feat: add preference for default View Data row limit (#10170)

The unqualified "View Data" action always ran with no LIMIT, unlike
"First/Last 100 Rows" which hardcode limit=100 — unusable on large
tables with no way to cap it.

Add view_data_default_row_limit preference (int, default 0 =
unlimited) under sqleditor Options. GridCommand.__init__ applies it
as self.limit when cmd_type == VIEW_ALL_ROWS and the value is
positive; objectquery.sql already renders LIMIT only when > 0, so
no template changes needed. First/Last 100 Rows untouched.

Closes #10104

web/pgadmin/tools/sqleditor/command.py

@@ -363,6 +363,14 @@ class GridCommand(BaseCommand, SQLFilter, FetchedRowTracker):
 
         if self.cmd_type in (VIEW_FIRST_100_ROWS, VIEW_LAST_100_ROWS):
             self.limit = 100
+        elif self.cmd_type == VIEW_ALL_ROWS:
+            # Apply the user-configurable default row limit (if any) for the
+            # "All Rows" option. A value of 0 (the default) means no limit,
+            # preserving the existing behaviour of fetching all rows.
+            default_row_limit = Preferences.module('sqleditor').preference(
+                'view_data_default_row_limit').get()
+            if default_row_limit and default_row_limit > 0:
+                self.limit = default_row_limit
 
         self.thread_native_id = None
         self.server_cursor = kwargs['server_cursor'] if\

web/pgadmin/tools/sqleditor/utils/query_tool_preferences.py

@@ -120,6 +120,21 @@ def register_query_tool_preferences(self):
                          "First/Last 100 Rows options, data is always sorted.")
     )
 
+    self.view_data_default_row_limit = self.preference.register(
+        'Options', 'view_data_default_row_limit',
+        gettext("Default row limit for View Data"), 'integer', 0,
+        min_val=0,
+        category_label=PREF_LABEL_OPTIONS,
+        help_str=gettext(
+            "Specify the maximum number of rows to fetch when using the "
+            "View/Edit Data - All Rows option. This appends a LIMIT clause "
+            "to the generated query, which can significantly improve "
+            "performance on very large tables. Set to 0 (the default) to "
+            "fetch all rows with no limit (the existing behavior). This "
+            "does not affect the First/Last 100 Rows options."
+        )
+    )
+
     self.show_prompt_save_data_changes = self.preference.register(
         'Options', 'prompt_save_data_changes',
         gettext("Prompt to save unsaved data changes?"), 'boolean', True,