stdTTL: to avoid ttl like absorlat(10,0), the simpler form should be abs(10).
If not standard, we may get too large merged ttl, otherwise we should check the values if == 0. Standard is better.
so after std, we may get two ttl, abs(0), abs(x), lat(0), lat(x), absandlat(x,y), absorlat(x,y), x>0 and y>0.
lat(0) to abs(0)?
If two ttl are the same type, it's ok to merge the value, 0 means never exipres.
If different types, I'll try my best to set a small ttl to cover the two ttl. 4 type merge 2, so there're 6 cases.
- absandlat + ?: 3 cases
absandlat(x,y)+abs(z), absandlat(x,y)+abs(0): don't merge lat(cuz abs type lat is0), so just merge abs, 0 means max.
absandlat(x,y)+lat(z), absandlat(x,y)+lat(0): the same
absandlat(x,y)+absorlat(k,j): we need to store more to avoid delete valid records, so use absandlat. e.g. when k>x, j>y, we must use absandlat, otherwise, try to use absorlat, the record in x(absandlat=0, no expires) will be expired if it is the j+1 record.
- absorlat + ?: 2 cases
absorlat(x,y)+abs(z), absorlat(x,y)+abs(0): leave abs, lat should be removed, even z<x, the records size in z may > y, but it shouldn't be expired.
absorlat(x,y)+lat(z), absorlat(x,y)+lat(0): the same
- abs + lat: 1 case
just absandlat, set values, don't merge abs(x,0) with lat(0,y) considering 0=max, it'll be both 0, never exipres.