diff --git a/src/ORM/ArrayList.php b/src/ORM/ArrayList.php
index 74a7cd600ea..d8dca3195fe 100644
--- a/src/ORM/ArrayList.php
+++ b/src/ORM/ArrayList.php
@@ -2,8 +2,8 @@
 
 namespace SilverStripe\ORM;
 
-use ArrayIterator;
 use InvalidArgumentException;
+use Iterator;
 use LogicException;
 use SilverStripe\Dev\Debug;
 use SilverStripe\Dev\Deprecation;
@@ -103,19 +103,16 @@ public function exists()
     /**
      * Returns an Iterator for this ArrayList.
      * This function allows you to use ArrayList in foreach loops
-     *
-     * @return ArrayIterator
      */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
-    {
-        $items = array_map(
-            function ($item) {
-                return is_array($item) ? new ArrayData($item) : $item;
-            },
-            $this->items ?? []
-        );
-        return new ArrayIterator($items);
+    public function getIterator(): Iterator
+    {
+        foreach ($this->items as $i => $item) {
+            if (is_array($item)) {
+                yield new ArrayData($item);
+            } else {
+                yield $item;
+            }
+        }
     }
 
     /**
diff --git a/src/ORM/Connect/DBSchemaManager.php b/src/ORM/Connect/DBSchemaManager.php
index 585fd8187c9..7e3eb3e63ac 100644
--- a/src/ORM/Connect/DBSchemaManager.php
+++ b/src/ORM/Connect/DBSchemaManager.php
@@ -380,7 +380,7 @@ public function requireTable(
             if ($dbID && isset($options[$dbID])) {
                 if (preg_match('/ENGINE=([^\s]*)/', $options[$dbID] ?? '', $alteredEngineMatches)) {
                     $alteredEngine = $alteredEngineMatches[1];
-                    $tableStatus = $this->query(sprintf('SHOW TABLE STATUS LIKE \'%s\'', $table))->first();
+                    $tableStatus = $this->query(sprintf('SHOW TABLE STATUS LIKE \'%s\'', $table))->record();
                     $tableOptionsChanged = ($tableStatus['Engine'] != $alteredEngine);
                 }
             }
diff --git a/src/ORM/Connect/MySQLQuery.php b/src/ORM/Connect/MySQLQuery.php
index c811386430a..d019167014b 100644
--- a/src/ORM/Connect/MySQLQuery.php
+++ b/src/ORM/Connect/MySQLQuery.php
@@ -2,6 +2,8 @@
 
 namespace SilverStripe\ORM\Connect;
 
+use Iterator;
+
 /**
  * A result-set from a MySQL database (using MySQLiConnector)
  * Note that this class is only used for the results of non-prepared statements
@@ -45,16 +47,13 @@ public function __destruct()
         }
     }
 
-    public function seek($row)
+    public function getIterator(): Iterator
     {
         if (is_object($this->handle)) {
-            // Fix for https://github.com/silverstripe/silverstripe-framework/issues/9097 without breaking the seek() API
-            $this->handle->data_seek($row);
-            $result = $this->nextRecord();
-            $this->handle->data_seek($row);
-            return $result;
+            while ($data = $this->handle->fetch_assoc()) {
+                yield $data;
+            }
         }
-        return null;
     }
 
     public function numRecords()
@@ -62,27 +61,7 @@ public function numRecords()
         if (is_object($this->handle)) {
             return $this->handle->num_rows;
         }
-        return null;
-    }
 
-    public function nextRecord()
-    {
-        $floatTypes = [MYSQLI_TYPE_FLOAT, MYSQLI_TYPE_DOUBLE, MYSQLI_TYPE_DECIMAL, MYSQLI_TYPE_NEWDECIMAL];
-
-        if (is_object($this->handle) && ($row = $this->handle->fetch_array(MYSQLI_NUM))) {
-            $data = [];
-            foreach ($row as $i => $value) {
-                if (!isset($this->columns[$i])) {
-                    throw new DatabaseException("Can't get metadata for column $i");
-                }
-                if (in_array($this->columns[$i]->type, $floatTypes ?? [])) {
-                    $value = (float)$value;
-                }
-                $data[$this->columns[$i]->name] = $value;
-            }
-            return $data;
-        } else {
-            return false;
-        }
+        return null;
     }
 }
diff --git a/src/ORM/Connect/MySQLStatement.php b/src/ORM/Connect/MySQLStatement.php
index 7bc54765fcd..eada8ad407b 100644
--- a/src/ORM/Connect/MySQLStatement.php
+++ b/src/ORM/Connect/MySQLStatement.php
@@ -2,6 +2,7 @@
 
 namespace SilverStripe\ORM\Connect;
 
+use Iterator;
 use mysqli_result;
 use mysqli_stmt;
 
@@ -56,6 +57,26 @@ class MySQLStatement extends Query
      */
     protected $boundValues = [];
 
