diff --git a/composer.json b/composer.json
index ecfca2e..8470564 100644
--- a/composer.json
+++ b/composer.json
@@ -17,11 +17,12 @@
   ],
   "require": {
     "php": "^7.2 || ^8.0",
+    "ext-json": "*",
     "ext-pdo": "*",
     "event-engine/php-persistence": "^0.9"
   },
   "require-dev": {
-    "infection/infection": "^0.15.3",
+    "infection/infection": "^0.26.6",
     "malukenho/docheader": "^0.1.8",
     "phpspec/prophecy": "^1.12.1",
     "phpstan/phpstan": "^0.12.48",
@@ -45,6 +46,10 @@
   "config": {
     "sort-packages": true,
     "platform": {
+    },
+    "allow-plugins": {
+      "ocramius/package-versions": true,
+      "infection/extension-installer": true
     }
   },
   "prefer-stable": true,
diff --git a/src/Filter/FilterClause.php b/src/Filter/FilterClause.php
new file mode 100644
index 0000000..8147c88
--- /dev/null
+++ b/src/Filter/FilterClause.php
@@ -0,0 +1,34 @@
+<?php
+/**
+ * This file is part of the event-engine/php-postgres-document-store.
+ * (c) 2019-2021 prooph software GmbH <contact@prooph.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace EventEngine\DocumentStore\Postgres\Filter;
+
+final class FilterClause
+{
+    private $clause;
+    private $args;
+
+    public function __construct(?string $clause, array $args = [])
+    {
+        $this->clause = $clause;
+        $this->args = $args;
+    }
+
+    public function clause(): ?string
+    {
+        return $this->clause;
+    }
+
+    public function args(): array
+    {
+        return $this->args;
+    }
+}
diff --git a/src/Filter/FilterProcessor.php b/src/Filter/FilterProcessor.php
new file mode 100644
index 0000000..3a62c53
--- /dev/null
+++ b/src/Filter/FilterProcessor.php
@@ -0,0 +1,19 @@
+<?php
+/**
+ * This file is part of the event-engine/php-postgres-document-store.
+ * (c) 2019-2021 prooph software GmbH <contact@prooph.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace EventEngine\DocumentStore\Postgres\Filter;
+
+use EventEngine\DocumentStore\Filter\Filter;
+
+interface FilterProcessor
+{
+    public function process(Filter $filter): FilterClause;
+}
diff --git a/src/Filter/PostgresFilterProcessor.php b/src/Filter/PostgresFilterProcessor.php
new file mode 100644
index 0000000..c8091c3
--- /dev/null
+++ b/src/Filter/PostgresFilterProcessor.php
@@ -0,0 +1,199 @@
+<?php
+/**
+ * This file is part of the event-engine/php-postgres-document-store.
+ * (c) 2019-2021 prooph software GmbH <contact@prooph.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace EventEngine\DocumentStore\Postgres\Filter;
+
+use EventEngine\DocumentStore;
+use EventEngine\DocumentStore\Filter\Filter;
+use EventEngine\DocumentStore\Postgres\Exception\InvalidArgumentException;
+use EventEngine\DocumentStore\Postgres\Exception\RuntimeException;
+
+/**
+ * Default filter processor class for converting a filter to a where clause.
+ */
+final class PostgresFilterProcessor implements FilterProcessor
+{
+    /**
+     * @var bool
+     */
+    private $useMetadataColumns;
+
+    public function __construct(bool $useMetadataColumns = false)
+    {
+        $this->useMetadataColumns = $useMetadataColumns;
+    }
+
+    public function process(Filter $filter): FilterClause
+    {
+        [$filterClause, $args] = $this->processFilter($filter);
+
+        return new FilterClause($filterClause, $args);
+    }
+
+    /**
+     * @param Filter $filter
+     * @param int $argsCount
+     * @return array
+     */
+    private function processFilter(Filter $filter, int $argsCount = 0): array
+    {
+        if($filter instanceof DocumentStore\Filter\AnyFilter) {
+            if($argsCount > 0) {
+                throw new InvalidArgumentException('AnyFilter cannot be used together with other filters.');
+            }
+            return [null, [], $argsCount];
+        }
+
