In Part 1 of the series, we covered in detail how the PQ_DISTRIBUTE can change the data distribution method across parallel query workers and the importance of avoiding BUFFERED hash joins. Through the remaining parts of the series, I showed…Read More >
Welcome to Part 6 of the series. The USE_PARTITION_WISE_GBY hint is “brand new,” introduced in 12.2. I personally welcome this hint as I’ve cursed many times in the past due to the lack of control for this aspect of parallelism…Read More >
Welcome to Part 5 of the series. First, some background: if you want to skip to the reference part, scroll down. This hint was introduced relatively recently – in Oracle 12.1 – where for the first time, SQL Windowing functions are…Read More >
Welcome to Part 4 of the series. The GBY_PUSHDOWN is a very interesting hint, introduced in 10.2 – it doesn’t have the PQ prefix, but nevertheless plays a crucial role in Parallel query plans. Purpose: When GBY_PUSHDOWN is activated, an…Read More >
In part one of this series on Oracle Parallel Query Hints, I looked at PQ_DISTRIBUTE, and part two was about PQ_Replicate. Now, for the third part in the series, I will take a look at PX_JOIN>FILTER. The PX_JOIN_FILTER is a…Read More >
In Part 1 of this series, we talked about the basic mechanics of the PQ_DISTRIBUTE hint. I did mention the PQ_REPLICATE, and here are all of the details. Oracle Database 12.2, has added a new feature that allows PQ processes…Read More >
One of the most powerful features of the Oracle database is its ability to leverage multiple cores spread across many RAC servers to execute a single query. Oracle’s optimizer tries its best to execute queries in the most efficient manner,…Read More >
Very often when reading data, we need to locate the most current record for a set of conditions. One typical example is that we read the data to find the most recent order for a particular customer. In this simple…Read More >
Christo Kutrovsky, ATCG Principal Consultant and Oracle ACE at Pythian, shares something useful he discovered by accident when playing with Auto DOP.Read More >
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