Oracle

Index on SUBSTR(string,1,n) – do you still need old index?

By Franck Pachot . In a previous post I’ve shown that from 12.1.0.2 when you have an index on trunc(date) you don’t need additional index. If you need the column with full precision, then you can add it(…)

Standard Edition on Oracle Database Appliance

By Franck Pachot . The Oracle Database Appliance is really interresting for small enterprises. It’s very good hardware for very good price. It’s capacity on demand licensing for Enteprise Edition. But small companies usually go to Standard Edition for(…)

12c: shutdown abort a PDB?

By Franck Pachot . Can we shutdown abort a PDB? Let’s try: SQL> show con_id CON_ID ------------------------------ 3SQL> shutdown abort; Pluggable Database closed. But is it really a shutdown abort? The shutdown abort we know in non-CDB – or(…)

Index on trunc(date) – do you still need old index?

By Franck Pachot . Sometimes we have to index on ( trunc(date) ) because a SQL statement uses predicate on it instead of giving a range from midnight to midnight. When you do that you probably keep the index(…)

Oracle compression, availability and licensing

By Franck Pachot . Various methods of table compression have been introduced at each release. Some require a specific storage system Some requires specific options. Some are only for static data. And it’s not always very clear for the(…)

Generic query for multicriteria search – part II: BIND_AWARE (Adaptive Cursor Sharing)

By Franck Pachot . In the previous post I explained the performance issue encountered when using a generic query to deal with optional search criteria on multiple columns. The statement was shared by all executions, was marked as(…)

Generic query for multicriteria search – part I: USE_CONCAT (OR Expansion)

By Franck Pachot . You have a multicriteria search screen on the EMPLOYEE table where you can enter an employee id, a department id, a manager id or a job id. Either you put the value you want to(…)

RAC Attack! next month 12c in Las Vegas

By Franck Pachot . RAC is the most complex installation you can have for an oracle database. A RAC DBA is involved not only on database, but storage, network, and system as well. It involves also(…)

Query the Enterprise Manager collected metrics

By Franck Pachot . Enterprise Manager (Cloud Control for example) gathers a lot of metrics. You can display them from the GUI, but you can also query the SYSMAN views directly. Today, I wanted to get the history of(…)

12c online statistics gathering and startup restrict

By Franck Pachot . I’ve written about 12c online statistics gathering in a UKOUG OracleScene article. My opinion is clear about it: you sill need to gather stale stats afterwards or you have mising, stale and inconsistent object(…)