from pgtoolkit import pgbrowser, toolbase

from pycolib import prettysize

class BigTablesTool(toolbase.SimpleTool):

    def __init__(self):

        toolbase.SimpleTool.__init__(self, name='bigtables', desc='List largest tables.')

        self.init()

    def main(self):

        browser = pgbrowser.PgBrowser(self.pgm.get_conn('target'))

        # scan all tables from all shemas, remember names and sizes

        all_tables = []

        schemas = browser.list_schemas()

        for schema in schemas:

            tables = browser.list_tables(schema['name'])

            for table in tables:

                table_name = '%s.%s' % (schema['name'], table['name'])

                all_tables.append({'name': table_name, 'size': table['size']})

        # print names and sizes of 20 largest tables

        for table in sorted(all_tables, reverse=True, key=lambda x: x['size'])[:20]:

            print(prettysize.prettysize_short(table['size']).rjust(8), table['name'], sep='  ')

tool = BigTablesTool()

tool.main()