Stream¶
When you take a backup with mydumper, it will connect to the database,
export the data and save into files in backup directory.
It is also possible to --stream the backup to STDOUT
to save the backup in a single file or to send it over the network.
myloader has also the availity to read a stream from the STDIN and
restore it.
Streaming backup¶
Even when mydumper uses --stream, it will
connect to the database and stores the backup in the directory.
After each time that a backup file is close, it will stream the header of the file
to STDOUT, and depending the option that we set, it will be write the content of the
file and delete from the directory.
The options that --stream allows are:
TRADITIONAL¶
It will write the content of the file to STDOUT and delete the file after. It is useful when you want to keep the backup in a single file, which is easier to transfer later.
NO_DELETE¶
It will write the content of the file to STDOUT and will not delete the file. This option is useful for debuging as you can review the files that are being sent to myloader.
NO_STREAM_AND_NO_DELETE¶
It will not write the content and it will not delete the file. In this case, only the header is being send to STDOUT, but the file is kept on the directory which is useful as myloader is able to read the file from it and delete it after restore it.
NO_STREAM¶
It will not write the content and it will delete the files. This is mostly for compatibility with myloader.
Restore Stream¶
By default, myloader reads the files from the directory,
but when --stream is used, it will be a bit more
complex.
It will create a thread that will read from STDIN the headers of the file and it
will into the directory the content depending what
we set on --stream:
TRADITIONAL¶
It will read the content from STDIN, write the files in the directory for processing and delete the file after. It is the common way to restore backups from a single file.
NO_DELETE¶
It will read the content from STDIN, write the files in the directory for processing and it will not delete the files after. This option is useful for debuging as you can review the files that are being restored.
NO_STREAM_AND_NO_DELETE¶
It will read the header from STDIN but it will not expect the content of the file, then it will process and it will not delete the files after. This is useful when mydumper shares the backup directory with myloader but you want to keep with the backup files.
NO_STREAM¶
It will read the header from STDIN but it will not expect the content of the file, then it will process and it will delete the files after. This is useful when mydumper shares the backup directory with myloader.