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databasedownloadbackupdumpsnapshot
Bruno Campos
Bruno Campos

Reputation: 666

What is the difference between dump, download, snapshot and backup?

I started studying the data area and didn't understand the difference between these terms dump, backup, snapshot and download.

Upvotes: 2

Views: 2768

Answers (1)

pifor
pifor

Reputation: 7892

In general there are 2 kinds of database backup:

  1. logical backup where data is turned ino another format (can be SQL statement or some binary format): mysqldump for MySQL, pg_dump for PostgreSQL, Data Pump export for Oracle.
  2. physical backup where database physical files are copied sometimes with operating system commands sometimes with special executables: this physical copy is a binary copy of the original database file: pg_basebackup for PostgreSQL, backup command for SQL Server., RMAN for Oracle. Some tools know to optimize backup and know how to not read unused part of database files (example: RMAN for Oracle).

Storage snapshot is a special kind of physical backup taken by the storage system that can take a file system snapshot of the file system used by database files.

AFAIK download is not used in database backup terminology.

Strictly speaking there is no standard terminology for database backup: AFAIK SQL standard does not take into account database backup and recovery because these commands are not really SQL statements that work at database object level or set of rows level.

Upvotes: 3

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