4 Commits (e110d713e0f0880e5621e6875c60e9c9c0239480)

Author	SHA1	Message	Date
Hui Xiao	5fc57eec2b	Support parallel read and write/delete to same key in NonBatchedOpsStressTest (#11058) ... Summary: **Context:** Current `NonBatchedOpsStressTest` does not allow multi-thread read (i.e, Get, Iterator) and write (i.e, Put, Merge) or delete to the same key. Every read or write/delete operation will acquire lock (`GetLocksForKeyRange`) on the target key to gain exclusive access to it. This does not align with RocksDB's nature of allowing multi-thread read and write/delete to the same key, that is concurrent threads can issue read/write/delete to RocksDB without external locking. Therefore this is a gap in our testing coverage. To close the gap, biggest challenge remains in verifying db value against expected state in presence of parallel read and write/delete. The challenge is due to read/write/delete to the db and read/write to expected state is not within one atomic operation. Therefore we may not know the exact expected state of a certain db read, as by the time we read the expected state for that db read, another write to expected state for another db write to the same key might have changed the expected state. **Summary:** Credited to ajkr's idea, we now solve this challenge by breaking the 32-bits expected value of a key into different parts that can be read and write to in parallel. Basically we divide the 32-bits expected value into `value_base` (corresponding to the previous whole 32 bits but now with some shrinking in the value base range we allow), `pending_write` (i.e, whether there is an ongoing concurrent write), `del_counter` (i.e, number of times a value has been deleted, analogous to value_base for write), `pending_delete` (similar to pending_write) and `deleted` (i.e whether a key is deleted). Also, we need to use incremental `value_base` instead of random value base as before because we want to control the range of value base a correct db read result can possibly be in presence of parallel read and write. In that way, we can verify the correctness of the read against expected state more easily. This is at the cost of reducing the randomness of the value generated in NonBatchedOpsStressTest we are willing to accept. (For detailed algorithm of how to use these parts to infer expected state of a key, see the PR) Misc: hide value_base detail from callers of ExpectedState by abstracting related logics into ExpectedValue class Pull Request resolved: https://github.com/facebook/rocksdb/pull/11058 Test Plan: - Manual test of small number of keys (i.e, high chances of parallel read and write/delete to same key) with equally distributed read/write/deleted for 30 min ``` python3 tools/db_crashtest.py --simple {blackbox|whitebox} --sync_fault_injection=1 --skip_verifydb=0 --continuous_verification_interval=1000 --clear_column_family_one_in=0 --max_key=10 --column_families=1 --threads=32 --readpercent=25 --writepercent=25 --nooverwritepercent=0 --iterpercent=25 --verify_iterator_with_expected_state_one_in=1 --num_iterations=5 --delpercent=15 --delrangepercent=10 --range_deletion_width=5 --use_merge={0|1} --use_put_entity_one_in=0 --use_txn=0 --verify_before_write=0 --user_timestamp_size=0 --compact_files_one_in=1000 --compact_range_one_in=1000 --flush_one_in=1000 --get_property_one_in=1000 --ingest_external_file_one_in=100 --backup_one_in=100 --checkpoint_one_in=100 --approximate_size_one_in=0 --acquire_snapshot_one_in=100 --use_multiget=0 --prefixpercent=0 --get_live_files_one_in=1000 --manual_wal_flush_one_in=1000 --pause_background_one_in=1000 --target_file_size_base=524288 --write_buffer_size=524288 --verify_checksum_one_in=1000 --verify_db_one_in=1000 ``` - Rehearsal stress test for normal parameter and aggressive parameter to see if such change can find what existing stress test can find (i.e, no regression in testing capability) - [Ongoing]Try to find new bugs with this change that are not found by current NonBatchedOpsStressTest with no parallel read and write/delete to same key Reviewed By: ajkr Differential Revision: D42257258 Pulled By: hx235 fbshipit-source-id: e6fdc18f1fad3753e5ac91731483a644d9b5b6eb	2 years ago
