They have all different sizes but how about performance issue between each other ? How can we compare them in sql ?
They have all different sizes but how about performance issue between each other ?
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They have all different sizes but how about performance issue between each other ? How can we compare them in sql ?
It depends on the db vendor’s implementation of I/O.
Edited (“32 bits” changed to “8 bits”)
Many DBs never use anything less than an 8-bit byte to write to disk. For example, the postgres doco states that its
booleandatatype actually takes 1 byte when stored on disk (not 1 bit). All postgres types use a whole number of bytes.Space on disk is even more important when the field is indexed. Less space means more index entries per I/O page. The less I/O the faster the query – recalling that I/O is roughly 1000 times slower than in-memory work.