Author: Christo Kutrovsky

Oracle Parallel Query Hints Reference – Part 7: PQ_DISTRIBUTE and Partitioned Tables

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 >

Oracle Parallel Query Hints Reference – Part 6: USE_PARTITION_WISE_GBY

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 >

Oracle Parallel Query Hints Reference – Part 5: PQ_DISTRIBUTE_WINDOW

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 >

Oracle Parallel Query Hints Reference – Part 4: GBY_PUSHDOWN

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 >

Oracle Parallel Query Hints – Part 3: PX_JOIN_FILTER

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 >

Oracle Parallel Query Hints. A reference series Part 2: PQ_REPLICATE

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 >

Oracle Parallel Query Hints – Part 1: PQ_DISTRIBUTE

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 >

Locating Most Current Record using ROW_NUMBER() vs. Index Full Scan (Min/Max)

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 >

Oracle’s CREATE INDEX command can take a hint

Christo Kutrovsky, ATCG Principal Consultant and Oracle ACE at Pythian, shares something useful he discovered by accident when playing with Auto DOP.

Read More >

Hybrid Databases: Key to Your Success

Christo Kutrovsky, ATCG Principal Consultant and Oracle ACE at Pythian, discusses the importance of hybrid databases, their challenges, and choosing the right database solution for your organization.

Read More >
Page 1 of 812345...Last Page »