MariaDB - avoid using correlated sub-queries

packages/backend-core/src/sql/sql.ts

@@ -930,7 +930,8 @@ class InternalBuilder {
       }
       const relatedTable = meta.tables?.[toTable]
       const toAlias = aliases?.[toTable] || toTable,
-        fromAlias = aliases?.[fromTable] || fromTable
+        fromAlias = aliases?.[fromTable] || fromTable,
+        throughAlias = (throughTable && aliases?.[throughTable]) || throughTable
       let toTableWithSchema = this.tableNameWithSchema(toTable, {
         alias: toAlias,
         schema: endpoint.schema,
@@ -957,38 +958,36 @@ class InternalBuilder {
       const primaryKey = `${toAlias}.${toPrimary || toKey}`
       let subQuery: Knex.QueryBuilder = knex
         .from(toTableWithSchema)
-        .limit(getRelationshipLimit())
         // add sorting to get consistent order
         .orderBy(primaryKey)
 
-      // many-to-many relationship with junction table
-      if (throughTable && toPrimary && fromPrimary) {
-        const throughAlias = aliases?.[throughTable] || throughTable
+      const isManyToMany = throughTable && toPrimary && fromPrimary
+      let correlatedTo = isManyToMany
+          ? `${throughAlias}.${fromKey}`
+          : `${toAlias}.${toKey}`,
+        correlatedFrom = isManyToMany
+          ? `${fromAlias}.${fromPrimary}`
+          : `${fromAlias}.${fromKey}`
+      // many-to-many relationship needs junction table join
+      if (isManyToMany) {
         let throughTableWithSchema = this.tableNameWithSchema(throughTable, {
           alias: throughAlias,
           schema: endpoint.schema,
         })
-        subQuery = subQuery
-          .join(throughTableWithSchema, function () {
-            this.on(`${toAlias}.${toPrimary}`, "=", `${throughAlias}.${toKey}`)
-          })
-          .where(
-            `${throughAlias}.${fromKey}`,
-            "=",
-            knex.raw(this.quotedIdentifier(`${fromAlias}.${fromPrimary}`))
-          )
-      }
-      // one-to-many relationship with foreign key
-      else {
-        subQuery = subQuery.where(
-          `${toAlias}.${toKey}`,
-          "=",
-          knex.raw(this.quotedIdentifier(`${fromAlias}.${fromKey}`))
-        )
+        subQuery = subQuery.join(throughTableWithSchema, function () {
+          this.on(`${toAlias}.${toPrimary}`, "=", `${throughAlias}.${toKey}`)
+        })
       }
 
+      // add the correlation to the overall query
+      subQuery = subQuery.where(
+        correlatedTo,
+        "=",
+        knex.raw(this.quotedIdentifier(correlatedFrom))
+      )
+
       const standardWrap = (select: string): Knex.QueryBuilder => {
-        subQuery = subQuery.select(`${toAlias}.*`)
+        subQuery = subQuery.select(`${toAlias}.*`).limit(getRelationshipLimit())
         // @ts-ignore - the from alias syntax isn't in Knex typing
         return knex.select(knex.raw(select)).from({
           [toAlias]: subQuery,
@@ -1009,8 +1008,11 @@ class InternalBuilder {
           )
           break
         case SqlClient.MY_SQL:
+          // can't use the standard wrap due to correlated sub-query limitations in MariaDB
           wrapperQuery = subQuery.select(
-            knex.raw(`json_arrayagg(json_object(${fieldList}))`)
+            knex.raw(
+              `json_arrayagg(json_object(${fieldList}) LIMIT ${getRelationshipLimit()})`
+            )
           )
           break
         case SqlClient.ORACLE:

packages/server/src/api/routes/tests/search.spec.ts

@@ -42,6 +42,7 @@ import { Knex } from "knex"
 import { structures } from "@budibase/backend-core/tests"
 import { DEFAULT_EMPLOYEE_TABLE_SCHEMA } from "../../../db/defaultData/datasource_bb_default"
 import { generateRowIdField } from "../../../integrations/utils"
+import { cloneDeep } from "lodash/fp"
 
 describe.each([
   ["in-memory", undefined],
@@ -66,6 +67,35 @@ describe.each([
   let table: Table
   let rows: Row[]
 
+  async function basicRelationshipTables(type: RelationshipType) {
+    const relatedTable = await createTable(
+      {
+        name: { name: "name", type: FieldType.STRING },
+      },
+      "productCategory"
+    )
+    table = await createTable(
+      {
+        name: { name: "name", type: FieldType.STRING },
+        productCat: {
+          type: FieldType.LINK,
+          relationshipType: type,
+          name: "productCat",
+          fieldName: "product",
+          tableId: relatedTable._id!,
+          constraints: {
+            type: "array",
+          },
+        },
+      },
+      "product"
+    )
+    return {
+      relatedTable: await config.api.table.get(relatedTable._id!),
+      table,
+    }
+  }
+
   beforeAll(async () => {
     await withCoreEnv({ TENANT_FEATURE_FLAGS: "*:SQS" }, () => config.init())
     if (isLucene) {
@@ -201,6 +231,7 @@ describe.each([
     // rows returned by the query will also cause the assertion to fail.
     async toMatchExactly(expectedRows: any[]) {
       const response = await this.performSearch()
+      const cloned = cloneDeep(response)
       const foundRows = response.rows
 
       // eslint-disable-next-line jest/no-standalone-expect
@@ -211,14 +242,15 @@ describe.each([
           expect.objectContaining(this.popRow(expectedRow, foundRows))
         )
       )
-      return response
+      return cloned
     }
 
