81db073a28
The initial implementation in commit 959b38d77 counted one action per TOC entry (except for some special cases for multi-blob BLOBS entries). This assumes that TOC entries are all about equally complex, but it turns out that that assumption doesn't hold up very well in binary-upgrade mode. For example, even after the previous commit I was able to cause backend bloat with tables having many inherited constraints. There may be other cases too. (Since no serious problems have been reported with --single-transaction mode, we can conclude that the backend copes well with psql's regular restore scripts; but before 959b38d77 we never ran binary-upgrade restores with multi-command transactions.) To fix, count multi-command TOC entries as N actions, allowing the transaction size to be scaled down when we hit a complex TOC entry. Rather than add a SQL parser to pg_restore, approximate "multi command" by counting semicolons in the TOC entry's defn string. This will be fooled by semicolons appearing in string literals --- but the error is in the conservative direction, so it doesn't seem worth working harder. The biggest risk is with function/procedure TOC entries, but we can just explicitly skip those. (This is undoubtedly a hack, and maybe someday we'll be able to revert it after fixing the backend's bloat issues or rethinking what pg_dump emits in binary upgrade mode. But that surely isn't a project for v17.) Thanks to Alexander Korotkov for the let's-count-semicolons idea. Per report from Justin Pryzby. Back-patch to v17 where txn_size mode was introduced. Discussion: https://postgr.es/m/ZqEND4ZcTDBmcv31@pryzbyj2023
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.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.