How to Restore Oracle Database using RMAN (with Examples) As a Linux sysadmin, you might recover a system from backup, which may include Oracle Database. So, it is essential for all admins to understand how to restore oracle database from backup. Typically,...
Tuning Tools We all know auto tracle and explain plan. Lets see the uncommon 10g auto tools: ADDM, Auto stats collection, Sql Tuning Advisor. AWR collects, processes and maintains performace stats for problem dedection and self tuning. SGA_TARGET - for...
Explain Plan: Execution Paths and Hints USE_MERGE - two inputs are seperately sorted and merged. No sort is required if the table has indexes. waits until both the sorts are performed. Good when NO INDEXES are in the tables. When both are almost equal...
SQL Tuning Tips Avoid un-necessary sorts - use union all, use compute stats while creating index. Hint when needed. Avoid Cartesian products Avoid full table scans on large tables Avoid joining too many tables Use SQL standards and conventions to reduce...
Database Tuning Tips Do as little as possible - Focus on simplyfing the processes instead of achiving a theoretical design perfection. Avoid multiple IO to the database - bundle queries to a procedure and call thay in ur app. again in procedures reduce...
Top Ten Mistakes Found in Oracle Systems 1. Bad Connection Management 2. Bad Use of Cursors and the Shared Pool 3. Bad SQL 4. Use of Nonstandard Initialization Parameters 5. Getting Database I/O Wrong 6. Redo Log Setup Problems 7. Serialization of data...
COLLECTION_IS_NULL you try to operate on an atomically null collection. NO_DATA_FOUND a subscript designates an element that was deleted, or a nonexistent element of an associative array. SUBSCRIPT_BEYOND_COUNT a subscript exceeds the number of elements...
RAISE_APPLICATION_ERROR? The RAISE_APPLICATION_ERROR is a procedure defined by Oracle that allows the developer to raise an exception and associate an error number and message with the procedure other than just Oracle errors. Raising an Application Error...
What is the purpose of FOR UPDATE? Selecting in FOR UPDATE mode locks the result set of rows in update mode, which means that row cannot be updated or deleted until a commit or rollback is issued which will release the row(s). If you plan on updating...
CHAR datatype Char contain alphanumeric data. Length of Char datatype is between 1 and 255 characters. If you don't specify a length, a char column stores a single character by default. Char datatypes stores data in the Fixed-Length Format. Be aware,...
