Initialize variable to placate compiler.

I don't think there's a real problem here, because if we reach
the loop over 'tles' then we will either find at least one
TimeLineHistoryEntry such that oldest_segno != 0, in which case
unsummarized_lsn will be initialized, or else unsummarized_tli
will remain 0 and an error will occur before unsummarized_lsn
is used for anything. But some compilers are complainining, as
reported on list by Nathan Bossart and off-list by Andrew Dunstan.

Discussion: http://postgr.es/m/20231223215147.GA69623@nathanxps13

diff --git a/src/backend/postmaster/walsummarizer.c b/src/backend/postmaster/walsummarizer.c
index 9b5d3cdeb00855b1df237c5f71f5a9e872468259..0cf6bbe59dcbfa0e3f8a90b80c97e209b123e576 100644 (file)
--- a/src/backend/postmaster/walsummarizer.c
+++ b/src/backend/postmaster/walsummarizer.c
@@ -438,7 +438,7 @@ GetOldestUnsummarizedLSN(TimeLineID *tli, bool *lsn_is_exact,
    LWLockMode  mode = reset_pending_lsn ? LW_EXCLUSIVE : LW_SHARED;
    int         n;
    List       *tles;
-   XLogRecPtr  unsummarized_lsn;
+   XLogRecPtr  unsummarized_lsn = InvalidXLogRecPtr;
    TimeLineID  unsummarized_tli = 0;
    bool        should_make_exact = false;
    List       *existing_summaries;