Comment by deathanatos
9 hours ago
> On a local SSD, a random read costs nothing if a page is cached, and costs under a millisecond in case of a page fault. […] The scarcest resource is not CPU, and not bytes, but the number of round trips you make to the object store, and most design decisions below follow from that
There's not really a difference here between S3 and your disk, aside from the literal amount of latency. Restructuring the format to require less reads to make S3 faster would proportionally benefit disk reads.
S3 is a lot easier manage, though. Storage is just then AWS's problem. (And what's a few ms of latency on the BE when pages take tens of seconds to load on the whole.)
> There's not really a difference here between S3 and your disk, aside from the literal amount of latency.
Latency is the whole point.
> Latency is the whole point.
The article's title is literally:
> What changes when your search index lives on S3?
None of this changes because your search index lives on S3; there's no property of S3 that says "this is an inherently better format for S3 than it is for disk". The format improvements are independent of the latency difference.
Article mentions GETs being slower and round trip latency as a major villain multiple times.
Article even dedicates a section titled "Caching on disk and in memory" for latency reduction.
Latency is the whole point as that is the ultimate villain when you decide to build index search on S3.
Its really hard to miss.
But otherwise agree.