Updated VisitRepository::findUnlocatedVisits methods so that it paginates the amount of elements loaded in memory

module/Common/src/Paginator/Adapter/PaginableQueryAdapter.php

@@ -0,0 +1,34 @@
+<?php
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Common\Paginator\Adapter;
+
+use Doctrine\ORM\Query;
+use Zend\Paginator\Adapter\AdapterInterface;
+
+class PaginableQueryAdapter implements AdapterInterface
+{
+    /** @var Query */
+    private $query;
+    /** @var int */
+    private $totalItems;
+
+    public function __construct(Query $query, int $totalItems)
+    {
+        $this->query = $query;
+        $this->totalItems = $totalItems;
+    }
+
+    public function getItems($offset, $itemCountPerPage): iterable
+    {
+        return $this->query
+            ->setMaxResults($itemCountPerPage)
+            ->setFirstResult($offset)
+            ->iterate();
+    }
+
+    public function count(): int
+    {
+        return $this->totalItems;
+    }
+}

module/Common/src/Paginator/ImplicitLoopPaginator.php

@@ -0,0 +1,38 @@
+<?php
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Common\Paginator;
+
+use IteratorAggregate;
+use Zend\Paginator\Paginator;
+
+class ImplicitLoopPaginator implements IteratorAggregate
+{
+    /** @var Paginator */
+    private $paginator;
+    /** @var callable */
+    private $valueParser;
+
+    public function __construct(Paginator $paginator, callable $valueParser = null)
+    {
+        $this->paginator = $paginator;
+        $this->valueParser = $valueParser ?? function ($value) {
+            return $value;
+        };
+    }
+
+    public function getIterator(): iterable
+    {
+        $totalPages = $this->paginator->count();
+        $processedPages = 0;
+
+        do {
+            $processedPages++;
+            $this->paginator->setCurrentPageNumber($processedPages);
+
+            foreach ($this->paginator as $key => $value) {
+                yield $key => ($this->valueParser)($value);
+            }
+        } while ($processedPages < $totalPages);
+    }
+}

module/Core/src/Repository/VisitRepository.php

@@ -5,17 +5,32 @@ namespace Shlinkio\Shlink\Core\Repository;
 
 use Doctrine\ORM\EntityRepository;
 use Doctrine\ORM\QueryBuilder;
+use Shlinkio\Shlink\Common\Paginator\Adapter\PaginableQueryAdapter;
+use Shlinkio\Shlink\Common\Paginator\ImplicitLoopPaginator;
 use Shlinkio\Shlink\Common\Util\DateRange;
 use Shlinkio\Shlink\Core\Entity\Visit;
+use Zend\Paginator\Paginator;
+use function array_shift;
 
 class VisitRepository extends EntityRepository implements VisitRepositoryInterface
 {
-    public function findUnlocatedVisits(): iterable
+    /**
+     * @return iterable|Visit[]
+     */
+    public function findUnlocatedVisits(int $blockSize = self::DEFAULT_BLOCK_SIZE): iterable
     {
-        $dql = 'SELECT v FROM Shlinkio\Shlink\Core\Entity\Visit AS v WHERE v.visitLocation IS NULL';
+        $count = $this->count(['visitLocation' => null]);
+        $dql = <<<DQL
+SELECT v FROM Shlinkio\Shlink\Core\Entity\Visit AS v WHERE v.visitLocation IS NULL
+DQL;
         $query = $this->getEntityManager()->createQuery($dql);
 
-        return $query->iterate();
+        $paginator = new Paginator(new PaginableQueryAdapter($query, $count));
+        $paginator->setItemCountPerPage($blockSize);
+
+        return new ImplicitLoopPaginator($paginator, function (array $value) {
+            return array_shift($value);
+        });
     }
 
     /**

module/Core/src/Repository/VisitRepositoryInterface.php

@@ -9,7 +9,12 @@ use Shlinkio\Shlink\Core\Entity\Visit;
 
 interface VisitRepositoryInterface extends ObjectRepository
 {
-    public function findUnlocatedVisits(): iterable;
+    public const DEFAULT_BLOCK_SIZE = 10000;
+
+    /**
+     * @return iterable|Visit[]
+     */
+    public function findUnlocatedVisits(int $blockSize = self::DEFAULT_BLOCK_SIZE): iterable;
 
     /**
      * @return Visit[]

module/Core/src/Service/VisitService.php

@@ -26,7 +26,7 @@ class VisitService implements VisitServiceInterface
         $repo = $this->em->getRepository(Visit::class);
         $results = $repo->findUnlocatedVisits();
 
-        foreach ($results as [$visit]) {
+        foreach ($results as $visit) {
             try {
                 /** @var Location $location */
                 $location = $geolocateVisit($visit);

module/Core/test-db/Repository/VisitRepositoryTest.php

@@ -12,6 +12,8 @@ use Shlinkio\Shlink\Core\Entity\VisitLocation;
 use Shlinkio\Shlink\Core\Model\Visitor;
 use Shlinkio\Shlink\Core\Repository\VisitRepository;
 use ShlinkioTest\Shlink\Common\DbTest\DatabaseTestCase;
+use function Functional\map;
+use function range;
 use function sprintf;
 
 class VisitRepositoryTest extends DatabaseTestCase
@@ -30,8 +32,11 @@ class VisitRepositoryTest extends DatabaseTestCase
         $this->repo = $this->getEntityManager()->getRepository(Visit::class);
     }
 
-    /** @test */
-    public function findUnlocatedVisitsReturnsProperVisits(): void
+    /**
+     * @test
+     * @dataProvider provideBlockSize
+     */
+    public function findUnlocatedVisitsReturnsProperVisits(int $blockSize): void
     {
         $shortUrl = new ShortUrl('');
         $this->getEntityManager()->persist($shortUrl);
@@ -50,7 +55,7 @@ class VisitRepositoryTest extends DatabaseTestCase
         $this->getEntityManager()->flush();
 
         $resultsCount = 0;
-        $results = $this->repo->findUnlocatedVisits();
+        $results = $this->repo->findUnlocatedVisits($blockSize);
         foreach ($results as $value) {
             $resultsCount++;
         }
@@ -58,6 +63,13 @@ class VisitRepositoryTest extends DatabaseTestCase
         $this->assertEquals(3, $resultsCount);
     }
 
+    public function provideBlockSize(): iterable
+    {
+        return map(range(1, 5), function (int $value) {
+            return [$value];
+        });
+    }
+
     /** @test */
     public function findVisitsByShortCodeReturnsProperData(): void
     {

module/Core/test/Service/VisitServiceTest.php

@@ -36,8 +36,8 @@ class VisitServiceTest extends TestCase
     public function locateVisitsIteratesAndLocatesUnlocatedVisits(): void
     {
         $unlocatedVisits = [
-            [new Visit(new ShortUrl('foo'), Visitor::emptyInstance())],
-            [new Visit(new ShortUrl('bar'), Visitor::emptyInstance())],
+            new Visit(new ShortUrl('foo'), Visitor::emptyInstance()),
+            new Visit(new ShortUrl('bar'), Visitor::emptyInstance()),
         ];
 
         $repo = $this->prophesize(VisitRepository::class);
@@ -71,7 +71,7 @@ class VisitServiceTest extends TestCase
     public function visitsWhichCannotBeLocatedAreIgnored()
     {
         $unlocatedVisits = [
-            [new Visit(new ShortUrl('foo'), Visitor::emptyInstance())],
+            new Visit(new ShortUrl('foo'), Visitor::emptyInstance()),
         ];
 
         $repo = $this->prophesize(VisitRepository::class);