For best performance, avoid filters for certain difficult
regular expressions and filters for noninitial strings.
Avoid difficult regular expressions
The MATCHES and LIKE keywords support wildcard matches,
which are technically known as regular expressions. Some regular
expressions are more difficult than others for the database server
to process.
Avoid noninitial substrings
For best performance, avoid filters for noninitial strings.
A filter based on a noninitial substring of a column requires the
database server to test every value in the column.