perf: build info log messages lazily so raising the log level actually saves work (#27837)

Raising GLOBAL_LOG_LEVEL to WARNING buys quieter output but not less work: 241 INFO call sites interpolate their payload into an f-string before the logging call gets to drop it. The heaviest is get_doc, which logs every chunk id and metadata dict in a collection, so on the full-context retrieval path that is the entire knowledge base, once per chat request.

That one line at WARNING, CPython 3.12:

| knowledge base | payload | before   | after   |
| -------------- | ------- | -------- | ------- |
| top-k of 3     | 1.2 kB  | 3.8 us   | 0.07 us |
| 500 chunks     | 201 kB  | 583.6 us | 0.08 us |
| 5000 chunks    | 2.0 MB  | 5.8 ms   | 0.15 us |

The lazy form log.info('query_doc:result %s %s', result.ids, result.metadatas) hands the payload to record.getMessage(), which the InterceptHandler only reaches once a record has passed the level check. Output at INFO is byte-identical. Two sites that already built their message eagerly, one str concat and one % operator, move to the same lazy form.

backend/open_webui/retrieval/vector/dbs/valkey.py

@@ -279,7 +279,7 @@ class ValkeyClient(VectorDBBase):
                 f'{self._format_version(MIN_VALKEY_VERSION)}. valkey-search 1.2.0 requires Valkey core '
                 '9.0.1 or later. Upgrade your server or use valkey-bundle:9.1.0-rc2+.'
             )
-        log.info(f'Valkey core version: {self._format_version(version) if version else "unknown"}')
+        log.info('Valkey core version: %s', self._format_version(version) if version else 'unknown')
 
     def _check_search_module(self) -> None:
         try:
@@ -331,7 +331,7 @@ class ValkeyClient(VectorDBBase):
                 'TEXT field type and filter-only FT.SEARCH support required by this backend. '
                 'Upgrade to valkey-bundle:9.1.0-rc2+ or load valkey-search 1.2.0+ as a module.'
             )
-        log.info(f'valkey-search version: {self._format_version(search_version) if search_version else "unknown"}')
+        log.info('valkey-search version: %s', self._format_version(search_version) if search_version else 'unknown')
 
     def _index_name(self, collection_name: str) -> str:
         return f'idx:{self.collection_prefix}:{collection_name}'
@@ -385,8 +385,11 @@ class ValkeyClient(VectorDBBase):
         try:
             g['glide_ft'].create(self.client, index_name, schema, options)
             log.info(
-                f'Created Valkey index {index_name} with dimension={dimension}, '
-                f'type={self.index_type}, metric={self.distance_metric}'
+                'Created Valkey index %s with dimension=%s, type=%s, metric=%s',
+                index_name,
+                dimension,
+                self.index_type,
+                self.distance_metric,
             )
         except g['RequestError'] as e:
             if 'already exists' in str(e).lower():
@@ -456,7 +459,7 @@ class ValkeyClient(VectorDBBase):
         index_name = self._index_name(collection_name)
         try:
             self._g['glide_ft'].dropindex(self.client, index_name)
-            log.info(f'Dropped index {index_name}')
+            log.info('Dropped index %s', index_name)
         except self._g['RequestError'] as e:
             log.debug('Could not drop index %s: %s', index_name, e)
 
@@ -656,7 +659,7 @@ class ValkeyClient(VectorDBBase):
                     collections.append(name[len(idx_prefix) :])
                     try:
                         glide_ft.dropindex(self.client, idx)
-                        log.info(f'Dropped index: {name}')
+                        log.info('Dropped index: %s', name)
                     except Exception as e:
                         log.error(f'Error dropping index {name}: {e}')
         except Exception as e:
@@ -664,7 +667,7 @@ class ValkeyClient(VectorDBBase):
 
         for collection in collections:
             self._delete_keys_by_prefix(self._key_prefix(collection))
-        log.info(f'Valkey vector store reset complete (prefix: {self.collection_prefix})')
+        log.info('Valkey vector store reset complete (prefix: %s)', self.collection_prefix)
 
     def _delete_keys_by_prefix(self, prefix: str) -> None:
         cursor = '0'