tiny.sql.history.instrumentation

1const std = @import("std");23pub const Phase = enum {4    batch_load,5    hash_verification,6    index_rebuild,7};89pub const Receipt = struct {10    sequence: usize,11    batch: usize,12    phase: Phase,13    duration_ns: u64,14    bytes: usize,15    records: usize,16};1718pub const Recorder = struct {19    storage: []Receipt,20    len: usize = 0,21    required: usize = 0,2223    pub fn init(storage: []Receipt) Recorder {24        return .{ .storage = storage };25    }2627    pub fn reset(self: *Recorder) void {28        self.len = 0;29        self.required = 0;30    }3132    pub fn record(33        self: *Recorder,34        batch: usize,35        phase: Phase,36        duration_ns: u64,37        bytes: usize,38        records: usize,39    ) void {40        const sequence = self.required;41        self.required += 1;42        if (self.len == self.storage.len) return;43        self.storage[self.len] = .{44            .sequence = sequence,45            .batch = batch,46            .phase = phase,47            .duration_ns = duration_ns,48            .bytes = bytes,49            .records = records,50        };51        self.len += 1;52    }5354    pub fn receipts(self: *const Recorder) []const Receipt {55        return self.storage[0..self.len];56    }5758    pub fn complete(self: *const Recorder) bool {59        return self.len != 0 and self.len == self.required;60    }6162    pub fn ordered(self: *const Recorder) bool {63        if (!self.complete() or self.len % 3 != 0) return false;64        for (self.receipts(), 0..) |receipt, sequence| {65            if (receipt.sequence != sequence) return false;66            if (receipt.batch != sequence / 3) return false;67            const expected: Phase = switch (sequence % 3) {68                0 => .batch_load,69                1 => .hash_verification,70                2 => .index_rebuild,71                else => unreachable,72            };73            if (receipt.phase != expected) return false;74        }75        return true;76    }77};7879pub fn elapsed(start_ns: i128, end_ns: i128) u64 {80    if (end_ns <= start_ns) return 0;81    return @intCast(@min(82        @as(u128, @intCast(end_ns - start_ns)),83        std.math.maxInt(u64),84    ));85}8687test "replay recorder rejects incomplete storage and preserves phase order" {88    var complete_storage: [6]Receipt = undefined;89    var complete = Recorder.init(&complete_storage);90    inline for (0..2) |batch| {91        complete.record(batch, .batch_load, 1, 16, 2);92        complete.record(batch, .hash_verification, 2, 16, 2);93        complete.record(batch, .index_rebuild, 3, 16, 2);94    }95    try std.testing.expect(complete.complete());96    try std.testing.expect(complete.ordered());9798    var short_storage: [2]Receipt = undefined;99    var short = Recorder.init(&short_storage);100    short.record(0, .batch_load, 1, 16, 2);101    short.record(0, .hash_verification, 2, 16, 2);102    short.record(0, .index_rebuild, 3, 16, 2);103    try std.testing.expect(!short.complete());104    try std.testing.expect(!short.ordered());105}

1pub const instrumentation = @import("instrumentation.zig");