50-60% is WordPress’ share of the global CMS market – making it the most popular CMS of them all. 
New York Observer, New York Post, TED, Thought Catalog, Williams, USA Today, CNN, Fortune.com, TIME.com, National Post, Spotify, TechCrunch, CBS Local, NBC all use WordPress. 
17 posts are published every second on WordPress sites around the world. 
37 million global Google searches for “WordPress” are made per month. 
Around 15,886,000 websites on the entire web use WordPress. 
8% of the top 100 blogs according to Technorati are managed with WordPress. 
2,645 of the top 10k websites on the web use WordPress. 
22,111 of the top 100k websites use WordPress. 
297,629 of the top 1M websites use WordPress. 
In 2014, non-English WordPress downloads surpassed English downloads for the first time. 22% of new domains in the US are run with WordPress. WordPress as a CMS (47%) is nearly 12 times more popular than Drupal (4%) in India.
The Schema Plays an important role in tuning joins
Choose data types for all primary and unique keys carefully, and remain consistent through out the schema
If you primary key column is varchar2(100), such a primary key is expensive because the large key must be carried in every referencing table, and also because Oracle bust compare long strings when performing a join
Create Index where necessary and if possible try to create indexes on multiple columns
Normalize your tables , so that there is not a lot of redundancy
Put necessary constraints on the table so that you have the right data.
Statistics are used by the optimizer to come up with a good execution plan
Sometimes optimizer statistics might be stale or missing
The statistics may not always be accurate because the size of the table might have changed from a few 100k rows to a few million rows. There fore statistics should be periodically collected and be made as part of the database maintenance routines.