+        if($filter instanceof DocumentStore\Filter\AndFilter) {
+            [$filterA, $argsA, $argsCount] = $this->processFilter($filter->aFilter(), $argsCount);
+            [$filterB, $argsB, $argsCount] = $this->processFilter($filter->bFilter(), $argsCount);
+            return ["($filterA AND $filterB)", array_merge($argsA, $argsB), $argsCount];
+        }
+
+        if($filter instanceof DocumentStore\Filter\OrFilter) {
+            [$filterA, $argsA, $argsCount] = $this->processFilter($filter->aFilter(), $argsCount);
+            [$filterB, $argsB, $argsCount] = $this->processFilter($filter->bFilter(), $argsCount);
+            return ["($filterA OR $filterB)", array_merge($argsA, $argsB), $argsCount];
+        }
+
+        switch (get_class($filter)) {
+            case DocumentStore\Filter\DocIdFilter::class:
+                /** @var DocumentStore\Filter\DocIdFilter $filter */
+                return ["id = :a$argsCount", ["a$argsCount" => $filter->val()], ++$argsCount];
+            case DocumentStore\Filter\AnyOfDocIdFilter::class:
+                /** @var DocumentStore\Filter\AnyOfDocIdFilter $filter */
+                return $this->makeInClause('id', $filter->valList(), $argsCount);
+            case DocumentStore\Filter\AnyOfFilter::class:
+                /** @var DocumentStore\Filter\AnyOfFilter $filter */
+                return $this->makeInClause($this->propToJsonPath($filter->prop()), $filter->valList(), $argsCount, $this->shouldJsonEncodeVal($filter->prop()));
+            case DocumentStore\Filter\EqFilter::class:
+                /** @var DocumentStore\Filter\EqFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                return ["$prop = :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
+            case DocumentStore\Filter\GtFilter::class:
+                /** @var DocumentStore\Filter\GtFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                return ["$prop > :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
+            case DocumentStore\Filter\GteFilter::class:
+                /** @var DocumentStore\Filter\GteFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                return ["$prop >= :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
+            case DocumentStore\Filter\LtFilter::class:
+                /** @var DocumentStore\Filter\LtFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                return ["$prop < :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
+            case DocumentStore\Filter\LteFilter::class:
+                /** @var DocumentStore\Filter\LteFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                return ["$prop <= :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
+            case DocumentStore\Filter\LikeFilter::class:
+                /** @var DocumentStore\Filter\LikeFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                $propParts = explode('->', $prop);
+                $lastProp = array_pop($propParts);
+                $prop = implode('->', $propParts) . '->>'.$lastProp;
+                return ["$prop iLIKE :a$argsCount", ["a$argsCount" => $filter->val()], ++$argsCount];
+            case DocumentStore\Filter\NotFilter::class:
+                /** @var DocumentStore\Filter\NotFilter $filter */
+                $innerFilter = $filter->innerFilter();
+
+                if (!$this->isPropFilter($innerFilter)) {
+                    throw new RuntimeException('Not filter cannot be combined with a non prop filter!');
+                }
+
+                [$innerFilterStr, $args, $argsCount] = $this->processFilter($innerFilter, $argsCount);
+
+                if($innerFilter instanceof DocumentStore\Filter\AnyOfFilter || $innerFilter instanceof DocumentStore\Filter\AnyOfDocIdFilter) {
+                    if ($argsCount === 0) {
