add migration for new lookup index

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

diff --git a/nominatim/db/utils.py b/nominatim/db/utils.py
index b376940d804af364c049864a07649c897b515f0f..87b0545fc5ecba66a956219cfbf247e633c16eaf 100644 (file)
--- a/nominatim/db/utils.py
+++ b/nominatim/db/utils.py
@@ -1,9 +1,16 @@
+# 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.

 """
 Helper functions for handling DB accesses.
 """
 import subprocess
 import logging
 import gzip
 """
 Helper functions for handling DB accesses.
 """
 import subprocess
 import logging
 import gzip

+import io

 
 from nominatim.db.connection import get_pg_env
 from nominatim.errors import UsageError
 
 from nominatim.db.connection import get_pg_env
 from nominatim.errors import UsageError


@@ -57,3 +64,50 @@ def execute_file(dsn, fname, ignore_errors=False, pre_code=None, post_code=None)
 
     if ret != 0 or remain > 0:
         raise UsageError("Failed to execute SQL file.")
 
     if ret != 0 or remain > 0:
         raise UsageError("Failed to execute SQL file.")

+
+
+# List of characters that need to be quoted for the copy command.
+_SQL_TRANSLATION = {ord(u'\\'): u'\\\\',
+                    ord(u'\t'): u'\\t',
+                    ord(u'\n'): u'\\n'}
+
+
+class CopyBuffer:
+    """ Data collector for the copy_from command.
+    """
+
+    def __init__(self):
+        self.buffer = io.StringIO()
+
+
+    def __enter__(self):
+        return self
+
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        if self.buffer is not None:
+            self.buffer.close()
+
+
+    def add(self, *data):
+        """ Add another row of data to the copy buffer.
+        """
+        first = True
+        for column in data:
+            if first:
+                first = False
+            else:
+                self.buffer.write('\t')
+            if column is None:
+                self.buffer.write('\\N')
+            else:
+                self.buffer.write(str(column).translate(_SQL_TRANSLATION))
+        self.buffer.write('\n')
+
+
+    def copy_out(self, cur, table, columns=None):
+        """ Copy all collected data into the given table.
+        """
+        if self.buffer.tell() > 0:
+            self.buffer.seek(0)
+            cur.copy_from(self.buffer, table, columns=columns)