Wednesday, May 8, 2013 Oracle Events' Latency Visualization and Heat Maps in SQL*plus Topic: This post is about a technique for Oracle performance tuning, the use of heat maps to investigate wait event latency (and in particular I/O-related l... 続きを読む
The above is so cool. The graphic shows the latency heatmap of “log file sync”. I was running a swingbench load and at the same time throttling I/O such that latencies started off good then got worse and then back to normal. All I did was t... 続きを読む
Miscellaneous Random Oracle Topics: Stop, Think, … Understand February 19, 2010 (Forward to the Next Post in the Series) A question recently appeared on the OTN forums asking what %CPU means in an explain plan output. I did not see a clear ... 続きを読む
Miscellaneous Random Oracle Topics: Stop, Think, … Understand May 1, 2013 I saw a decent SQL brain teaser this morning in the comp.databases.oracle.server Usenet group. The OP in the message thread is attempting to summarize data in one of ... 続きを読む
Focusing Specifically On Oracle Indexes, Database Administration and Some Great Music Home Richard Foote Presentations & Demos Index Internals Seminar Public Appearances Recommendations Important !! Clustering Factor Calculation Improvement (... 続きを読む
When an Oracle process starts executing a query and needs to do a full segment scan, it needs to make a decision if it’s going to use ‘blockmode’, which is the normal way of working on non-Exadata Oracle databases, where blocks are read fr... 続きを読む
LPI-Japan、Oracleプロフェッシナルサービスプロバイダー株式会社コーソルのLPI-Japanビジネスパートナー制度加入を発表 OSS/Linux技術者認定機関として「LPIC」および「OSS-DB技術者認定制度」を 実施する特定非営利活動法人エルピーアイジャパン(以下:LPI-J... 続きを読む
Introduction: Oracle defines the ORA-7445 as an unhandled exception error that could be result of an Oracle bug. The ORA-7445 errors depend on the version of the Oracle software, OS version. For more details about the error, you need to check... 続きを読む
It is not uncommon for Oracle to have something undocumented , and this is just another case of this ailment. We have a database in which we have two copies of the same backup, one we keep in the FRA, the other one in an external disk, which ... 続きを読む
UNIXサーバ分野において緊密な協業を行ってきたOracleと富士通の関係が、ここにきて新たな段階を迎えているようだ。さらなる発展へと向かうのか、それとも……。 Oracleの新製品発表に沈黙し続ける富士通 「本日、世界最速のSPARCプロセッサを搭載したUNIXサー... 続きを読む
NTTドコモが顧客情報管理システムのアプリケーション実行基盤として「Oracle WebLogic Server」を導入し稼働開始 ・日本オラクル株式会社(本社:東京都港区、代表執行役社長 最高経営責任者: 遠藤 隆雄)は本日、株式会社エヌ・ティ・ティ・ドコモ(本社:東... 続きを読む
In last week’s post we addressed the most popular question surrounding statistics gathering, what sample size should be used? Once that decision has been made, folks typically turn their attention to histograms and the time honored question ... 続きを読む
select /*+ leading(t2 t1) use_nl(t2 t1) index(t2 pk_high_clustering_factor) */ t2.id ,t2.name ,t1.name from low_clustering_factor t1 inner join high_clustering_factor t2 on t1.id = t2.id where t2.id between 30001 and 35000 call count cpu elap... 続きを読む
I was recently playing with an Oracle XE database. The main benefit of Oracle XE is that it can be used free of charge. And unlike the other database editions on the Oracle Technology Network, it is free the restrictions in the OTN license ag... 続きを読む
クラウドで手軽にデータベースアプリを開発:Oracle Database Cloud Serviceとは? 4月9日に開催された「Oracle CloudWorld Tokyo」のセッションから、クラウド環境におけるOracle DBアプリケーション開発のさわりを紹介する。 オラクル製品といえば開発者にと... 続きを読む
When it comes to gathering statistics, one of the most critical decisions you have to make is, what sample size should be used? A 100% sample will ensure accurate statistics but could take a really long time. Whereas a 1% sample will finish q... 続きを読む
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This is a very short blog post to share a good news I learned last week at the great New Zealand Oracle User Group 2013 conference. During a keynote Tom Kyte mentioned that Oracle is going to introduce a Temporary Undo. Most of us know that... 続きを読む
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When reviewing the performance of some queries, it is sometimes useful to review the sessions statistics for each execution of the query. These session statistics complement the wait events found in ASH and trace files. The wait events do not... 続きを読む