add script for detailed explaing of indexing trigger

diff --git a/utils/analyse_indexing.py b/utils/analyse_indexing.py
new file mode 100755 (executable)
index 0000000..d461f89
--- /dev/null
+++ b/utils/analyse_indexing.py
@@ -0,0 +1,119 @@
+#!/usr/bin/python3
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim.
+# Copyright (C) 2020 Sarah Hoffmann
+
+"""
+Script for analysing the indexing process.
+
+The script enables detailed logging for nested statements and then
+runs the indexing process for teh given object. Detailed 'EXPLAIN ANALYSE'
+information is printed for each executed query in the trigger. The
+transaction is then rolled back, so that no actual changes to the database
+happen. It also disables logging into the system log, so that the
+log files are not cluttered.
+"""
+
+from argparse import ArgumentParser, RawDescriptionHelpFormatter, ArgumentTypeError
+import psycopg2
+import getpass
+import re
+
+class Analyser(object):
+
+    def __init__(self, options):
+        password = None
+        if options.password_prompt:
+            password = getpass.getpass("Database password: ")
+
+        self.options = options
+        self.conn = psycopg2.connect(dbname=options.dbname,
+                                     user=options.user,
+                                     password=password,
+                                     host=options.host,
+                                     port=options.port)
+
+
+
+    def run(self):
+        c = self.conn.cursor()
+
+        if self.options.placeid:
+            place_id = self.options.placeid
+        else:
+            if self.options.rank:
+                c.execute(f"""select place_id from placex
+                              where rank_address = {self.options.rank}
+                              and linked_place_id is null
+                              limit 1""")
+                objinfo = f"rank {self.options.rank}"
+
+            if self.options.osmid:
+                osm_type = self.options.osmid[0].upper()
+                if osm_type not in ('N', 'W', 'R'):
+                    raise RuntimeError("OSM ID must be of form <N|W|R><id>")
+                try:
+                    osm_id = int(self.options.osmid[1:])
+                except ValueError:
+                    raise RuntimeError("OSM ID must be of form <N|W|R><id>")
+
+                c.execute(f"""SELECT place_id FROM placex
+                              WHERE osm_type = '{osm_type}' AND osm_id = {osm_id}""")
+                objinfo = f"OSM object {self.options.osmid}"
+
+
+            if c.rowcount < 1:
+                raise RuntimeError(f"Cannot find a place for {objinfo}.")
+            place_id = c.fetchone()[0]
+
+        c.execute(f"""update placex set indexed_status = 2 where
+                      place_id = {place_id}""")
+
+        c.execute("""SET auto_explain.log_min_duration = '0';
+                     SET auto_explain.log_analyze = 'true';
+                     SET auto_explain.log_nested_statements = 'true';
+                     LOAD 'auto_explain';
+                     SET client_min_messages = LOG;
+                     SET log_min_messages = FATAL""");
+
+        c.execute(f"""update placex set indexed_status = 0 where
+                      place_id = {place_id}""")
+
+        c.close() # automatic rollback
+
+        for l in self.conn.notices:
+            print(l)
+
+
+if __name__ == '__main__':
+    def h(s):
+        return re.sub("\s\s+" , " ", s)
+
+    p = ArgumentParser(description=__doc__,
+                       formatter_class=RawDescriptionHelpFormatter)
+
+    group = p.add_mutually_exclusive_group(required=True)
+    group.add_argument('--rank', dest='rank', type=int,
+                       help='Analyse indexing of the given address rank')
+    group.add_argument('--osm-id', dest='osmid', type=str,
+                       help='Analyse indexing of the given OSM object')
+    group.add_argument('--place-id', dest='placeid', type=int,
+                       help='Analyse indexing of the given Nominatim object')
+    p.add_argument('-d', '--database',
+                   dest='dbname', action='store', default='nominatim',
+                   help='Name of the PostgreSQL database to connect to.')
+    p.add_argument('-U', '--username',
+                   dest='user', action='store',
+                   help='PostgreSQL user name.')
+    p.add_argument('-W', '--password',
+                   dest='password_prompt', action='store_true',
+                   help='Force password prompt.')
+    p.add_argument('-H', '--host',
+                   dest='host', action='store',
+                   help='PostgreSQL server hostname or socket location.')
+    p.add_argument('-P', '--port',
+                   dest='port', action='store',
+                   help='PostgreSQL server port')
+
+    Analyser(p.parse_args()).run()