+    /**
+     * Hook the result-set given into a Query class, suitable for use by SilverStripe.
+     * @param mysqli_stmt $statement The related statement, if present
+     * @param mysqli_result $metadata The metadata for this statement
+     */
+    public function __construct($statement, $metadata)
+    {
+        $this->statement = $statement;
+        $this->metadata = $metadata;
+
+        // Immediately bind and buffer
+        $this->bind();
+    }
+
+    public function __destruct()
+    {
+        $this->statement->close();
+        $this->currentRecord = false;
+    }
+
     /**
      * Binds this statement to the variables
      */
@@ -82,58 +103,20 @@ protected function bind()
         call_user_func_array([$this->statement, 'bind_result'], $variables ?? []);
     }
 
-    /**
-     * Hook the result-set given into a Query class, suitable for use by SilverStripe.
-     * @param mysqli_stmt $statement The related statement, if present
-     * @param mysqli_result $metadata The metadata for this statement
-     */
-    public function __construct($statement, $metadata)
-    {
-        $this->statement = $statement;
-        $this->metadata = $metadata;
-
-        // Immediately bind and buffer
-        $this->bind();
-    }
-
-    public function __destruct()
+    public function getIterator(): Iterator
     {
-        $this->statement->close();
-        $this->currentRecord = false;
-    }
-
-    public function seek($row)
-    {
-        $this->rowNum = $row - 1;
-
-        // Fix for https://github.com/silverstripe/silverstripe-framework/issues/9097 without breaking the seek() API
-        $this->statement->data_seek($row);
-        $result = $this->next();
-        $this->statement->data_seek($row);
-        return $result;
+        while ($this->statement->fetch()) {
+            // Dereferenced row
+            $row = [];
+            foreach ($this->boundValues as $key => $value) {
+                $row[$key] = $value;
+            }
+            yield $row;
+        }
     }
 
     public function numRecords()
     {
         return $this->statement->num_rows();
     }
-
-    public function nextRecord()
-    {
-        // Skip data if out of data
-        if (!$this->statement->fetch()) {
-            return false;
-        }
-
-        // Dereferenced row
-        $row = [];
-        foreach ($this->boundValues as $key => $value) {
-            $floatTypes = [MYSQLI_TYPE_FLOAT, MYSQLI_TYPE_DOUBLE, MYSQLI_TYPE_DECIMAL, MYSQLI_TYPE_NEWDECIMAL];
-            if (in_array($this->types[$key], $floatTypes ?? [])) {
-                $value = (float)$value;
-            }
-            $row[$key] = $value;
-        }
-        return $row;
-    }
 }
diff --git a/src/ORM/Connect/PDOQuery.php b/src/ORM/Connect/PDOQuery.php
index 7180de28d0e..24f9712eb8a 100644
--- a/src/ORM/Connect/PDOQuery.php
+++ b/src/ORM/Connect/PDOQuery.php
@@ -2,6 +2,9 @@
 
 namespace SilverStripe\ORM\Connect;
 
+use ArrayIterator;
+use Iterator;
+
 /**
  * A result-set from a PDO database.
  */
@@ -14,7 +17,7 @@ class PDOQuery extends Query
 
     /**
      * Hook the result-set given into a Query class, suitable for use by SilverStripe.
-     * @param PDOStatement $statement The internal PDOStatement containing the results
+     * @param PDOStatementHandle $statement The internal PDOStatement containing the results
      */
     public function __construct(PDOStatementHandle $statement)
     {
@@ -26,25 +29,13 @@ public function __construct(PDOStatementHandle $statement)
         $statement->closeCursor();
     }
 
-    public function seek($row)
+    public function getIterator(): Iterator
     {
-        $this->rowNum = $row - 1;
-        return $this->nextRecord();
+        return new ArrayIterator($this->results);
     }
 
     public function numRecords()
     {
-        return count($this->results ?? []);
-    }
-
-    public function nextRecord()
-    {
-        $index = $this->rowNum + 1;
-
-        if (isset($this->results[$index])) {
-            return $this->results[$index];
-        } else {
-            return false;
-        }
+        return count($this->results);
     }
 }
diff --git a/src/ORM/Connect/Query.php b/src/ORM/Connect/Query.php
index af9e0c3a540..8aac231b2b5 100644
--- a/src/ORM/Connect/Query.php
+++ b/src/ORM/Connect/Query.php
@@ -27,30 +27,9 @@
  * on providing the specific data-access methods that are required: {@link nextRecord()}, {@link numRecords()}
  * and {@link seek()}
  */
-abstract class Query implements Iterator
+abstract class Query implements \IteratorAggregate
 {
 