+                        return [
+                            str_replace(' 1 != 1 ', ' 1 = 1 ', $innerFilterStr),
+                            $args,
+                            $argsCount
+                        ];
+                    }
+
+                    $inPos = strpos($innerFilterStr, ' IN(');
+                    $filterStr = substr_replace($innerFilterStr, ' NOT IN(', $inPos, 4 /* " IN(" */);
+                    return [$filterStr, $args, $argsCount];
+                }
+
+                return ["NOT $innerFilterStr", $args, $argsCount];
+            case DocumentStore\Filter\InArrayFilter::class:
+                /** @var DocumentStore\Filter\InArrayFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                return ["$prop @> :a$argsCount", ["a$argsCount" => '[' . $this->prepareVal($filter->val(), $filter->prop()) . ']'], ++$argsCount];
+            case DocumentStore\Filter\ExistsFilter::class:
+                /** @var DocumentStore\Filter\ExistsFilter $filter */
+                $prop = $this->propToJsonPath($filter->prop());
+                $propParts = explode('->', $prop);
+                $lastProp = trim(array_pop($propParts), "'");
+                $parentProps = implode('->', $propParts);
+                return ["JSONB_EXISTS($parentProps, '$lastProp')", [], $argsCount];
+            default:
+                throw new RuntimeException('Unsupported filter type. Got ' . get_class($filter));
+        }
+    }
+
+    private function makeInClause(string $prop, array $valList, int $argsCount, bool $jsonEncode = false): array
+    {
+        if ($valList === []) {
+            return [' 1 != 1 ', [], 0];
+        }
+        $argList = [];
+        $params = \implode(",", \array_map(function ($val) use (&$argsCount, &$argList, $jsonEncode) {
+            $param = ":a$argsCount";
+            $argList["a$argsCount"] = $jsonEncode? \json_encode($val) : $val;
+            $argsCount++;
+            return $param;
+        }, $valList));
+
+        return ["$prop IN($params)", $argList, $argsCount];
+    }
+
+    private function shouldJsonEncodeVal(string $prop): bool
+    {
+        if($this->useMetadataColumns && strpos($prop, 'metadata.') === 0) {
+            return false;
+        }
+
+        return true;
+    }
+
+    private function propToJsonPath(string $field): string
+    {
+        if($this->useMetadataColumns && strpos($field, 'metadata.') === 0) {
+            return str_replace('metadata.', '', $field);
+        }
+
+        return "doc->'" . str_replace('.', "'->'", $field) . "'";
+    }
+
+    private function isPropFilter(Filter $filter): bool
+    {
+        switch (get_class($filter)) {
+            case DocumentStore\Filter\AndFilter::class:
+            case DocumentStore\Filter\OrFilter::class:
+            case DocumentStore\Filter\NotFilter::class:
+                return false;
+            default:
+                return true;
+        }
+    }
+
+    private function prepareVal($value, string $prop)
+    {
+        if(!$this->shouldJsonEncodeVal($prop)) {
+            return $value;
+        }
+
+        return \json_encode($value);
+    }
+}
diff --git a/src/PostgresDocumentStore.php b/src/PostgresDocumentStore.php
index ddbbfc2..39e0925 100644
--- a/src/PostgresDocumentStore.php
+++ b/src/PostgresDocumentStore.php
@@ -16,8 +16,9 @@
 use EventEngine\DocumentStore\Index;
 use EventEngine\DocumentStore\OrderBy\OrderBy;
 use EventEngine\DocumentStore\PartialSelect;
-use EventEngine\DocumentStore\Postgres\Exception\InvalidArgumentException;
 use EventEngine\DocumentStore\Postgres\Exception\RuntimeException;
+use EventEngine\DocumentStore\Postgres\Filter\PostgresFilterProcessor;
+use EventEngine\DocumentStore\Postgres\Filter\FilterProcessor;
 use EventEngine\Util\VariableType;
 
