dendro 0.3.2

A segmented-parquet archive with a write-ahead log, in a single SQLite file
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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167

//! Per-stream retention bounds the clock-offset series the way whole-source
//! retention does: at the oldest row the source still holds anywhere.

use std::collections::BTreeMap;

use dendro::archive::{Archive, ArchiveMut, SegmentMeta, SourceMeta, WalRow};

fn source() -> SourceMeta {
    SourceMeta {
        labels: BTreeMap::new(),
        metadata: BTreeMap::new(),
        clock_anchor_wall_ns: 0,
    }
}

fn segment(db: &mut ArchiveMut, id: i64, stream: &str, seq: u64, first_ts: i64, last_ts: i64) {
    db.insert_segment(
        id,
        stream,
        seq,
        &SegmentMeta {
            rows: 1,
            first_ts,
            last_ts,
        },
        b"x",
    )
    .unwrap();
}

fn offsets(db: &Archive, id: i64) -> Vec<i64> {
    db.read_clock_offsets(id)
        .unwrap()
        .into_iter()
        .map(|(ts, _)| ts)
        .collect()
}

#[test]
fn per_stream_eviction_cuts_clock_offsets_at_the_oldest_surviving_row() {
    let dir = tempfile::tempdir().unwrap();
    let path = dir.path().join("r.dendro");
    let mut db = ArchiveMut::create(&path).unwrap();
    let id = db.insert_source(&source()).unwrap();
    // Stream `a` is expensive and kept briefly; `b` is kept longer.
    segment(&mut db, id, "a", 0, 100, 100);
    segment(&mut db, id, "a", 1, 200, 200);
    segment(&mut db, id, "b", 0, 150, 150);
    db.insert_wal_rows(
        id,
        &[WalRow {
            stream: "b".to_string(),
            ts: 250,
            wall_offset: 0,
            row: vec![1],
        }],
    )
    .unwrap();
    db.transaction(|tx| {
        for ts in [100, 150, 200, 250] {
            tx.insert_clock_offset(id, ts, 0)?;
        }
        Ok(())
    })
    .unwrap();

    // Evict `a` before 250: both of its segments go. `b` still holds a row
    // at 150, so the series must keep 150 and everything after it — and drop
    // 100, which no surviving row needs.
    let evicted = db.evict_streams_before(id, 250, &|s| s == "a").unwrap();
    assert_eq!(evicted.segments, 2);
    assert_eq!(offsets(&db, id), vec![150, 200, 250]);

    // Evict `b` before 300 as well: nothing is left, so the cutoff applies.
    db.evict_streams_before(id, 300, &|s| s == "b").unwrap();
    assert!(db.all_streams(id).unwrap().is_empty());
    assert!(offsets(&db, id).is_empty());
}

/// Retention that deletes rows no segment held is data loss the caller's
/// two policies caused between them, and it is reported, not hidden.
#[test]
fn eviction_reports_the_unsealed_rows_it_deleted() {
    let dir = tempfile::tempdir().unwrap();
    let path = dir.path().join("r.dendro");
    let mut db = ArchiveMut::create(&path).unwrap();
    let id = db.insert_source(&source()).unwrap();
    // `a`: sealed through 100, with a shadowed (pruned-later) row at 100
    // still in the WAL, and live rows at 150 and 250.
    segment(&mut db, id, "a", 0, 50, 100);
    db.insert_wal_rows(
        id,
        &[
            WalRow {
                stream: "a".to_string(),
                ts: 100,
                wall_offset: 0,
                row: vec![1],
            },
            WalRow {
                stream: "a".to_string(),
                ts: 150,
                wall_offset: 0,
                row: vec![1],
            },
            WalRow {
                stream: "a".to_string(),
                ts: 250,
                wall_offset: 0,
                row: vec![1],
            },
        ],
    )
    .unwrap();
    // `b`: never sealed, live rows at 10 and 300.
    db.insert_wal_rows(
        id,
        &[
            WalRow {
                stream: "b".to_string(),
                ts: 10,
                wall_offset: 0,
                row: vec![1],
            },
            WalRow {
                stream: "b".to_string(),
                ts: 300,
                wall_offset: 0,
                row: vec![1],
            },
        ],
    )
    .unwrap();

    let evicted = db.evict_before(id, 200).unwrap();
    // Deleted: the segment; WAL rows 100 (shadowed), 150 (live!), 10 (live!).
    assert_eq!(evicted.segments, 1);
    assert_eq!(evicted.wal_rows, 3);
    assert_eq!(
        evicted.live_rows, 2,
        "150 on `a` and 10 on `b` were in no segment"
    );

    // Per stream, the same accounting, per stream.
    let mut db2 = ArchiveMut::create(&dir.path().join("r2.dendro")).unwrap();
    let id2 = db2.insert_source(&source()).unwrap();
    db2.insert_wal_rows(
        id2,
        &[
            WalRow {
                stream: "b".to_string(),
                ts: 10,
                wall_offset: 0,
                row: vec![1],
            },
            WalRow {
                stream: "c".to_string(),
                ts: 10,
                wall_offset: 0,
                row: vec![1],
            },
        ],
    )
    .unwrap();
    let evicted = db2.evict_streams_before(id2, 200, &|s| s == "b").unwrap();
    assert_eq!((evicted.wal_rows, evicted.live_rows), (1, 1));
}