streaming generates lots of small sstables with large token range,
which triggers O(N^2) in space in interval map.
level 0 sstables will now be stored in a structure that has O(N)
in space complexity and which will be included for every read.
Fixes#2287.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20170417185509.6633-1-raphaelsc@scylladb.com>
When compacting a fully expired sstable, we're not allowing that sstable
to be purged because expired cell is *unconditionally* converted into a
dead cell. Why not check if the expired cell can be purged instead using
gc before and max purgeable timestamp?
Currently, we need two compactions to get rid of a fully expired sstable
which cells could have always been purged.
look at this sstable with expired cell:
{
"partition" : {
"key" : [ "2" ],
"position" : 0
},
"rows" : [
{
"type" : "row",
"position" : 120,
"liveness_info" : { "tstamp" : "2017-04-09T17:07:12.702597Z",
"ttl" : 20, "expires_at" : "2017-04-09T17:07:32Z", "expired" : true },
"cells" : [
{ "name" : "country", "value" : "1" },
]
now this sstable data after first compaction:
[shard 0] compaction - Compacted 1 sstables to [...]. 120 bytes to 79
(~65% of original) in 229ms = 0.000328997MB/s.
{
...
"rows" : [
{
"type" : "row",
"position" : 79,
"cells" : [
{ "name" : "country", "deletion_info" :
{ "local_delete_time" : "2017-04-09T17:07:12Z" },
"tstamp" : "2017-04-09T17:07:12.702597Z"
},
]
now another compaction will actually get rid of data:
compaction - Compacted 1 sstables to []. 79 bytes to 0 (~0% of original)
in 1ms = 0MB/s. ~2 total partitions merged to 0
NOTE:
It's a waste of time to wait for second compaction because the expired
cell could have been purged at first compaction because it satisfied
gc_before and max purgeable timestamp.
Fixes#2249, #2253
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20170413001049.9663-1-raphaelsc@scylladb.com>
"sstable_streamed_mutation::fast_forward_to() is changed to use promoted index
(via index_reader) to optimize skipping in large partitions.
In addition to that, sstable mutation_reader is changed to use the index
to skip to the next partition.
Performance impact was evaluated using newly added tests/perf/perf_fast_forward
What's beyond this series:
- Using index_reader for single-partition reads as well
- Using index_reader for skipping across ranges in clustering restrictions"
* tag 'tgrabiec/skip-within-partition-using-index-v2' of github.com:cloudius-systems/seastar-dev: (47 commits)
tests: Add performance test for fast forwarding of sstable readers
tests: Allow starting cql_test_env on pre-existing data
config: Allow specifying source when setting value
tests: sstable: Add test for fast forwarding within partition using index
sstables: sstable_streamed_mutation: use index in fast_forward_to()
sstables: Store parsed promoted index in index_entry
sstables: Add trace-level logging for sstable consumption
sstables: Define deletion_time earlier
sstables: Make parsing throw exception on malformed promoted index
tests: Add tests for ordering of position_in_partition relative to composites
position_range: Introduce all_clustered_rows() factory method
position_in_partition: Introduce for_key()/after_key() factory methods
position_in_partition: Add factory methods for positions around all rows
position_in_partition: Introduce for_range_start()/for_range_end()
position_in_partition: Fix friendship declaration
keys: Introduce is_empty() for prefixes
position_in_partition: Make comparable with composites
types: Enhance lexicographical comparators
compound_compat: Accept marker value in serialize_value()
compound_compat: Add trichotomic comparator
...
quick introduction to level starvation:
high levels may be left uncompacted (thus starved) for a long time if user
makes something that make they contain little data, such as cleanup or change
of max sstable size (default 160M). Leveled strategy handles this problem as
follow: consider we're compacting L1 to L2. If L3 is starved, we look for one
of its sstable that is fully contained in token range of candidates L1->L2,
so that we won't end up with an overlapping in L2.
now the problem:
the functionality isn't working properly now because range of candidates is
being incorrectly calculated due to an accident when converting the code to
C++. It won't cause an overlap because it's actually being more restrictive
about which sstable from starved level can be used.
A test case was added to confirm the problem.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20170328223753.15398-1-raphaelsc@scylladb.com>
Add a boolean to short circuit the read path on empty range
hoping for some speedup.
tested in read write with cs using:
cl=QUORUM duration=1m -mode native cql3 -rate threads=700 -node localhost
Will do some additional benchmark.
