util.dumpTables()：导出表

util.dumpSchemas()：导出单个或多个 schema

util.dumpInstance()：导出整个实例

util.dumpTables()的使用

语法：

util.dumpTables(schema, tables, outputUrl[, options])

其中：

·schema：是表所在的schema

·tables：是一个数组，表示要导出的表的列表

·outputUrl：存放的路径，该目录必须为空

比如导出单个表：

util.dumpTables('myabc',['abce'],'/data/dump')

这里将 myabc 库中的表 abce 导出到 /data/dump 目录中。

 MySQL  localhost  JS > util.dumpTables('myabc',['abce'],'/data/dump')
Acquiring global read lock
Global read lock acquired
Initializing - done 
1 tables and 0 views will be dumped.
Gathering information - done 
All transactions have been started
Locking instance for backup
Global read lock has been released
Writing global DDL files
Running data dump using 4 threads.
NOTE: Progress information uses estimated values and may not be accurate.
Writing schema metadata - done       
Writing DDL - done       
Writing table metadata - done       
Starting data dump
100% (1.82K rows / ~1.82K rows), 0.00 rows/s, 0.00 B/s uncompressed, 0.00 B/s compressed
Dump duration: 00:00:00s                                                                
Total duration: 00:00:00s                                                               
Schemas dumped: 1                                                                       
Tables dumped: 1                                                                        
Uncompressed data size: 573.68 KB                                                       
Compressed data size: 146.79 KB                                                         
Compression ratio: 3.9                                                                  
Rows written: 1818                                                                      
Bytes written: 146.79 KB                                                                
Average uncompressed throughput: 573.68 KB/s                                            
Average compressed throughput: 146.79 KB/s

以下是导出产生的文件：

缺省的并发度是4，可以手动指定并发度：

util.dumpTables('myabc',['abce'],'/data/dump',{threads:8})

导出过程可以做一些过滤，格式是使用json格式的过滤条件：

util.dumpTables('myabc',['abce'],'/data/dump', {where: {"myabc.abce":"title like 'abc%'"}})

数据加载

无论是使用util.dumpTables(), util.dumpSchemas(), 还是 util.dumpInstance()导出数据后，都是使用 util.loadDump() 加载数据。

util.loadDump('/data/dump', {schema: 'myabc-2', threads:8})

这会将上面备份的数据加载到新库 myabc-2 中。如果该数据库不存在，则会新建数据库。如果表已经存在，则会给出报错信息。

 MySQL  localhost  JS > util.loadDump('/data/dump', {schema: 'myabc-2'})
Loading DDL and Data from '/data/dump' using 4 threads.
Opening dump...
Target is MySQL 8.0.36. Dump was produced from MySQL 8.0.36
Scanning metadata - done       
Checking for pre-existing objects...
Executing common preamble SQL
Executing DDL - done       
Executing view DDL - done       
Starting data load
Executing common postamble SQL                       
100% (573.68 KB / 573.68 KB), 0.00 B/s, 1 / 1 tables done
Recreating indexes - done 
2 chunks (1.82K rows, 573.68 KB) for 1 tables in 1 schemas were loaded in 0 sec (avg throughput 573.68 KB/s)
0 warnings were reported during the load.

util.dumpSchemas()的使用

可以同时导出多个数据库：

util.dumpSchemas(schemas, outputUrl[, options])

其中：

·schemas：是一个数据库数组

导出单个 schema

util.dumpSchemas(['myabc'], '/data/dump', {threads: 4})

加载数据

util.loadDump('/data/dump', {schema: 'myabc-3', threads: 8})

这会将上面备份的数据加载到新库 myabc-3 中。如果该数据库不存在，则会新建数据库。

导出多个schema

util.dumpSchemas(['myabc', 'myabc-2'], '/data/dump', {threads: 4})

 MySQL  localhost  JS > util.dumpSchemas(['myabc', 'myabc-2'], '/data/dump', {threads: 4})
Acquiring global read lock
Global read lock acquired
Initializing - done 
2 schemas will be dumped and within them 3 tables, 0 views.
Gathering information - done 
All transactions have been started
Locking instance for backup
Global read lock has been released
Writing global DDL files
Running data dump using 4 threads.
NOTE: Progress information uses estimated values and may not be accurate.
Writing schema metadata - done       
Writing DDL - done       
Writing table metadata - done       
Starting data dump
100% (8.76K rows / ~8.76K rows), 0.00 rows/s, 0.00 B/s uncompressed, 0.00 B/s compressed
Dump duration: 00:00:00s                                                                
Total duration: 00:00:00s                                                               
Schemas dumped: 2                                                                       
Tables dumped: 3                                                                        
Uncompressed data size: 2.51 MB                                                         
Compressed data size: 532.64 KB                                                         
Compression ratio: 4.7                                                                  
Rows written: 8755                                                                      
Bytes written: 532.64 KB                                                                
Average uncompressed throughput: 2.51 MB/s                                              
Average compressed throughput: 532.64 KB/s 

加载数据

util.loadDump('/data/dump')

如果导入多个schemas，就不用指定schema选项了。但是需要确目标实例不包含相同的库或者库中不包含有相同的表。否则会报错。

 MySQL  localhost  JS > util.loadDump('/data/dump', {threads:8})
Loading DDL and Data from '/data/dump' using 8 threads.
Opening dump...
Target is MySQL 8.0.36. Dump was produced from MySQL 8.0.36
Scanning metadata - done       
Checking for pre-existing objects...
Executing common preamble SQL
Executing DDL - done       
Executing view DDL - done       
Starting data load
Executing common postamble SQL                     
100% (2.51 MB / 2.51 MB), 0.00 B/s, 3 / 3 tables done
Recreating indexes - done 
6 chunks (8.76K rows, 2.51 MB) for 3 tables in 2 schemas were loaded in 0 sec (avg throughput 2.51 MB/s)
0 warnings were reported during the load.

util.dumpInstance()的使用

util.dumpInstance('/data/dump', {threads:8})

不过，不会导出MySQL 的系统表(比如information_schema, performance_schema等)

加载数据

util.loadDump('/data/dump', {threads: 8})