     // Asserts that the query returns rows matching exactly the set of rows
     // passed in. The order of the rows is not important, but extra rows will
     // cause the assertion to fail.
     async toContainExactly(expectedRows: any[]) {
       const response = await this.performSearch()
+      const cloned = cloneDeep(response)
       const foundRows = response.rows
 
       // eslint-disable-next-line jest/no-standalone-expect
@@ -231,14 +263,15 @@ describe.each([
           )
         )
       )
-      return response
+      return cloned
     }
 
     // Asserts that the query returns some property values - this cannot be used
     // to check row values, however this shouldn't be important for checking properties
     // typing for this has to be any, Jest doesn't expose types for matchers like expect.any(...)
     async toMatch(properties: Record<string, any>) {
       const response = await this.performSearch()
+      const cloned = cloneDeep(response)
       const keys = Object.keys(properties) as Array<keyof SearchResponse<Row>>
       for (let key of keys) {
         // eslint-disable-next-line jest/no-standalone-expect
@@ -248,24 +281,26 @@ describe.each([
           expect(response[key]).toEqual(properties[key])
         }
       }
-      return response
+      return cloned
     }
 
     // Asserts that the query doesn't return a property, e.g. pagination parameters.
     async toNotHaveProperty(properties: (keyof SearchResponse<Row>)[]) {
       const response = await this.performSearch()
+      const cloned = cloneDeep(response)
       for (let property of properties) {
         // eslint-disable-next-line jest/no-standalone-expect
         expect(response[property]).toBeUndefined()
       }
-      return response
+      return cloned
     }
 
     // Asserts that the query returns rows matching the set of rows passed in.
     // The order of the rows is not important. Extra rows will not cause the
     // assertion to fail.
     async toContain(expectedRows: any[]) {
       const response = await this.performSearch()
+      const cloned = cloneDeep(response)
       const foundRows = response.rows
 
       // eslint-disable-next-line jest/no-standalone-expect
@@ -276,7 +311,7 @@ describe.each([
           )
         )
       )
-      return response
+      return cloned
     }
 
     async toFindNothing() {
@@ -2196,28 +2231,10 @@ describe.each([
       let productCategoryTable: Table, productCatRows: Row[]
 
       beforeAll(async () => {
-        productCategoryTable = await createTable(
-          {
-            name: { name: "name", type: FieldType.STRING },
-          },
-          "productCategory"
-        )
-        table = await createTable(
-          {
-            name: { name: "name", type: FieldType.STRING },
-            productCat: {
-              type: FieldType.LINK,
-              relationshipType: RelationshipType.ONE_TO_MANY,
-              name: "productCat",
-              fieldName: "product",
-              tableId: productCategoryTable._id!,
-              constraints: {
-                type: "array",
-              },
-            },
-          },
-          "product"
+        const { relatedTable } = await basicRelationshipTables(
+          RelationshipType.ONE_TO_MANY
         )
+        productCategoryTable = relatedTable
 
         productCatRows = await Promise.all([
           config.api.row.save(productCategoryTable._id!, { name: "foo" }),
@@ -2262,6 +2279,31 @@ describe.each([
         }).toContainExactly([{ name: "baz", productCat: undefined }])
       })
     })
+
+  isSql &&
+    describe("big relations", () => {
+      beforeAll(async () => {
+        const { relatedTable } = await basicRelationshipTables(
+          RelationshipType.MANY_TO_ONE
+        )
+        const mainRow = await config.api.row.save(table._id!, {
+          name: "foo",
+        })
+        for (let i = 0; i < 11; i++) {
+          await config.api.row.save(relatedTable._id!, {
+            name: i,
+            product: [mainRow._id!],
+          })
+        }
+      })
+
+      it("can only pull 500 related rows", async () => {
+        await withCoreEnv({ SQL_MAX_RELATED_ROWS: "10" }, async () => {
+          const response = await expectQuery({}).toContain([{ name: "foo" }])
+          expect(response.rows[0].productCat).toBeArrayOfSize(10)
+        })
+      })
+    })
   ;(isSqs || isLucene) &&
     describe("relations to same table", () => {
       let relatedTable: Table, relatedRows: Row[]

packages/server/src/sdk/app/tables/external/index.ts

@@ -198,6 +198,7 @@ export async function save(
       }
     }
     generateRelatedSchema(schema, relatedTable, tableToSave, relatedColumnName)
+    tables[relatedTable.name] = relatedTable
     schema.main = true
   }
 
@@ -231,7 +232,10 @@ export async function save(
   // remove the rename prop
   delete tableToSave._rename
 
-  datasource.entities[tableToSave.name] = tableToSave
+  datasource.entities = {
+    ...datasource.entities,
+    ...tables,
+  }
 
   // store it into couch now for budibase reference
   await db.put(populateExternalTableSchemas(datasource))

packages/server/src/sdk/app/tables/external/utils.ts

@@ -22,12 +22,16 @@ export function cleanupRelationships(
   tables: Record<string, Table>,
   oldTable?: Table
 ) {
+  if (!oldTable) {
+    return
+  }
   const tableToIterate = oldTable ? oldTable : table
   // clean up relationships in couch table schemas
   for (let [key, schema] of Object.entries(tableToIterate.schema)) {
     if (
       schema.type === FieldType.LINK &&
-      (!oldTable || table.schema[key] == null)
+      oldTable.schema[key] != null &&
+      table.schema[key] == null
     ) {
       const schemaTableId = schema.tableId
       const relatedTable = Object.values(tables).find(