Date: Sat, 23 Dec 2023 15:51:47 -0600
From: Nathan Bossart <nathandbossart@gmail.com>
To: Alexander Lakhin <exclusion@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>,
	Jakub Wartak <jakub.wartak@enterprisedb.com>,
	Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Andres Freund <andres@anarazel.de>,
	Peter Eisentraut <peter@eisentraut.org>,
	Dilip Kumar <dilipbalaut@gmail.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: trying again to get incremental backup
Message-ID: <20231223215147.GA69623@nathanxps13>
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My compiler has the following complaint:

../postgresql/src/backend/postmaster/walsummarizer.c: In function ‘GetOldestUnsummarizedLSN’:
../postgresql/src/backend/postmaster/walsummarizer.c:540:32: error: ‘unsummarized_lsn’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  540 |  WalSummarizerCtl->pending_lsn = unsummarized_lsn;
      |  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~

I haven't looked closely to see whether there is actually a problem here,
but the attached patch at least resolves the warning.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

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diff --git a/src/backend/postmaster/walsummarizer.c b/src/backend/postmaster/walsummarizer.c
index 9b5d3cdeb0..0cf6bbe59d 100644
--- 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;

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