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| -rw-r--r-- | doc/TODO | 15 |
1 files changed, 12 insertions, 3 deletions
@@ -6,7 +6,7 @@ TODO list for PostgreSQL Bracketed items "[]" have more detail. Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) -Last updated: Mon Nov 8 15:16:11 EST 2004 +Last updated: Mon Nov 8 22:57:34 EST 2004 The most recent version of this document can be viewed at the PostgreSQL web site, http://www.PostgreSQL.org. @@ -815,8 +815,17 @@ Miscellaneous * Use mmap() rather than SYSV shared memory or to write WAL files (?) [mmap] This would remove the requirement for SYSV SHM but would introduce - portability issues. Anonymous mmap is required to prevent I/O - overhead. + portability issues. Anonymous mmap (or mmap to /dev/zero) is required + to prevent I/O overhead. + +* Consider mmap()'ing files into a backend? + + Doing I/O to large tables would consume a lot of address space or + require frequent mapping/unmapping. Extending the file also causes + mapping problems that might require mapping only individual pages, + leading to thousands of mappings. Another problem is that there is no + way to _prevent_ I/O to disk from the dirty shared buffers so changes + could hit disk before WAL is written. * Add a script to ask system configuration questions and tune postgresql.conf * Use a phantom command counter for nested subtransactions to reduce |