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Question
· Jan 21

$Storage and Private global

#Globals #InterSystems IRIS #InterSystems IRIS for Health

Hello Community,

The process private global doesn't impact the $storage. But, Why the value has decreases at first time of initialization. 

LEARNING>write $zversion
IRIS for Windows (x86-64) 2023.3 (Build 254) Wed Nov 8 2023 13:28:10 EST
LEARNING>write "$Storage: ",$storage
$Storage: 2199023141712
LEARNING>set ^||Test="Test"
 
LEARNING>write "$Storage: ",$storage
$Storage: 2199023136848
LEARNING>write 2199023141712-$storage
4864

Just want to ensure about it.

Product version: IRIS 2023.3
$ZV: IRIS for Windows (x86-64) 2023.3 (Build 254)
Discussion (4)1
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Julius Kavay · Jan 21

Oh, I see, at the very first use of a (new) private global,  the storage is decremented (on my  machine) by 768 bytes. I think, that bytes will hold some management data for each provate global (name).

Instance: cindy:ICINDY
Version : IRIS for UNIX (Ubuntu Server LTS for x86-64) 2021.2 (Build 649U) Thu Jan 20 2022 08:49:51 EST

Username: kav
Password: ******
USER>s x=$storage

USER>set x=$storage, ^myKav=123 write x-$storage
768
USER>set x=$storage, ^myKav2=123 write x-$storage
768
USER>set x=$storage, ^myKav3=123 write x-$storage
768
USER>set x=$storage, ^myKav3=123 write x-$storage
0
USER>set x=$storage, ^myKav2=123 write x-$storage
0
USER>set x=$storage, ^myKav=123 write x-$storage
0
USER>
1 0
Ashok Kumar · Jan 24

Thanks @Julius Kavay ,

Ok. Yes, both global and private global storage at the first time of initialization.  Why does it consumes minimum 8 byte(seems default and Is this Default byte size) regardless of single character(1 byte) in $storage. It consumes same or more than same byte when store in to global. Is this actual physical storage size(bytes) for the global.

 LEARNING>Set ^TEST="a"
 LEARNING>d ^%GSIZE
Global ^TEST
directory: c:\intersystems\irishealth\mgr\learning\
Page: 1                           GLOBAL SIZE                        24 Jan 2024
                                                                        11:26 AM
      Global        Blocks       Bytes Used  Packing   Contig.
      --------    --------  ---------------  -------   -------
      TEST               1               12      0 %         0
      TOTAL         Blocks       Bytes Used  Packing   Contig.
      --------    --------  ---------------  -------   -------
                         1               12      0 %         0
                                        <RETURN> to continue or '^' to STOP:
0 0