Catch harmless error seen in apache logs during shutdown

We saw a bug where renamed streams had missing data at the end.  I
think what happened is:

- Write data to /old/path
- Rename to /new/path
- Write data to /new/path
- Cache entry for /old/path gets evicted, file gets truncated

Instead, make sure we evict /old/path right away when renaming.

Makefile

@@ -23,10 +23,6 @@ docs:
 lint:
 	pylint --rcfile=.pylintrc nilmdb
 
-fscktest:
-#	python -c "import nilmdb.fsck; nilmdb.fsck.Fsck('/home/jim/wsgi/db').check()"
-	python -c "import nilmdb.fsck; nilmdb.fsck.Fsck('/home/jim/mnt/bucket/mnt/sharon/data/db').check()"
-
 test:
 ifeq ($(INSIDE_EMACS), t)
 # Use the slightly more flexible script

README.txt

@@ -8,7 +8,8 @@ Prerequisites:
 
   # Base NilmDB dependencies
   sudo apt-get install python-cherrypy3 python-decorator python-simplejson
-  sudo apt-get install python-requests python-dateutil python-tz python-psutil
+  sudo apt-get install python-requests python-dateutil python-tz
+  sudo apt-get install python-progressbar python-psutil
 
   # Other dependencies (required by some modules)
   sudo apt-get install python-numpy
@@ -26,6 +27,7 @@ Install:
 Usage:
 
   nilmdb-server --help
+  nilmdb-fsck --help
   nilmtool --help
 
 See docs/wsgi.md for info on setting up a WSGI application in Apache.

nilmdb/client/httpclient.py

@@ -9,7 +9,7 @@ import requests
 
 class HTTPClient(object):
     """Class to manage and perform HTTP requests from the client"""
-    def __init__(self, baseurl = "", post_json = False):
+    def __init__(self, baseurl = "", post_json = False, verify_ssl = True):
         """If baseurl is supplied, all other functions that take
         a URL can be given a relative URL instead."""
         # Verify / clean up URL
@@ -19,6 +19,7 @@ class HTTPClient(object):
         self.baseurl = reparsed.rstrip('/') + '/'
 
         # Build Requests session object, enable SSL verification
+        self.verify_ssl = verify_ssl
         self.session = requests.Session()
         self.session.verify = True
 
@@ -67,7 +68,8 @@ class HTTPClient(object):
                                             params = query_data,
                                             data = body_data,
                                             stream = stream,
-                                            headers = headers)
+                                            headers = headers,
+                                            verify = self.verify_ssl)
         except requests.RequestException as e:
             raise ServerError(status = "502 Error", url = url,
                               message = str(e.message))

nilmdb/cmdline/cmdline.py

@@ -19,9 +19,8 @@ except ImportError: # pragma: no cover
 
 # Valid subcommands.  Defined in separate files just to break
 # things up -- they're still called with Cmdline as self.
-subcommands = [ "help", "info", "create", "list", "metadata",
-                "insert", "extract", "remove", "destroy",
-                "intervals", "rename" ]
+subcommands = [ "help", "info", "create", "rename", "list", "intervals",
+                "metadata", "insert", "extract", "remove", "destroy" ]
 
 # Import the subcommand modules
 subcmd_mods = {}
@@ -122,7 +121,7 @@ class Cmdline(object):
         group = self.parser.add_argument_group("General options")
         group.add_argument("-h", "--help", action='help',
                            help='show this help message and exit')
-        group.add_argument("-V", "--version", action="version",
+        group.add_argument("-v", "--version", action="version",
                            version = nilmdb.__version__)
 
         group = self.parser.add_argument_group("Server")

nilmdb/cmdline/list.py

@@ -45,6 +45,8 @@ def setup(self, sub):
                        help="Show raw timestamps when printing times")
     group.add_argument("-l", "--layout", action="store_true",
                        help="Show layout type next to path name")
+    group.add_argument("-n", "--no-decim", action="store_true",
+                       help="Skip paths containing \"~decim-\"")
 
