Posted by peter |
…are quite related
to each other but how do they
compare in terms… quite
the same task in terms
of query optimization.
Derived
Tables … do not want
to join
two derived
tables for example).
One …v as select * from test;
Query OK, 0
rows affected (0.08 …
Posted by peter |
… cope with writes
to the same file position. That kind
of access is… are slower with Flash disks
compared to Reads because Flash requires “…GB
table!
If you have inserted in an ascending order
of the PRIMARY KEY, then InnoDB should have placed
the rows …
Posted by
peter @ 11:29 am ::
Innodb ::
Posted by peter |
…”. Spin locks are low cost wait,
compared to OS wait, it is however …too many threads competing
to enter innodb queue at
the same time Innodb makes … with hit rate
of 995/1000.
————–
ROW OPERATIONS
————–
0
queries inside InnoDB, 0…
Posted by
peter @ 12:18 am ::
Innodb ::
Posted by peter |
… B-tree node. We could not
compare a search key K…they were not matched by
query where clause when it was…However:
1. if
the total size
of the row is less…x? Is it possible
to get
the same benefit if you…form a single
table), it might make sense for a foreign…
Posted by peter |
… or it does quite well –
two main things stopping you is … multiple key caches for
the same table, for example caching even/…waiting on “efficient” Information Schema
Query Execution (as you may guess…10x
compared to using single shared key cache
of the same…
Posted by Alexey Kovyrin |
…4th variant which is not
comparable directly, which is using integer…zero cost
of the join, which we always claimed
to be…results are almost
the same, but join
query performance is 30…themselves – traversing about
same amount
of rows full
table scan performs…
Posted by Baron Schwartz |
… is at doing basically
the same thing
the subquery code does …id: 1
select_type: PRIMARY
table: ci
type: ALL
possible_keys:…
to the first
table shown above, but
the further
two rows…first
query! (If you think
of a better way
to compare…
Posted by peter |
…
row level locks for Innodb or
table locks for MyISAM and any DDL…000.000
rows you do not do it in
the same query but…runs in single thread (
two threads, but only one
of them executes
the… thread was busy processing events
compared to being idle. This would …
Posted by peter |
… such as building summary
tables, significant schema changes, use
of replication, caching, using …. If single user
CPU bound
query takes 30 seconds you unlikely will be … get 10x capacity
compared to naive implementation.
At
the same time one would …
Posted by peter |
…if there are a lot
of locks (
table/
row level locks) or other… is rather parallel (ie many
queries will run at once) and … outstanding requests a bit better
compared to requests coming one after …
the same – until you’re able
to explore parallel abilities
of …
del.icio.us
digg