…On-Time about USA domestic flights with information about flight length and delays. The data is available from 1988 to 2009 in…with ICE version is very limited and I had to transform files to quote each field. After that load statement is: …if you want to compare or get info about air performance.
Post: INSERT ON DUPLICATE KEY UPDATE and summary counters.
May 29, 2006 By 48 Comments
…_aton and inet_ntoa functions which can convert IP address strings to integers and back. This allows to save on field length significantly by using 4 bytes instead of 15 The third feature this example takes advantage of is TIMESTAMP field. By…, depending on number of new rows and data set size. 30% speedup should be typical. Performance increase is not the only benefit…
Post: PROCEDURE ANALYSE
March 23, 2009 By 9 Comments
… ? These and similar tasks are often done by bunch of SQL queries while really MySQL has a native feature to perform this… NULL *************************** 3. row *************************** Field_name: percona_drupal.node.type Min_value: blog Max_value: webform Min_length: 4 Max_length: 13 Empties_or… – maximum length of data actually stored often can tell us if we defined varchar field too wide. Comparing maximum field length to average length we…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…length is rather short for such hack as BIGINT itself is 8 bytes and the difference in the index length…# and 2 additional fields for vendor_id and order…performance loss because of having too many indexes. Q: Is there a difference between “`id` = 5″ and “`id` IN (5)” regarding indexes and performance…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… the usage and performance of the splitter. It is multi-threaded(actually multi-process) and is able…Compact Rows: 6697533 Avg_row_length: 241 Data_length: 1616904192 Max_data_length: 0 Index_length: 539279360 Data_free:… the EC2 console. That the “private ip” field is selected in the list of columns …
Post: Picking datatype for STATUS fields
August 9, 2008 By 24 Comments
… to change allowed values for such field anyway. For status fields with more than two values …performance are you going to lose? This depends on number of rows as well as their average length… allows to save on the storage and get extra performance without application modification. ENUM takes just …
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… option and variable reference… max_length_for…Performance_schema_mutex_classes_lostblogpercona.commanual Performance_schema_mutex_instances_lostblogpercona.commanual Performance_schema_rwlock_classes_lostblogpercona.commanual Performance_schema_rwlock_instances_lostblogpercona.commanual Performance…
Post: What exactly is read_rnd_buffer_size
July 24, 2007 By 4 Comments
… sort is performed it can be performed having only row pointers together with key value – which are offsets for MyISAM and primary key… for small data lengths). In case sort with row pointer storage is used and the fields which are being length can be converted to… you retrieve few fields (less than max_length_for_sort_data) data should be stored in sort buffer and sort file so there…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…performance counters, statistics, information about transaction processing and all kinds of other things. In MySQL 5 number of Innodb performance counters were exported and…n:o < 0 0 History list length 6 Total number of lock… insert buffer merge. Values for “state” field are rather self explanatory. …
Post: Dynamic row format for MEMORY tables
September 6, 2011 By 5 Comments
…non-key variable-length columns. For performance reasons, the key columns are stored in a fixed-length block …: 10069048 kB Here we can see that the performance and memory usage is about the same for …row format delivers the memory savings for VARCHAR fields agains the fixed row format. For that …