     return cmd
 
@@ -71,6 +73,8 @@ def cmd_list(self):
             (path, layout, int_min, int_max, rows, time) = stream[:6]
             if not fnmatch.fnmatch(path, argpath):
                 continue
+            if self.args.no_decim and "~decim-" in path:
+                continue
 
             if self.args.layout:
                 printf("%s %s\n", path, layout)

nilmdb/fsck/.#fsck.py

@@ -1 +0,0 @@
-jim@pilot.lees.18066:1373305995

nilmdb/fsck/fsck.py

@@ -1,9 +1,13 @@
 # -*- coding: utf-8 -*-
 
-"""Check database consistency"""
+"""Check database consistency, with some ability to fix problems.
+This should be able to fix cases where a database gets corrupted due
+to unexpected system shutdown, and detect other cases that may cause
+NilmDB to return errors when trying to manipulate the database."""
 
 import nilmdb.utils
 import nilmdb.server
+import nilmdb.client.numpyclient
 from nilmdb.utils.interval import IntervalError
 from nilmdb.server.interval import Interval, IntervalSet
 from nilmdb.utils.printf import *
@@ -12,13 +16,26 @@ from nilmdb.utils.time import timestamp_to_string
 from collections import defaultdict
 import sqlite3
 import os
+import sys
 import progressbar
+import re
 import time
+import shutil
 import cPickle as pickle
+import numpy
 
 class FsckError(Exception):
-    def __init__(self, format, *args):
-        Exception.__init__(self, sprintf(format, *args))
+    def __init__(self, msg = "", *args):
+        if args:
+            msg = sprintf(msg, *args)
+        Exception.__init__(self, msg)
+class FixableFsckError(FsckError):
+    def __init__(self, msg = "", *args):
+        if args:
+            msg = sprintf(msg, *args)
+        FsckError.__init__(self, "%s\nThis may be fixable with \"--fix\".", msg)
+class RetryFsck(FsckError):
+    pass
 
 def log(format, *args):
     printf(format, *args)
@@ -26,9 +43,29 @@ def log(format, *args):
 def err(format, *args):
     fprintf(sys.stderr, format, *args)
 
+# Decorator that retries a function if it returns a specific value
+def retry_if_raised(exc, message = None, max_retries = 100):
+    def f1(func):
+        def f2(*args, **kwargs):
+            for n in range(max_retries):
+                try:
+                    return func(*args, **kwargs)
+                except exc as e:
+                    if message:
+                        log("%s\n\n", message)
+            raise Exception("Max number of retries (%d) exceeded; giving up")
+        return f2
+    return f1
+
 class Progress(object):
     def __init__(self, maxval):
-        self.bar = progressbar.ProgressBar(maxval = maxval)
+        if maxval == 0:
+            maxval = 1
+        self.bar = progressbar.ProgressBar(
+            maxval = maxval,
+            widgets = [ progressbar.Percentage(), ' ',
+                        progressbar.Bar(), ' ',
+                        progressbar.ETA() ])
         if self.bar.term_width == 0:
             self.bar.term_width = 75
     def __enter__(self):
@@ -42,45 +79,68 @@ class Progress(object):
             printf("\n")
     def update(self, val):
         self.bar.update(val)
-        #now = time.time()
-        #if now - self.last_update < 0.005:
-        #   time.sleep(0.005)
-        #self.last_update = now
 
 class Fsck(object):
 
-    def __init__(self, path):
+    def __init__(self, path, fix = False):
         self.basepath = path
         self.sqlpath = os.path.join(path, "data.sql")
         self.bulkpath = os.path.join(path, "data")
         self.bulklock = os.path.join(path, "data.lock")
+        self.fix = fix
 