-    /**
-     * The current record in the iterator.
-     *
-     * @var array
-     */
-    protected $currentRecord = null;
-
-    /**
-     * The number of the current row in the iterator.
-     *
-     * @var int
-     */
-    protected $rowNum = -1;
-
-    /**
-     * Flag to keep track of whether iteration has begun, to prevent unnecessary seeks
-     *
-     * @var bool
-     */
-    protected $queryHasBegun = false;
-
     /**
      * Return an array containing all the values from a specific column. If no column is set, then the first will be
      * returned
@@ -62,7 +41,7 @@ public function column($column = null)
     {
         $result = [];
 
-        while ($record = $this->next()) {
+        foreach ($this as $record) {
             if ($column) {
                 $result[] = $record[$column];
             } else {
@@ -82,6 +61,7 @@ public function column($column = null)
     public function keyedColumn()
     {
         $column = [];
+
         foreach ($this as $record) {
             $val = $record[key($record)];
             $column[$val] = $val;
@@ -106,13 +86,22 @@ public function map()
     }
 
     /**
-     * Returns the next record in the iterator.
+     * Returns the first record in the result
      *
      * @return array
      */
     public function record()
     {
-        return $this->next();
+        return $this->getIterator()->current();
+    }
+
+    /**
+     * @deprecated Use record() instead
+     * @return array
+     */
+    public function first()
+    {
+        return $this->record();
     }
 
     /**
@@ -122,7 +111,7 @@ public function record()
      */
     public function value()
     {
-        $record = $this->next();
+        $record = $this->record();
         if ($record) {
             return $record[key($record)];
         }
@@ -164,94 +153,10 @@ public function table()
         return $result;
     }
 
-    /**
-     * Iterator function implementation. Rewind the iterator to the first item and return it.
-     * Makes use of {@link seek()} and {@link numRecords()}, takes care of the plumbing.
-     *
-     * @return void
-     */
-    #[\ReturnTypeWillChange]
-    public function rewind()
-    {
-        if ($this->queryHasBegun && $this->numRecords() > 0) {
-            $this->queryHasBegun = false;
-            $this->currentRecord = null;
-            $this->seek(0);
-        }
-    }
-
-    /**
-     * Iterator function implementation. Return the current item of the iterator.
-     *
-     * @return array
-     */
-    #[\ReturnTypeWillChange]
-    public function current()
-    {
-        if (!$this->currentRecord) {
-            return $this->next();
-        } else {
-            return $this->currentRecord;
-        }
-    }
-
-    /**
-     * Iterator function implementation. Return the first item of this iterator.
-     *
-     * @return array
-     */
-    public function first()
-    {
-        $this->rewind();
-        return $this->current();
-    }
-
-    /**
-     * Iterator function implementation. Return the row number of the current item.
-     *
-     * @return int
-     */
-    #[\ReturnTypeWillChange]
-    public function key()
-    {
-        return $this->rowNum;
-    }
-
-    /**
-     * Iterator function implementation. Return the next record in the iterator.
-     * Makes use of {@link nextRecord()}, takes care of the plumbing.
-     *
-     * @return array
-     */
-    #[\ReturnTypeWillChange]
-    public function next()
-    {
-        $this->queryHasBegun = true;
-        $this->currentRecord = $this->nextRecord();
-        $this->rowNum++;
-        return $this->currentRecord;
-    }
-
-    /**
-     * Iterator function implementation. Check if the iterator is pointing to a valid item.
-     *
-     * @return bool
-     */
-    #[\ReturnTypeWillChange]
-    public function valid()
-    {
-        if (!$this->queryHasBegun) {
-            $this->next();
-        }
-        return $this->currentRecord !== false;
-    }
-
     /**
      * Return the next record in the query result.
-     *
-     * @return array
      */
-    abstract public function nextRecord();
+    abstract public function getIterator(): Iterator;
 
     /**
      * Return the total number of items in the query result.
@@ -259,12 +164,4 @@ abstract public function nextRecord();
      * @return int
      */
     abstract public function numRecords();
-
-    /**
-     * Go to a specific row number in the query result and return the record.
-     *
-     * @param int $rowNum Row number to go to.
-     * @return array
-     */
-    abstract public function seek($rowNum);
 }
diff --git a/src/ORM/DataList.php b/src/ORM/DataList.php
index 72dfaf02ef2..124ceefb02e 100644
--- a/src/ORM/DataList.php
+++ b/src/ORM/DataList.php
@@ -6,10 +6,12 @@
 use SilverStripe\Dev\Debug;
 use SilverStripe\ORM\Filters\SearchFilter;
 use SilverStripe\ORM\Queries\SQLConditionGroup;
+use SilverStripe\View\TemplateIterator;
 use SilverStripe\View\ViewableData;
 use ArrayIterator;
 use Exception;
 use InvalidArgumentException;
+use Iterator;
 use LogicException;
 
 /**
@@ -49,6 +51,13 @@ class DataList extends ViewableData implements SS_List, Filterable, Sortable, Li
      */
     protected $dataQuery;
 
