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store measured as the base (baseline.py, 046's shim and journal: list bytes a message, the log and images, at 1 / 16 / 256 messages a commit: entries' appends 65.5 / 15.7 / 12.4, the bank's transfers 122 / 35.6 / 30.1, the tree apart), and a byte-accounting model (model.py) of commits writing the leaves they changed in memory's own bytes (leaf 296 to 1,320 B, inner node 680 B, cow; tail appends in place past every kept snapshot's count; inplace, which may not be, to show why), its bars written before the run (appends at most today's, sparse updates at most twice, no write a kept snapshot sees) and what a pass for appends with a miss for updates would mean (two units, not one); 046's Run takes pure-run's arguments; 045's keyed file says 24 refused, not the 26 its commit said
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and the numbers: an owner (pure-run --store) with shim.so preloaded ships every change its store makes to its files (ops.h: create, write, truncate, allocate, rename, unlink, mkdir), cut at each fsync or fdatasync, over pure link (shipper.c, follower.c), and its sync returns once the follower has the cut (synchronous: one cut in flight, no log); identity: 100,000 messages (200,081 cuts; 34 compactions, an image written again) and 200,000 (400,149 cuts; 67 compactions, a second log segment), the stores compared byte for byte every 1,999 and 3,001 cuts and at the end: 0 differences, the follower's store opened as owner holding every message; takeover: 70 kill -9s (owner alone, the whole node, the node with cuts of 512 and 64 B records): all open, hold every message the owner said done, none not sent, the entries in order (and equal to the owner's own store each time); prefixes: 867 op boundaries of a 100,000-message stream (568 within cuts, 266 around installs) opened as stores: all pass; the price: 204 to 400 us a message on tmpfs (155 us waiting for acks, two cuts a message), 903 bytes shipped a message, 42% of them zeros written ahead (a compaction's new file and the tree's tail)
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