Thread: pgsql: Rewrite the way GIN posting lists are packed on a page, to reduc
pgsql: Rewrite the way GIN posting lists are packed on a page, to reduc
From
Heikki Linnakangas
Date:
Rewrite the way GIN posting lists are packed on a page, to reduce WAL volume. Inserting (in retail) into the new 9.4 format GIN posting tree created much larger WAL records than in 9.3. The previous strategy to WAL logging was basically to log the whole page on each change, with the exception of completely unmodified segments up to the first modified one. That was not too bad when appending to the end of the page, as only the last segment had to be WAL-logged, but per Fujii Masao's testing, even that produced 2x the WAL volume that 9.3 did. The new strategy is to keep track of changes to the posting lists in a more fine-grained fashion, and also make the repacking" code smarter to avoid decoding and re-encoding segments unnecessarily. Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/14d02f0bb352d70d50106e153aca4af9c4b0b842 Modified Files -------------- src/backend/access/gin/gindatapage.c | 629 +++++++++++++++++++++---------- src/backend/access/gin/ginpostinglist.c | 3 +- src/backend/access/gin/ginxlog.c | 161 +++++++- src/backend/access/rmgrdesc/gindesc.c | 65 +++- src/include/access/gin_private.h | 35 +- 5 files changed, 666 insertions(+), 227 deletions(-)