Andrew Kryczka	c9818b3325	db_stress verify with lost unsynced operations (#8966) ... Summary: When a previous run left behind historical state/trace files (implying it was run with --sync_fault_injection set), this PR uses them to restore the expected state according to the DB's recovered sequence number. That way, a tail of latest unsynced operations are permitted to be dropped, as is the case when data in page cache or certain `Env`s is lost. The point of the verification in this scenario is just to ensure there is no hole in the recovered data. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8966 Test Plan: - ran it a while, made sure it is restoring expected values using the historical state/trace files: ``` $ rm -rf ./tmp-db/ ./exp/ && mkdir -p ./tmp-db/ ./exp/ && while ./db_stress -compression_type=none -clear_column_family_one_in=0 -expected_values_dir=./exp -sync_fault_injection=1 -destroy_db_initially=0 -db=./tmp-db -max_key=1000000 -ops_per_thread=10000 -reopen=0 -threads=32 ; do : ; done ``` Reviewed By: pdillinger Differential Revision: D31219445 Pulled By: ajkr fbshipit-source-id: f0e1d51fe5b35465b00565c33331190ea38ba0ad	3 years ago
Andrew Kryczka	a6a6aad74e	db_stress support tracking historical values (#8960) ... Summary: When `--sync_fault_injection` is set, this PR takes a snapshot of the expected values and starts an operation trace when the DB is opened. These files are stored in `--expected_values_dir`. They will be used for recovering the expected state of the DB following a crash where a suffix of unsynced operations are allowed to be lost. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8960 Test Plan: injected crashed at various points in `FileExpectedStateManager` and verified the next run recovers the state/trace file with highest seqno and removes all older/temporary files. Note we don't use sync_fault_injection in CI crash tests yet. Reviewed By: pdillinger Differential Revision: D31194941 Pulled By: ajkr fbshipit-source-id: b0f935a529a0186c5a9c7709fcaa8829de8a84cf	3 years ago
Andrew Kryczka	559943cdc0	Refactor expected state in stress/crash test (#8913) ... Summary: This is a precursor refactoring to enable an upcoming feature: persistence failure correctness testing. - Changed `--expected_values_path` to `--expected_values_dir` and migrated "db_crashtest.py" to use the new flag. For persistence failure correctness testing there are multiple possible correct states since unsynced data is allowed to be dropped. Making it possible to restore all these possible correct states will eventually involve files containing snapshots of expected values and DB trace files. - The expected values directory is managed by an `ExpectedStateManager` instance. Managing expected state files is separated out of `SharedState` to prevent `SharedState` from becoming too complex when the new files and features (snapshotting, tracing, and restoring) are introduced. - Migrated expected values file access/management out of `SharedState` into a separate class called `ExpectedState`. This is not exposed directly to the test but rather the `ExpectedState` for the latest values file is accessed via a pass-through API on `ExpectedStateManager`. This forces the test to always access the single latest `ExpectedState`. - Changed the initialization of the latest expected values file to use a tempfile followed by rename, and also add cleanup logic for possible stranded tempfiles. Pull Request resolved: https://github.com/facebook/rocksdb/pull/8913 Test Plan: run in several ways; try to make sure it's not obviously broken. - crashtest blackbox without TEST_TMPDIR ``` $ python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --duration=120 --interval=10 --compression_type=none --blob_compression_type=none ``` - crashtest blackbox with TEST_TMPDIR ``` $ TEST_TMPDIR=/dev/shm python3 tools/db_crashtest.py blackbox --simple --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --duration=120 --interval=10 --compression_type=none --blob_compression_type=none ``` - crashtest whitebox with TEST_TMPDIR ``` $ TEST_TMPDIR=/dev/shm python3 tools/db_crashtest.py whitebox --simple --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --duration=120 --interval=10 --compression_type=none --blob_compression_type=none --random_kill_odd=88887 ``` - db_stress without expected_values_dir ``` $ ./db_stress --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --ops_per_thread=10000 --clear_column_family_one_in=0 --destroy_db_initially=true ``` - db_stress with expected_values_dir and manual corruption ``` $ ./db_stress --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --ops_per_thread=10000 --clear_column_family_one_in=0 --destroy_db_initially=true --expected_values_dir=./ // modify one byte in "./LATEST.state" $ ./db_stress --write_buffer_size=1048576 --target_file_size_base=1048576 --max_bytes_for_level_base=4194304 --max_key=100000 --value_size_mult=33 --compression_type=none --ops_per_thread=10000 --clear_column_family_one_in=0 --destroy_db_initially=false --expected_values_dir=./ ... Verification failed for column family 0 key 0000000000000000 (0): Value not found: NotFound: ... ``` Reviewed By: riversand963 Differential Revision: D30921951 Pulled By: ajkr fbshipit-source-id: babfe218062e55d018c9b046536c0289fb78f41c	3 years ago