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The PERFORMANCE_SCHEMA insists on distinguishing read-update-write locks from read-write locks, so we must add template<bool support_u_lock> in rd_lock() and wr_lock() operations. rd_lock::read_trylock(): Add template<bool prioritize_updater=false> which is used by the srw_lock_low::read_lock() loop. As long as an UPDATE lock has already been granted to some thread, we will grant subsequent READ lock requests even if a waiting WRITE lock request exists. This will be necessary to be compatible with existing usage pattern of InnoDB rw_lock_t where the holder of SX-latch (which we will rename to UPDATE latch) may acquire an additional S-latch on the same object. For normal read-write locks without update operations this should make no difference at all, because the rw_lock::UPDATER flag would never be set. |
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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 | ||