-    def check(self):
-        self.check_paths()
-        self.check_sql()
-        self.check_streams()
+    ### Main checks
+
+    @retry_if_raised(RetryFsck, "Something was fixed: restarting fsck")
+    def check(self, skip_data = False):
+        self.bulk = None
+        self.sql = None
+        try:
+            self.check_paths()
+            self.check_sql()
+            self.check_streams()
+            self.check_intervals()
+            if skip_data:
+                log("skipped data check\n")
+            else:
+                self.check_data()
+        finally:
+            if self.bulk:
+                self.bulk.close()
+            if self.sql:
+                self.sql.commit()
+                self.sql.close()
         log("ok\n")
 
+    ### Check basic path structure
+
     def check_paths(self):
         log("checking paths\n")
+        if self.bulk:
+            self.bulk.close()
         if not os.path.isfile(self.sqlpath):
-            raise FsckError("SQL database missing")
+            raise FsckError("SQL database missing (%s)", self.sqlpath)
         if not os.path.isdir(self.bulkpath):
-            raise FsckError("Bulk data directory missing")
+            raise FsckError("Bulk data directory missing (%s)", self.bulkpath)
         with open(self.bulklock, "w") as lockfile:
             if not nilmdb.utils.lock.exclusive_lock(lockfile):
-                raise FsckError('database already locked by another process')
+                raise FsckError('Database already locked by another process\n'
+                                'Make sure all other processes that might be '
+                                'using the database are stopped.\n'
+                                'Restarting apache will cause it to unlock '
+                                'the db until a request is received.')
+            # unlocked immediately
         self.bulk = nilmdb.server.bulkdata.BulkData(self.basepath)
-        # override must_close warning
-        if "_must_close" in dir(self.bulk):
-            del self.bulk._must_close
+
+    ### Check SQL database health
 
     def check_sql(self):
         log("checking sqlite database\n")
 
         self.sql = sqlite3.connect(self.sqlpath)
-        with self.sql as con:
-            ver = con.execute("PRAGMA user_version").fetchone()[0]
+        with self.sql:
+            cur = self.sql.cursor()
+            ver = cur.execute("PRAGMA user_version").fetchone()[0]
             good = max(nilmdb.server.nilmdb._sql_schema_updates.keys())
             if ver != good:
                 raise FsckError("database version %d too old, should be %d",
@@ -88,7 +148,7 @@ class Fsck(object):
             self.stream_path = {}
             self.stream_layout = {}
             log("  loading paths\n")
-            result = con.execute("SELECT id, path, layout FROM streams")
+            result = cur.execute("SELECT id, path, layout FROM streams")
             for r in result:
                 if r[0] in self.stream_path:
                     raise FsckError("duplicated ID %d in stream IDs", r[0])
@@ -97,8 +157,9 @@ class Fsck(object):
 
             log("  loading intervals\n")
             self.stream_interval = defaultdict(list)
-            result = con.execute("SELECT stream_id, start_time, end_time, "
-                                 "start_pos, end_pos FROM ranges")
+            result = cur.execute("SELECT stream_id, start_time, end_time, "
+                                 "start_pos, end_pos FROM ranges "
+                                 "ORDER BY start_time")
             for r in result:
                 if r[0] not in self.stream_path:
                     raise FsckError("interval ID %d not in streams", k)
@@ -106,7 +167,7 @@ class Fsck(object):
 
             log("  loading metadata\n")
             self.stream_meta = defaultdict(dict)
-            result = con.execute("SELECT stream_id, key, value FROM metadata")
+            result = cur.execute("SELECT stream_id, key, value FROM metadata")
             for r in result:
                 if r[0] not in self.stream_path:
                     raise FsckError("metadata ID %d not in streams", k)
@@ -115,9 +176,11 @@ class Fsck(object):
                                     r[1], r[0])
                 self.stream_meta[r[0]][r[1]] = r[2]
 
