Observations About the Scalability of Data Loads in Snowflake
In the last weeks, I was running a number of tests based on the TPC-DS benchmark against Snowflake. One of the first thing I did is of course to create the TPC-DS schema and populate it. The aim of this blog post is to share…
AWR: Multitenant-Specific Initialization Parameters
By default, the database engine automatically takes snapshots in the root container only. Such snapshots cover the root container as well as all open PDBs belonging to it. From version 12.2 onward, you can control whether the database engine automatically takes also PDB-level snapshots through…
AWR Flush Levels
From version 12.1.0.2 onward, for taking AWR snapshots, you have the choice between four AWR flush levels: BESTFIT, LITE, TYPICAL and ALL. If you check the Oracle Database documentation, you won’t find much information about the difference between them. The best you will find, in…
MIN/MAX Optimization and Asynchronous Global Index Maintenance
In this short post I would like to point out a non-obvious issue that one of my customers recently hit. On the one hand, it’s a typical case where the query optimizer generates a different (suboptimal) execution plan even though nothing relevant (of course, at…
V$SQL_CS_HISTOGRAMS: What Are the Buckets’ Thresholds?
The contents of the V$SQL_CS_HISTOGRAM view is used by the SQL engine to decide when a cursor is made bind aware, and therefore, when it should use adaptive cursor sharing. For each child cursor, the view shows three buckets. It is of general knowledge that…
Observations About the Scalability of Data Loads in ADWC
In the last days, I am running a number of tests based on the TPC-DS benchmark against Oracle’s Autonomous Data Warehouse Cloud service (ADWC). One of the first thing I did is of course to create the TPC-DS schema and populate it. The aim of…
Which Privileges Are Required to Use the ADWC Service Console?
The Autonomous Data Warehouse Cloud (ADWC) service provides a Service Console that can be used to monitor the service activity and to carry out a small number of administration tasks (e.g. changing some resource management rules). The documentation specifically says to use the ADMIN user…
DBMS_CLOUD Package – A Reference Guide
The Appendix A of the Using Oracle Autonomous Data Warehouse Cloud guide describes the DBMS_CLOUD package. Unfortunately, it documents only a subset of the subroutines. And, for some of them, the description could also be enhanced. Therefore, while I was testing all the subroutines the…
Partition-Wise Operations – New Features in 12c and 18c
Partition-wise operations are not something new. I do not remember when they were introduced, but at that time the release number was still a single digit. Anyway, the aim of this post is not to describe the basics, but only to describe what is new…
TKPROF’s Argument PDBTRACE
If you run TKPROF without arguments, you get a complete list of its arguments with a short description for each of them (here the output generated by version 18.1.0): $ tkprof Usage: tkprof tracefile outputfile [explain= ] [table= ] [print= ] [insert= ] [sys= ]…
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