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In generate_orderedappend_paths(), there is an assumption that a child relation's row estimate is always greater than zero. There is an Assert verifying this assumption, and the estimate is also used to convert an absolute tuple count into a fraction. However, this assumption is not always valid -- for example, upper relations can have their row estimates unset, resulting in a value of zero. This can cause an assertion failure in debug builds or lead to the tuple fraction being computed as infinity in production builds. To fix, use the row estimate from the cheapest_total path to compute the tuple fraction. The row estimate in this path should already have been forced to a valid value. In passing, update the comment for generate_orderedappend_paths() to note that the function also considers the cheapest-fractional case when not all tuples need to be retrieved. That is, it collects all the cheapest fractional paths and builds an ordered append path for each interesting ordering. Backpatch to v18, where this issue was introduced. Bug: #19102 Reported-by: Kuntal Ghosh <kuntalghosh.2007@gmail.com> Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Kuntal Ghosh <kuntalghosh.2007@gmail.com> Reviewed-by: Andrei Lepikhov <lepihov@gmail.com> Discussion: https://postgr.es/m/19102-93480667e1200169@postgresql.org Backpatch-through: 18
PostgreSQL tests ================ This directory contains a variety of test infrastructure as well as some of the tests in PostgreSQL. Not all tests are here -- in particular, there are more in individual contrib/ modules and in src/bin. Not all these tests get run by "make check". Check src/test/Makefile to see which tests get run automatically. authentication/ Tests for authentication (but see also below) examples/ Demonstration programs for libpq that double as regression tests via "make check" isolation/ Tests for concurrent behavior at the SQL level kerberos/ Tests for Kerberos/GSSAPI authentication and encryption ldap/ Tests for LDAP-based authentication locale/ Sanity checks for locale data, encodings, etc mb/ Tests for multibyte encoding (UTF-8) support modules/ Extensions used only or mainly for test purposes, generally not suitable for installing in production databases perl/ Infrastructure for Perl-based TAP tests recovery/ Test suite for recovery and replication regress/ PostgreSQL's main regression test suite, pg_regress ssl/ Tests to exercise and verify SSL certificate handling subscription/ Tests for logical replication