 use function implode;
@@ -37,24 +38,35 @@ final class PostgresDocumentStore implements DocumentStore\DocumentStore
      */
     private $connection;
 
+    /**
+     * @var FilterProcessor
+     */
+    private $filterProcessor;
+
     private $tablePrefix = 'em_ds_';
 
     private $docIdSchema = 'UUID NOT NULL';
 
     private $manageTransactions;
 
-    private $useMetadataColumns = false;
+    private $useMetadataColumns;
 
     public function __construct(
         \PDO $connection,
         string $tablePrefix = null,
         string $docIdSchema = null,
         bool $transactional = true,
-        bool $useMetadataColumns = false
+        bool $useMetadataColumns = false,
+        FilterProcessor $filterProcessor = null
     ) {
         $this->connection = $connection;
         $this->connection->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
 
+        if (null === $filterProcessor) {
+            $filterProcessor = new PostgresFilterProcessor($useMetadataColumns);
+        }
+        $this->filterProcessor = $filterProcessor;
+
         if(null !== $tablePrefix) {
             $this->tablePrefix = $tablePrefix;
         }
@@ -384,9 +396,11 @@ public function updateDoc(string $collectionName, string $docId, array $docOrSub
      */
     public function updateMany(string $collectionName, Filter $filter, array $set): void
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
-        $where = $filterStr? "WHERE $filterStr" : '';
+        $where = $filterStr ? "WHERE $filterStr" : '';
 
         $metadataStr = '';
         $metadata = [];
@@ -477,7 +491,9 @@ public function replaceDoc(string $collectionName, string $docId, array $doc): v
      */
     public function replaceMany(string $collectionName, Filter $filter, array $set): void
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $where = $filterStr? "WHERE $filterStr" : '';
 
@@ -534,7 +550,9 @@ public function deleteDoc(string $collectionName, string $docId): void
      */
     public function deleteMany(string $collectionName, Filter $filter): void
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $where = $filterStr? "WHERE $filterStr" : '';
 
@@ -603,7 +621,9 @@ public function getPartialDoc(string $collectionName, PartialSelect $partialSele
      */
     public function filterDocs(string $collectionName, Filter $filter, int $skip = null, int $limit = null, OrderBy $orderBy = null): \Traversable
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $where = $filterStr ? "WHERE $filterStr" : '';
 
@@ -634,7 +654,9 @@ public function filterDocs(string $collectionName, Filter $filter, int $skip = n
      */
     public function findDocs(string $collectionName, Filter $filter, int $skip = null, int $limit = null, OrderBy $orderBy = null): \Traversable
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $where = $filterStr ? "WHERE $filterStr" : '';
 
@@ -662,7 +684,9 @@ public function findDocs(string $collectionName, Filter $filter, int $skip = nul
 
     public function findPartialDocs(string $collectionName, PartialSelect $partialSelect, Filter $filter, int $skip = null, int $limit = null, OrderBy $orderBy = null): \Traversable
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $select = $this->makeSelect($partialSelect);
 
@@ -698,7 +722,9 @@ public function findPartialDocs(string $collectionName, PartialSelect $partialSe
      */
     public function filterDocIds(string $collectionName, Filter $filter): array
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $where = $filterStr ? "WHERE {$filterStr}" : '';
         $query = "SELECT id FROM {$this->schemaName($collectionName)}.{$this->tableName($collectionName)} {$where}";
@@ -721,7 +747,9 @@ public function filterDocIds(string $collectionName, Filter $filter): array
      */
     public function countDocs(string $collectionName, Filter $filter): int
     {
-        [$filterStr, $args] = $this->filterToWhereClause($filter);
+        $filterClause = $this->filterProcessor->process($filter);
+        $filterStr = $filterClause->clause();
+        $args = $filterClause->args();
 
         $where = $filterStr? "WHERE $filterStr" : '';
 
@@ -756,105 +784,6 @@ private function transactional(callable $callback)
         }
     }
 
