tessarikv 0.1.0

A pure-Rust, lock-free-first LSM key-value storage engine
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

//! Keyspaces in a version: added and dropped by edits, rebuilt by the version's own edit, and
//! every contradiction refused.

use tessarikv_format::{KeyspaceRecord, ManifestEdit, TableMeta, TableRef};
use tessarikv_types::{SequenceNumber, Trailer, ValueKind, encode_internal};

use super::Version;

fn key(user: &[u8]) -> Vec<u8> {
    let mut out = Vec::new();
    let trailer = Trailer::new(SequenceNumber::new(1).expect("valid"), ValueKind::Value);
    encode_internal(user, trailer, &mut out);
    out
}

fn table(keyspace: u32, id: u64) -> TableMeta {
    TableMeta {
        keyspace,
        level: 1,
        id,
        size: 100,
        smallest: key(b"a"),
        largest: key(b"b"),
        min_sequence: 1,
        max_sequence: 1,
    }
}

fn added(id: u32, name: &str) -> ManifestEdit {
    ManifestEdit {
        added_keyspaces: vec![KeyspaceRecord {
            id,
            name: name.to_owned(),
        }],
        next_keyspace: Some(id + 1),
        next_file: Some(100),
        ..ManifestEdit::default()
    }
}

fn names(version: &Version) -> Vec<(u32, String)> {
    version
        .keyspaces()
        .map(|(id, name)| (id, name.to_owned()))
        .collect()
}

#[test]
fn keyspaces_are_added_and_dropped_and_survive_the_versions_own_edit() {
    let version = Version::empty()
        .apply(&added(1, "users"))
        .and_then(|version| version.apply(&added(2, "orders")))
        .expect("added");
    let with_table = version
        .apply(&ManifestEdit {
            added: vec![table(2, 7)],
            ..ManifestEdit::default()
        })
        .expect("table added");
    assert_eq!(
        names(&with_table),
        [(1, "users".to_owned()), (2, "orders".to_owned())]
    );
    let rebuilt = Version::empty()
        .apply(&with_table.as_edit())
        .expect("rebuilt");
    assert_eq!(rebuilt, with_table);
    let dropped = with_table
        .apply(&ManifestEdit {
            dropped_keyspaces: vec![2],
            removed: vec![TableRef {
                keyspace: 2,
                level: 1,
                id: 7,
            }],
            ..ManifestEdit::default()
        })
        .expect("dropped");
    assert_eq!(names(&dropped), [(1, "users".to_owned())]);
    assert_eq!(dropped.next_keyspace(), 3, "ids are never reused");
}

#[test]
fn edits_contradicting_the_keyspaces_are_refused() {
    let version = Version::empty().apply(&added(1, "users")).expect("added");
    let refused = |edit: ManifestEdit| {
        let error = version.apply(&edit).expect_err("refused");
        assert_eq!(error.code(), "corruption", "{error}");
    };
    refused(added(1, "again"));
    refused(added(2, "users"));
    refused(added(0, "default"));
    refused(ManifestEdit {
        added_keyspaces: vec![KeyspaceRecord {
            id: 5,
            name: "ahead".to_owned(),
        }],
        ..ManifestEdit::default()
    });
    refused(ManifestEdit {
        next_keyspace: Some(1),
        ..ManifestEdit::default()
    });
    refused(ManifestEdit {
        dropped_keyspaces: vec![0],
        ..ManifestEdit::default()
    });
    refused(ManifestEdit {
        dropped_keyspaces: vec![9],
        ..ManifestEdit::default()
    });
    refused(ManifestEdit {
        added: vec![table(9, 7)],
        next_file: Some(100),
        ..ManifestEdit::default()
    });
    let with_table = version
        .apply(&ManifestEdit {
            added: vec![table(1, 7)],
            next_file: Some(100),
            ..ManifestEdit::default()
        })
        .expect("table added");
    let error = with_table
        .apply(&ManifestEdit {
            dropped_keyspaces: vec![1],
            ..ManifestEdit::default()
        })
        .expect_err("a dropped keyspace keeps no tables");
    assert_eq!(error.code(), "corruption");
}