obey命令的使用。 我们可以将一些在GGSCI命令行工具中输入的命令,放到一个文件中。例如将下面的命令,放到direnv/db.oby文件中。ADD EXTRACT d_ncbs, EXTTRAILSOURCE ./dirdat/e0, params ./dirprm/d_epcis_ncbs.prmADD RMTTRAIL ./dirdat/d6, EXTRACT d_ncb
obey命令的使用。我们可以将一些在GGSCI命令行工具中输入的命令,放到一个文件中。例如将下面的命令,放到direnv/db.oby文件中。 ADD EXTRACT d_ncbs, EXTTRAILSOURCE ./dirdat/e0, params ./dirprm/d_epcis_ncbs.prm ADD RMTTRAIL ./dirdat/d6, EXTRACT d_ncbs, MEGABYTES 50 alter d_ncbs, begin now
然后打开ggsci工具,输入obey ./direnv/db.oby,即可批量执行这个文件中的命令。 这就有点像sqlplus当中的@命令一样。
一般我们如果要给几百上千个表添加trandata,就得通过obey命令了,不然,一个个地敲命令可累死人。

MySQLhandlesconcurrencyusingamixofrow-levelandtable-levellocking,primarilythroughInnoDB'srow-levellocking.ComparedtootherRDBMS,MySQL'sapproachisefficientformanyusecasesbutmayfacechallengeswithdeadlocksandlacksadvancedfeatureslikePostgreSQL'sSerializa

MySQLhandlestransactionseffectivelyusingtheInnoDBengine,supportingACIDpropertiessimilartoPostgreSQLandOracle.1)MySQLusesREPEATABLEREADasthedefaultisolationlevel,whichcanbeadjustedtoREADCOMMITTEDforhigh-trafficscenarios.2)Itoptimizesperformancewithabu

MySQL data types are divided into numerical, date and time, string, binary and spatial types. Selecting the correct type can optimize database performance and data storage.

Best practices include: 1) Understanding the data structure and MySQL processing methods, 2) Appropriate indexing, 3) Avoid SELECT*, 4) Using appropriate JOIN types, 5) Use subqueries with caution, 6) Analyzing queries with EXPLAIN, 7) Consider the impact of queries on server resources, 8) Maintain the database regularly. These practices can make MySQL queries not only fast, but also maintainability, scalability and resource efficiency.

MySQLisbetterforspeedandsimplicity,suitableforwebapplications;PostgreSQLexcelsincomplexdatascenarioswithrobustfeatures.MySQLisidealforquickprojectsandread-heavytasks,whilePostgreSQLispreferredforapplicationsrequiringstrictdataintegrityandadvancedSQLf

MySQL processes data replication through three modes: asynchronous, semi-synchronous and group replication. 1) Asynchronous replication performance is high but data may be lost. 2) Semi-synchronous replication improves data security but increases latency. 3) Group replication supports multi-master replication and failover, suitable for high availability requirements.

The EXPLAIN statement can be used to analyze and improve SQL query performance. 1. Execute the EXPLAIN statement to view the query plan. 2. Analyze the output results, pay attention to access type, index usage and JOIN order. 3. Create or adjust indexes based on the analysis results, optimize JOIN operations, and avoid full table scanning to improve query efficiency.

Using mysqldump for logical backup and MySQLEnterpriseBackup for hot backup are effective ways to back up MySQL databases. 1. Use mysqldump to back up the database: mysqldump-uroot-pmydatabase>mydatabase_backup.sql. 2. Use MySQLEnterpriseBackup for hot backup: mysqlbackup--user=root-password=password--backup-dir=/path/to/backupbackup. When recovering, use the corresponding life


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