add function for parallel execution of SQL scripts

[nominatim.git] / nominatim / db / sql_preprocessor.py

diff --git a/nominatim/db/sql_preprocessor.py b/nominatim/db/sql_preprocessor.py
index a1bf5b7f1418a0d65abd1199264a892f3d74f918..31b4a8c0f9a0042877cb652f6578fe2e896a899a 100644 (file)
--- a/nominatim/db/sql_preprocessor.py
+++ b/nominatim/db/sql_preprocessor.py
@@ -1,10 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
 """
 Preprocessing of SQL files.
 """
+from typing import Set, Dict, Any
 import jinja2
 
+from nominatim.db.connection import Connection
+from nominatim.db.async_connection import WorkerPool
+from nominatim.config import Configuration
 
-def _get_partitions(conn):
+def _get_partitions(conn: Connection) -> Set[int]:
     """ Get the set of partitions currently in use.
     """
     with conn.cursor() as cur:
@@ -16,7 +26,7 @@ def _get_partitions(conn):
     return partitions
 
 
-def _get_tables(conn):
+def _get_tables(conn: Connection) -> Set[str]:
     """ Return the set of tables currently in use.
         Only includes non-partitioned
     """
@@ -26,22 +36,22 @@ def _get_tables(conn):
         return set((row[0] for row in list(cur)))
 
 
-def _setup_tablespace_sql(config):
+def _setup_tablespace_sql(config: Configuration) -> Dict[str, str]:
     """ Returns a dict with tablespace expressions for the different tablespace
         kinds depending on whether a tablespace is configured or not.
     """
     out = {}
     for subset in ('ADDRESS', 'SEARCH', 'AUX'):
         for kind in ('DATA', 'INDEX'):
-            tspace = getattr(config, 'TABLESPACE_{}_{}'.format(subset, kind))
+            tspace = getattr(config, f'TABLESPACE_{subset}_{kind}')
             if tspace:
-                tspace = 'TABLESPACE "{}"'.format(tspace)
-            out['{}_{}'.format(subset.lower, kind.lower())] = tspace
+                tspace = f'TABLESPACE "{tspace}"'
+            out[f'{subset.lower()}_{kind.lower()}'] = tspace
 
     return out
 
 
-def _setup_postgresql_features(conn):
+def _setup_postgresql_features(conn: Connection) -> Dict[str, Any]:
     """ Set up a dictionary with various optional Postgresql/Postgis features that
         depend on the database version.
     """
@@ -63,11 +73,11 @@ class SQLPreprocessor:
         and follows its syntax.
     """
 
-    def __init__(self, conn, config):
+    def __init__(self, conn: Connection, config: Configuration) -> None:
         self.env = jinja2.Environment(autoescape=False,
                                       loader=jinja2.FileSystemLoader(str(config.lib_dir.sql)))
 
-        db_info = {}
+        db_info: Dict[str, Any] = {}
         db_info['partitions'] = _get_partitions(conn)
         db_info['tables'] = _get_tables(conn)
         db_info['reverse_only'] = 'search_name' not in db_info['tables']
@@ -78,7 +88,7 @@ class SQLPreprocessor:
         self.env.globals['postgres'] = _setup_postgresql_features(conn)
 
 
-    def run_sql_file(self, conn, name, **kwargs):
+    def run_sql_file(self, conn: Connection, name: str, **kwargs: Any) -> None:
         """ Execute the given SQL file on the connection. The keyword arguments
             may supply additional parameters for preprocessing.
         """
@@ -87,3 +97,21 @@ class SQLPreprocessor:
         with conn.cursor() as cur:
             cur.execute(sql)
         conn.commit()
+
+
+    def run_parallel_sql_file(self, dsn: str, name: str, num_threads: int = 1,
+                              **kwargs: Any) -> None:
+        """ Execure the given SQL files using parallel asynchronous connections.
+            The keyword arguments may supply additional parameters for
+            preprocessing.
+
+            After preprocessing the SQL code is cut at lines containing only
+            '---'. Each chunk is sent to one of the `num_threads` workers.
+        """
+        sql = self.env.get_template(name).render(**kwargs)
+
+        parts = sql.split('\n---\n')
+
+        with WorkerPool(dsn, num_threads) as pool:
+            for part in parts:
+                pool.next_free_worker().perform(part)