ac81101551
This commit allows using copy_file_range() for efficient combining of data from multiple files, instead of simply reading/writing the blocks. Depending on the filesystem and other factors (size of the increment, distribution of modified blocks etc.) this may be faster than the block-by-block copy, but more importantly it enables various features provided by CoW filesystems. If a checksum needs to be calculated for the file, the same strategy as when copying whole files is used - copy_file_range is used to copy the blocks, but the file is also read for the checksum calculation. While the checksum calculation is rarely needed when cloning whole files, when reconstructing the files from multiple backups it needs to happen almost always (the only exception is when the user specified --no-manifest). Author: Tomas Vondra Reviewed-by: Thomas Munro, Jakub Wartak, Robert Haas Discussion: https://postgr.es/m/3024283a-7491-4240-80d0-421575f6bb23%40enterprisedb.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.