Determining Sizes of Globals

InterSystems IRIS® data platform provides tools you can use to measure the size of any global.

^%GSIZE Routine

The ^%GSIZE routine enables you to determine the size of one or more globals. To use this routine:

Start an ObjectScript shell.
Start the routine:
```
 do ^%GSIZE
```
The first prompt lets you specify the database to look at. The prompt refers to the directory that contains the database file:
```
Directory name: c:\intersystems\iris211\mgr\enslib\ =>
```
The default is the globals database used by the namespace that you are currently in. You can either press Enter to accept this default, or type a full directory name and then press Enter.
The next prompt is as follows:
```
All Globals? No =>
```
If you want information on all globals, enter Y (case-insensitive). Otherwise press Enter.

Note:

If you request information on all globals, that includes all the internal, undocumented globals as well as your own globals. Some of these are quite large.
If you did not enter Y in the previous step, the next prompt looks like the following, which is asking for a global name:
```
Global ^
```
Type the global name, without the leading caret and press Enter.
Repeat as necessary. When you are done entering global names, press Enter again. Then the routine displays a message indicating how many globals you have selected:
```
All Globals? No => No
Global ^IRIS.Msg
Global ^
1 global selected from 64 available globals.
```
The next prompt asks about the kind of report to generate:
```
1) Get exact packing details
2) Get block counts only
3) Use fast stochastic estimate
 
Please select an option:  3 =>
```
Option 1 scans the entire global and obtains full information; this is time-consuming for a large global. Option 2 obtains only the block counts. Option 3 (a new feature in release 2023.3) estimates the size, which is faster than scanning the entire global.
Enter 1, 2 or 3.
Press Enter for the next two prompts, which let you specify where to write the output:
```
Device:
```
and
```
Right margine: 80 =>
```

The routine then displays output like the following, when using option 1 or 3:

Page: 1
        Global              Blocks          Bytes Used Packing
      ----------- ---------------- ------------------- -------
      IRIS.Msg                942           5,791,760     75 %
 
 
      TOTAL                 Blocks          Bytes Used Packing
      ----------- ---------------- ------------------- -------
                              942           5,791,760     75 %

When using option 2, the report displays only the block counts.

APIs for Getting Global Sizes

Several classes provide APIs for getting sizes of globals:

The class %GlobalEditOpens in a new tab provides methods such as the following:
- CheckIntegrity()
- GetGlobalSize()
- GetGlobalSizeBySubscript()
- And others
The class %SYS.GlobalQueryOpens in a new tab provides the following queries:
- DirectoryList()
- NameSpaceList()
- NameSpaceListChui()
- Size()

Determining Sizes of Globals

^%GSIZE Routine

APIs for Getting Global Sizes

See Also