+    ### Check streams and basic interval overlap
+
     def check_streams(self):
-        log("checking streams\n")
         ids = self.stream_path.keys()
+        log("checking %s streams\n", "{:,d}".format(len(ids)))
         with Progress(len(ids)) as pbar:
             for i, sid in enumerate(ids):
                 pbar.update(i)
@@ -152,7 +215,7 @@ class Fsck(object):
                         timeiset += new
                     except IntervalError:
                         raise FsckError("%s: overlap in intervals:\n"
-                                        "set: %s\nnew: %s\n",
+                                        "set: %s\nnew: %s",
                                         path, str(timeiset), str(new))
                     if spos != epos:
                         new = Interval(spos, epos)
@@ -160,14 +223,13 @@ class Fsck(object):
                             posiset += new
                         except IntervalError:
                             raise FsckError("%s: overlap in file offsets:\n"
-                                            "set: %s\nnew: %s\n",
+                                            "set: %s\nnew: %s",
                                             path, str(posiset), str(new))
 
                 # check bulkdata
                 self.check_bulkdata(sid, path, bulk)
 
-                continue
-                # verify we can can open it with bulkdata
+                # Check that we can open bulkdata
                 try:
                     tab = None
                     try:
@@ -175,11 +237,13 @@ class Fsck(object):
                     except Exception as e:
                         raise FsckError("%s: can't open bulkdata: %s",
                                         path, str(e))
-                    self.check_bulkdata(path, tab)
                 finally:
                     if tab:
                         tab.close()
 
