Maintain backward compatibility.

Author: khustup2

cpp/deeplake_pg/table_storage.cpp

@@ -200,6 +200,39 @@ void table_storage::load_table_metadata()
         return;
     }
 
+    // Backward compatibility: Check if table_oid column exists
+    // If not, drop and recreate the table with the correct schema
+    if (!pg::utils::check_column_exists("pg_deeplake_tables", "table_oid")) {
+        base::log_warning(base::log_channel::generic,
+            "Detected old schema for pg_deeplake_tables without table_oid column. "
+            "Dropping and recreating table to match current schema.");
+
+        pg::utils::spi_connector connector;
+        const char* drop_query = "DROP TABLE IF EXISTS public.pg_deeplake_tables CASCADE";
+        if (SPI_execute(drop_query, false, 0) != SPI_OK_UTILITY) {
+            base::log_warning(base::log_channel::generic, "Failed to drop old pg_deeplake_tables table");
+        }
+
+        const char* create_query =
+            "CREATE TABLE public.pg_deeplake_tables ("
+            "    id SERIAL PRIMARY KEY,"
+            "    table_oid OID NOT NULL UNIQUE,"
+            "    table_name NAME NOT NULL UNIQUE,"
+            "    ds_path TEXT NOT NULL UNIQUE"
+            ")";
+        if (SPI_execute(create_query, false, 0) != SPI_OK_UTILITY) {
+            base::log_warning(base::log_channel::generic, "Failed to create new pg_deeplake_tables table");
+        }
+
+        const char* grant_query = "GRANT SELECT, INSERT, UPDATE, DELETE ON public.pg_deeplake_tables TO PUBLIC";
+        if (SPI_execute(grant_query, false, 0) != SPI_OK_UTILITY) {
+            base::log_warning(base::log_channel::generic, "Failed to grant permissions on pg_deeplake_tables table");
+        }
+
+        // Table is now empty, so we can return early
+        return;
+    }
+
     const char* query = "SELECT table_oid, table_name, ds_path FROM public.pg_deeplake_tables";
 
     pg::utils::spi_connector connector;

cpp/deeplake_pg/utils.hpp

@@ -663,6 +663,15 @@ inline bool check_table_exists(const std::string& table_name, const std::string&
     return SPI_execute(query.c_str(), true, 0) == SPI_OK_SELECT && SPI_processed > 0;
 }
 
+inline bool check_column_exists(const std::string& table_name, const std::string& column_name, const std::string& schema_name = "public")
+{
+    std::string query = fmt::format("SELECT 1 FROM information_schema.columns WHERE "
+                                    "table_schema = '{}' AND table_name = '{}' AND column_name = '{}'",
+                                    schema_name, table_name, column_name);
+    spi_connector connector;
+    return SPI_execute(query.c_str(), true, 0) == SPI_OK_SELECT && SPI_processed > 0;
+}
+
 } // namespace utils
 
 } // namespace pg