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Remove one of the arguments to btvacuumpage(), and give up on the idea that it's a recursive function. We now use the term "backtracking" to refer to the case where an earlier block must be visited to make sure no tuples that need to be removed were missed. Advertising btvacuumpage() as a recursive function was unhelpful. In reality the function always simulates recursion with a loop (it doesn't actually call itself). This wasn't just necessary as a precaution (per the comments mentioning tail recursion), though. There is no reliable natural limit on the number of times we can backtrack. There are important behavioral difference when "recursing"/backtracking, mostly related to page deletion. We don't perform page deletion when backtracking due to the extra complexity. And when we recurse, we're not performing a physical order scan anymore, so we expect fairly different conditions to hold for the page. Structuring the code like this makes it clearer how _bt_pagedel() cooperates with btvacuumpage() and btvacuumscan() (as established in commitb0229f26and commit73a076b0). Author: Peter Geoghegan Reviewed-By: Masahiko Sawada Discussion: https://postgr.es/m/CAH2-WzmRGMDWiLMcb+zagG9652PboNN4Gfcq1Gc_wJL6A716MA@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/.