feat: db storage usage report (#18464)

Basic report to check storage usage by each table.

Note: This is not 100% accurate and will never be 100% accurate but gives rough indication of which table is consuming how much storage.

`no-docs`

[skip ci]

frappe/core/report/database_storage_usage_by_tables/database_storage_usage_by_tables.js

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+// Copyright (c) 2022, Frappe Technologies and contributors
+// For license information, please see license.txt
+/* eslint-disable */
+
+frappe.query_reports["Database Storage Usage By Tables"] = {
+	filters: [],
+};

frappe/core/report/database_storage_usage_by_tables/database_storage_usage_by_tables.json

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+{
+ "add_total_row": 1,
+ "columns": [],
+ "creation": "2022-10-19 02:25:24.326791",
+ "disable_prepared_report": 0,
+ "disabled": 0,
+ "docstatus": 0,
+ "doctype": "Report",
+ "filters": [],
+ "idx": 0,
+ "is_standard": "Yes",
+ "letter_head": "abc",
+ "modified": "2022-10-19 02:59:00.365307",
+ "modified_by": "Administrator",
+ "module": "Core",
+ "name": "Database Storage Usage By Tables",
+ "owner": "Administrator",
+ "prepared_report": 0,
+ "query": "",
+ "ref_doctype": "Error Log",
+ "report_name": "Database Storage Usage By Tables",
+ "report_type": "Script Report",
+ "roles": [
+  {
+   "role": "System Manager"
+  }
+ ]
+}

frappe/core/report/database_storage_usage_by_tables/database_storage_usage_by_tables.py

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+# Copyright (c) 2022, Frappe Technologies and contributors
+# For license information, please see license.txt
+
+import frappe
+
+COLUMNS = [
+	{"label": "Table", "fieldname": "table", "fieldtype": "Data", "width": 200},
+	{"label": "Size (MB)", "fieldname": "size", "fieldtype": "Float"},
+	{"label": "Data (MB)", "fieldname": "data_size", "fieldtype": "Float"},
+	{"label": "Index (MB)", "fieldname": "index_size", "fieldtype": "Float"},
+]
+
+
+def execute(filters=None):
+	frappe.only_for("System Manager")
+
+	data = frappe.db.multisql(
+		{
+			"mariadb": """
+				SELECT table_name AS `table`,
+						round(((data_length + index_length) / 1024 / 1024), 2) `size`,
+						round((data_length / 1024 / 1024), 2) as data_size,
+						round((index_length / 1024 / 1024), 2) as index_size
+				FROM information_schema.TABLES
+				ORDER BY (data_length + index_length) DESC;
+			""",
+			"postgres": """
+				SELECT
+				  table_name as "table",
+				  round(pg_total_relation_size(quote_ident(table_name)) / 1024 / 1024, 2) as "size",
+				  round(pg_relation_size(quote_ident(table_name)) / 1024 / 1024, 2) as "data_size",
+				  round(pg_indexes_size(quote_ident(table_name)) / 1024 / 1024, 2) as "index_size"
+				FROM information_schema.tables
+				WHERE table_schema = 'public'
+				ORDER BY 2 DESC;
+			""",
+		},
+		as_dict=1,
+	)
+	return COLUMNS, data

frappe/core/report/database_storage_usage_by_tables/test_database_storage_usage_by_tables.py

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+# Copyright (c) 2022, Frappe Technologies and contributors
+# For license information, please see license.txt
+
+
+from frappe.core.report.database_storage_usage_by_tables.database_storage_usage_by_tables import (
+	execute,
+)
+from frappe.tests.utils import FrappeTestCase
+
+
+class TestDBUsageReport(FrappeTestCase):
+	def test_basic_query(self):
+		_, data = execute()
+		tables = [d.table for d in data]
+		self.assertFalse({"tabUser", "tabDocField"}.difference(tables))