On 2020-May-26, Tom Lane wrote:
> Are you sure you correctly identified the source of the bogus error
> report?
This version's better. It doesn't touch the write side at all.
On the read side, only report a short read as such if errno's not set.
This error isn't frequently seen. This page
https://blog.csdn.net/pg_hgdb/article/details/106279303
(A Postgres fork; blames the error on the temp hash files being encrypted,
suggests to increase temp_buffers) is the only one I found.
There are more uses of BufFileRead that don't bother to distinguish
these two cases apart, though -- logtape.c, tuplestore.c,
gistbuildbuffers.c all do the same.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
diff --git a/src/backend/executor/nodeHashjoin.c b/src/backend/executor/nodeHashjoin.c
index d13efc4d98..f91e69a09d 100644
--- a/src/backend/executor/nodeHashjoin.c
+++ b/src/backend/executor/nodeHashjoin.c
@@ -930,9 +930,17 @@ ExecHashJoinGetSavedTuple(HashJoinState *hjstate,
return NULL;
}
if (nread != sizeof(header))
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not read from hash-join temporary file: %m")));
+ {
+ if (errno == 0)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read from hash-join temporary file: read only %d of %d bytes",
+ (int) nread, (int) sizeof(header))));
+ else
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read from hash-join temporary file: %m")));
+ }
*hashvalue = header[0];
tuple = (MinimalTuple) palloc(header[1]);
tuple->t_len = header[1];
@@ -940,9 +948,17 @@ ExecHashJoinGetSavedTuple(HashJoinState *hjstate,
(void *) ((char *) tuple + sizeof(uint32)),
header[1] - sizeof(uint32));
if (nread != header[1] - sizeof(uint32))
- ereport(ERROR,
- (errcode_for_file_access(),
- errmsg("could not read from hash-join temporary file: %m")));
+ {
+ if (errno == 0)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read from hash-join temporary file: read only %d of %d bytes",
+ (int) nread, (int) (header[1] - sizeof(uint32)))));
+ else
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not read from hash-join temporary file: %m")));
+ }
return ExecStoreMinimalTuple(tuple, tupleSlot, true);
}
