0001-Better-error-messages-for-short-reads-writes-in-SLRU.patch

text/plain

Filename: 0001-Better-error-messages-for-short-reads-writes-in-SLRU.patch
Type: text/plain
Part: 0
Message: fix "Success" error messages

Patch

Same data as JSON: GET /api/v1/attachments/:id/patch the parsed metadata as JSON — format, series position, per-file stats; never the diff bytes. API reference →
Format: format-patch
Series: patch 0001
Subject: Better error messages for short reads/writes in SLRU
File+
src/backend/access/transam/slru.c 8 4
From 680651938e30b5208a73b9d76813a5880af4ab54 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 18 Jun 2019 14:27:53 +0200
Subject: [PATCH 1/2] Better error messages for short reads/writes in SLRU

This avoids getting a

    Could not read from file ...: Success.

for a short read or write (since errno is not set in that case).
Instead, report a more specific error messages.
---
 src/backend/access/transam/slru.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
index 2dbc65b125..315c0612e6 100644
--- a/src/backend/access/transam/slru.c
+++ b/src/backend/access/transam/slru.c
@@ -923,15 +923,19 @@ SlruReportIOError(SlruCtl ctl, int pageno, TransactionId xid)
 			ereport(ERROR,
 					(errcode_for_file_access(),
 					 errmsg("could not access status of transaction %u", xid),
-					 errdetail("Could not read from file \"%s\" at offset %u: %m.",
-							   path, offset)));
+					 errno == 0
+					 ? errdetail("Short read from file \"%s\" at offset %u.", path, offset)
+					 : errdetail("Could not read from file \"%s\" at offset %u: %m.",
+								 path, offset)));
 			break;
 		case SLRU_WRITE_FAILED:
 			ereport(ERROR,
 					(errcode_for_file_access(),
 					 errmsg("could not access status of transaction %u", xid),
-					 errdetail("Could not write to file \"%s\" at offset %u: %m.",
-							   path, offset)));
+					 errno == 0
+					 ? errdetail("Short write to file \"%s\" at offset %u.", path, offset)
+					 : errdetail("Could not write to file \"%s\" at offset %u: %m.",
+								 path, offset)));
 			break;
 		case SLRU_FSYNC_FAILED:
 			ereport(data_sync_elevel(ERROR),
-- 
2.22.0