11 de março de 2012

Backup Parcial PostgreSQL com "pg_dump"

Em continuidade ao post principal "Soluções de Backup e Restore para PostgreSQL", vamos ver outra opção de backup e restore para PostgreSQL, desta vez utilizando, o "pg_dump" e "pg_restore". Diferente do "pg_dumpall", evidenciado no post "", o "pg_dump" permite realizar o backup apenas dos bancos de dados do cluster.
A principal vantagem do "pg_dump", é permitir a restauração de apenas um banco de dados, ou seja, utilizando o "pg_restore", você escolhe o banco de dados a ser restaurado. Como desvantagem, não faz backup ou permite restore de usuários e schemas do cluster.
Nos exemplos realizados no backup utilizando o "pg_dumpall", utilizaremos um cluster, onde serão utilizados nos exemplos as configurações default:
porta [5432]
usuário [postgres]
host [localhost]
sem tablespace.

Backup Parcial
Sintaxe:
pg_dump -Fc -p <porta> -U <usuario> -h <host> <banco_dados> -f <path/nome_arquivo_backup> 
Onde:
porta: porta do cluster
usuario: usuário com perfil superusuário
host: identificação do servidor
banco_dados: Banco de Dados a ser backupeado
path/nome_arquivo_backup: Caminho e Nome do arquivo de backup

Exemplo (com usuário postgres):
~$ pg_dump -Fc -p 5432 -U postgres -h localhost bdexemplo -f /backup/backup_bdexemplo_postgres-AAMMDDhhmm.sql
Exemplo (com usuário root):
~# su - postgres -c 'pg_dump -Fc -p 5432 -U postgres -h localhost bdexemplo -f /backup/backup_bdexemplo_postgres-AAMMDDhhmm.sql' 

Restore Parcial
Sintaxe:
pg_restore -p <porta> -U <usuario> -h <host> -d <banco_dados_> <path/nome_arquivo_backup>
Exemplo (com usuário postgres):
~$ pg_restore -p 5432 -U postgres -h localhost -d bdexemplo /backup/backup_bdexemplo_postgres-AAMMDDhhmm.sql

Veja também:

Vale lembrar, que os exemplos acima são básicos e facilitam nossos trabalhos no dia a dia, uma vez estes utilitários possuem outros recursos adicionais, a saber.
Help "pg_dump"
~$ pg_dump --help
pg_dump dumps a database as a text file or to other formats.
Usage:
  pg_dump [OPTION]... [DBNAME]
General options:
  -f, --file=FILENAME         output file or directory name
  -F, --format=c|d|t|p        output file format (custom, directory, tar, plain text)
  -v, --verbose               verbose mode
  -Z, --compress=0-9          compression level for compressed formats
  --lock-wait-timeout=TIMEOUT fail after waiting TIMEOUT for a table lock
  --help                      show this help, then exit
  --version                   output version information, then exit
Options controlling the output content:
  -a, --data-only             dump only the data, not the schema
  -b, --blobs                 include large objects in dump
  -c, --clean                 clean (drop) database objects before recreating
  -C, --create                include commands to create database in dump
  -E, --encoding=ENCODING     dump the data in encoding ENCODING
  -n, --schema=SCHEMA         dump the named schema(s) only
  -N, --exclude-schema=SCHEMA do NOT dump the named schema(s)
  -o, --oids                  include OIDs in dump
  -O, --no-owner              skip restoration of object ownership in
                              plain-text format
  -s, --schema-only           dump only the schema, no data
  -S, --superuser=NAME        superuser user name to use in plain-text format
  -t, --table=TABLE           dump the named table(s) only
  -T, --exclude-table=TABLE   do NOT dump the named table(s)
  -x, --no-privileges         do not dump privileges (grant/revoke)
  --binary-upgrade            for use by upgrade utilities only
  --column-inserts            dump data as INSERT commands with column names
  --disable-dollar-quoting    disable dollar quoting, use SQL standard quoting
  --disable-triggers          disable triggers during data-only restore
  --inserts                   dump data as INSERT commands, rather than COPY
  --no-security-labels        do not dump security label assignments
  --no-tablespaces            do not dump tablespace assignments
  --no-unlogged-table-data    do not dump unlogged table data
  --quote-all-identifiers     quote all identifiers, even if not key words
  --serializable-deferrable   wait until the dump can run without anomalies
  --use-set-session-authorization
                              use SET SESSION AUTHORIZATION commands instead of
                              ALTER OWNER commands to set ownership
Connection options:
  -h, --host=HOSTNAME      database server host or socket directory
  -p, --port=PORT          database server port number
  -U, --username=NAME      connect as specified database user
  -w, --no-password        never prompt for password
  -W, --password           force password prompt (should happen automatically)
  --role=ROLENAME          do SET ROLE before dump
If no database name is supplied, then the PGDATABASE environment
variable value is used.
Report bugs to <pgsql-bugs@postgresql.org>.

Help "pg_restore"
~$ pg_restore --help
pg_restore restores a PostgreSQL database from an archive created by pg_dump.
Usage:
  pg_restore [OPTION]... [FILE]
General options:
  -d, --dbname=NAME        connect to database name
  -f, --file=FILENAME      output file name
  -F, --format=c|d|t       backup file format (should be automatic)
  -l, --list               print summarized TOC of the archive
  -v, --verbose            verbose mode
  --help                   show this help, then exit
  --version                output version information, then exit
Options controlling the restore:
  -a, --data-only          restore only the data, no schema
  -c, --clean              clean (drop) database objects before recreating
  -C, --create             create the target database
  -e, --exit-on-error      exit on error, default is to continue
  -I, --index=NAME         restore named index
  -j, --jobs=NUM           use this many parallel jobs to restore
  -L, --use-list=FILENAME  use table of contents from this file for
                           selecting/ordering output
  -n, --schema=NAME        restore only objects in this schema
  -O, --no-owner           skip restoration of object ownership
  -P, --function=NAME(args)
                           restore named function
  -s, --schema-only        restore only the schema, no data
  -S, --superuser=NAME     superuser user name to use for disabling triggers
  -t, --table=NAME         restore named table
  -T, --trigger=NAME       restore named trigger
  -x, --no-privileges      skip restoration of access privileges (grant/revoke)
  -1, --single-transaction
                           restore as a single transaction
  --disable-triggers       disable triggers during data-only restore
  --no-data-for-failed-tables
                           do not restore data of tables that could not be
                           created
  --no-security-labels     do not restore security labels
  --no-tablespaces         do not restore tablespace assignments
  --use-set-session-authorization
                           use SET SESSION AUTHORIZATION commands instead of
                           ALTER OWNER commands to set ownership
Connection options:
  -h, --host=HOSTNAME      database server host or socket directory
  -p, --port=PORT          database server port number
  -U, --username=NAME      connect as specified database user
  -w, --no-password        never prompt for password
  -W, --password           force password prompt (should happen automatically)
  --role=ROLENAME          do SET ROLE before restore
If no input file name is supplied, then standard input is used.
Report bugs to <pgsql-bugs@postgresql.org>.


Sem mais, abraço.
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