+    ### Check that bulkdata is good enough to be opened
+
+    @retry_if_raised(RetryFsck)
     def check_bulkdata(self, sid, path, bulk):
         with open(os.path.join(bulk, "_format"), "rb") as f:
             fmt = pickle.load(f)
@@ -192,3 +256,205 @@ class Fsck(object):
         if layout != self.stream_layout[sid]:
             raise FsckError("%s: layout mismatch %s != %s", path,
                             layout, self.stream_layout[sid])
+
+        # Every file should have a size that's the multiple of the row size
+        rkt = nilmdb.server.rocket.Rocket(layout, None)
+        row_size = rkt.binary_size
+        rkt.close()
+
+        # Find all directories
+        regex = re.compile("^[0-9a-f]{4,}$")
+        subdirs = sorted(filter(regex.search, os.listdir(bulk)),
+                         key = lambda x: int(x, 16), reverse = True)
+        for subdir in subdirs:
+            # Find all files in that dir
+            subpath = os.path.join(bulk, subdir)
+            files = filter(regex.search, os.listdir(subpath))
+            if not files:
+                self.fix_empty_subdir(subpath)
+                raise RetryFsck
+            # Verify that their size is a multiple of the row size
+            for filename in files:
+                filepath = os.path.join(subpath, filename)
+                offset = os.path.getsize(filepath)
+                if offset % row_size:
+                    self.fix_bad_filesize(path, filepath, offset, row_size)
+
+    def fix_empty_subdir(self, subpath):
+        msg = sprintf("bulkdata path %s is missing data files", subpath)
+        if not self.fix:
+            raise FixableFsckError(msg)
+        # Try to fix it by just deleting whatever is present,
+        # as long as it's only ".removed" files.
+        err("\n%s\n", msg)
+        for fn in os.listdir(subpath):
+            if not fn.endswith(".removed"):
+                raise FsckError("can't fix automatically: please manually "
+                                "remove the file %s and try again",
+                                os.path.join(subpath, fn))
+        # Remove the whole thing
+        err("Removing empty subpath\n")
+        shutil.rmtree(subpath)
+        raise RetryFsck
+
+    def fix_bad_filesize(self, path, filepath, offset, row_size):
+        extra = offset % row_size
+        msg = sprintf("%s: size of file %s (%d) is not a multiple" +
+                      " of row size (%d): %d extra bytes present",
+                      path, filepath, offset, row_size, extra)
+        if not self.fix:
+            raise FixableFsckError(msg)
+        # Try to fix it by just truncating the file
+        err("\n%s\n", msg)
+        newsize = offset - extra
+        err("Truncating file to %d bytes and retrying\n", newsize)
+        with open(filepath, "r+b") as f:
+            f.truncate(newsize)
+            raise RetryFsck
+
+    ### Check interval endpoints
+
+    def check_intervals(self):
+        total_ints = sum(len(x) for x in self.stream_interval.values())
+        log("checking %s intervals\n", "{:,d}".format(total_ints))
+        done = 0
+        with Progress(total_ints) as pbar:
+            for sid in self.stream_interval:
+                try:
+                    bulk = self.bulkpath + self.stream_path[sid]
+                    tab = nilmdb.server.bulkdata.Table(bulk)
+                    def update(x):
+                        pbar.update(done + x)
+                    ints = self.stream_interval[sid]
+                    done += self.check_table_intervals(sid, ints, tab, update)
+                finally:
+                    tab.close()
+
+    def check_table_intervals(self, sid, ints, tab, update):
+        # look in the table to make sure we can pick out the interval's
+        # endpoints
+        path = self.stream_path[sid]
+        tab.file_open.cache_remove_all()
+        for (i, intv) in enumerate(ints):
+            update(i)
+            (stime, etime, spos, epos) = intv
+            if spos == epos and spos >= 0 and spos <= tab.nrows:
+                continue
+            try:
+                srow = tab[spos]
+                erow = tab[epos-1]
+            except Exception as e:
+                self.fix_bad_interval(sid, intv, tab, str(e))
+                raise RetryFsck
+        return len(ints)
+
+    def fix_bad_interval(self, sid, intv, tab, msg):
+        path = self.stream_path[sid]
+        msg = sprintf("%s: interval %s error accessing rows: %s",
+                      path, str(intv), str(msg))
+        if not self.fix:
+            raise FixableFsckError(msg)
+        err("\n%s\n", msg)
+
+        (stime, etime, spos, epos) = intv
+        # If it's just that the end pos is more than the number of rows
+        # in the table, lower end pos and truncate interval time too.
+        if spos < tab.nrows and epos >= tab.nrows:
+            err("end position is past endrows, but it can be truncated\n")
+            err("old end: time %d, pos %d\n", etime, epos)
+            new_epos = tab.nrows
+            new_etime = tab[new_epos-1] + 1
+            err("new end: time %d, pos %d\n", new_etime, new_epos)
+            if stime < new_etime:
+                # Change it in SQL
+                with self.sql:
+                    cur = self.sql.cursor()
+                    cur.execute("UPDATE ranges SET end_time=?, end_pos=? "
+                                "WHERE stream_id=? AND start_time=? AND "
+                                "end_time=? AND start_pos=? AND end_pos=?",
+                                (new_etime, new_epos, sid, stime, etime,
+                                 spos, epos))
+                    if cur.rowcount != 1:
+                        raise FsckError("failed to fix SQL database")
+                raise RetryFsck
+            err("actually it can't be truncated; times are bad too")
+
+        # Otherwise, the only hope is to delete the interval entirely.
+        err("*** Deleting the entire interval from SQL.\n")
+        err("This may leave stale data on disk.  To fix that, copy all\n")
+        err("data from this stream to a new stream, then remove all data\n")
+        err("from and destroy %s.\n", path)
+        with self.sql:
+            cur = self.sql.cursor()
+            cur.execute("DELETE FROM ranges WHERE "
+                        "stream_id=? AND start_time=? AND "
+                        "end_time=? AND start_pos=? AND end_pos=?",
+                        (sid, stime, etime, spos, epos))
+            if cur.rowcount != 1:
+                raise FsckError("failed to remove interval")
+        raise RetryFsck
+
+    ### Check data in each interval
+
+    def check_data(self):
+        total_rows = sum(sum((y[3] - y[2]) for y in x)
+                         for x in self.stream_interval.values())
+        log("checking %s rows of data\n", "{:,d}".format(total_rows))
+        done = 0
+        with Progress(total_rows) as pbar:
+            for sid in self.stream_interval:
+                try:
+                    bulk = self.bulkpath + self.stream_path[sid]
+                    tab = nilmdb.server.bulkdata.Table(bulk)
+                    def update(x):
+                        pbar.update(done + x)
+                    ints = self.stream_interval[sid]
+                    done += self.check_table_data(sid, ints, tab, update)
+                finally:
+                    tab.close()
+
+    def check_table_data(self, sid, ints, tab, update):
+        # Pull out all of the interval's data and verify that it's
+        # monotonic.
+        maxrows = 100000
+        path = self.stream_path[sid]
+        layout = self.stream_layout[sid]
+        dtype = nilmdb.client.numpyclient.layout_to_dtype(layout)
+        tab.file_open.cache_remove_all()
+        done = 0
+        for intv in ints:
+            last_ts = None
+            (stime, etime, spos, epos) = intv
+            if spos == epos:
+                continue
+            for start in xrange(*slice(spos, epos, maxrows).indices(epos)):
+                stop = min(start + maxrows, epos)
+                count = stop - start
+                # Get raw data, convert to NumPy arary
+                try:
+                    raw = tab.get_data(start, stop, binary = True)
+                    data = numpy.fromstring(raw, dtype)
+                except Exception as e:
+                    raise FsckError("%s: failed to grab rows %d through %d: %s",
+                                    path, start, stop, repr(e))
+
+                # Verify that timestamps are monotonic
+                if (numpy.diff(data['timestamp']) <= 0).any():
+                    raise FsckError("%s: non-monotonic timestamp(s) in rows "
+                                    "%d through %d", path, start, stop)
+                first_ts = data['timestamp'][0]
+                if last_ts is not None and first_ts <= last_ts:
+                    raise FsckError("%s: first interval timestamp %d is not "
+                                    "greater than the previous last interval "
+                                    "timestamp %d, at row %d",
+                                    path, first_ts, last_ts, start)
+                last_ts = data['timestamp'][-1]
+
+                # These are probably fixable, by removing the offending
+                # intervals.  But I'm not going to bother implementing
+                # that yet.
+
+                # Done
+                done += count
+                update(done)
+        return done

