MobileRead Forums - View Single Post - A few questions about how size of library impacts memory usage

BetterRed · 11-11-2016, 08:17 PM

@LadyKate - 2.4 gig (i.e. 2,400 Megabytes) seems like a really massive number to me

Even memory hogs like Firefox, Autocad, and my video editors don't get that high - collectively. How much time does calibre take to start and switch between those two libraries?

Anyway pending Kovid's definitive answers, here are some thoughts.

As I understand matters, when calibre is running, the database is memory resident. It gets loaded at start and on a library switch. So I imagine the number of books, the number of custom columns, and the size of the column data items would be major determinants of the amount of memory needed for the in-memory database. I think most data values are normalised - i.e. there will only be one instance of the string 'Miguel de Cervantes Saavedra'.

Assuming they are held in memory, and I don't know that they're not, if you have lots of very large Comments or custom long text columns, I imagine that could have a major impact on memory usage.

I normally run three library servers via command files. The main usage is to access metadata, I rarely access format files from the server. I've not looked to see how much memory they use, but they've never given me any reason for concern - most of the time I assume they'd be paged out.

BR

11-11-2016, 08:17 PM	#2
BetterRed null operator (he/him) Posts: 21,829 Karma: 30277270 Join Date: Mar 2012 Location: Sydney Australia Device: none	@LadyKate - 2.4 gig (i.e. 2,400 Megabytes) seems like a really massive number to me Even memory hogs like Firefox, Autocad, and my video editors don't get that high - collectively. How much time does calibre take to start and switch between those two libraries? Anyway pending Kovid's definitive answers, here are some thoughts. As I understand matters, when calibre is running, the database is memory resident. It gets loaded at start and on a library switch. So I imagine the number of books, the number of custom columns, and the size of the column data items would be major determinants of the amount of memory needed for the in-memory database. I think most data values are normalised - i.e. there will only be one instance of the string 'Miguel de Cervantes Saavedra'. Assuming they are held in memory, and I don't know that they're not, if you have lots of very large Comments or custom long text columns, I imagine that could have a major impact on memory usage. I normally run three library servers via command files. The main usage is to access metadata, I rarely access format files from the server. I've not looked to see how much memory they use, but they've never given me any reason for concern - most of the time I assume they'd be paged out. BR