+    /**
+     * A cached Query to save repeated database calls. {@see DataList::getTemplateIteratorCount()}
+     *
+     * @var SilverStripe\ORM\Connect\Query
+     */
+    protected $finalisedQuery;
+
     /**
      * Create a new DataList.
      * No querying is done on construction, but the initial query schema is set up.
@@ -79,6 +88,7 @@ public function dataClass()
     public function __clone()
     {
         $this->dataQuery = clone $this->dataQuery;
+        $this->finalisedQuery = null;
     }
 
     /**
@@ -863,13 +873,32 @@ public function getQueryParams()
     /**
      * Returns an Iterator for this DataList.
      * This function allows you to use DataLists in foreach loops
+     */
+    public function getIterator(): Iterator
+    {
+        foreach ($this->getFinalisedQuery() as $row) {
+            yield $this->createDataObject($row);
+        }
+
+        // Re-set the finaliseQuery so that it can be re-executed
+        $this->finalisedQuery = null;
+    }
+
+    /**
+     * Returns the Query result for this DataList. Repeated calls will return
+     * a cached result, unless the DataQuery underlying this list has been
+     * modified
      *
-     * @return ArrayIterator
+     * @return SilverStripe\ORM\Connect\Query
+     * @internal This API may change in minor releases
      */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    protected function getFinalisedQuery()
     {
-        return new ArrayIterator($this->toArray());
+        if (!$this->finalisedQuery) {
+            $this->finalisedQuery = $this->dataQuery->query()->execute();
+        }
+
+        return $this->finalisedQuery;
     }
 
     /**
@@ -880,6 +909,10 @@ public function getIterator()
     #[\ReturnTypeWillChange]
     public function count()
     {
+        if ($this->finalisedQuery) {
+            return $this->finalisedQuery->numRecords();
+        }
+
         return $this->dataQuery->count();
     }
 
@@ -1027,8 +1060,7 @@ public function byID($id)
      */
     public function column($colName = "ID")
     {
-        $dataQuery = clone $this->dataQuery;
-        return $dataQuery->distinct(false)->column($colName);
+        return $this->dataQuery->distinct(false)->column($colName);
     }
 
     /**
diff --git a/src/ORM/ListDecorator.php b/src/ORM/ListDecorator.php
index d3f006e64b5..f34e5ea5a91 100644
--- a/src/ORM/ListDecorator.php
+++ b/src/ORM/ListDecorator.php
@@ -2,6 +2,7 @@
 
 namespace SilverStripe\ORM;
 
+use Iterator;
 use SilverStripe\View\ViewableData;
 use LogicException;
 
@@ -96,8 +97,7 @@ public function remove($itemObject)
         $this->list->remove($itemObject);
     }
 
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    public function getIterator(): Iterator
     {
         return $this->list->getIterator();
     }
diff --git a/src/ORM/ManyManyList.php b/src/ORM/ManyManyList.php
index 5ad69cd8f46..ff841a9dc65 100644
--- a/src/ORM/ManyManyList.php
+++ b/src/ORM/ManyManyList.php
@@ -521,7 +521,7 @@ public function getExtraData($componentName, $itemID)
         $query->addWhere([
             "\"{$this->joinTable}\".\"{$this->localKey}\"" => $itemID
         ]);
-        $queryResult = $query->execute()->current();
+        $queryResult = $query->execute()->record();
         if ($queryResult) {
             foreach ($queryResult as $fieldName => $value) {
                 $result[$fieldName] = $value;
diff --git a/src/ORM/Map.php b/src/ORM/Map.php
index 6bcd68494db..a29116c539b 100644
--- a/src/ORM/Map.php
+++ b/src/ORM/Map.php
@@ -4,6 +4,7 @@
 
 use ArrayAccess;
 use Countable;
+use Iterator;
 use IteratorAggregate;
 
 /**
@@ -250,23 +251,55 @@ public function offsetUnset($key)
     }
 
     /**
-     * Returns an Map_Iterator instance for iterating over the complete set
+     * Returns an Iterator for iterating over the complete set
      * of items in the map.
      *
-     * Satisfies the IteratorAggreagte interface.
+     * Satisfies the IteratorAggregate interface.
+     */
+    public function getIterator(): Iterator
+    {
+        $keyField = $this->keyField;
+        $valueField = $this->valueField;
+
+        foreach ($this->firstItems as $k => $v) {
+            yield $k => $v;
+        }
+
+        foreach ($this->list as $record) {
+            if (isset($this->firstItems[$record->$keyField])) {
+                continue;
+            }
+            if (isset($this->lastItems[$record->$keyField])) {
+                continue;
+            }
+            yield $this->extractValue($record, $this->keyField) => $this->extractValue($record, $this->valueField);
+        }
+
+        foreach ($this->lastItems as $k => $v) {
+            yield $k => $v;
+        }
+    }
+
+    /**
+     * Extracts a value from an item in the list, where the item is either an
+     * object or array.
      *
-     * @return Map_Iterator
+     * @param  array|object $item
+     * @param  string $key
+     * @return mixed
      */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    protected function extractValue($item, $key)
     {
-        return new Map_Iterator(
-            $this->list->getIterator(),
-            $this->keyField,
-            $this->valueField,
-            $this->firstItems,
-            $this->lastItems
-        );
+        if (is_object($item)) {
+            if (method_exists($item, 'hasMethod') && $item->hasMethod($key)) {
+                return $item->{$key}();
+            }
+            return $item->{$key};
+        } else {
+            if (array_key_exists($key, $item)) {
+                return $item[$key];
+            }
+        }
     }
 
