milestone 26: upstream health answers for the selected period

src/storage/querylog_schema.zig

@@ -45,6 +45,24 @@ pub const ddl: [:0]const u8 =
     \\CREATE INDEX idx_query_log_ts ON query_log(timestamp);
     \\CREATE INDEX idx_query_log_client ON query_log(client_ip);
     \\CREATE INDEX idx_query_log_domain ON query_log(domain_id);
+    \\
+    \\CREATE TABLE upstream_targets (
+    \\    id INTEGER PRIMARY KEY,
+    \\    url TEXT NOT NULL UNIQUE   -- the historical identity: config.db ids cannot cross database files
+    \\);
+    \\
+    \\CREATE TABLE upstream_minute (
+    \\    upstream_id INTEGER NOT NULL REFERENCES upstream_targets(id),
+    \\    minute_ts INTEGER NOT NULL,
+    \\    successes INTEGER NOT NULL,
+    \\    failures INTEGER NOT NULL,
+    \\    last_failure_ts INTEGER,
+    \\    last_error TEXT,
+    \\    PRIMARY KEY (upstream_id, minute_ts),
+    \\    CHECK (successes >= 0),
+    \\    CHECK (failures >= 0)
+    \\) WITHOUT ROWID;
+    \\CREATE INDEX idx_upstream_minute_ts ON upstream_minute(minute_ts);
 ;
 
 /// `PRAGMA user_version` is a signed 32-bit field. Deriving the fingerprint from
@@ -215,20 +233,21 @@ test "fingerprint matches a fresh hash of the DDL" {
     try testing.expectEqual(fingerprint, @as(i32, @bitCast(std.hash.Crc32.hash(ddl))));
 }
 
-test "ddl creates domains, query_log and the three indexes" {
+test "ddl creates the query-log tables, the upstream-history tables and every index" {
     var database = try db.Db.open(":memory:", .{ .mode = .memory });
     defer database.close();
     try db.applyPragmas(&database, .{});
     try database.exec(ddl);
 
     try testing.expectEqual(
-        @as(i64, 2),
+        @as(i64, 4),
         try database.queryInt("SELECT count(*) FROM sqlite_schema WHERE type='table'"),
     );
     const objects = [_][]const u8{
         "domains",              "query_log",
         "idx_query_log_ts",     "idx_query_log_client",
-        "idx_query_log_domain",
+        "idx_query_log_domain", "upstream_targets",
+        "upstream_minute",      "idx_upstream_minute_ts",
     };
     for (objects) |name| {
         var stmt = try database.prepare("SELECT count(*) FROM sqlite_schema WHERE name = ?1");