Prevent summarizer hang when summarize_wal turned off and back on.
Before this commit, when the WAL summarizer started up or recovered
from an error, it would resume summarization from wherever it left
off. That was OK normally, but wrong if summarize_wal=off had been
turned off temporary, allowing some WAL to be removed, and then turned
back on again. In such cases, the WAL summarizer would simply hang
forever. This commit changes the reinitialization sequence for WAL
summarizer to rederive the starting position in the way we were
already doing at initial startup, fixing the problem.
Per report from Israel Barth Rubio. Reviewed by Tom Lane.
Discussion: http://postgr.es/m/CA+TgmoYN6x=YS+FoFOS6=nr6=qkXZFWhdiL7k0oatGwug2hcuA@mail.gmail.com
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/065583cf460f980a182498941ac52810f709a897
Modified Files
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src/backend/access/transam/xlog.c | 2 +-
src/backend/postmaster/walsummarizer.c | 83 ++++++++++++++++++----------------
src/include/postmaster/walsummarizer.h | 3 +-
3 files changed, 45 insertions(+), 43 deletions(-)