     /**
diff --git a/src/ORM/Map_Iterator.php b/src/ORM/Map_Iterator.php
deleted file mode 100644
index d645ca07df8..00000000000
--- a/src/ORM/Map_Iterator.php
+++ /dev/null
@@ -1,200 +0,0 @@
-<?php
-
-namespace SilverStripe\ORM;
-
-use Iterator;
-
-/**
- * Builds a map iterator around an Iterator.  Called by Map
- */
-class Map_Iterator implements Iterator
-{
-
-    /**
-     * @var Iterator
-     **/
-    protected $items;
-
-    protected $keyField, $titleField;
-
-    protected $firstItemIdx = 0;
-
-    protected $endItemIdx;
-
-    protected $firstItems = [];
-    protected $lastItems = [];
-
-    protected $excludedItems = [];
-
-    /**
-     * @param Iterator $items The iterator to build this map from
-     * @param string $keyField The field to use for the keys
-     * @param string $titleField The field to use for the values
-     * @param array $firstItems An optional map of items to show first
-     * @param array $lastItems An optional map of items to show last
-     */
-    public function __construct(Iterator $items, $keyField, $titleField, $firstItems = null, $lastItems = null)
-    {
-        $this->items = $items;
-        $this->keyField = $keyField;
-        $this->titleField = $titleField;
-        $this->endItemIdx = null;
-
-        if ($firstItems) {
-            foreach ($firstItems as $k => $v) {
-                $this->firstItems[] = [$k, $v];
-                $this->excludedItems[] = $k;
-            }
-        }
-
-        if ($lastItems) {
-            foreach ($lastItems as $k => $v) {
-                $this->lastItems[] = [$k, $v];
-                $this->excludedItems[] = $k;
-            }
-        }
-    }
-
-    /**
-     * Rewind the Iterator to the first element.
-     *
-     * @return mixed
-     */
-    #[\ReturnTypeWillChange]
-    public function rewind()
-    {
-        $this->firstItemIdx = 0;
-        $this->endItemIdx = null;
-
-        $rewoundItem = $this->items->rewind();
-
-        if (isset($this->firstItems[$this->firstItemIdx])) {
-            return $this->firstItems[$this->firstItemIdx][1];
-        } else {
-            if ($rewoundItem) {
-                return $this->extractValue($rewoundItem, $this->titleField);
-            } else {
-                if (!$this->items->valid() && $this->lastItems) {
-                    $this->endItemIdx = 0;
-
-                    return $this->lastItems[0][1];
-                }
-            }
-        }
-    }
-
-    /**
-     * Return the current element.
-     *
-     * @return mixed
-     */
-    #[\ReturnTypeWillChange]
-    public function current()
-    {
-        if (($this->endItemIdx !== null) && isset($this->lastItems[$this->endItemIdx])) {
-            return $this->lastItems[$this->endItemIdx][1];
-        } else {
-            if (isset($this->firstItems[$this->firstItemIdx])) {
-                return $this->firstItems[$this->firstItemIdx][1];
-            }
-        }
-        return $this->extractValue($this->items->current(), $this->titleField);
-    }
-
-    /**
-     * Extracts a value from an item in the list, where the item is either an
-     * object or array.
-     *
-     * @param  array|object $item
-     * @param  string $key
-     * @return mixed
-     */
-    protected function extractValue($item, $key)
-    {
-        if (is_object($item)) {
-            if (method_exists($item, 'hasMethod') && $item->hasMethod($key)) {
-                return $item->{$key}();
-            }
-            return $item->{$key};
-        } else {
-            if (array_key_exists($key, $item ?? [])) {
-                return $item[$key];
-            }
-        }
-    }
-
-    /**
-     * Return the key of the current element.
-     *
-     * @return string
-     */
-    #[\ReturnTypeWillChange]
-    public function key()
-    {
-        if (($this->endItemIdx !== null) && isset($this->lastItems[$this->endItemIdx])) {
-            return $this->lastItems[$this->endItemIdx][0];
-        } else {
-            if (isset($this->firstItems[$this->firstItemIdx])) {
-                return $this->firstItems[$this->firstItemIdx][0];
-            } else {
-                return $this->extractValue($this->items->current(), $this->keyField);
-            }
-        }
-    }
-
-    /**
-     * Move forward to next element.
-     *
-     * @return mixed
-     */
-    #[\ReturnTypeWillChange]
-    public function next()
-    {
-        $this->firstItemIdx++;
-
-        if (isset($this->firstItems[$this->firstItemIdx])) {
-            return $this->firstItems[$this->firstItemIdx][1];
-        } else {
-            if (!isset($this->firstItems[$this->firstItemIdx - 1])) {
-                $this->items->next();
-            }
-
-            if ($this->excludedItems) {
-                while (($c = $this->items->current()) && in_array($c->{$this->keyField}, $this->excludedItems ?? [], true)) {
-                    $this->items->next();
-                }
-            }
-        }
-
-        if (!$this->items->valid()) {
-            // iterator has passed the preface items, off the end of the items
-            // list. Track through the end items to go through to the next
-            if ($this->endItemIdx === null) {
-                $this->endItemIdx = -1;
-            }
-
-            $this->endItemIdx++;
-
-            if (isset($this->lastItems[$this->endItemIdx])) {
-                return $this->lastItems[$this->endItemIdx];
-            }
-
-            return false;
-        }
-    }
-
-    /**
-     * Checks if current position is valid.
-     *
-     * @return boolean
-     */
-    #[\ReturnTypeWillChange]
-    public function valid()
-    {
-        return (
-            (isset($this->firstItems[$this->firstItemIdx])) ||
-            (($this->endItemIdx !== null) && isset($this->lastItems[$this->endItemIdx])) ||
-            $this->items->valid()
-        );
-    }
-}
diff --git a/src/ORM/PaginatedList.php b/src/ORM/PaginatedList.php
index f7289e9a8bd..b962c0e546a 100644
--- a/src/ORM/PaginatedList.php
+++ b/src/ORM/PaginatedList.php
@@ -8,6 +8,7 @@
 use SilverStripe\View\ArrayData;
 use ArrayAccess;
 use Exception;
+use Iterator;
 use IteratorIterator;
 
