…condition: USING (order_id) mview_join_order: 999 3 rows in set (0.00 sec) Using the dictionary The following SQL…SQL statement, similar to a regular view. If you choose to use only the complete refresh method, then FlexCDC is not required to use Flexviews. In…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
…to show how to count the number of unique words, an how many times those words appear in…to use the words of the Constitution of the United States of America as an example. It is my favourite document in…to the where clause. This creates boundary conditions… version: — SQL TO SEND TO SHARDS: Array ( …
Post: MySQL 5.6.10 Optimizer Limitations: Index Condition Pushdown
March 14, 2013 By 2 Comments
…, in order to understand it I must provide you with more background information. My buffer pool was big enough to…: Using index condition 1 row in set (0.00 sec) With ICP, the actual number of rows read at SQL…you to join me at the webinar I have prepared for this Friday, March 15: “Learn How MySQL…
Post: The two even more fundamental performance metrics
May 5, 2011 By 6 Comments
…how to maintain cheaply in the previous post. Here are some things we can do: Plot the data as time-series or in…conditions are true. Analyze the distribution of completion times. This is extremely useful… #2 in my numbered …SQL in hand, we might be able to answer questions about what’s happening in…
Post: Four ways to optimize paginated displays
September 24, 2008 By 27 Comments
…use an index (commonly the case), it uses a filesort. Suppose there are a million rows that meet any WHERE conditions…to show the list of pages and the total count, you either a) use SQL…in the same way doesn’t mean you need to. Think about how you use such pages. Do you really go clicking directly to…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…in the hash table by using values of the columns participating in the equijoin condition. The hash table is accessed by using…in memory to a large table with no WHERE clause The SQL used…used by setting appropriate values of “join_cache_level”. For example in my test I forced the optimizer to use…
Post: Tools and Techniques for Index Design Webinar Questions Followup
October 4, 2012 By 5 Comments
…how to register to attend. During my webinar, I got a number of good questions. Here are the questions (paraphrased), with my…use indexes, such as: Index merge improvements. But I expect that defining the right compound index will still be superior. Index condition…
Comment: Linux schedulers in tpcc like benchmark
January 31, 2009 By 19 Comments
…in those conditions, user’s perceived performances may be more reflected by per-request time to…to happen?) neither how well do the different I/O elevators handles those features. And to the best of my knowledge, SQL…
Post: Debugging problems with row based replication
May 6, 2010 By 12 Comments
…SQL…in particular that the server is trying to find is c1=1, but how…conditions under which replication went out of sync? To determine exactly what row is having an issue, we can use the ‘mysqlbinlog’ utility in…
