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gpcrondump important flags and file layouts

Environment 

Product Version
Pivotal Greenplum (GPDB) 4.3.x
OS RHEL 6.x

Purpose 

This article will give an overview of how the GPDB dump works to backup file layouts and important flags to note. 

Procedure

  • How GPDB dump works

-gpcrondump: This writes out a database to SQL script files. The script files can be used to restore the database using the gpdbrestore utility. The gpcrondump utility can be called directly or from a crontab entry.

-gp_dump: This is called inside gpcrondump; gpcrondump is a wrapper to gp_dump that does basic validations before starting gp_dump.

  • Files

The master first starts to write to /home/gpadmin/gpAdminlogs/gpcrondump_YYYYMMDD.log and writes to this log file until we see "Starting Dump process". Then, it switches to write to the status file (gp_dump_status_0_2_<timestamp> on the master and all the segments. Once the database backup is completed, it creates a "create database" command file only on the master.

Under the $MASTER_DATA_DIRECTORY/db_dumps/yyyymmdd folder, we should see the following files (in addition to the gzipped dump files):

gp_dump_1_1_20160414091125.gz - Contains complete DDL for DB including schemas, functions, tables (not indexes and constraints)

gp_dump_1_1_20160414091125_post_data.gz - DDL for dropping and recreating constraints and indexes

gp_cdatabase_1_1_20160413141720 - Contains the CREATE DATABASE command

gp_dump_status_1_1_20160413141720 - Status file that has high level logging on the gpcrondump job

gp_dump_20160413141720.rpt - Has one line status if the backup was successful on each per segment

gp_dump_20160413141720_ao_state_file - File offset of AO tables for incremental recovery

gp_dump_20160413141720_co_state_file - File offset of CO tables for incremental recovery

gp_dump_20160413141720_last_operation - Last DDL on each relation

On the segment data directory, there should be a db_dumps/yyyymmdd folder and the following files should be present (in addition to the gzipped dump files):

gp_dump_status_0_6_20160413141720 - Status file that has high level logging on the gpcrondump job
  •  Important Flags

 The following are important flags to note: 

-B <parallel_processes> - The number of segments to check in parallel, default 60
-c (clear old dump files first) - Specify this option to delete old backups before performing a back up
-g (copy config files) - Copy postgresql.conf, pg_ident.conf, and pg_hba.conf )both Master and Segments)
-G (dump global objects) - Use pg_dumpall to dump global objects such as roles and tablespaces
-h (record dump details) - Record details of database dump in DB table public.gpcrondump_history
-j (vacuum before dump) - Run VACUUM before the dump starts
-k (vacuum after dump) - Run VACUUM after the dump has completed successfully
-o (clear old dump files only) - Clear out old dump files only, but do not run a dump
--oids - Include object identifiers (oid) in dump data




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