From d1d306f80c53a59b67823ae044bf85a2718ea94e Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Mon, 26 Aug 2019 21:37:10 +0200 Subject: [PATCH v2 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 | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c index 0fbcb4e6fe..e38f9199dd 100644 --- a/src/backend/access/transam/slru.c +++ b/src/backend/access/transam/slru.c @@ -920,18 +920,29 @@ SlruReportIOError(SlruCtl ctl, int pageno, TransactionId xid) path, offset))); break; case SLRU_READ_FAILED: - 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))); + if (errno) + 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))); + else + ereport(ERROR, + (errmsg("could not access status of transaction %u", xid), + errdetail("Could not read from file \"%s\" at offset %u: read too few bytes.", 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))); + if (errno) + 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))); + else + ereport(ERROR, + (errmsg("could not access status of transaction %u", xid), + errdetail("Could not write to file \"%s\" at offset %u: wrote too few bytes.", + path, offset))); break; case SLRU_FSYNC_FAILED: ereport(data_sync_elevel(ERROR), base-commit: acb96eb7d294a003a9392cdd445630ef137d9918 -- 2.22.0