 /**
@@ -208,11 +209,7 @@ public function setLimitItems($limit)
         return $this;
     }
 
-    /**
-     * @return IteratorIterator
-     */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    public function getIterator(): Iterator
     {
         $pageLength = $this->getPageLength();
         if ($this->limitItems && $pageLength) {
@@ -225,6 +222,21 @@ public function getIterator()
         }
     }
 
+    /**
+     * @return array
+     */
+    public function toArray()
+    {
+        $result = [];
+
+        // Use getIterator()
+        foreach ($this as $record) {
+            $result[] = $record;
+        }
+
+        return $result;
+    }
+
     /**
      * Returns a set of links to all the pages in the list. This is useful for
      * basic pagination.
@@ -344,8 +356,8 @@ public function PaginationSummary($context = 4)
             $num = $i + 1;
 
             $emptyRange = $num != 1 && $num != $total && (
-                $num == $left - 1 || $num == $right + 1
-            );
+                    $num == $left - 1 || $num == $right + 1
+                );
 
             if ($emptyRange) {
                 $result->push(new ArrayData([
diff --git a/src/ORM/UnsavedRelationList.php b/src/ORM/UnsavedRelationList.php
index 51cde920fd9..0206ef19edb 100644
--- a/src/ORM/UnsavedRelationList.php
+++ b/src/ORM/UnsavedRelationList.php
@@ -4,6 +4,7 @@
 
 use InvalidArgumentException;
 use ArrayIterator;
+use Iterator;
 use SilverStripe\ORM\FieldType\DBField;
 
 /**
@@ -120,11 +121,8 @@ public function dataClass()
 
     /**
      * Returns an Iterator for this relation.
-     *
-     * @return ArrayIterator
      */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    public function getIterator(): Iterator
     {
         return new ArrayIterator($this->toArray());
     }
diff --git a/src/View/SSViewer_Scope.php b/src/View/SSViewer_Scope.php
index 224fd07530a..28d1b541f0d 100644
--- a/src/View/SSViewer_Scope.php
+++ b/src/View/SSViewer_Scope.php
@@ -3,6 +3,7 @@
 namespace SilverStripe\View;
 
 use ArrayIterator;
+use Countable;
 use Iterator;
 
 /**
@@ -289,16 +290,31 @@ public function next()
         }
 
         if (!$this->itemIterator) {
+            // Note: it is important that getIterator() is called before count() as implemenations may rely on
+            // this to efficiency get both the number of records and an iterator (e.g. DataList does this)
+
+            // Item may be an array or a regular IteratorAggregate
             if (is_array($this->item)) {
                 $this->itemIterator = new ArrayIterator($this->item);
             } else {
                 $this->itemIterator = $this->item->getIterator();
+
+                // This will execute code in a generator up to the first yield. For example, this ensures that
+                // DataList::getIterator() is called before Datalist::count()
+                $this->itemIterator->rewind();
+            }
+
+            // If the item implements Countable, use that to fetch the count, otherwise we have to inspect the
+            // iterator and then rewind it.
+            if ($this->item instanceof Countable) {
+                $this->itemIteratorTotal = count($this->item);
+            } else {
+                $this->itemIteratorTotal = iterator_count($this->itemIterator);
+                $this->itemIterator->rewind();
             }
 
