Get memory used by a Memtable record??

[Ian Branch 121]

Hi Team,

D11.

I am playing with TFDMemTable.

I have the following line of code...

FDMemTable1.CopyDataSet(Company, [coStructure, coAppend]);

Company is previously filtered so there is only one record 'visible'.

How can I tell how much memory has been used as a result of just this code/action please?

Regards & TIA,

Ian

[Der schöne Günther 306]

I had the same question a few years back. The TClientDataSet had a somewhat plausible DataSize property, but the FireDAC memory table had no such thing.

 

A rather desperate approach would be saving the entire memory table into a stream and then determining the stream size which is rather silly and does not necessarily reflect how much the data actually takes up in your memory.

[Lajos Juhász 243]

4 hours ago, Der schöne Günther said:

A rather desperate approach would be saving the entire memory table into a stream and then determining the stream size which is rather silly and does not necessarily reflect how much the data actually takes up in your memory.

The memory required for the stream doesn't have to be the same as for internal representation for the data. The only way to firure out is to query the memory manager before and after the operation.

[Der schöne Günther 306]

I don't think comparing "memory usage before" and "memory usage after" in a release build is going to yield anything useful. There might be a lot of other things going on in separate threads.

[Guest]

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Edited March 7, 2022 by Guest

[SwiftExpat 65]

2 hours ago, Der schöne Günther said:

I don't think comparing "memory usage before" and "memory usage after" in a release build is going to yield anything useful.

I would agree with not much useful here. What is the threshold you are willing to allow for that memtable?

 

What level of precision are you looking for? Task Manager / Perfmon will get you close enough.

[Pat Foley 50]

Task Manager mentioned in Cary Jensen's question on SO about fd copydatasset memory issue.

 

https://stackoverflow.com/questions/61018590/is-there-a-solution-to-the-firedac-copydataset-and-copyrecord-memory-loss

Edited March 7, 2022 by Pat Foley
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[Fr0sT.Brutal 897]

Use FastMM which has extended diagnostics about what it allocated and compare values before/after