bitsCN.com
查了不少资料,也尝试了一些,最后采用的办法如下:
1. 导出mysql表定义(无数据)
mysqldump --no-data [dbname] >dbdef.sql
2. 使用mysql2postgres把脚本转换为pgsql
3. 上面生成的脚本还不一定很完美,可以尝试导入pgsql,调试错误并手动修改之。我遇到的问题就只有一个,mysql列定义中的zerofill需要手工去掉。一些unsinged定义会生成constraint,如果不需要可以去掉。另外,trigger都有问题,只能后面手工重建
4. 导出mysql数据:
mysqldump -v -nt --complete-insert=TRUE --compact --no-create-info --skip-quote-names [dbname] >dbdata.sql
老一些版本的pgsql如果不支持批量插入的话还需要加上--extended-insert=FALSE,这个性能损失巨大。
5. 转义符
mysql默认字符串里的'/'是转义符,而pgsql默认不是,修改postgresql.conf:
backslash_quote = on
escape_string_warning = off
standard_conforming_strings = off
数据导入完成后可以改回默认值。
5. pgsql里导入表定义和数据 6. 重建trigger 7. 自增主键(字段)的处理 最后,如果数据量大,导入时考虑性能可以先把主键、索引、约束都去掉,导入完成后再加上。另外,psql客户端从管道导入数据似乎不够快,可以用tcp方式psql -h localhost ,还有一些为大数据量导入优化的参数,大概列一下: autovacuum = off wal_level = minimal archive_mode = off full_page_writes = off fsync = off checkpoint_segments = 50 maintenance_work_mem视内存情况尽量大点
psql -d [dbname]
由于导入数据时此字段都是有值的,所以pgsql里面seq并不会增加,可以用如下语句设置自增列的当前值:
SELECT setval('sample_id_seq',max(id)) from sample;
checkpoint_timeout = 1h
作者 RuralHunter

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi

MySQL functions can be used for data processing and calculation. 1. Basic usage includes string processing, date calculation and mathematical operations. 2. Advanced usage involves combining multiple functions to implement complex operations. 3. Performance optimization requires avoiding the use of functions in the WHERE clause and using GROUPBY and temporary tables.

Efficient methods for batch inserting data in MySQL include: 1. Using INSERTINTO...VALUES syntax, 2. Using LOADDATAINFILE command, 3. Using transaction processing, 4. Adjust batch size, 5. Disable indexing, 6. Using INSERTIGNORE or INSERT...ONDUPLICATEKEYUPDATE, these methods can significantly improve database operation efficiency.

In MySQL, add fields using ALTERTABLEtable_nameADDCOLUMNnew_columnVARCHAR(255)AFTERexisting_column, delete fields using ALTERTABLEtable_nameDROPCOLUMNcolumn_to_drop. When adding fields, you need to specify a location to optimize query performance and data structure; before deleting fields, you need to confirm that the operation is irreversible; modifying table structure using online DDL, backup data, test environment, and low-load time periods is performance optimization and best practice.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SublimeText3 Linux new version
SublimeText3 Linux latest version

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

Dreamweaver CS6
Visual web development tools

Dreamweaver Mac version
Visual web development tools

WebStorm Mac version
Useful JavaScript development tools
