ruby-on-rails - GraphQL Ruby N+1 批处理问题

Question

我在 Ruby 中使用 GraphQL 以及 Batch 和 QueryResolver gems。除了这个问题之外，他们工作得非常好，并且似乎无法弄清楚为什么会发生这种情况。它似乎正在加载“所有关系”，然后不久之后加载“第一个:X”关系。这导致数百个 ID 被传递到 SELECT * ... IN (...) 查询中，而不是首先在 IN () 查询中执行 hte: X。这是我的查询:

query getCenterPayments(
  $centerId: ID!
  $first: Int
) {
  viewer {
    id
    centers(id: $centerId) {
      edges {
        node {
          id
          currency
          payments(
            first: $first
          ) {
            pageInfo {
              hasNextPage
              hasPreviousPage
              endCursor
              startCursor
            }
            edges {
              cursor
              node {
                id
                participant { <---- N+1 Queries here
                  id
                  name
                }
              }
            }
          }
        }
      }
    }
  }
}

这是在后台执行的查询...

User Load (0.4ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1 LIMIT $2[["id", 1], ["LIMIT", 1]]
  Center Load (1.4ms)  SELECT "centers".* FROM "centers" INNER JOIN "members" ON "centers"."id" = "members"."center_id" WHERE "members"."user_id" = $1 AND (centers.uid = 'xxxxx' OR centers.slug = 'xxxxx')  [["user_id", 1]]
  Payment Load (15.5ms)  SELECT "payments".* FROM "payments" WHERE "payments"."center_id" = 1
  User Load (7.0ms)  SELECT "users".* FROM "users" WHERE "users"."id" IN (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, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231,232, 233, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, 315, 316, 317,318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 353, 354, 355, 356, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, 387, 388, 389, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 403,404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 416, 417, 418, 419, 420, 421, 422, 423, 424, 425, 426, 427, 428, 429, 430, 431, 432, 433, 434, 435, 436, 437, 438, 439, 440, 441, 442, 443, 444, 445, 446, 447, 448, 449, 450, 451, 452, 453, 454, 455, 456, 457, 458, 459, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 470, 471, 472, 473, 474, 475, 476, 477, 478, 479, 480, 481, 482, 483, 484, 485, 486, 487, 488, 489,490, 491, 492, 493, 494, 495, 496, 497, 498, 499, 500, 501, 502, 503, 504, 505, 506, 507)
  Member Exists (0.7ms)  SELECT  1 AS one FROM "members" WHERE "members"."center_id" = $1 AND "members"."discarded_at" IS NULL AND "members"."role" = $2 AND "members"."user_id" = $3 LIMIT $4  [["center_id", 1], ["role", "admin"], ["user_id", 1], ["LIMIT", 1]]
  Payment Load (13.9ms)  SELECT "payments".* FROM "payments" WHERE "payments"."center_id" = $1 ORDER BY "payments"."date" DESC  [["center_id", 1]]
