Github user paul-guo- commented on a diff in the pull request:
https://github.com/apache/incubator-hawq/pull/1243#discussion_r119278591
--- Diff: src/backend/executor/nodeMaterial.c ---
@@ -759,3 +764,30 @@ ExecEagerFreeMaterial(MaterialState *node)
}
}
+
+/*
+ * mkLockFileForWriter
+ *
+ * Create a unique lock file for writer, then use flock() to lock/unlock
the lock file.
+ * We can make sure the lock file will be locked forerver until the writer
process quits.
+ */
+static void mkLockFileForWriter(int size, int share_id, char * name)
+{
+ char *lock_file;
+ int lock;
+
+ lock_file = (char *)palloc0(sizeof(char) * MAXPGPATH);
+ generate_lock_file_name(lock_file, size, share_id, name);
+ elog(DEBUG3, "The lock file for writer in SISC is %s", lock_file);
+ sisc_writer_lock_fd = open(lock_file, O_CREAT, S_IRWXU);
+ if(sisc_writer_lock_fd < 0)
+ {
+ elog(ERROR, "Could not create lock file %s for writer in SISC.
The error number is %d", lock_file, errno);
+ }
+ lock = flock(sisc_writer_lock_fd, LOCK_EX | LOCK_NB);
+ if(lock == -1)
+ elog(DEBUG3, "Could not lock lock file \"%s\" for writer in
SISC . The error number is %d", lock_file, errno);
+ else if(lock == 0)
+ elog(DEBUG3, "Successfully locked lock file \"%s\" for writer
in SISC.The error number is %d", lock_file, errno);
--- End diff --
For (lock == 0), there is no need of errno in log.
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