I have run into these limitations on my miranda (32bit); completely unknowingly, and it resulted in a complete data loss. Database backups were also "silently broken" because of this - they were producing files, but the files were invalid somehow (when loaded they would result in a loss of all data in them). So basically the only reason I did not lose my data was because I have offloading to text files by MsgExport turned on by default, and I was able to then import my histories back.
I too am somewhat unhappy with the current database spec. There are many advantages of this database but as far as I can see, current Miranda is not taking advantage of them. This means that we have a bloated database (about 2x the size of dbx_mmap), it's got random hidden limitations and in case you run into a problem with your DB, you're pretty much screwed because the debug tools are not very helpful (whereas with dbx_mmap - albeit maybe not the fastest DB, it worked fine).
I think that because there are so few developers active @ Miranda, maybe if we don't plan on utilizing the functionality in dbx_mdbx, we should not impose it on the users, especially if technically miranda is still capable of operating with dbx_mmap.
There are still those that use miranda on WinXP too, and for example now they run the risk of losing all of their data if they run into the text limitations. It's not some hypothetical scenario because I have already run into them myself.
Therefore, I would welcome discussion or maybe re-assessment of the mdbx format and whether or not we could return to mmap.
Just my two cents after having no working backups, constantly corrupted profile and having to live in fear of losing my data any moment, forcing me to randomly turn off my miranda to make a copy of the file manually. (cause you cannot copy it when miranda runs anymore either...).
Others with similar (dismal) experience:
https://forum.miranda-ng.org/index.php?topic=5515.0https://forum.miranda-ng.org/index.php?topic=5510.0
