Question

I have a query . I have two tables on two different servers .Both the tables have the same structure . The master table on one server gets updated on a daily basis , so i want a cron job or a php script cron to update the second slave table on a different server .
I have seen a lot of scripts but none resolved my requirements .

Answer 1

I can’t believe you didn’t find a suitable script to do this. Depending on server-to-server bandwidth and connectivity, and table data size, you can:

• directly transfer the whole table:

  mysqldump [options] sourcedatabase tablename \
    | mysql [options] --host remoteserver --user username ...
  

• transfer the table with MySQL compression

  # same as above, mysql has the "-C" flag
  

• transfer using SSH encryption and compression; mysql is executed remotely

  mysqldump [options] sourcedatabase tablename \
    | ssh -C user@remoteserver 'mysql [options]'
  

• transfer using intermediate SQL file and rsync to transfer only modifications

  mysqldump [options] sourcedb tbl > dump.sql
  rsync [-z] dump.sql user@remoteserver:/path/to/remote/dump.sql
  ssh user@remoteserver "mysql [options] < /path/to/remote/dump.sql"
  

The above are all simple table overwrites, remote data is LOST and replaced by the master copy. The mysqldump-plus-rsync-plus-ssh runs in a time roughly proportional to modifications, which means that if you have a 10-GB SQL dump and add a dozen INSERTS, the transfer stage will need at most a couple seconds to synchronize the two SQL files.

To optimize the insert stage too, either you go for full MySQL replication, or you will need a way to identify operations on the table in order to replicate them manually at sync time. This may require alterations to the table structure, e.g. adding “last-synced-on” and “needs-deleting” columns, or even introduction of ancillary tables.