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[Issue #228] documentation update

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This commit is contained in:
Grigory Smolkin 2020-06-22 13:49:47 +03:00
parent 345c26be79
commit 0410ff8408
1 changed files with 12 additions and 6 deletions
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doc/pgprobackup.xml
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@ -1732,7 +1732,7 @@ pg_probackup restore -B <replaceable>backup_dir</replaceable> --instance <replac
header and checksum in every page and replace only invalid header and checksum in every page and replace only invalid
pages and those with checksum and LSN not matching with pages and those with checksum and LSN not matching with
corresponding page in backup. This is the simplest, corresponding page in backup. This is the simplest,
the most fool-proof incremental mode. the most fool-proof incremental mode. Recommended to use by default.
</para> </para>
</listitem> </listitem>
<listitem> <listitem>
@ -1740,7 +1740,7 @@ pg_probackup restore -B <replaceable>backup_dir</replaceable> --instance <replac
LSN — read the <replaceable>pg_control</replaceable> in the LSN — read the <replaceable>pg_control</replaceable> in the
data directory to obtain redo LSN and redo TLI, which allows data directory to obtain redo LSN and redo TLI, which allows
to determine a point in history(shiftpoint), where data directory to determine a point in history(shiftpoint), where data directory
state shifted from backup chain history. If shiftpoint is not within state shifted from target backup chain history. If shiftpoint is not within
reach of backup chain history, then restore is aborted. reach of backup chain history, then restore is aborted.
If shiftpoint is within reach of backup chain history, then read If shiftpoint is within reach of backup chain history, then read
all data files in the data directory, validate header and checksum in all data files in the data directory, validate header and checksum in
@ -1755,7 +1755,7 @@ pg_probackup restore -B <replaceable>backup_dir</replaceable> --instance <replac
Second, the <replaceable>pg_control</replaceable> file must be Second, the <replaceable>pg_control</replaceable> file must be
synched with state of data directory. This condition cannot checked synched with state of data directory. This condition cannot checked
at the start of restore, so it is a user responsibility to ensure at the start of restore, so it is a user responsibility to ensure
that pg_control contain valid information. Because of that is not that pg_control contain valid information. Therefore it is not
recommended to use LSN mode in any situation, where pg_control has recommended to use LSN mode in any situation, where pg_control has
been tampered with: been tampered with:
after <replaceable>pg_resetxlog</replaceable> execution, after <replaceable>pg_resetxlog</replaceable> execution,
@ -1769,6 +1769,12 @@ pg_probackup restore -B <replaceable>backup_dir</replaceable> --instance <replac
</listitem> </listitem>
</itemizedlist> </itemizedlist>
<para>
Regardless of chosen incremental mode, pg_probackup will check, that postmaster
in given destination directory is not running and <varname>system-identifier</varname> is
the same as in the backup.
</para>
<para> <para>
Suppose you want to return an old master as replica after switchover Suppose you want to return an old master as replica after switchover
using incremental restore in LSN mode: using incremental restore in LSN mode:
@ -1794,12 +1800,12 @@ INFO: Redundant files are removed, time elapsed: 1s
INFO: Start restoring backup files. PGDATA size: 15GB INFO: Start restoring backup files. PGDATA size: 15GB
INFO: Backup files are restored. Transfered bytes: 1693MB, time elapsed: 43s INFO: Backup files are restored. Transfered bytes: 1693MB, time elapsed: 43s
INFO: Restore incremental ratio (less is better): 11% (1693MB/15GB) INFO: Restore incremental ratio (less is better): 11% (1693MB/15GB)
INFO: Restore of backup QBRHT8 completed. INFO: Restore of backup QBRNBP completed.
</programlisting> </programlisting>
<note> <note>
<para> <para>
Incremental restore is possible only for backups with Incremental restore is possible only for backups with
<literal>program_version</literal> equal or greater than 2.3.0. <literal>program_version</literal> equal or greater than 2.4.0.
</para> </para>
</note> </note>
</refsect3> </refsect3>