-    private function filterToWhereClause(Filter $filter, $argsCount = 0): array
-    {
-        if($filter instanceof DocumentStore\Filter\AnyFilter) {
-            if($argsCount > 0) {
-                throw new InvalidArgumentException('AnyFilter cannot be used together with other filters.');
-            }
-            return [null, [], $argsCount];
-        }
-
-        if($filter instanceof DocumentStore\Filter\AndFilter) {
-            [$filterA, $argsA, $argsCount] = $this->filterToWhereClause($filter->aFilter(), $argsCount);
-            [$filterB, $argsB, $argsCount] = $this->filterToWhereClause($filter->bFilter(), $argsCount);
-            return ["($filterA AND $filterB)", array_merge($argsA, $argsB), $argsCount];
-        }
-
-        if($filter instanceof DocumentStore\Filter\OrFilter) {
-            [$filterA, $argsA, $argsCount] = $this->filterToWhereClause($filter->aFilter(), $argsCount);
-            [$filterB, $argsB, $argsCount] = $this->filterToWhereClause($filter->bFilter(), $argsCount);
-            return ["($filterA OR $filterB)", array_merge($argsA, $argsB), $argsCount];
-        }
-
-        switch (get_class($filter)) {
-            case DocumentStore\Filter\DocIdFilter::class:
-                /** @var DocumentStore\Filter\DocIdFilter $filter */
-                return ["id = :a$argsCount", ["a$argsCount" => $filter->val()], ++$argsCount];
-            case DocumentStore\Filter\AnyOfDocIdFilter::class:
-                /** @var DocumentStore\Filter\AnyOfDocIdFilter $filter */
-                return $this->makeInClause('id', $filter->valList(), $argsCount);
-            case DocumentStore\Filter\AnyOfFilter::class:
-                /** @var DocumentStore\Filter\AnyOfFilter $filter */
-                return $this->makeInClause($this->propToJsonPath($filter->prop()), $filter->valList(), $argsCount, $this->shouldJsonEncodeVal($filter->prop()));
-            case DocumentStore\Filter\EqFilter::class:
-                /** @var DocumentStore\Filter\EqFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                return ["$prop = :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
-            case DocumentStore\Filter\GtFilter::class:
-                /** @var DocumentStore\Filter\GtFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                return ["$prop > :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
-            case DocumentStore\Filter\GteFilter::class:
-                /** @var DocumentStore\Filter\GteFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                return ["$prop >= :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
-            case DocumentStore\Filter\LtFilter::class:
-                /** @var DocumentStore\Filter\LtFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                return ["$prop < :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
-            case DocumentStore\Filter\LteFilter::class:
-                /** @var DocumentStore\Filter\LteFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                return ["$prop <= :a$argsCount", ["a$argsCount" => $this->prepareVal($filter->val(), $filter->prop())], ++$argsCount];
-            case DocumentStore\Filter\LikeFilter::class:
-                /** @var DocumentStore\Filter\LikeFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                $propParts = explode('->', $prop);
-                $lastProp = array_pop($propParts);
-                $prop = implode('->', $propParts) . '->>'.$lastProp;
-                return ["$prop iLIKE :a$argsCount", ["a$argsCount" => $filter->val()], ++$argsCount];
-            case DocumentStore\Filter\NotFilter::class:
-                /** @var DocumentStore\Filter\NotFilter $filter */
-                $innerFilter = $filter->innerFilter();
-
-                if (!$this->isPropFilter($innerFilter)) {
-                    throw new RuntimeException('Not filter cannot be combined with a non prop filter!');
-                }
-
-                [$innerFilterStr, $args, $argsCount] = $this->filterToWhereClause($innerFilter, $argsCount);
-
-                if($innerFilter instanceof DocumentStore\Filter\AnyOfFilter || $innerFilter instanceof DocumentStore\Filter\AnyOfDocIdFilter) {
-                    if ($argsCount === 0) {
-                        return [
-                            str_replace(' 1 != 1 ', ' 1 = 1 ', $innerFilterStr),
-                            $args,
-                            $argsCount
-                        ];
-                    }
-
-                    $inPos = strpos($innerFilterStr, ' IN(');
-                    $filterStr = substr_replace($innerFilterStr, ' NOT IN(', $inPos, 4 /* " IN(" */);
-                    return [$filterStr, $args, $argsCount];
-                }
-
-                return ["NOT $innerFilterStr", $args, $argsCount];
-            case DocumentStore\Filter\InArrayFilter::class:
-                /** @var DocumentStore\Filter\InArrayFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                return ["$prop @> :a$argsCount", ["a$argsCount" => '[' . $this->prepareVal($filter->val(), $filter->prop()) . ']'], ++$argsCount];
-            case DocumentStore\Filter\ExistsFilter::class:
-                /** @var DocumentStore\Filter\ExistsFilter $filter */
-                $prop = $this->propToJsonPath($filter->prop());
-                $propParts = explode('->', $prop);
-                $lastProp = trim(array_pop($propParts), "'");
-                $parentProps = implode('->', $propParts);
-                return ["JSONB_EXISTS($parentProps, '$lastProp')", [], $argsCount];
-            default:
-                throw new RuntimeException('Unsupported filter type. Got ' . get_class($filter));
-        }
-    }
-
     private function propToJsonPath(string $field): string
     {
         if($this->useMetadataColumns && strpos($field, 'metadata.') === 0) {
@@ -864,34 +793,6 @@ private function propToJsonPath(string $field): string
         return "doc->'" . str_replace('.', "'->'", $field) . "'";
     }
 
