bef47ff85d
The base backup code has accumulated a healthy number of new features over the years, but it's becoming increasingly difficult to maintain and further enhance that code because there's no real separation of concerns. For example, the code that understands knows the details of how we send data to the client using the libpq protocol is scattered throughout basebackup.c, rather than being centralized in one place. To try to improve this situation, introduce a new 'bbsink' object which acts as a recipient for archives generated during the base backup progress and also for the backup manifest. This commit introduces three types of bbsink: a 'copytblspc' bbsink forwards the backup to the client using one COPY OUT operation per tablespace and another for the manifest, a 'progress' bbsink performs command progress reporting, and a 'throttle' bbsink performs rate-limiting. The 'progress' and 'throttle' bbsink types also forward the data to a successor bbsink; at present, the last bbsink in the chain will always be of type 'copytblspc'. There are plans to add more types of 'bbsink' in future commits. This abstraction is a bit leaky in the case of progress reporting, but this still seems cleaner than what we had before. Patch by me, reviewed and tested by Andres Freund, Sumanta Mukherjee, Dilip Kumar, Suraj Kharage, Dipesh Pandit, Tushar Ahuja, Mark Dilger, and Jeevan Ladhe. Discussion: https://postgr.es/m/CA+TgmoZGwR=ZVWFeecncubEyPdwghnvfkkdBe9BLccLSiqdf9Q@mail.gmail.com Discussion: https://postgr.es/m/CA+TgmoZvqk7UuzxsX1xjJRmMGkqoUGYTZLDCH8SmU1xTPr1Xig@mail.gmail.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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.