nilmdb/scripts/nilmdb_fsck.py

@@ -10,14 +10,17 @@ def main():
 
     parser = argparse.ArgumentParser(
         description = 'Check database consistency',
-        formatter_class = argparse.ArgumentDefaultsHelpFormatter)
-    parser.add_argument("-V", "--version", action="version",
-                        version = nilmdb.__version__)
-    parser.add_argument('-d', '--database', help = 'Database directory',
-                        default = "./db")
+        formatter_class = argparse.ArgumentDefaultsHelpFormatter,
+        version = nilmdb.__version__)
+    parser.add_argument("-f", "--fix", action="store_true",
+                        default=False, help = 'Fix errors when possible '
+                        '(which may involve removing data)')
+    parser.add_argument("-n", "--no-data", action="store_true",
+                        default=False, help = 'Skip the slow full-data check')
+    parser.add_argument('database', help = 'Database directory')
     args = parser.parse_args()
 
-    nilmdb.fsck.Fsck(args.database).check()
+    nilmdb.fsck.Fsck(args.database, args.fix).check(skip_data = args.no_data)
 
 if __name__ == "__main__":
     main()

nilmdb/scripts/nilmdb_server.py

@@ -10,10 +10,8 @@ def main():
 
     parser = argparse.ArgumentParser(
         description = 'Run the NilmDB server',
-        formatter_class = argparse.ArgumentDefaultsHelpFormatter)
-
-    parser.add_argument("-V", "--version", action="version",
-                        version = nilmdb.__version__)
+        formatter_class = argparse.ArgumentDefaultsHelpFormatter,
+        version = nilmdb.__version__)
 
     group = parser.add_argument_group("Standard options")
     group.add_argument('-a', '--address',

nilmdb/server/bulkdata.py

@@ -194,6 +194,9 @@ class BulkData(object):
         if oldospath == newospath:
             raise ValueError("old and new paths are the same")
 
