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spec/util_indexedbheap_spec.lua @ 13186:affaf6d08d26
util.datamanager: Pad list writes to avoid crossing block boundaries
By padding items so that they do not cross block boundaries, it becomes
eaiser to delete whole blocks with fallocate() without cutting items
in half, improving efficiency of such operations.
Since list stores are used for message archives, where the most common
deletion operation would be of the oldest entires, at the top of the
file. With this, all blocks that contain items to be removed could be
deleted without needing to read, delete and write out the whole file.
author | Kim Alvefur <zash@zash.se> |
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date | Wed, 07 Jun 2023 00:39:30 +0200 |
parent | 11116:d334f2bebe55 |
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local ibh = require"util.indexedbheap"; local function verify_heap_property(priorities) for k in ipairs(priorities) do local parent = priorities[k]; local childA = priorities[2*k]; local childB = priorities[2*k+1]; -- print("-", parent, childA, childB) assert(childA == nil or childA > parent, "heap property violated"); assert(childB == nil or childB > parent, "heap property violated"); end end local h setup(function () h = ibh.create(); end) describe("util.indexedbheap", function () it("item can be moved from end to top", function () verify_heap_property(h); h:insert("a", 1); verify_heap_property(h); h:insert("b", 2); verify_heap_property(h); h:insert("c", 3); verify_heap_property(h); local id = h:insert("*", 10); verify_heap_property(h); h:reprioritize(id, 0); verify_heap_property(h); assert.same({ 0, "*", id }, { h:pop() }); end) end);