… as in memory nature of MEMORY storage engine, clustering by Primary key in Innodb and distributed nature of NDB makes it more… file when all transaction engines have their own ! Quality Assurance Multiple storage engines are much more complicated to test. And I… enough. In fact people already do not love to mix multiple storage engines very actively because of potential complications involved. Now…
Post: Sharing an auto_increment value across multiple MySQL tables
October 4, 2010 By 9 Comments
… the insert_id: CREATE TABLE option1 (id int not null primary key auto_increment) engine=innodb; # each insert does one operations to… one just row: CREATE TABLE option2 (id int not null primary key) engine=innodb; INSERT INTO option2 VALUES (1); # start from 1…
Post: Concatenating MyISAM files
November 19, 2012 By 5 Comments
… are flat files, that should be faster, especially with the keys disabled. At that point, I remembered, from a previous disaster…. mysql> create table test_concat(id int unsigned not null, primary key (id)) engine=myisam; Query OK, 0 rows affected (0.01… sec) So, yes, you can concatenate MyISAM files, even when multiple keys are defined. Not for everyday use but still pretty cool…
Comment: Using UNION to implement loose index scan in MySQL
January 21, 2010 By 15 Comments
… with multiple key: table: Create table tabData ( channel_id Int NOT NULL, date_time Datetime NOT NULL, value Double NOT NULL, Primary Key (channel…
Comment: What to tune in MySQL Server after installation
October 4, 2006 By 118 Comments
Hey all, I am attempting multiple key_cache’s, it’s just a matter of determining which … the alternate cache. One thing I noticed is that the primary cache, when set to 4GB, usage never goes over 2GB… back to 1.8GB or so. After adding a second key_cache, I’ve notice it go past that 2GB mark…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
…do you assess current state of Innodb scalability with multiple threads and multiple concurrent transactions ? HT: The scalability in my opinion …foreign key not reference an entire primary key or unique constraint (something that is mandatory in every other RDBMS that suppors foreign key constraints…
Comment: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… index based on (in order) the primary key you specify (an auto_increment), a unique key, or one it creates for you. It… try to make InnoDB use a composite UNIQUE key on a table as a primary key taking up far more space than even… per host and archiving great performance by doing so. > Using multiple tables gives some very important benefits – your data > becomes managable…
Post: Falcon Storage Engine Design Review
January 12, 2007 By 19 Comments
… support Unlike Innodb Falcon does not cluster data by Primary Key or any other key. This is good for some applications bad for… its internal hidden primary key) but this functionality is not exported well as it requires you to get rid of primary keys etc. Some… it can be the problem – if transaction spawns multiple databases you need multiple log flushes on commit, plus ether you use XA…
Post: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 100 Comments
…stick to simple MySQL using multiple indexes on most selective … table | type | possible_keys | key | key_len | ref | rows | Extra | +—-+————-+——-+——-+—————+———+———+——-+——+————-+ | 1 | SIMPLE | test | const | PRIMARY,k | PRIMARY | 4 | const | 1 …
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… on it is greater than the join_buffer_size, then multiple hash tables would be created. For example if the left… NULL, PRIMARY KEY (`l_orderkey`,`l_linenumber`), KEY `i_l_shipdate` (`l_shipDATE`), KEY `i_l_suppkey_partkey` (`l_partkey`,`l_suppkey`), KEY `i_l… NULL, `o_comment` varchar(79) DEFAULT NULL, PRIMARY KEY (`o_orderkey`), KEY `i_o_orderdate` (`o_orderDATE`), KEY `i_o_custkey` (`o_custkey`) ) ENGINE…
