sql query running slow oracle database

Label:Problem Description: 1:oracle database connection suddenly becomes very slow when landing; Sqldeveloper link database is slow; 2:kettle-spoon ETL Program Access database, task execution times:

I put the question on the StackOverflow, but I didn't answer it. Write it yourself.My need is to show MySQL slow queries on the page. But if the original show, will take different parameters, not very good group and so on. The only thing we care about is SQL itself, like--These two are actually a slow query .Select *

difference between Xxx_bin and XXX is case sensitive. Here we will a.s all add binary qualification, first to lowercase, that is, to convert the temporary result set to Utf8_bin, then use B. The index can be used directly when the s is matched. In fact, the essence of the two rewriting methods is the same, the difference is that 1 is implicit conversion. In theory, 2 is faster. Summary The fields that do join are designed to be exactly the same as the type. » Reprint Please indicate so

The reason why Oracle SQL Execution is slow and the solution is described in the following article is the reason why Oracle SQL Execution is slow. If the data of a table in Oracle

showcontig is scanning ' table ' tables ...Table: ' Table ' (53575229); index id:1, Database id:14A TABLE-level scan has been performed.-Number of pages ...........: 154........ £ º-Number of scan zones ............: 20.......-Zone switching times ...........: 19....... £ º-The average number of pages in each area ....: 7.7 ...... £ º..-Scan density [best count: Actual Count] ...: 100% [20:20]-Logical scan fragment ....: 0%-----...-area Scan fragment

) A. Need to display the account opening date under each customer account B. Need to display the date on which the customer placed the order C. Need to display all orders placed on a specific date D. Need to display all orders with the same release date as the order numbered 25950 8. Which of the following SELECT statements should be used if you want to display the product names in the report that cost values are higher than the average cost of all products? (B) A. Select Product name from produ

Database Tuning tutorial (2) Prepare slow query data and optimize Databases 1. Slow query found In the previous section, we talked about the definition of slow queries. This section describes how to create a large table and prepar

MySQL queries the currently running SQL statement by using the status command to view the Slow queries item. if the value is greater than 0 for a long time, it indicates that the query execution time is too long. The following is a reference clip: Mysql> status; -------------- mysql Ver 11.18 Distrib 3.23.58, for redh

will look at examples. The following is a brief discussion of the multi-table syndication scenario. For the most visible equivalent table connection query, the CBO may generally use two connection modes nested loop and hash join (the MERGE join efficiency is less efficient than the hash join, and the general CBO will not consider it). Here, because paging is used, the maximum number of records to be returned is specified, and the NESTED loop can imme

Run the "status" command to query running SQL statements in MySQL. if the value of Slow queries is greater than 0 for a long time, the query execution time is too long. The following is a reference clip: 　mysql> status; -------------- mysql Ver 11.18 Distrib 3.23.

1, MySQL database when the slow query, is more dangerous, once there are other DDL operations, may cause the entire database waitingCan be divided into the following situations:When the table is a MyISAM table, the table has a slow query