+        # Remove Table object at old path from cache
+        self.getnode.cache_remove(self, oldunicodepath)
+
         # Move the table to a temporary location
         tmpdir = tempfile.mkdtemp(prefix = "rename-", dir = self.root)
         tmppath = os.path.join(tmpdir, "table")

nilmdb/server/server.py

@@ -74,8 +74,8 @@ class Root(NilmApp):
         dbsize = nilmdb.utils.du(path)
         return { "path": path,
                  "size": dbsize,
-                 "other": usage.used - dbsize,
-                 "reserved": usage.total - usage.used - usage.free,
+                 "other": max(usage.used - dbsize, 0),
+                 "reserved": max(usage.total - usage.used - usage.free, 0),
                  "free": usage.free }
 
 class Stream(NilmApp):

nilmdb/utils/diskusage.py

@@ -21,7 +21,8 @@ def du(path):
     errors that might occur if we encounter broken symlinks or
     files in the process of being removed."""
     try:
-        size = os.path.getsize(path)
+        st = os.stat(path)
+        size = st.st_blocks * 512
         if os.path.isdir(path):
             for thisfile in os.listdir(path):
                 filepath = os.path.join(path, thisfile)

nilmdb/utils/serializer.py

@@ -117,7 +117,10 @@ def serializer_proxy(obj_or_type):
             return ret
 
         def __del__(self):
-            self.__call_queue.put((None, None, None, None))
-            self.__thread.join()
+            try:
+                self.__call_queue.put((None, None, None, None))
+                self.__thread.join()
+            except TypeError: # pragma: no cover
+                pass
 
     return SerializerObjectProxy(obj_or_type)

setup.py

@@ -118,6 +118,7 @@ setup(name='nilmdb',
                            'pytz',
                            'psutil >= 0.3.0',
                            'requests >= 1.1.0, < 2.0.0',
+                           'progressbar >= 2.2',
                            ],
       packages = [ 'nilmdb',
                    'nilmdb.utils',

tests/test_cmdline.py

@@ -290,6 +290,7 @@ class TestCmdline(object):
         self.ok("create /newton/zzz/rawnotch uint16_9")
         self.ok("create /newton/prep float32_8")
         self.ok("create /newton/raw uint16_6")
+        self.ok("create /newton/raw~decim-1234 uint16_6")
 
         # Create a stream that already exists
         self.fail("create /newton/raw uint16_6")
@@ -305,13 +306,23 @@ class TestCmdline(object):
         self.fail("create /newton/zzz float32_8")
         self.contain("subdirs of this path already exist")
 
-        # Verify we got those 3 streams and they're returned in
+        # Verify we got those 4 streams and they're returned in
         # alphabetical order.
         self.ok("list -l")
         self.match("/newton/prep float32_8\n"
                    "/newton/raw uint16_6\n"
+                   "/newton/raw~decim-1234 uint16_6\n"
                    "/newton/zzz/rawnotch uint16_9\n")
 
+        # No decimated streams if -n specified
+        self.ok("list -n -l")
+        self.match("/newton/prep float32_8\n"
+                   "/newton/raw uint16_6\n"
+                   "/newton/zzz/rawnotch uint16_9\n")
+
+        # Delete that decimated stream
+        self.ok("destroy /newton/raw~decim-1234")
+
         # Match just one type or one path.  Also check
         # that --path is optional
         self.ok("list --layout /newton/raw")