One, Oracle 11gThe automatic collection of statistics data is available in the 11g version of Oracle. One of the steps in deploying 11g Oracle software during deployment is to prompt for the ability to start this feature (which is enabled by default).Here's how to enable and disable this feature:1. View the tasks and status of automatically collecting statistics:Sql> select Client_name,status from Dba_autotask_client;Client_name STATUS----------------
Ext.: http://www.cnblogs.com/zhangweizhong/p/5577842.htmlRecently in a BI project, the need for a large number of SQL data statistics related to the application, deepened my understanding and use of SQL.So, a summary of the SQL statements commonly used to share several data statistics:1. Statistical data under various conditionsSelectbatchid,sum (cardsum) total amount, sum (case when Status=1 then cardsum e
Used Baidu statistics or CNZZ statistics of children's shoes should know, backstage there is a map statistics, different visits to the provinces show the color is not the same, today I will lead you to develop a case like this. In an article on "Using Raphael.js to map China", I gave you a description of how to use Raphael.js to draw a map of China, today I would
pretty dry reading. What are probably want to know are how to monitor checkpoints on your production system, and how to Tell if they ' re happening too often. Even though things have improved, "Checkpoint spikes" where disk I/O becomes really heavy is still possible even in Curre NT PostgreSQL versions. and it doesn ' t help, the default configuration is tuned-very low disk space and fast Crash recovery rather than performance . The checkpoint_segments parameter that's one input on what oft
If we want the CBO to use the statistics of reasonable use of the data to correctly determine the quickest way to execute any SQL query, it is necessary to use the Analyze command or dbms_stats the statistics of the data in a timely manner.For example, in the index skip scan example, if you do not collect statistics for table employee and index, it is not the ind
Welcome to the Oracle community forum and interact with 2 million technical staff. system statistics mainly describe some features related to system hardware, such as the performance and utilization of cpu and io systems. This information is very important for the query optimizer. During the execution plan selection process, the oracle optimizer will use the system statistics to evaluate the execution plan.
Question: I want to understand when to export and import by dbms_stats statistics and learn when it is a good idea to export and import statistics.
Answer: importing and exporting statistics for the CBO and the systems stats (external system statistics for CPU, I/O. etc) and useful in a variety of areas:
Export produ
In addition to the execution plan, there are other factors to consider when running a statement, such as the statement Compilation Time, execution time, and number of disk reads.
If the DBA can test the problem statement separately, you can enable the following three switches before running to collect statistics about the statement running.This information is of great value for analysis.Copy codeThe Code is as follows: SET
Brief introductionSQL Server Query Analyzer is cost-based. Typically, the Query Analyzer determines how to choose an efficient query route based on predicates, such as which index to choose. And every time the Query Analyzer looking for the path, and not every time to statistics the number of rows included in the index, the range of values, but based on certain conditions to create and update the information after the save to the database, which is ca
However, statistics are inaccurate after dbms_stats analysis on some forums, and some bugs are found on dbms_stats (which may be related to the version, which is to be checked ).
However, statistics are inaccurate after dbms_stats analysis on some forums, and some bugs are found on dbms_stats (which may be related to the version, which is to be checked ).
Use dbms_stats or analyze
Since Oracle8.1.5 int
Comparison | traffic | Statistics recently tried a few traffic statistics tools, a rough comparison, the improper place to look at:
163 Traffic Statistics: (not fully tested)
Advantages: Almost no ads, page clean
Disadvantages: 1, the location is not brilliant
2, after installation, the Web page display speed has been reduced, browser alarm "block
Label: CREATE OR REPLACE PROCEDURE schameb.prc_gather_stats
Current_User is
BEGIN
SYS. Dbms_stats. Gather_table_stats ('schname'TableName' CASCADE= TRUE);
END ;
/ Select Owner,table_name,last_analyzed,num_rows from dba_tables where owner= ' SYSTEM ' and Table_name= ' aq$_internet_agents ' Last_analyzed: The last time the information of related tables is counted; Num_rows: Number of records in the table stored in the optimizer (may not match the actual situation ) When you EXEC the
Parameters related to MySQL statistics:1. Innodb_stats_on_metadata (whether statistics are automatically updated), the default is off in MySQL 5.7Takes effect only when the statistics are configured as non-persistent.That is, when the innodb_stats_persistent is configured to OFF, the Innodb_stats_on_metadata's settings are not valid until the hand that stores the
Tags: auto persist dex statistic override otherwise statistics SEL default valueParameters related to MySQL statistics: 1. Innodb_stats_on_metadata (whether statistics are automatically updated), the default is off in MySQL 5.7 Takes effect only when the statistics are configured as non-persistent.That is, when the inn
In C + +, it is often necessary to count performance information by timing, and to analyze performance bottlenecks through statistical time-consuming information, which can often be sufficient for millisecond-level time statistics, but in the case of least bit performance hotspots, millisecond-level statistics are not enough, Requires at least a microsecond level of statistical information, even to the CPU'
Now the internet is precarious, insecure, and constantly appear let us surprised things! From yesterday to see statistics found 51LA free statistics stop service! At first I thought it was an attack, it might not be long before it would be good. The disappointment is still not available until now! So I searched the internet for the cause of the event, so the big stop, It's going to be a lot of talk! But I w
In the school's academic year exam examination work, in order to facilitate the marking process and avoid students cheating, often the same grade different classes of students to separate mixed. After the examination is completed, how to do not change the original form of the status of the class score statistics? With the three functions sumif, countif and sumproduct, everything will be very easy. The following examples illustrate.
First, the book on
Plaid little weave feels that the work is busy, the days are like quicksand, slowly flow away, work writing summary is difficult to contemplate yomail mail statistics function, can help us to automatically record colleagues, customers, friends and relatives of the number of mail exchanges, click on the name can also jump mail dialogue, mail clearly visible. For this function is still pretty good, save a lot of time, then we come to see the statistical
Count the number of files in a folderLs-l |grep "^-" |wc-lCount the number of directories under a folderLs-l |grep "^d" |wc-lThe number of files under the statistics folder, including subfoldersLs-lr|grep "^-" |wc-lAll txt files in the statistics/imagedata/data/20161108 directory (including subdirectories)Ls-lr/imagedata/data/20161108|grep txt|wc-l or LS-LR "/imagedata/data/20161108" |grep "TXT" |wc-l------
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