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UniversalCompactionPicker::PickCompaction(): avoid to form compactions if there is no file

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Summary:
Currently RocksDB may break in lines like this:

for (size_t i = sorted_runs.size() - 1; i >= first_index_after; i--) {

if options.level0_file_num_compaction_trigger=0.

Fix it by not executing the logic of picking compactions if there is no file (sorted_runs.size() = 0). Also internally set options.level0_file_num_compaction_trigger=1 if users give a 0. 0 is a value makes no sense in RocksDB.

Test Plan: Run all tests. Will add a unit test too.

Reviewers: yhchiang, IslamAbdelRahman, anthony, kradhakrishnan, rven

Reviewed By: rven

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D50727
This commit is contained in:
sdong 2015-11-13 12:01:52 -08:00
parent d06b63e99f
commit dac5b248b1
3 changed files with 47 additions and 2 deletions
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6
db/column_family.cc
View File

@ -175,6 +175,12 @@ ColumnFamilyOptions SanitizeOptions(const DBOptions& db_options,
result.level0_stop_writes_trigger = std::numeric_limits<int>::max();
}
if (result.level0_file_num_compaction_trigger == 0) {
Warn(db_options.info_log.get(),
"level0_file_num_compaction_trigger cannot be 0");
result.level0_file_num_compaction_trigger = 1;
}
if (result.level0_stop_writes_trigger <
result.level0_slowdown_writes_trigger ||
result.level0_slowdown_writes_trigger <

5
db/compaction_picker.cc
View File

@ -1248,8 +1248,9 @@ Compaction* UniversalCompactionPicker::PickCompaction(
std::vector<SortedRun> sorted_runs =
CalculateSortedRuns(*vstorage, ioptions_);
if (sorted_runs.size() <
(unsigned int)mutable_cf_options.level0_file_num_compaction_trigger) {
if (sorted_runs.size() == 0 ||
sorted_runs.size() <
(unsigned int)mutable_cf_options.level0_file_num_compaction_trigger) {
LogToBuffer(log_buffer, "[%s] Universal: nothing to do\n", cf_name.c_str());
return nullptr;
}

38
db/db_universal_compaction_test.cc
View File

@ -112,6 +112,44 @@ class DelayFilterFactory : public CompactionFilterFactory {
};
} // namespace
// Make sure we don't trigger a problem if the trigger conditon is given
// to be 0, which is invalid.
TEST_P(DBTestUniversalCompaction, UniversalCompactionSingleSortedRun) {
Options options;
options = CurrentOptions(options);
options.compaction_style = kCompactionStyleUniversal;
options.num_levels = num_levels_;
// Config universal compaction to always compact to one single sorted run.
options.level0_file_num_compaction_trigger = 0;
options.compaction_options_universal.size_ratio = 10;
options.compaction_options_universal.min_merge_width = 2;
options.compaction_options_universal.max_size_amplification_percent = 1;
options.write_buffer_size = 105 << 10; // 105KB
options.arena_block_size = 4 << 10;
options.target_file_size_base = 32 << 10; // 32KB
// trigger compaction if there are >= 4 files
KeepFilterFactory* filter = new KeepFilterFactory(true);
filter->expect_manual_compaction_.store(false);
options.compaction_filter_factory.reset(filter);
DestroyAndReopen(options);
ASSERT_EQ(1, db_->GetOptions().level0_file_num_compaction_trigger);
Random rnd(301);
int key_idx = 0;
filter->expect_full_compaction_.store(true);
for (int num = 0; num < 16; num++) {
// Write 100KB file. And immediately it should be compacted to one file.
GenerateNewFile(&rnd, &key_idx);
dbfull()->TEST_WaitForCompact();
ASSERT_EQ(NumSortedRuns(0), 1);
}
}
// TODO(kailiu) The tests on UniversalCompaction has some issues:
// 1. A lot of magic numbers ("11" or "12").
// 2. Made assumption on the memtable flush conditions, which may change from