Question regarding Data Consolidation

[timtrader]

I received the following message on the MT Shutdown (just before the auto restart after installing the latest version 1.0.7189.1850) and am wondering if it makes sense to you.  It says that is will consolidate the data since most of it is empty, but its showing that the data file will grow, not shrink.  I clicked "Yes" to see what it would do and it did indeed grow.  I checked the SDATA.BIN file size in Windows Explorer before and after the consolidation.   It grew from 459,155K to 492,912K after the consolidation.  I do tend to review a lot of symbols and delete them off of the portfolios as I review them, so it makes sense that most of the file space should be empty....I'm just surprised that the consolidation process made the file size grow and that it expected that.

 

 

Please let me know if you need any other information from me.

 

Thanks,

Tim

 

[Jerry Medved]

Hmm, I need to check the code - the file size is not supposed to grow

 

Basically, the data file is organized in chunks (pages) of data. MT allocates more and more as they are needed. As some data is cleared, those chunks are then flagged as free and re-used before other new ones are allocated.  The file never shrinks.

 

If you for example clear all data right now, you will have almost all pages empty but the file will still be 500 MGB.  Well, consolidate basically creates a new file, copies only the used pages, which should result in a much smaller file. 

[Jerry Medved]

Ok, I see - the other time PREVIOUS versions prompted is if there was a problem detected that would be fixed by consolidation.  I changed it so in that situation, a prompt is not shown.