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c561f9e6e8
Many InnoDB rw-locks unnecessarily depend on the complex InnoDB rw_lock_t implementation that support the SX lock mode as well as recursive acquisition of X or SX locks. One of them is the bunch of adaptive hash index search latches, instrumented as btr_search_latch in PERFORMANCE_SCHEMA. Let us introduce a simpler lock for those in order to reduce overhead. srw_lock: A simple read-write lock that does not support recursion. On Microsoft Windows, this wraps SRWLOCK, only adding runtime overhead if PERFORMANCE_SCHEMA is enabled. On Linux (all architectures), this is implemented with std::atomic<uint32_t> and the futex system call. On other platforms, we will wrap mysql_rwlock_t with zero runtime overhead. The PERFORMANCE_SCHEMA instrumentation differs from InnoDB rw_lock_t in that we will only invoke PSI_RWLOCK_CALL(start_rwlock_wrwait) or PSI_RWLOCK_CALL(start_rwlock_rdwait) if there is an actual conflict. |
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| .. | ||
| archive | ||
| blackhole | ||
| columnstore | ||
| connect | ||
| csv | ||
| example | ||
| federated | ||
| federatedx | ||
| heap | ||
| innobase | ||
| maria | ||
| mroonga | ||
| myisam | ||
| myisammrg | ||
| oqgraph | ||
| perfschema | ||
| rocksdb | ||
| sequence | ||
| sphinx | ||
| spider | ||
| test_sql_discovery | ||