             $this->itemStack[$this->localIndex][SSViewer_Scope::ITEM_ITERATOR] = $this->itemIterator;
-            $this->itemIteratorTotal = iterator_count($this->itemIterator); // Count the total number of items
             $this->itemStack[$this->localIndex][SSViewer_Scope::ITEM_ITERATOR_TOTAL] = $this->itemIteratorTotal;
-            $this->itemIterator->rewind();
         } else {
             $this->itemIterator->next();
         }
diff --git a/src/View/ViewableData.php b/src/View/ViewableData.php
index 2755b1da4a8..4fd3051c206 100644
--- a/src/View/ViewableData.php
+++ b/src/View/ViewableData.php
@@ -5,6 +5,7 @@
 use ArrayIterator;
 use Exception;
 use InvalidArgumentException;
+use Iterator;
 use IteratorAggregate;
 use LogicException;
 use SilverStripe\Core\ClassInfo;
@@ -573,11 +574,8 @@ public function getXMLValues($fields)
      *
      * This is useful so you can use a single record inside a <% control %> block in a template - and then use
      * to access individual fields on this object.
-     *
-     * @return ArrayIterator
      */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
+    public function getIterator(): Iterator
     {
         return new ArrayIterator([$this]);
     }
diff --git a/tests/php/ORM/DatabaseTest.php b/tests/php/ORM/DatabaseTest.php
index 25fa3deed8e..33a45caaf38 100644
--- a/tests/php/ORM/DatabaseTest.php
+++ b/tests/php/ORM/DatabaseTest.php
@@ -74,7 +74,7 @@ public function testMySQLCreateTableOptions()
                 'SHOW TABLE STATUS WHERE "Name" = \'%s\'',
                 'DatabaseTest_MyObject'
             )
-        )->first();
+        )->record();
         $this->assertEquals(
             $ret['Engine'],
             'InnoDB',
diff --git a/tests/php/ORM/MySQLDatabaseTest.php b/tests/php/ORM/MySQLDatabaseTest.php
index 7b084b04522..e4ffdfd2fd6 100644
--- a/tests/php/ORM/MySQLDatabaseTest.php
+++ b/tests/php/ORM/MySQLDatabaseTest.php
@@ -45,58 +45,47 @@ public function testPreparedStatements()
         $this->assertInstanceOf(MySQLQuery::class, $result3);
 
         // Iterating one level should not buffer, but return the right result
+        $result1Array = [];
+        foreach ($result1 as $record) {
+            $result1Array[] = $record;
+        }
         $this->assertEquals(
             [
-                'Sort' => 1,
-                'Title' => 'First Item'
-            ],
-            $result1->next()
-        );
-        $this->assertEquals(
-            [
-                'Sort' => 2,
-                'Title' => 'Second Item'
-            ],
-            $result1->next()
-        );
-
-        // Test first
-        $this->assertEquals(
-            [
-                'Sort' => 1,
-                'Title' => 'First Item'
-            ],
-            $result1->first()
-        );
-
-        // Test seek
-        $this->assertEquals(
-            [
-                'Sort' => 2,
-                'Title' => 'Second Item'
+                [ 'Sort' => 1, 'Title' => 'First Item' ],
+                [ 'Sort' => 2, 'Title' => 'Second Item' ],
+                [ 'Sort' => 3, 'Title' => 'Third Item' ],
+                [ 'Sort' => 4, 'Title' => 'Last Item' ],
             ],
-            $result1->seek(1)
+            $result1Array
         );
 
         // Test count
         $this->assertEquals(4, $result1->numRecords());
 
         // Test second statement
+        $result2Array = [];
+        foreach ($result2 as $record) {
+            $result2Array[] = $record;
+            break;
+        }
         $this->assertEquals(
             [
-                'Sort' => 3,
-                'Title' => 'Third Item'
+                [ 'Sort' => 3, 'Title' => 'Third Item' ],
             ],
-            $result2->next()
+            $result2Array
         );
 
         // Test non-prepared query
+        $result3Array = [];
+        foreach ($result3 as $record) {
+            $result3Array[] = $record;
+            break;
+        }
         $this->assertEquals(
             [
-                'Sort' => 1,
-                'Title' => 'First Item'
+                [ 'Sort' => 1, 'Title' => 'First Item' ],
             ],
-            $result3->next()
+            $result3Array
         );
     }
 
diff --git a/tests/php/ORM/PDODatabaseTest.php b/tests/php/ORM/PDODatabaseTest.php
index fa91676c536..5462056711a 100644
--- a/tests/php/ORM/PDODatabaseTest.php
+++ b/tests/php/ORM/PDODatabaseTest.php
@@ -43,58 +43,47 @@ public function testPreparedStatements()
         $this->assertInstanceOf(PDOQuery::class, $result3);
 
