Possible fix for indexing bug (close #9 #10)

Setup/Patch/Data/MySQLCatalogSearchTableCreation.php

@@ -0,0 +1,74 @@
+<?php
+declare(strict_types=1);
+
+namespace Swissup\SearchMysqlLegacy\Setup\Patch\Data;
+
+use Magento\CatalogSearch\Model\Indexer\IndexStructure;
+use Magento\Framework\Indexer\DimensionProviderInterface;
+use Magento\Framework\Search\EngineResolverInterface;
+use Magento\CatalogSearch\Model\Indexer\Fulltext;
+
+/**
+ * This patch will create catalogsearch_fulltext tables in MySQL DB.
+ */
+class MySQLCatalogSearchTableCreation implements \Magento\Framework\Setup\Patch\DataPatchInterface
+{
+    /**
+     * @var IndexStructure
+     */
+    private $indexStructure;
+
+    /**
+     * @var DimensionProviderInterface
+     */
+    private $dimensionProvider;
+
+    /**
+     * @var EngineResolverInterface
+     */
+    private $searchEngineResolver;
+
+    /**
+     * MySQLCatalogSearchTableCreation constructor.
+     * @param IndexStructure $indexStructure
+     * @param DimensionProviderInterface $dimensionProvider
+     * @param EngineResolverInterface $searchEngineResolver
+     */
+    public function __construct(
+        IndexStructure $indexStructure,
+        DimensionProviderInterface $dimensionProvider,
+        EngineResolverInterface $searchEngineResolver
+    ) {
+        $this->indexStructure = $indexStructure;
+        $this->dimensionProvider = $dimensionProvider;
+        $this->searchEngineResolver = $searchEngineResolver;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function apply()
+    {
+        if ($this->searchEngineResolver->getCurrentSearchEngine() === 'lmysql') {
+            foreach ($this->dimensionProvider->getIterator() as $dimension) {
+                $this->indexStructure->create(Fulltext::INDEXER_ID, [], $dimension);
+            }
+        }
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getAliases()
+    {
+        return [];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public static function getDependencies()
+    {
+        return [];
+    }
+}

etc/di.xml

@@ -335,4 +335,12 @@
         </arguments>
     </type>
 
+    <type name="Swissup\SearchMysqlLegacy\Setup\Patch\Data\MySQLCatalogSearchTableCreation">
+        <arguments>
+            <argument name="dimensionProvider" xsi:type="object" shared="false">
+                Magento\Store\Model\StoreDimensionProvider
+            </argument>
+        </arguments>
+    </type>
+
 </config>