The code removed here deleted already-used data from a partially-read
WAL segment's hashtable entry. The intent was evidently to try to
keep the entry's memory consumption below the WAL segment's total
size, but we don't use WAL segments that are so large as to make that
a big win. The important memory-space optimization is to remove
hashtable entries altogether when done with them, and that's handled
elsewhere. To buy that, we must accept a substantially more complex
(and under-documented) logical invariant about what is in entry->buf,
as well as complex and under-documented interactions with the entry
spilling logic, various re-checking code paths in xlogreader.c,
and pg_waldump's overall data processing order. Any of those aspects
could have bugs lurking still, and are quite likely to be prone to
new bugs after future code changes.
Given the number of bugs we've already found in commit
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| configure | ||
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| COPYRIGHT | ||
| GNUmakefile.in | ||
| HISTORY | ||
| Makefile | ||
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| README.md | ||
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/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/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/.