Oracle

Oracle and Analytic Queries before In-Memory option

By Franck Pachot . Next Tuesday in Geneva I'm presenting Oracle In-Memory Column Store to Business Intelligence people at the Swiss BI Day After defining what is an analytic query, I show the different approaches to optimize that in(…)

Result Cache and 12c ‘fetch first n rows’

By Franck Pachot . At our bi-annual dbiXchange I was talking with Nicolas Jardot about his presentation on Result Cache (don't forget Jérome witt session about RC at DOAG) where he has shown an unexpected behavior on(…)

Query V$UNDOSTAT for relevant time window

By Franck Pachot . When you have a query failing in 'ORA-01555: snapshot too old: rollback segment number ... with name ... too small' you have two things to do: Convince the developer that the rollback segment is not too(…)

Nothing in feature usage statistics since 12c?

By Franck Pachot . It don't want to rub salt in the wound about 12c upgrades and Adaptive Dynamic Sampling being overzealous, but here is a case with an unexpected consequence: you see nothing in the 'Database Feature Usage' since(…)

Do you use SQL Plan Baselines?

By Franck Pachot . I can hear a lot of complaints about the instability coming from the adaptive features introduced into the optimizer logic at each release. Giving more intelligence to the optimizer is very good to improve the response(…)

You are in Standard Edition One? Don’t worry.

By Franck Pachot . You want the amazing features of Oracle SQL and PL/SQL with minimal cost. Your database is too large for Oracle XE edition, but not big enough to require the cost of Enterprise Edition. You accept to(…)

Invisible indexes: it’s online in 12c – even in Standard Edition

By Franck Pachot . Do you think that online operations are available only on Enterprise Edition? That changed in 12c, there is an operation that is online (without the need for the ONLINE keyword) and available in Standard Edition and(…)

Waiting for row lock. But which row is locked?

By Franck Pachot . When you are waiting on a locked row, the locked resource is the transaction that has locked the row. We have no information about which row is locked. Here is how to get it from V$SESSION.

DataBase Cloud Service performance – Network

By Franck Pachot . In previous posts, I've installed SLOB on the Cloud Services, measured IOPS and(…)

Windows 10 – I tried and came back

By Franck Pachot . I've tried Windows 10 one month ago, and I had to roll back because VirtualBox failed to create host-only interfaces. Today, it forced me to upgrade again, so I tried a little further... and finally rolled(…)