In addition to the existing options of "any" and "read-write", we now support "read-only", "primary", "standby", and "prefer-standby". "read-write" retains its previous meaning of "transactions are read-write by default", and "read-only" inverts that. The other three modes test specifically for hot-standby status, which is not quite the same thing. (Setting default_transaction_read_only on a primary server renders it read-only to this logic, but not a standby.) Furthermore, if talking to a v14 or later server, no extra network round trip is needed to detect the session's status; the GUC_REPORT variables delivered by the server are enough. When talking to an older server, a SHOW or SELECT query is issued to detect session read-only-ness or server hot-standby state, as needed. Haribabu Kommi, Greg Nancarrow, Vignesh C, Tom Lane; reviewed at various times by Laurenz Albe, Takayuki Tsunakawa, Peter Smith. Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com |
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configure.ac |
README
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/.