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96 lines
2.9 KiB
Groff
96 lines
2.9 KiB
Groff
.\" Copyright 2015-2025 Leonid Yuriev <leo@yuriev.ru>.
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.\" Copyright 2015,2016 Peter-Service R&D LLC <http://billing.ru/>.
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.\" Copyright 2012-2015 Howard Chu, Symas Corp. All Rights Reserved.
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.\" Copying restrictions apply. See COPYRIGHT/LICENSE.
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.TH MDBX_COPY 1 "2025-01-14" "MDBX 0.14"
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.SH NAME
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mdbx_copy \- MDBX environment copy tool
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.SH SYNOPSIS
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.B mdbx_copy
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[\c
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.BR \-V ]
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[\c
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.BR \-q ]
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[\c
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.BR \-c ]
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[\c
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.BR \-d ]
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[\c
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.BR \-p ]
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[\c
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.BR \-n ]
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.B src_path
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[\c
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.BR dest_path ]
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.SH DESCRIPTION
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The
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.B mdbx_copy
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utility copies an MDBX environment. The environment can
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be copied regardless of whether it is currently in use.
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No lockfile is created, since it gets recreated at need.
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If
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.I dest_path
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is specified it must be the path of an empty directory
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for storing the backup. Otherwise, the backup will be
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written to stdout.
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.SH OPTIONS
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.TP
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.BR \-V
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Write the library version number to the standard output, and exit.
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.TP
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.BR \-q
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Be quiet.
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.TP
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.BR \-c
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Compact while copying. Only current data pages will be copied; freed
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or unused pages will be omitted from the copy. This option will
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slow down the backup process as it is more CPU-intensive.
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Currently it fails if the environment has suffered a page leak.
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.TP
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.BR \-d
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Alters geometry to enforce the copy to be a dynamic size DB,
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which could be growth and shrink by reasonable steps on the fly.
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.TP
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.BR \-p
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Use read transaction parking/ousting during copying MVCC-snapshot.
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This allows the writing transaction to oust the read
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transaction used to copy the database if copying takes so long
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that it will interfere with the recycling old MVCC snapshots
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and may lead to an overflow of the database.
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However, if the reading transaction is ousted the copy will
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be aborted until successful completion. Thus, this option
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allows copy the database without interfering with write
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transactions and a threat of database overflow, but at the cost
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that copying will be aborted to prevent such conditions.
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.TP
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.BR \-u
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Warms up the DB before copying via notifying OS kernel of subsequent access to the database pages.
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.TP
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.BR \-U
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Warms up the DB before copying, notifying the OS kernel of subsequent access to the database pages,
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then forcibly loads ones by sequential access and tries to lock database pages in memory.
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.TP
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.BR \-n
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Open MDBX environment(s) which do not use subdirectories.
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This is legacy option. For now MDBX handles this automatically.
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.SH DIAGNOSTICS
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Exit status is zero if no errors occur.
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Errors result in a non-zero exit status and
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a diagnostic message being written to standard error.
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.SH CAVEATS
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This utility can trigger significant file size growth if run
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in parallel with write transactions, because pages which they
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free during copying cannot be reused until the copy is done.
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.SH "SEE ALSO"
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.BR mdbx_dump (1),
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.BR mdbx_chk (1),
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.BR mdbx_stat (1),
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.BR mdbx_load (1)
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.BR mdbx_drop (1)
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.SH AUTHOR
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Howard Chu of Symas Corporation <http://www.symas.com>,
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Leonid Yuriev <https://gitflic.ru/user/erthink>
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