Demonstrate how resizing needs less disk space than creating orphans

t_zbigarray_resize.py

+import os
+import sys
+
+from golang import defer, func
+import numpy as np
+import transaction
+import ZODB, ZODB.FileStorage
+
+from wendelin.bigarray.array_zodb import ZBigArray
+
+storage_path = "tzbigarray.fs"
+
+try:
+    os.remove(storage_path)
+except:
+    pass
+
+@func
+def root(func):
+    storage = ZODB.FileStorage.FileStorage(storage_path, pack_gc=False)
+
+    db = ZODB.DB(storage)
+    connection = db.open()
+    root = connection.root
+
+    defer(connection.close)
+    defer(db.close)
+    defer(storage.close)
+
+    func(root, storage, db)
+
+
+def t(root, storage, db):
+    def _(msg):
+        print(msg + '\n')
+        #print("array: %s" % str(arr[:]))
+        print("\tshape: %s" % str(arr.shape))
+        print("\tstorage length: %s" % len(storage))
+        print("\tstorage size: %s" % _getstoragesize())
+        print('\n')
+
+    arr = root.zbigarray = ZBigArray(shape=[0, 2], dtype=int)
+    transaction.commit()
+    _("Create new ZBigArray")
+
+    _append_zblk(arr)
+    _("Append ~one ZBlk to ZBigAray")
+
+    db.pack()
+    _("Pack database (1)")
+
+    arr.resize((0, 2))
+    transaction.commit()
+    _("Resize array (set length to 0)")
+
+    _append_zblk(arr)
+    _("Add new data again to array (to have same size as before)")
+
+    db.pack()
+    _("Pack database (2)")
+
+    _append_zblk(arr)
+    _("Add more new data")
+
+    db.pack()
+    _("Pack database (3)")
+
+
+def _append_zblk(arr, size=2):
+    elements = 200000  # roughly the size of 1xZBlk0
+    arr.append([[0 for _ in range(size)] for _ in range(int(elements / size))]) 
+    transaction.commit()
+
+def _getstoragesize():
+    return os.path.getsize(storage_path)
+
+
+if __name__ == "__main__":
+    root(t)
+

t_zbigarray_set_none.py

+import os
+import sys
+
+from golang import defer, func
+import numpy as np
+import transaction
+import ZODB, ZODB.FileStorage
+
+from wendelin.bigarray.array_zodb import ZBigArray
+
+storage_path = "tzbigarray.fs"
+
+try:
+    os.remove(storage_path)
+except:
+    pass
+
+@func
+def root(func):
+    storage = ZODB.FileStorage.FileStorage(storage_path, pack_gc=False)
+
+    db = ZODB.DB(storage)
+    connection = db.open()
+    root = connection.root
+
+    defer(connection.close)
+    defer(db.close)
+    defer(storage.close)
+
+    func(root, storage, db)
+
+
+def t(root, storage, db):
+    def _(msg):
+        print(msg + '\n')
+        #print("array: %s" % str(arr[:]))
+        print("\tshape: %s" % str(arr.shape))
+        print("\tstorage length: %s" % len(storage))
+        print("\tstorage size: %s" % _getstoragesize())
+        print('\n')
+
+    arr = root.zbigarray = ZBigArray(shape=[0, 2], dtype=int)
+    transaction.commit()
+    _("Create new ZBigArray (1)")
+
+    _append_zblk(arr)
+    _("Append ~one ZBlk to ZBigAray")
+
+    db.pack()
+    _("Pack database (1)")
+
+    root.zbigarray = None
+    transaction.commit()
+    _("De-refer initial ZBigArray")
+
+    arr = root.zbigarray = ZBigArray(shape=[0, 2], dtype=int)
+    transaction.commit()
+    _("Create new ZBigArray (2)")
+
+    _append_zblk(arr)
+    _("Add new data to newly created array")
+
+    db.pack()
+    _("Pack database (2)")
+
+    _append_zblk(arr)
+    _("Add more new data")
+
+    db.pack()
+    _("Pack database (3)")
+
+
+def _append_zblk(arr, size=2):
+    elements = 200000  # roughly the size of 1xZBlk0
+    arr.append([[0 for _ in range(size)] for _ in range(int(elements / size))]) 
+    transaction.commit()
+
+def _getstoragesize():
+    return os.path.getsize(storage_path)
+
+
+if __name__ == "__main__":
+    root(t)
+