Improve default `net_buffer_length`

[staabm]

Is your feature request related to a problem? Please describe. I am researching ways to make the gdpr-dump run faster for big databases. (running https://github.com/Smile-SA/gdpr-dump/commit/e4770ce210be8420ab1d420453ed86406775bcc8)

I tried different net_buffer_length settings. the default is 1000000 (1 Megabyte) and I tried with 10000000 (10 Megabyte), which seem to improve performance quite a bit.

when using 10 Megabyte it looks like the progressbar roughly updates once every 2 seconds, which I think is still fast enough

Describe the solution you'd like I feel the default of 1000000 is pretty conservative and a higher default could improve dump performance in a default setting quite a bit

[guvra]

Strange, I did the same test last week on a Magento database and the dump time was exactly the same (~1m16 with 1000000 and 10000000). What results did you get?

[staabm]

my export runs a few hours. lets see how it goes when doing a full project dump

[staabm]

the following tests create a dump of ~2,6GB file-size (bz2 compressed)

10 Mbyte

mstaab@mst22:/www/www/gdpr-dump$ php bin/gdpr-dump config.yaml -vvv > dump.sql.bz2
Database settings
  - Dsn: mysql:host=192.168.54.10:33065;dbname=mydb
  - Using password: yes

Dump settings
  - output: php://stdout
  - add_drop_database: false
  - add_drop_table: true
  - add_drop_trigger: true
  - add_locks: true
  - complete_insert: false
  - compress: bzip2
  - default_character_set: utf8
  - disable_keys: true
  - events: false
  - extended_insert: true
  - hex_blob: false
  - init_commands: []
  - insert_ignore: false
  - lock_tables: false
  **- net_buffer_length: 10000000**
  - no_autocommit: true
  - no_create_info: false
  - routines: true
  - single_transaction: true
  - skip_comments: false
  - skip_definer: false
  - skip_dump_date: false
  - skip_triggers: false
  - skip_tz_utc: false

 405/405 [============================] 100% - z_102_9235_return_shipment_log (598 rows) - 1 hr, 14 mins - 44.0 MiB

vs.

1 Mbyte

mstaab@mst22:/www/www/gdpr-dump$ php bin/gdpr-dump config.yaml -vvv > dump.sql.bz2
Database settings
  - Dsn: mysql:host=192.168.54.10:33065;dbname=mydb
  - Using password: yes

Dump settings
  - output: php://stdout
  - add_drop_database: false
  - add_drop_table: true
  - add_drop_trigger: true
  - add_locks: true
  - complete_insert: false
  - compress: bzip2
  - default_character_set: utf8
  - disable_keys: true
  - events: false
  - extended_insert: true
  - hex_blob: false
  - init_commands: []
  - insert_ignore: false
  - lock_tables: false
  **- net_buffer_length: 1000000**
  - no_autocommit: true
  - no_create_info: false
  - routines: true
  - single_transaction: true
  - skip_comments: false
  - skip_definer: false
  - skip_dump_date: false
  - skip_triggers: false
  - skip_tz_utc: false

Dump progress
 405/405 [=========] 100% - z_102_9235_return_shipment_log (598 rows) - 1 hr, 14 mins - 46.0 MiB

I had initially a feeling it is faster, but my testing has the same result as yours.