Config: rows: 10000000, value size: 2000
Before:
read skip 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 cpu
1 0 36.429822 4 10000000 274500 62 274521 274429 153889.2 153883 19696986 153853 0 0 0 0 0 0 0 22.5%
1 1 36.856236 4 5000000 135662 7 135670 135650 155652.0 155652 19704117 139326 1 0 1 1 0 0 0 38.1%
1 8 36.347667 4 1111112 30569 0 30570 30569 155652.0 155652 19704117 139071 1 0 1 1 0 0 0 19.5%
1 16 36.278866 4 588236 16214 1 16215 16213 155652.0 155652 19704117 139073 1 0 1 1 0 0 0 16.6%
1 32 36.174784 4 303031 8377 0 8377 8376 155652.0 155652 19704117 139056 1 0 1 1 0 0 0 12.3%
1 64 36.147104 4 153847 4256 0 4256 4256 155652.0 155652 19704117 139109 1 0 1 1 0 0 0 11.1%
1 256 9.895288 4 38911 3932 1 3933 3930 100869.2 100868 3178298 59944 38912 0 1 1 0 0 0 14.3%
1 1024 2.599921 4 9757 3753 0 3753 3753 26604.0 26604 801850 15071 9758 0 1 1 0 0 0 14.6%
1 4096 0.784568 4 2441 3111 1 3111 3109 7982.0 7982 205946 3772 2442 0 1 1 0 0 0 13.8%
64 1 36.553975 4 9846154 269359 10 269369 269337 155663.8 155652 19704117 139230 1 0 1 1 0 0 0 28.2%
64 8 36.509694 4 8888896 243467 8 243475 243449 155652.0 155652 19704117 139120 1 0 1 1 0 0 0 26.5%
64 16 36.466282 4 8000000 219381 4 219385 219374 155652.0 155652 19704117 139232 1 0 1 1 0 0 0 24.8%
64 32 36.395926 4 6666688 183171 6 183180 183165 155652.0 155652 19704117 139158 1 0 1 1 0 0 0 21.8%
64 64 36.296856 4 5000000 137753 4 137757 137737 155652.0 155652 19704117 139105 1 0 1 1 0 0 0 17.7%
64 256 20.590392 4 2000000 97133 18 97151 94996 135248.8 131395 7877402 98335 31282 0 1 1 0 0 0 15.7%
64 1024 6.225773 4 588288 94492 1436 95434 88748 46066.5 41321 2324378 30360 9193 0 1 1 0 0 0 15.8%
64 4096 1.856069 4 153856 82893 54 82948 82721 16115.0 16043 583674 11574 2675 0 1 1 0 0 0 16.3%
After:
read skip 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 cpu
1 0 36.429240 4 10000000 274505 38 274515 274417 153887.8 153883 19696986 153849 0 0 0 0 0 0 0 22.4%
1 1 36.933806 4 5000000 135377 15 135385 135354 155658.0 155658 19704085 139398 1 0 1 1 0 0 0 40.0%
1 8 36.419187 4 1111112 30509 2 30510 30507 155658.0 155658 19704085 139233 1 0 1 1 0 0 0 22.0%
1 16 36.353475 4 588236 16181 0 16182 16181 155658.0 155658 19704085 139183 1 0 1 1 0 0 0 19.2%
1 32 36.251356 4 303031 8359 0 8359 8359 155658.0 155658 19704085 139120 1 0 1 1 0 0 0 14.8%
1 64 36.203692 4 153847 4249 0 4250 4249 155658.0 155658 19704085 139071 1 0 1 1 0 0 0 13.0%
1 256 9.965876 4 38911 3904 0 3906 3904 100875.2 100874 3178266 60108 38912 0 1 1 0 0 0 17.9%
1 1024 2.637501 4 9757 3699 1 3700 3697 26610.0 26610 801818 15071 9758 0 1 1 0 0 0 19.5%
1 4096 0.806745 4 2441 3026 1 3027 3024 7988.0 7988 205914 3773 2442 0 1 1 0 0 0 18.3%
64 1 36.611243 4 9846154 268938 5 268942 268921 155669.8 155705 19704085 139330 2 0 1 1 0 0 0 29.9%
64 8 36.559471 4 8888896 243135 11 243156 243124 155658.0 155658 19704085 139261 1 0 1 1 0 0 0 28.1%
