Stop counting at 10,000 rows when listing tables, refs #2398

datasette/database.py

@@ -29,6 +29,9 @@ AttachedDatabase = namedtuple("AttachedDatabase", ("seq", "name", "file"))
 
 
 class Database:
+    # For table counts stop at this many rows:
+    count_limit = 10000
+
     def __init__(
         self,
         ds,
@@ -376,7 +379,7 @@ class Database:
             try:
                 table_count = (
                     await self.execute(
-                        f"select count(*) from [{table}]",
+                        f"select count(*) from (select * from [{table}] limit {self.count_limit + 1})",
                         custom_time_limit=limit,
                     )
                 ).rows[0][0]

datasette/templates/database.html

@@ -60,7 +60,7 @@
 <div class="db-table">
     <h3><a href="{{ urls.table(database, table.name) }}">{{ table.name }}</a>{% if table.private %} 🔒{% endif %}{% if table.hidden %}<em> (hidden)</em>{% endif %}</h3>
     <p><em>{% for column in table.columns %}{{ column }}{% if not loop.last %}, {% endif %}{% endfor %}</em></p>
-    <p>{% if table.count is none %}Many rows{% else %}{{ "{:,}".format(table.count) }} row{% if table.count == 1 %}{% else %}s{% endif %}{% endif %}</p>
+    <p>{% if table.count is none %}Many rows{% elif table.count == count_limit + 1 %}&gt;{{ "{:,}".format(count_limit) }} rows{% else %}{{ "{:,}".format(table.count) }} row{% if table.count == 1 %}{% else %}s{% endif %}{% endif %}</p>
 </div>
 {% endif %}
 {% endfor %}

datasette/views/database.py

@@ -159,6 +159,7 @@ class DatabaseView(View):
             "show_hidden": request.args.get("_show_hidden"),
             "editable": True,
             "metadata": metadata,
+            "count_limit": db.count_limit,
             "allow_download": datasette.setting("allow_download")
             and not db.is_mutable
             and not db.is_memory,
@@ -272,7 +273,7 @@ class QueryContext:
 async def get_tables(datasette, request, db):
     tables = []
     database = db.name
-    table_counts = await db.table_counts(5)
+    table_counts = await db.table_counts(100)
     hidden_table_names = set(await db.hidden_table_names())
     all_foreign_keys = await db.get_all_foreign_keys()