         // Iterating one level should not buffer, but return the right result
+        $result1Array = [];
+        foreach ($result1 as $record) {
+            $result1Array[] = $record;
+        }
         $this->assertEquals(
             [
-                'Sort' => 1,
-                'Title' => 'First Item'
-            ],
-            $result1->next()
-        );
-        $this->assertEquals(
-            [
-                'Sort' => 2,
-                'Title' => 'Second Item'
-            ],
-            $result1->next()
-        );
-
-        // Test first
-        $this->assertEquals(
-            [
-                'Sort' => 1,
-                'Title' => 'First Item'
-            ],
-            $result1->first()
-        );
-
-        // Test seek
-        $this->assertEquals(
-            [
-                'Sort' => 2,
-                'Title' => 'Second Item'
+                [ 'Sort' => 1, 'Title' => 'First Item' ],
+                [ 'Sort' => 2, 'Title' => 'Second Item' ],
+                [ 'Sort' => 3, 'Title' => 'Third Item' ],
+                [ 'Sort' => 4, 'Title' => 'Last Item' ],
             ],
-            $result1->seek(1)
+            $result1Array
         );
 
         // Test count
         $this->assertEquals(4, $result1->numRecords());
 
         // Test second statement
+        $result2Array = [];
+        foreach ($result2 as $record) {
+            $result2Array[] = $record;
+            break;
+        }
         $this->assertEquals(
             [
-                'Sort' => 3,
-                'Title' => 'Third Item'
+                [ 'Sort' => 3, 'Title' => 'Third Item' ],
             ],
-            $result2->next()
+            $result2Array
         );
 
         // Test non-prepared query
+        $result3Array = [];
+        foreach ($result3 as $record) {
+            $result3Array[] = $record;
+            break;
+        }
         $this->assertEquals(
             [
-                'Sort' => 1,
-                'Title' => 'First Item'
+                [ 'Sort' => 1, 'Title' => 'First Item' ],
             ],
-            $result3->next()
+            $result3Array
         );
     }
 
diff --git a/tests/php/ORM/PaginatedListTest.php b/tests/php/ORM/PaginatedListTest.php
index fb63403d6ec..d6690e612f5 100644
--- a/tests/php/ORM/PaginatedListTest.php
+++ b/tests/php/ORM/PaginatedListTest.php
@@ -90,7 +90,7 @@ public function testSetCurrentPage()
         $this->assertEquals(1, $list->CurrentPage());
     }
 
-    public function testGetIterator()
+    public function testIteration()
     {
         $list = new PaginatedList(
             new ArrayList([
@@ -105,26 +105,23 @@ public function testGetIterator()
 
         $this->assertListEquals(
             [['Num' => 1], ['Num' => 2]],
-            ArrayList::create($list->getIterator()->getInnerIterator()->getArrayCopy())
+            $list
         );
 
         $list->setCurrentPage(2);
         $this->assertListEquals(
             [['Num' => 3], ['Num' => 4]],
-            ArrayList::create($list->getIterator()->getInnerIterator()->getArrayCopy())
+            $list
         );
 
         $list->setCurrentPage(3);
         $this->assertListEquals(
             [['Num' => 5]],
-            ArrayList::create($list->getIterator()->getInnerIterator()->getArrayCopy())
+            $list
         );
 
         $list->setCurrentPage(999);
-        $this->assertListEquals(
-            [],
-            ArrayList::create($list->getIterator()->getInnerIterator()->getArrayCopy())
-        );
+        $this->assertListEquals([], $list);
 
         // Test disabled paging
         $list->setPageLength(0);
@@ -137,14 +134,13 @@ public function testGetIterator()
                 ['Num' => 4],
                 ['Num' => 5],
             ],
-            ArrayList::create($list->getIterator()->getInnerIterator()->getArrayCopy())
+            $list
         );
 
         // Test with dataobjectset
         $players = Player::get();
         $list = new PaginatedList($players);
         $list->setPageLength(1);
-        $list->getIterator();
         $this->assertEquals(
             4,
             $list->getTotalItems(),
@@ -223,10 +219,10 @@ public function testLimitItems()
         $list = new PaginatedList($list);
 
         $list->setCurrentPage(3);
-        $this->assertCount(10, $list->getIterator()->getInnerIterator());
+        $this->assertEquals(10, count($list));
 
         $list->setLimitItems(false);
-        $this->assertCount(50, $list->getIterator()->getInnerIterator());
+        $this->assertEquals(50, count($list));
     }
 
     public function testCurrentPage()