Github user paul-guo- commented on a diff in the pull request: https://github.com/apache/incubator-hawq/pull/1243#discussion_r118222465 --- Diff: src/backend/executor/nodeMaterial.c --- @@ -759,3 +764,30 @@ ExecEagerFreeMaterial(MaterialState *node) } } + +/* + * mkLockFileForWriter + * + * Create a unique lock file for writer. Then use flock's unblock way to lock the lock file. + * We can make sure the lock file will be locked forerver until the writer process has quit. + */ +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 : %m. The error number is %d", lock_file, errno); + else if(lock == 0) + elog(DEBUG3, "Successfully locked lock file \"%s\" for writer in SISC: %m.The error number is %d", lock_file, errno); + pfree(lock_file); --- End diff -- ditto.
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