Database Administrator

Oracle's simplest Automatic startup with the System As the saying goes, users are God. Sometimes it is very simple to ask a question. It takes only one sentence and one minute to complete the process. But when we get the DBA, it may take at least

MySQL Error Log) Like most relational databases, log files are an important part of MySQL databases. MySQL has several different log files, such as error log files, binary logs, common logs, and slow query logs. These logs help us to define what

Oracle ORA-01555 (snapshot old) I. Introduction: [Oracle@www.bkjia.com] $ oerr ora 0155501555,000 00, "snapshot too old: rollback segment number % s with name \" % s \ "too small"// * Cause: rollback records needed by a reader for consistent read

Oracle unrecoverable nologging database objects Unrecoverable NOLOGGING database objects 1) Back up users tablespaces [Oracle @ ocmu ~] $ Rman target/ Recovery Manager: Release 11.2.0.1.0-Production on Sat Mar 16 10:41:05 2013 Copyright (c) 1982,200

Analysis and Solution of ORA-12516 errors A ORA-12516 error occurs when you use swingbench to perform a stress test on the Oracle database. This error is generally because the number of oracle sessions exceeds the limit, generally because multiple

Adjust the redo log file size in Oracle RAC Adjust the size of the redo log file in Oracle RAC. (1) view the current log information: Select * from v $ logfile; (The path in step 2 can be seen in the MEMBER column here. The redo file name is named

MySQL index design principles 1. The index column to be searched is not necessarily the column to be selected. In other words, the column most suitable for indexing is the column that appears in the WHERE clause or the column specified in the join

Troubleshooting of errors in PL/SQL In PL/SQL, error handling is an important part, just like the exception handling in the Write Program. The normal process implementation in the program may not be very complicated, but it takes more than half of

Oracle deletes a shell script instance for a tablespace Shell script code for Oracle tablespace Deletion #! /Bin/bash# Ocpyang@126.com# Drop tablespace If [$ #-ne 1]; thenEcho "Usage: $0 TABLESPACE_NAME"Exit 1Fi # Configure oracle env: about oracle

Memory_target for Oracle initialization parameters I. Introduction: Oracle 9i introduces pga_aggregate_target to automatically adjust the PGA; Oracle 10 Gb introduces sga_target to automatically adjust SGA; Oracle 11g combines these two parts and

Example of Oracle full-text index performance advantages 1. Experiment description: Operating System: rhel 5.4x86 Database: Oracle 11g R2 Ii. Procedure: 2.1 create a t_btree table and create a B-Tree index. The index key is object_name: SQL> create

When installing oracle10g, libXp. so.6: cannot open shared object file, export dobject   The following error occurs when installing oracle10g: [oracle10@rac1 clusterware]$ ./runInstaller ***************************************************************

Redis source code analysis (5) --- sparkline micro-line chart, redissparkline I didn't know what it meant when I read sparkline for the first time. I never heard of it before, but it actually appeared in the redis code, at the beginning, I thought

Why is the full table scan COST (COST) divided by sreadtim and costsreadtim? The cost of full table scan is calculated as follows: Cost = ( #SRds * sreadtim + #MRds * mreadtim + CPUCycles / cpuspeed ) / sreadtim During

Database Table naming rules and database table naming rules 1. Table names are generally implemented using [module name_specific table name]. The prefixes of the same module are the same. (Oracle is case sensitive. You do not need to use "_" in SQL,

Rman database recovery; key/non-key files, image copies, control files, restore points, non-archive, incremental, new databases, catastrophic replies, and rman copies Perform full recovery: the system's key data files are lost in ARCHIVELOG mode: If

Practice: mysql version upgrades   /*************************************** * ************ Upgrade mysql to 5.6.21 ********************* * ******************************/backup is required before the upgrade! ---- 1. view the data directory location

Develop CRUD with Mybatis annotation and crud with mybatis Annotation The previous article demonstrated how to use XML to operate Mybatis to implement CRUD, but writing a large number of XML configuration files is very annoying. Therefore Mybatis

[Mongo] group statistics time: aggregate, group, distinct, mongoaggregateSome records recorded by date in development require statistics in various dimensions, such as day, month, year, and hour ,.. For Grouping statistics, some fields need to be de-

Cocould not drop object 'student 'because it is referenced by a foreign key constraint, constraint 1. Find foreign keys SELECT * FROM sys. foreign_keysWHERE referenced_object_id = object_id ('student ') 2. Delete foreign keys SELECT 'alter table' +