64 16 36.510319 4 8000000 219116 15 219126 219101 155658.0 155658 19704085 139173 1 0 1 1 0 0 0 26.3%
64 32 36.439069 4 6666688 182954 9 182964 182943 155658.0 155658 19704085 139274 1 0 1 1 0 0 0 23.2%
64 64 36.334808 4 5000000 137609 11 137612 137596 155658.0 155658 19704085 139258 2 0 1 1 0 0 0 19.1%
64 256 20.624759 4 2000000 96971 88 97059 92717 138296.0 131401 7877370 98332 31282 0 1 1 0 0 0 17.2%
64 1024 6.260598 4 588288 93967 1429 94905 88051 45939.5 41327 2324346 30361 9193 0 1 1 0 0 0 17.8%
64 4096 1.881338 4 153856 81780 140 81920 81520 16109.8 16092 582714 11617 2678 0 1 1 0 0 0 18.2%
4) perf_fast_forward --run-tests=large-partition-slicing
Caching enabled, each line shows the median run from many iterations
TL;DR: We can observe reduction in IO which translates to reduction in execution time,
especially for slicing in the middle of partition.
perf_fast_forward --run-tests=large-partition-slicing --datasets=large-part-ds1 -c1 -m1G --keep-cache-across-test-cases
Config: rows: 10000000, value size: 2000
Before:
offset read 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
0 1 0.000491 127 1 2037 24 2109 127 4.0 4 128 2 2 0 1 1 0 0 0 157 80 3058208 15.0%
0 32 0.000561 1740 32 56995 410 60031 47208 5.0 5 160 3 2 0 1 1 0 0 0 386 111 113353 17.5%
0 256 0.002052 488 256 124736 7111 144762 89053 16.6 17 672 14 2 0 1 1 0 0 0 2113 446 52669 18.6%
0 4096 0.016437 61 4096 249199 692 252389 244995 69.4 69 8640 57 5 0 1 1 0 0 0 26638 1717 23321 22.4%
5000000 1 0.002171 221 1 461 2 466 221 25.0 25 268 3 3 0 1 1 0 0 0 638 376 14311524 10.2%
5000000 32 0.002392 404 32 13376 48 13528 13015 27.0 27 332 5 3 0 1 1 0 0 0 931 432 489691 11.9%
5000000 256 0.003659 279 256 69967 764 73130 52563 39.5 41 780 19 3 0 1 1 0 0 0 2689 825 93756 15.8%
5000000 4096 0.018592 55 4096 220313 433 234214 218803 94.2 94 9484 62 9 0 1 1 0 0 0 27349 2213 26562 21.0%
After:
offset read 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
0 1 0.000229 115 1 4371 85 4585 115 2.1 2 64 1 1 1 0 0 0 0 0 90 31 1314749 22.2%
0 32 0.000277 2174 32 115674 1015 128109 14144 3.0 3 96 2 1 1 0 0 0 0 0 319 62 52508 26.1%
0 256 0.001786 576 256 143298 5534 179142 113715 14.7 17 544 15 1 1 0 0 0 0 0 2110 453 45419 21.4%
0 4096 0.015498 61 4096 264289 2006 268850 259342 67.4 67 8576 59 4 1 0 0 0 0 0 26657 1738 22897 23.7%
5000000 1 0.000415 233 1 2411 15 2456 234 4.1 4 128 2 2 1 0 0 0 0 0 199 72 2644719 16.8%
5000000 32 0.000635 1413 32 50398 349 51149 46439 6.0 6 192 4 2 1 0 0 0 0 0 458 128 125893 18.6%
5000000 256 0.002028 486 256 126228 3024 146327 82559 17.8 18 1024 13 4 1 0 0 0 0 0 2123 385 51787 19.6%
5000000 4096 0.016836 61 4096 243294 814 263434 241660 73.0 73 9344 62 8 1 0 0 0 0 0 26922 1920 24389 22.4%
Future work:
- Check the impact on non-uniform workloads. Caching sstable indexes takes space away from the row cache
which may reduce the hit ratio.
