Oracle Performance Tuning Summary
A principle, the order noted in the where clause is connected
Prior to Oracle using bottom-up parsing where clause, according to this principle, the connection between the table where you must uninstall other conditions, which can filter out the maximum number of records of conditions must be written at the end where clause.
Principle II, in the select clause to avoid the use *
Use local index must be noted
1, avoid using NOT in the index
2, avoid the use of columns in the index calculation
3, avoid the use is null and is not null columns in the index
4, pay attention to the impact of the wildcard%
5, to avoid changing the type of index column
When comparing the character and value, Oracle will give priority to convert numeric type to character type
Related features and improve the performance of Oracle
index
Parallel execution
Hash clusters and clusters
Partition
Multi-threaded server
A plurality of data simultaneously read