-    private function isPropFilter(Filter $filter): bool
-    {
-        switch (get_class($filter)) {
-            case DocumentStore\Filter\AndFilter::class:
-            case DocumentStore\Filter\OrFilter::class:
-            case DocumentStore\Filter\NotFilter::class:
-                return false;
-            default:
-                return true;
-        }
-    }
-
-    private function makeInClause(string $prop, array $valList, int $argsCount, bool $jsonEncode = false): array
-    {
-        if ($valList === []) {
-            return [' 1 != 1 ', [], 0];
-        }
-        $argList = [];
-        $params = \implode(",", \array_map(function ($val) use (&$argsCount, &$argList, $jsonEncode) {
-            $param = ":a$argsCount";
-            $argList["a$argsCount"] = $jsonEncode? \json_encode($val) : $val;
-            $argsCount++;
-            return $param;
-        }, $valList));
-
-        return ["$prop IN($params)", $argList, $argsCount];
-    }
-
     private function makeSelect(PartialSelect $partialSelect): string
     {
         $select = 'id as "'.self::PARTIAL_SELECT_DOC_ID.'", ';
@@ -1016,24 +917,6 @@ private function indexToSqlCmd(Index $index, string $collectionName): string
         return $cmd;
     }
 
-    private function prepareVal($value, string $prop)
-    {
-        if(!$this->shouldJsonEncodeVal($prop)) {
-            return $value;
-        }
-
-        return \json_encode($value);
-    }
-
-    private function shouldJsonEncodeVal(string $prop): bool
-    {
-        if($this->useMetadataColumns && strpos($prop, 'metadata.') === 0) {
-            return false;
-        }
-
-        return true;
-    }
-
     private function getIndexName(Index $index): ?string
     {
         if(method_exists($index, 'name')) {
@@ -1066,12 +949,12 @@ private function tableName(string $collectionName): string
         return mb_strtolower($this->tablePrefix . $collectionName);
     }
 
-     private function schemaName(string $collectionName): string
-     {
-         $schemaName = 'public';
-         if (false !== $dotPosition = strpos($collectionName, '.')) {
-             $schemaName = substr($collectionName, 0, $dotPosition);
-         }
-         return mb_strtolower($schemaName);
-     }
+    private function schemaName(string $collectionName): string
+    {
+        $schemaName = 'public';
+        if (false !== $dotPosition = strpos($collectionName, '.')) {
+            $schemaName = substr($collectionName, 0, $dotPosition);
+        }
+        return mb_strtolower($schemaName);
+    }
 }