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0 pointsthesz5y ago0 comments

These blocks of 256 bytes most probably are stored in wear-leveling database of some sort hidden inside NVME. These databases are often LSM-tree-based. So, writing larger blocks still has benefits, especially when you use compression.

If you think you only need 256 byte pages, average price for 10G hard disk drive is ~$300 [1] and average price for 2G SSD drive is also ~$300 [2].

[1] https://pcpartpicker.com/trends/internal-hard-drive/?__cf_ch...

[2] https://pcpartpicker.com/trends/internal-hard-drive/?__cf_ch...

Five times price/Gb difference. If you need large storage, you need hard disks.

B-trees are good with hard disks, is PGM index good with them too?

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gvinciguerra5y ago

From a Big-Oh point of view, the answer is a big yes. No matter the memory technology or the disk page size, be it 256B or 16KB, the PGM-index can scale as B-trees or even better (see my comment here https://news.ycombinator.com/item?id=25901889).

theszOP5y ago

Can you provide us with (preferably drop-in) replacement of LMDB as a proof?

Because your big-O looks like big-O of cache-oblivious algorithm and I saw no proof of that.

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