Un punto unico de encuentro para compartir el conocimiento sobre bases de datos.


Who is using your UNDO space?

Sure you've faced this situation: a growing undo tablespace, that seems it could engulf your entire disk space... until finally stops demanding additional space, and within some minutes (or hours, depends on your UNDO_RETENTION setting) you start to see more and more free space in your tablespace. If you scratched your head wondering 'what happened?' or 'who the User did this?', this post may be helpful.

Cariño, encogi los indices - Parte 2

Como escoger a los candidatos perfectos

Cuidado: la compresión de los indices puede afectar adversamente los planes de ejecución y degradar el performance, le recomendamos que efectue estas pruebas en un ambiente de replica o pruebas, y verifique el comportamiento de las consultas SQL y el código PL/SQL.

No todos los indices pueden ser comprimidos, pues algunas veces la reduccion de espacio obtenida al comprimirlos no amerita el trabajo extra que implican los procesos de compresion/descompresion. Pero ¿Como sabemos eso por anticipado?

Permitanme sugerirles dos aproximaciones al tema:
1) Orientado al tamaño
2) Orientado a la frecuencia de acceso

Honey, I shrunk the indexes - Part 2

How to pick the perfect candidates

Warning: index compression may change execution plans and affect performance, try this on a test database and check if application SQL and PL/SQL code execution improves.

Not every index must be compressed, sometimes compression will give minimal space reductions, that don't compensate the overhead incurred. But how do we know that?

I may suggest two approaches:
1) Size oriented
2) Access frequency oriented

Oracle Wait Interface-Introduction

Sure you remember the Star Wars zaga ... and Obi-wan-kenobi as the first 'Force'-instructor of Luke. Well, my point here is how to use the Force with Oracle Server... with OWI or Oracle Wait Interface as its long name stands.

Guia de 2 minutos para instalar Statspack

Statspack es una herramienta de oracle que es al mismo tiempo poderosa y subutilizada, a pesar de ser el primer recurso de analisis del que se puede disponer por estar incluido en el paquete de instalacion (es gratis!).

2 Minute guide to Statspack install

Statspack is an Oracle database tool that is both powerful and underused, it's the first reporting resource you have (it's free, comes in the box) to see what is happening in your DB at a glance.



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