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The TID isn't stable enough: we might queue an sinval event before a VACUUM FULL, and then process it afterwards, when the target tuple no longer has the same TID. So we must invalidate entries on the basis of hash value only. The old coding can be shown to result in various bizarre, hard-to-reproduce errors in the presence of concurrent VACUUM FULLs on system catalogs, and could easily result in permanent catalog corruption, up to and including complete loss of tables. This commit is just a minimal fix that removes the unsafe comparison. We should remove transmission of the tuple TID from sinval messages altogether, and then arrange to suppress the extra message in the common case of a heap_update that doesn't change the key hashvalue. But that's going to be much more invasive, and will only produce a probably-marginal performance gain, so it doesn't seem like material for a back-patch. Back-patch to 9.0. Before that, VACUUM FULL refused to do any tuple moving if it found any INSERT_IN_PROGRESS or DELETE_IN_PROGRESS tuples (and CLUSTER would give up altogether), so there was no risk of moving a tuple that might be the subject of an unsent sinval message. |
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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/.