Maintaining a sortable database, garbage creation

[corveroth]

I have an issue, to the tune of 80 KB of junk every time COMPANION_UPDATE fires.

For my addon, I find it necessary to keep up to date information on your companions. Beyond simply registering COMPANION_UPDATE and calling GetCompanionInfo, I also pull some extra data from tooltips and hard-coded tables, in order to offer more information to the user (such as mount speed).

The issues arose when I added in the capacity to sort that data. Three columns appear in the display, and the tabs at the top of each enable sorting, much like the Guild or Who frames. To allow for this behavior, I found it necessary to store several pieces of information in a table, which I could later sort, and whenever the display needed to be refreshed, I read off the appropriate rows from the table. The problem appears to lie in the need to rebuild the entire table every time that COMPANION_UPDATE fires (very common in cities, as it fires for nearby players as well).

What recommendations might you have to offer to cut down on the garbage generation inherent to this approach? What alternative approaches might exist?

local MountData = {}
local function UpdateMountData()
    MountData = {}
    local creatureName, spellID, icon, active
    local speed, mountType, numPassengers, isUsable, varies
    local notes
    
    for i=1, GetNumCompanions("MOUNT") do
        notes = ""
        _, creatureName, spellID, icon, active = GetCompanionInfo("MOUNT", i)
        -- GetExtraCompanionData is my function that does the tooltip scanning and such
        speed, mountType, numPassengers, isUsable, varies = unpack(GetExtraCompanionData("MOUNT", spellID),1,5)
        
        if numPassengers > 0 then
            -- NOTE: addLine is just a utility function to insert newlines as appropriate
            notes = addLine(notes, format(L["Passengers: %d"], numPassengers))
        end
        
        if varies then
            notes = addLine(notes, L["Varies"])
        end
        
        if not strfind(notes, "\n") then
            if mountType == MOUNTTYPE_LAND then
                notes = addLine(notes, L["Ground"])
            elseif mountType == MOUNTTYPE_FLYING then
                notes = addLine(notes, L["Flying"])
            elseif mountType == MOUNTTYPE_AQUATIC then
                notes = addLine(notes, L["Aquatic"])
            end
        end
        
        tinsert(MountData, {NAME = creatureName, NOTES = notes, SPEED = speed, ICON = icon, ACTIVE = active, ISUSABLE = isUsable, ID = i})
    end
end