• Oracle

    Oracle Memory Tuning-18

    Memory Tuning Shared pool (LC, DDC) Database buffer cache (Default, Keep & Recycle) Redo buffer cache Library cache: To find out the issue we can use the following methods. V$librarycache , AWR & OEM V$librarycache Columns: Namespace – Object Name Gets – No. of parsing Gethistratio – Ratio of Phrasing Pins – No.of execution plan Pinhistratio – Ratio of execution plan Reloads – No. of rephrasing Invalidation – No. of rephrasing for DDL alter table, Column invalidation. Formula: Sql> select gethistratio100, pinhitration100 from v$librarycache; 90% – Good <90% – Problem on LB. OR Sql> select [sum(reloads)/sum(pins)] from v$librarycache; <5% – Good 5% – Problem on LB. Data Dictionary cache V$rowcache,…