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row_cache: Fix crash on memtable flush with LCS

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Presence checker is constructed and destroyed in the standard
allocator context, but the presence check was invoked in the LSA
context. If the presence checker allocates and caches some managed
objects, there will be alloc-dealloc mismatch.

That is the case with LeveledCompactionStrategy, which uses
incremental_selector.

Fix by invoking the presence check in the standard allocator context.

Fixes #4063.

Message-Id: <1547547700-16599-1-git-send-email-tgrabiec@scylladb.com>
(cherry picked from commit 32f711ce56)
This commit is contained in:
Tomasz Grabiec
2019-01-15 11:21:40 +01:00
committed by Avi Kivity
parent d427a23d42
commit 2d181da656
2 changed files with 43 additions and 1 deletions
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4
row_cache.cc
View File

@@ -1029,7 +1029,9 @@ future<> row_cache::update(external_updater eu, memtable& m) {
_tracker.on_partition_merge();
return entry.partition().apply_to_incomplete(*_schema, std::move(mem_e.partition()), *mem_e.schema(), _tracker.memtable_cleaner(),
alloc, _tracker.region(), _tracker, _underlying_phase, acc);
} else if (cache_i->continuous() || is_present(mem_e.key()) == partition_presence_checker_result::definitely_doesnt_exist) {
} else if (cache_i->continuous()
|| with_allocator(standard_allocator(), [&] { return is_present(mem_e.key()); })
== partition_presence_checker_result::definitely_doesnt_exist) {
// Partition is absent in underlying. First, insert a neutral partition entry.
cache_entry* entry = current_allocator().construct<cache_entry>(cache_entry::evictable_tag(),
_schema, dht::decorated_key(mem_e.key()),

40
tests/row_cache_test.cc
View File

@@ -688,6 +688,46 @@ SEASTAR_TEST_CASE(test_reading_from_random_partial_partition) {
});
}
SEASTAR_TEST_CASE(test_presence_checker_runs_under_right_allocator) {
return seastar::async([] {
cache_tracker tracker;
random_mutation_generator gen(random_mutation_generator::generate_counters::no);
memtable_snapshot_source underlying(gen.schema());
// Create a snapshot source whose presence checker allocates and stores a managed object.
// The presence checker may assume that it runs and is destroyed in the context
// of the standard allocator. If that isn't the case, there will be alloc-dealloc mismatch.
auto src = snapshot_source([&] {
auto ms = underlying();
return mutation_source([ms = std::move(ms)] (schema_ptr s,
const dht::partition_range& pr,
const query::partition_slice& slice,
const io_priority_class& pc,
tracing::trace_state_ptr tr,
streamed_mutation::forwarding fwd,
mutation_reader::forwarding mr_fwd,
reader_resource_tracker rrt) mutable {
return ms.make_reader(s, pr, slice, pc, std::move(tr), fwd, mr_fwd, std::move(rrt));
}, [] {
return [saved = managed_bytes()] (const dht::decorated_key& key) mutable {
// size large enough to defeat the small blob optimization
saved = managed_bytes(managed_bytes::initialized_later(), 1024);
return partition_presence_checker_result::maybe_exists;
};
});
});
row_cache cache(gen.schema(), std::move(src), tracker);
auto m1 = make_fully_continuous(gen());
auto mt = make_lw_shared<memtable>(gen.schema());
mt->apply(m1);
cache.update([&] { underlying.apply(m1); }, *mt).get();
});
}
SEASTAR_TEST_CASE(test_random_partition_population) {
return seastar::async([] {
cache_tracker tracker;