… Join to join two or more tables. What this means is that, select rows from first table participating… other optimizations like for example if columns other then the secondary key columns are required to be … either for MariaDB or MySQL, but you need to appropriately increase read_rnd_buffer_size/mrr…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…being fetched do not belong to the secondary index definition (and hence covering index optimization is not used), then primary key lookups have to be…be needed, however if the buffer size is small as compared to…to be performed. As in the table…
Post: MariaDB 5.3 is released as GA!
March 5, 2012 By 17 Comments
… present the results in an “optimizer standoff” talk at the upcoming…be helpful to you. So what‘s new and great in MariaDB as compared to… subqueries, and elimination of useless tables in joins Thread pooling …versions of MySQL that suit different needs and personalities, with different characteristics…
Post: Goal driven performance optimization
December 22, 2008 By Leave a Comment
… The log table should contain URL, IP and all the data you need to be able to repeat request if you need to. It may…in place all you have to do is to run the query to see what are contributing factors to the response time …MySQL server causing the problem or if application code needs to be optimized….
Post: ORDER BY ... LIMIT Performance Optimization
September 1, 2006 By 93 Comments
… cause of MySQL Performance problems. Here is what you need to know about ORDER BY … LIMIT optimization to avoid these problems ORDER BY with LIMIT… queries actually being run and data selectivity to come up with good set of indexes for such case, it also may need to be adjusted… try hard to have sorting column(s) to be in the leading table. If ORDER BY is going by field from the table which is…
Post: Missing Data - rows used to generate result set
July 20, 2008 By 15 Comments
…tables or if you have GROUP BY query the number of rows which need to be utilized to create the result set will be larger than number of rows returned. What I would like to…
Post: Database access Optimization in Web Applications.
September 12, 2006 By 10 Comments
…rows which need to be used to generate result set – if you have to join 10 tables to compose…need to be used to generate result sets Sometimes query needs to use many rows to provide result set just because schema is not optimally…maxes this query to use 10 rows to return 10 rows – exactly what we’re …
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
…great performance. What could be the reason ? The reason is normally table design and …disk bound workloads. There are certain optimizations in works which would improve performance…need to do the join. Some people assume join would be close to two full table scans (as 60mil of rows need to be…
Post: When to use Hardware upgrade instead of Software Optimization
December 5, 2008 By 5 Comments
…to be optimal and so they want to run it on some old box even if it costs them more to optimize it. It may be…to understand what needs to be done (gettings SSD, upgrading memory, upgrading CPUs). There are number of balancing questions you have to…
Post: Optimizing slow web pages with mk-query-digest
April 7, 2011 By 14 Comments
…QC Hit 78% yes, 21% no # Tmp table 2% yes, 97% no # Tmp table on 0% yes, 99% no # … in > out Now I know exactly what needs to be fixed first to make the greatest impact to this page response time. …but then even better than that would be if it would optimize the queries all together! Unfortunately …
