mirror of https://github.com/facebook/rocksdb.git
d13825e586
Summary:
This PR does not affect write-committed.
Add a member, `rollback_deletion_type_callback` to TransactionDBOptions
so that a write-prepared transaction, when rolling back, can call this
callback to decide if a `Delete` or `SingleDelete` should be used to
cancel a prior `Put` written to the database during prepare phase.
The purpose of this PR is to prevent mixing `Delete` and `SingleDelete`
for the same key, causing undefined behaviors. Without this PR, the
following can happen:
```
// The application always issues SingleDelete when deleting keys.
txn1->Put('a');
txn1->Prepare(); // writes to memtable and potentially gets flushed/compacted to Lmax
txn1->Rollback(); // inserts DELETE('a')
txn2->Put('a');
txn2->Commit(); // writes to memtable and potentially gets flushed/compacted
```
In the database, we may have
```
L0: [PUT('a', s=100)]
L1: [DELETE('a', s=90)]
Lmax: [PUT('a', s=0)]
```
If a compaction compacts L0 and L1, then we have
```
L1: [PUT('a', s=100)]
Lmax: [PUT('a', s=0)]
```
If a future transaction issues a SingleDelete, we have
```
L0: [SD('a', s=110)]
L1: [PUT('a', s=100)]
Lmax: [PUT('a', s=0)]
```
Then, a compaction including L0, L1 and Lmax leads to
```
Lmax: [PUT('a', s=0)]
```
which is incorrect.
Similar bugs reported and addressed in
https://github.com/cockroachdb/pebble/issues/1255. Based on our team's
current priority, we have decided to take this approach for now. We may
come back and revisit in the future.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/9873
Test Plan: make check
Reviewed By: ltamasi
Differential Revision: D35762170
Pulled By: riversand963
fbshipit-source-id: b28d56eefc786b53c9844b9ef4a7807acdd82c8d
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|---|---|---|
| .. | ||
| agg_merge | ||
| backup | ||
| blob_db | ||
| cassandra | ||
| checkpoint | ||
| compaction_filters | ||
| convenience | ||
| leveldb_options | ||
| memory | ||
| merge_operators | ||
| option_change_migration | ||
| options | ||
| persistent_cache | ||
| simulator_cache | ||
| table_properties_collectors | ||
| trace | ||
| transactions | ||
| ttl | ||
| write_batch_with_index | ||
| cache_dump_load.cc | ||
| cache_dump_load_impl.cc | ||
| cache_dump_load_impl.h | ||
| compaction_filters.cc | ||
| counted_fs.cc | ||
| counted_fs.h | ||
| debug.cc | ||
| env_mirror.cc | ||
| env_mirror_test.cc | ||
| env_timed.cc | ||
| env_timed.h | ||
| env_timed_test.cc | ||
| fault_injection_env.cc | ||
| fault_injection_env.h | ||
| fault_injection_fs.cc | ||
| fault_injection_fs.h | ||
| fault_injection_secondary_cache.cc | ||
| fault_injection_secondary_cache.h | ||
| memory_allocators.h | ||
| merge_operators.cc | ||
| merge_operators.h | ||
| object_registry.cc | ||
| object_registry_test.cc | ||
| util_merge_operators_test.cc | ||
| wal_filter.cc | ||