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7abaa6b9d3
The GUC check hooks for transaction_read_only and transaction_isolation tried to check RecoveryInProgress(), so as to disallow setting read/write mode or serializable isolation level (respectively) in hot standby sessions. However, GUC check hooks can be called in many situations where we're not connected to shared memory at all, resulting in a crash in RecoveryInProgress(). Among other cases, this results in EXEC_BACKEND builds crashing during child process start if default_transaction_isolation is serializable, as reported by Heikki Linnakangas. Protect those calls by silently allowing any setting when not inside a transaction; which is okay anyway since these GUCs are always reset at start of transaction. Also, add a check to GetSerializableTransactionSnapshot() to complain if we are in hot standby. We need that check despite the one in check_XactIsoLevel() because default_transaction_isolation could be serializable. We don't want to complain any sooner than this in such cases, since that would prevent running transactions at all in such a state; but a transaction can be run, if SET TRANSACTION ISOLATION is done before setting a snapshot. Per report some months ago from Robert Haas. Back-patch to 9.1, since these problems were introduced by the SSI patch. Kevin Grittner and Tom Lane, with ideas from Heikki Linnakangas |
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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: http://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. Changes between all PostgreSQL releases are recorded in the file HISTORY. 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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.