Fixes#1056
Signed-off-by: Benoît Canet <benoit@scylladb.com>
Message-Id: <20170118194451.16836-1-benoit@scylladb.com>
This hopefully will make it more apparent that
the time complexity of this method is O(N) not O(1).
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
This reverts commit aa392810ff, reversing
changes made to a24ff47c637e6a5fd158099b8a65f1191fc2d023; it uses
boost::intrusive::detail directly, which it must not, and doesn't compile on
all boost versions as a consequence.
"Reduce the size of mutation_partition by implementing intrusive set using
bi::rbtree_algorithms directly and using tree nodes optimized for size.
This will reduce the size of mutation_partition by:
24 bytes + <number of cql rows> * 8 bytes
This should have a positive impact on performance because mutation_partitions
are stored both in memtable and cache.
Fixes #742."
* 'haaawk/742' of github.com:cloudius-systems/seastar-dev:
intrusive_set: rename size() to calculate_size()
Make intrusive_set_external_comparator::_value_traits static
Implement intrusive set using rbtree_algorithms
mutation_partition: make apply_reversibly_intrusive_set nongeneric
mutation_partition: take schema in find_row and clustered_row
mutation_partition: Extract intrusive set logic to a class.
mutation_partition: Replace value_comp with key_comp calls
This hopefully will make it more apparent that
the time complexity of this method is O(N) not O(1).
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
- moved to seastar thread
- extracted sstable creation and validation logic
- reduced code duplication
- switched to mutation_reader assertions
- used result of compact_sstable() to locate the new sstable
- rather than setting gc timestamp in the past, bump the clock
before compacting
Problem will cause size tiered to return small jobs when there are
more than max_threshold sstables of similar size. For example, if
max_threshold is 32, and there are 36 sstables of similar size,
strategy will only return 4 sstables to be compacted. That's because
we incorrectly create a new bucket when it meets the max threshold.
What we should do is to allow buckets to grow beyond max threshold
and trim them when selecting the most suitable one for compaction.
Important to mention that estimation for size tiered will now
work better when there are more than max_threshold sstables of
similar size.
Fixes#1901.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <080bad70d6cb86eaf52ac1bdd6765ac47aab5b03.1478316140.git.raphaelsc@scylladb.com>
After 7c28ed, the schemas defined in the test became compressed by
default. This patch changes the test so that it is explicit about
which schemas shouldn't define a compressor.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <1478646530-5558-1-git-send-email-duarte@scylladb.com>
When max sstable size is increased, higher levels are suffering from
starvation because we decide to compact a given level if the following
calculation results in a number greater than 1.001:
level_size(L) / max_size_for_level_l(L)
Fixes#1720.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Uniform token range distribution across sstables in a level > 1 was broken,
because we were only choosing sstable with lowest first key, when compacting
a level > 0. This resulted in performance problem because L1->L2 may have a
huge overlap over time, for example.
Last compacted key will now be stored for each level to ensure sort of
"round robin" selection of sstables for compactions at level >= 1.
That's also done by C*, and they were once affected by it as described in
https://issues.apache.org/jira/browse/CASSANDRA-6284.
Fixes#1719.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
That will be needed for optimization that will store decorated keys
in the sstable object, and also for a subsequent work that will
detect wrong metadata (min/max column names) by looking at columns
in the schema. As schema is stored in sstable, there's no longer
a need to store ks and cf names in it.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Remove clustering_key_filter_factory and clustering_key_filtering_context.
Use partition_slice directly with a static get_ranges method.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
That was a bug in the test itself. It could happen that a sstable would
incorrectly belong to the next time window if the current minute is
approaching its end. Fix is about having all sstables that we want in
the same time window with the same min/max timestamp.
Fixes#1448.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <ee25d49e7ed12b4cf7d018a08163404c3d122e56.1468782787.git.raphaelsc@scylladb.com>
Originally, streamed_mutations guaranteed that emitted tombstones are
disjoint. In order to achieve that two separate objects were produced
for each range tombstone: range_tombstone_begin and range_tombstone_end.
Unfortunately, this forced sstable writer to accumulate all clustering
rows between range_tombstone_begin and range_tombstone_end.
However, since there is no need to write disjoint tombstones to sstables
(see #1153 "Write range tombstones to sstables like Cassandra does") it
is also not necessary for streamed_mutations to produce disjoint range
tombstones.
This patch changes that by making streamed_mutation produce
range_tombstone objects directly.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
sstable_list is now a map<generation, sstable>; change it to a set
in preparation for replacing it with sstable_set. The change simplifies
a lot of code; the only casualty is the code that computes the highest
generation number.
