Hi, Sergey! On Nov 28, Sergey Vojtovich wrote:
> Eh, that's what I was afraid of. Not seeing elements that were added at about > the same time should always be acceptable. Can't it miss elements that were > in the list before iteration started (because it has moved to a different > location)? The latter is unacceptable in many cases. No, in this hash implementation elements are never moved in the list. It's prety difficult to move elements lock-free, that's why it wasn't easy to create a good performing lock-free hash. And this one works around this problem by not moving elements at all. > But let's see: > - print_cached_tables() - old debug stuff, remove it? > - I_S.OPEN_TABLES - seeing elements twice is not good, use PFS? Duplicates can be removed on the upper layer. Like, I_S data are inserted into a temp table anyway, so a UNIQUE key would solve the issue of duplicates. Or a Unique object. > - close_cached_tables() - seeing elements twice is not a problem. > - close_cached_connection_tables() - seeing elements twice is not a problem. > - tc_purge() - seeing elements twice is not a problem. > - tc_add_table() - seeing elements twice is not a problem. > - mdl_iterate() - seeing elements twice is not good, use PFS? mdl_iterate() - is it for metadata_lock_info plugin? Same answer then. > What about this: > sizeof(mysql_rwlock_t)= 64 (just rough estimation) > sizeof(pad[128 - sizeof(mysql_rwlock_t)])= 64 > > It gives: > > +---------------+---------------+-------------+---------------+---------------+ > | rw_lock_t 32b | rw_lock_t 32b | padding 64b | rw_lock_t 32b | rw_lock_t > 32b | > > +---------------+---------------+-------------+---------------+---------------+ > Cache line 128b | Cache line 128b |Cache line > 128b > > ----------------+---------------------------------------------+---------------- Okay, indeed. You're right. Regards, Sergei _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : maria-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
