spg-engine 7.37.18

//! v7.37.22 (22.x-stat-db) — `pg_catalog.pg_stat_database` view.

use spg_engine::{Engine, QueryResult};
use spg_storage::Value;

#[test]
fn pg_stat_database_emits_pg_canonical_columns() {
    let mut e = Engine::new();
    let r = e
        .execute("SELECT * FROM pg_catalog.pg_stat_database")
        .unwrap();
    let QueryResult::Rows { columns, .. } = r else {
        panic!("Rows");
    };
    let names: Vec<&str> = columns.iter().map(|c| c.name.as_str()).collect();
    for must in [
        "datid",
        "datname",
        "numbackends",
        "xact_commit",
        "xact_rollback",
        "blks_read",
        "blks_hit",
        "tup_returned",
        "tup_fetched",
        "tup_inserted",
        "tup_updated",
        "tup_deleted",
        "conflicts",
        "deadlocks",
        "temp_files",
        "temp_bytes",
        "blk_read_time",
        "blk_write_time",
    ] {
        assert!(
            names.contains(&must),
            "pg_stat_database missing column {must}, got {names:?}"
        );
    }
}

#[test]
fn pg_stat_database_returns_single_spg_row() {
    let mut e = Engine::new();
    let r = e
        .execute("SELECT * FROM pg_catalog.pg_stat_database")
        .unwrap();
    let QueryResult::Rows { rows, .. } = r else {
        panic!("Rows");
    };
    assert_eq!(rows.len(), 1, "expected single spg row, got {rows:?}");
    let row = &rows[0];
    // Position 0 = datid, 1 = datname.
    assert!(matches!(row.values[0], Value::BigInt(16384)));
    assert!(matches!(&row.values[1], Value::Text(s) if s.as_ref() == "spg"));
}

#[test]
fn pg_stat_database_tuple_counters_are_real() {
    // v7.38 (read01 P3.12) — tup_inserted / tup_updated / tup_deleted are
    // wired to the cumulative affected-row counts (were hardcoded 0).
    let mut e = Engine::new();
    e.execute("CREATE TABLE t(id int)").unwrap();
    e.execute("INSERT INTO t VALUES(1),(2),(3)").unwrap();
    e.execute("UPDATE t SET id = id + 1 WHERE id < 3").unwrap(); // 2 rows
    e.execute("DELETE FROM t WHERE id = 4").unwrap(); // now table is 2,3,3 → deletes 0
    e.execute("DELETE FROM t WHERE id = 3").unwrap(); // 2 rows
    let r = e
        .execute(
            "SELECT tup_inserted, tup_updated, tup_deleted \
             FROM pg_catalog.pg_stat_database",
        )
        .unwrap();
    let QueryResult::Rows { rows, .. } = r else {
        panic!("expected rows");
    };
    assert_eq!(
        rows[0].values,
        vec![Value::BigInt(3), Value::BigInt(2), Value::BigInt(2)]
    );
}