  User Load (7.1ms)  SELECT "users".* FROM "users" WHERE "users"."id" IN (237, 149, 298, 506, 278, 497, 76, 138, 139, 4, 61, 274, 449, 450, 243, 311, 93, 239, 496, 307, 78, 59, 453, 499, 500, 490, 489, 447, 337, 437, 300, 255, 187, 186, 446, 387, 401, 371, 481, 502, 390, 340, 341, 504, 505, 494, 151, 7, 465, 393, 174, 419, 103, 487, 503, 454, 498, 417, 418, 495, 472, 58, 442, 501, 263, 275, 285, 476, 486, 140, 116, 479, 493, 488, 178, 507, 226, 229, 372, 373, 134, 133, 228, 483, 484, 114, 431, 258, 463, 468, 462, 441, 68, 459, 460, 438, 403, 404, 148, 242, 204, 439, 46, 70, 127, 429, 492, 350, 317, 366, 491, 358, 360, 150, 84, 407, 455, 456, 164, 363, 365, 413, 155, 402, 485, 238, 482, 314, 315, 142, 221, 480, 478, 383, 389, 470, 85, 458, 477, 445, 467, 466, 250,251, 412, 411, 165, 475, 432, 461, 474, 216, 361, 334, 473, 436, 451, 427, 471, 464, 272, 271, 422, 302, 95, 94, 469, 400, 380, 231, 434, 448, 378, 457, 67, 382, 381, 430,6, 452, 206, 428, 220, 367, 368, 444, 167, 408, 443, 130, 426, 109, 440, 224, 410, 24, 421, 435, 312, 313, 433, 384, 335, 283, 423, 424, 357, 392, 141, 425, 388, 30, 420, 168, 266, 321, 336, 416, 415, 414, 377, 399, 406, 83, 288, 292, 409, 405, 398, 396, 351, 359, 297, 397, 395, 394, 391, 214, 105, 364, 369, 386, 370, 333, 379, 296, 40, 385,352, 189, 346, 342, 375, 376, 332, 353, 374, 338, 323, 356, 354, 236, 362, 355, 347, 185, 326, 325, 324, 179, 348, 349, 219, 166, 249, 193, 345, 322, 343, 344, 111, 316, 299, 339, 331, 203, 276, 31, 293, 304, 329, 112, 113, 328, 327, 330, 319, 241, 240, 91,308, 309, 270, 310, 320, 55, 318, 210, 306, 200, 102, 247, 248, 235, 173, 305, 232, 264, 201, 202, 154, 217, 294, 265, 252, 303, 12, 213, 147, 301, 282, 286, 287, 291, 295, 290, 279, 289, 284, 38, 225, 227, 106, 245, 280, 19, 281, 244, 277, 159, 273, 268, 77, 269, 51, 246, 234, 230, 65, 66, 260, 56, 267, 262, 223, 261, 146, 259, 254, 253, 190, 257, 256, 181, 74, 162, 97, 175, 121, 233, 171, 194, 16, 188, 163, 222, 60, 41, 212, 208, 215, 218, 137, 26, 207, 209, 176, 211, 195, 131, 132, 144, 136, 196, 197, 199, 143, 129, 180, 184, 71, 156, 183, 128, 34, 191, 192, 205, 11, 198, 182, 152, 82, 29, 172, 27, 28, 170, 169, 177, 101, 99, 145, 17, 160, 48, 49, 124, 100, 161, 108, 107, 122, 157, 158, 123, 115, 110, 125, 8, 153, 57, 135, 44, 9, 119, 126, 3, 10, 13, 22, 75, 104, 118, 21, 120, 2, 117, 15, 50, 25, 90, 80, 96, 36, 47, 89, 87, 98, 23, 86, 92, 81, 88, 53, 63, 64, 37, 14, 73, 72, 18, 20, 32, 45, 39, 79, 42, 43, 62, 54, 33, 69, 52, 35, 5)
  Payment Load (0.6ms)  SELECT  "payments".* FROM "payments" WHERE "payments"."center_id" = $1 ORDER BY "payments"."date" DESC LIMIT $2  [["center_id", 1], ["LIMIT", 10]]
   (2.0ms)  SELECT COUNT(*) FROM "payments" WHERE "payments"."center_id" = $1  [["center_id", 1]]
  Center Load (0.5ms)  SELECT "centers".* FROM "centers" WHERE "centers"."id" = 1
  User Load (1.0ms)  SELECT "users".* FROM "users" WHERE "users"."id" IN (237, 149, 298, 506, 278, 497, 76, 138, 139, 4)
Completed 200 OK in 680ms (Views: 1.6ms | ActiveRecord: 50.3ms)

正如您所看到的，它加载了很多不必要的用户，尽管我是为了用户的解析器这样做的:

field :participant do
  type UserType

  resolve -> (obj, args, ctx) {
    RecordLoader.for(User).load(obj.participant_id)
  }
end

您以前也遇到过这种情况吗？

Answer 1

问题在于同时使用两个解析器。看起来 QueryResolver 在限制之前就已解析，因为下一个查询解析器正在寻求解析其查询。它造成了困惑。我最终选择了 Shopify 的 Batch gem，并对它非常满意。