- Reduce memory footprint of partition index cache. Currently, about 8x bloat over the on-disk size.
- Disable cache population for "bypass cache" reads
- Add a switch to disable sstable index caching, per-node, maybe per-table
- Better sstable index format. Current format leads to inefficiency in caching since only some elements of the cached
page can be hot. A B-tree index would be more efficient. Same applies to the partition index. Only some elements in
the partition index page can be hot.
- Add heuristic for reducing index file IO size when large partitions are anticipated. If we're bound by disk's
bandwidth it's wasteful to read the front of promoted index using 32K IO, better use 4K which should cover the
partition entry and then let binary search read the rest.
In V2:
- Fixed perf_fast_forward regression in the number of IOs used to read partition index page
The reader uses 32K reads, which were split by page cache into 4K reads
Fix by propagating IO size hints to page cache and using single IO to populate it.
New patch: "cached_file: Issue single I/O for the whole read range on miss"
- Avoid large allocations to store partition index page entries (due to managed_vector storage).
There is a unit test which detects this and fails.
Fixed by implementing chunked_managed_vector, based on chunked_vector.
- fixed bug in cached_file::evict_gently() where the wrong allocation strategy was used to free btree chunks
- Simplify region_impl::free_buf() according to Avi's suggestions
- Fit segment_kind in segment_descriptor::_free_space and lift requirement that _buf_pointers emptiness determines the kind
- Workaround sigsegv which was most likely due to coroutine miscompilation. Worked around by manipulating local object scope.
- Wire up system/drop_sstable_caches RESTful API
- Fix use-after-move on permit for the old scanning ka/la index reader
- Fixed more cases of double open_data() in tests leading to assert failure
- Adjusted cached_file class doc to account for changes in behavior.
- Rebased
Fixes#7079.
Refs #363.
"
* tag 'sstable-index-caching-v2' of github.com:tgrabiec/scylla: (39 commits)
api: Drop sstable index caches on system/drop_sstable_caches
cached_file: Issue single I/O for the whole read range on miss
row_cache: cache_tracker: Do not register metrics when constructed for tests
sstables, cached_file: Evict cache gently when sstable is destroyed
sstables: Hide partition_index_cache implementation away from sstables.hh
sstables: Drop shared_index_lists alias
sstables: Destroy partition index cache gently
sstables: Cache partition index pages in LSA and link to LRU
utils: Introduce lsa::weak_ptr<>
sstables: Rename index_list to partition_index_page and shared_index_lists to partition_index_cache
sstables, cached_file: Avoid copying buffers from cache when parsing promoted index
cached_file: Introduce get_page_units()
sstables: read: Document that primitive_consumer::read_32() is alloc-free
sstables: read: Count partition index page evictions
sstables: Drop the _use_binary_search flag from index entries
sstables: index_reader: Keep index objects under LSA
lsa: chunked_managed_vector: Adapt more to managed_vector
utils: lsa: chunked_managed_vector: Make LSA-aware
test: chunked_managed_vector_test: Make exception_safe_class standard layout
lsa: Copy chunked_vector to chunked_managed_vector
...
`query_processor::execute_direct()` takes a non-const ref
to query options, meaning it's not safe to pass the same
instance to subsequent invocations of `execute_direct()`
in the tests.
Copy default query options at each invocation of `execute_cql()`
so no possible side-effects can occur.
Tests: unit(dev, debug)
Signed-off-by: Pavel Solodovnikov <pa.solodovnikov@scylladb.com>
Message-Id: <20210705094824.243573-2-pa.solodovnikov@scylladb.com>
In pull request #8568, the CDC API changed slightly, with preimage data
gaining extra "delete$k" values for columns whose preimage was missing.
In this new test, we verify that this change did not break Alternator.
We didn't expect it to break Alternator, because it just outputs the known
base-table columns and ignores the columns which weren't a real base-table
column - like this "delete$k".
In the test we set up a stream with preimages, ensure that a real column
(note that an LSI key is a real column instead of a map element) has a
null preimage - and see that the preimage is returned as expected,
without fake columns like "delete$k".
The test passes, showing that PR #8568 was ok.
The test also passes, as expected, on DynamoDB.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20210504120121.915829-1-nyh@scylladb.com>
