diff options
Diffstat (limited to 'synapse/storage/databases/main/search.py')
| -rw-r--r-- | synapse/storage/databases/main/search.py | 197 |
1 files changed, 162 insertions, 35 deletions
diff --git a/synapse/storage/databases/main/search.py b/synapse/storage/databases/main/search.py index 1b79acf955..a89fc54c2c 100644 --- a/synapse/storage/databases/main/search.py +++ b/synapse/storage/databases/main/search.py @@ -11,10 +11,22 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. - +import enum import logging import re -from typing import TYPE_CHECKING, Any, Collection, Iterable, List, Optional, Set, Tuple +from collections import deque +from dataclasses import dataclass +from typing import ( + TYPE_CHECKING, + Any, + Collection, + Iterable, + List, + Optional, + Set, + Tuple, + Union, +) import attr @@ -27,7 +39,7 @@ from synapse.storage.database import ( LoggingTransaction, ) from synapse.storage.databases.main.events_worker import EventRedactBehaviour -from synapse.storage.engines import BaseDatabaseEngine, PostgresEngine, Sqlite3Engine +from synapse.storage.engines import PostgresEngine, Sqlite3Engine from synapse.types import JsonDict if TYPE_CHECKING: @@ -421,8 +433,6 @@ class SearchStore(SearchBackgroundUpdateStore): """ clauses = [] - search_query = _parse_query(self.database_engine, search_term) - args: List[Any] = [] # Make sure we don't explode because the person is in too many rooms. @@ -444,20 +454,24 @@ class SearchStore(SearchBackgroundUpdateStore): count_clauses = clauses if isinstance(self.database_engine, PostgresEngine): + search_query = search_term + tsquery_func = self.database_engine.tsquery_func sql = ( - "SELECT ts_rank_cd(vector, to_tsquery('english', ?)) AS rank," + f"SELECT ts_rank_cd(vector, {tsquery_func}('english', ?)) AS rank," " room_id, event_id" " FROM event_search" - " WHERE vector @@ to_tsquery('english', ?)" + f" WHERE vector @@ {tsquery_func}('english', ?)" ) args = [search_query, search_query] + args count_sql = ( "SELECT room_id, count(*) as count FROM event_search" - " WHERE vector @@ to_tsquery('english', ?)" + f" WHERE vector @@ {tsquery_func}('english', ?)" ) count_args = [search_query] + count_args elif isinstance(self.database_engine, Sqlite3Engine): + search_query = _parse_query_for_sqlite(search_term) + sql = ( "SELECT rank(matchinfo(event_search)) as rank, room_id, event_id" " FROM event_search" @@ -469,7 +483,7 @@ class SearchStore(SearchBackgroundUpdateStore): "SELECT room_id, count(*) as count FROM event_search" " WHERE value MATCH ?" ) - count_args = [search_term] + count_args + count_args = [search_query] + count_args else: # This should be unreachable. raise Exception("Unrecognized database engine") @@ -501,7 +515,9 @@ class SearchStore(SearchBackgroundUpdateStore): highlights = None if isinstance(self.database_engine, PostgresEngine): - highlights = await self._find_highlights_in_postgres(search_query, events) + highlights = await self._find_highlights_in_postgres( + search_query, events, tsquery_func + ) count_sql += " GROUP BY room_id" @@ -510,7 +526,6 @@ class SearchStore(SearchBackgroundUpdateStore): ) count = sum(row["count"] for row in count_results if row["room_id"] in room_ids) - return { "results": [ {"event": event_map[r["event_id"]], "rank": r["rank"]} @@ -542,9 +557,6 @@ class SearchStore(SearchBackgroundUpdateStore): Each match as a dictionary. """ clauses = [] - - search_query = _parse_query(self.database_engine, search_term) - args: List[Any] = [] # Make sure we don't explode because the person is in too many rooms. @@ -582,20 +594,23 @@ class SearchStore(SearchBackgroundUpdateStore): args.extend([origin_server_ts, origin_server_ts, stream]) if isinstance(self.database_engine, PostgresEngine): + search_query = search_term + tsquery_func = self.database_engine.tsquery_func sql = ( - "SELECT ts_rank_cd(vector, to_tsquery('english', ?)) as rank," + f"SELECT ts_rank_cd(vector, {tsquery_func}('english', ?)) as rank," " origin_server_ts, stream_ordering, room_id, event_id" " FROM event_search" - " WHERE vector @@ to_tsquery('english', ?) AND " + f" WHERE vector @@ {tsquery_func}('english', ?) AND " ) args = [search_query, search_query] + args count_sql = ( "SELECT room_id, count(*) as count FROM event_search" - " WHERE vector @@ to_tsquery('english', ?) AND " + f" WHERE vector @@ {tsquery_func}('english', ?) AND " ) count_args = [search_query] + count_args elif isinstance(self.database_engine, Sqlite3Engine): + # We use CROSS JOIN here to ensure we use the right indexes. # https://sqlite.org/optoverview.html#crossjoin # @@ -614,13 +629,14 @@ class SearchStore(SearchBackgroundUpdateStore): " CROSS JOIN events USING (event_id)" " WHERE " ) + search_query = _parse_query_for_sqlite(search_term) args = [search_query] + args count_sql = ( "SELECT room_id, count(*) as count FROM event_search" " WHERE value MATCH ? AND " ) - count_args = [search_term] + count_args + count_args = [search_query] + count_args else: # This should be unreachable. raise Exception("Unrecognized database engine") @@ -660,7 +676,9 @@ class SearchStore(SearchBackgroundUpdateStore): highlights = None if isinstance(self.database_engine, PostgresEngine): - highlights = await self._find_highlights_in_postgres(search_query, events) + highlights = await self._find_highlights_in_postgres( + search_query, events, tsquery_func + ) count_sql += " GROUP BY room_id" @@ -686,7 +704,7 @@ class SearchStore(SearchBackgroundUpdateStore): } async def _find_highlights_in_postgres( - self, search_query: str, events: List[EventBase] + self, search_query: str, events: List[EventBase], tsquery_func: str ) -> Set[str]: """Given a list of events and a search term, return a list of words that match from the content of the event. @@ -697,6 +715,7 @@ class SearchStore(SearchBackgroundUpdateStore): Args: search_query events: A list of events + tsquery_func: The tsquery_* function to use when making queries Returns: A set of strings. @@ -729,7 +748,7 @@ class SearchStore(SearchBackgroundUpdateStore): while stop_sel in value: stop_sel += ">" - query = "SELECT ts_headline(?, to_tsquery('english', ?), %s)" % ( + query = f"SELECT ts_headline(?, {tsquery_func}('english', ?), %s)" % ( _to_postgres_options( { "StartSel": start_sel, @@ -760,20 +779,128 @@ def _to_postgres_options(options_dict: JsonDict) -> str: return "'%s'" % (",".join("%s=%s" % (k, v) for k, v in options_dict.items()),) -def _parse_query(database_engine: BaseDatabaseEngine, search_term: str) -> str: - """Takes a plain unicode string from the user and converts it into a form - that can be passed to database. - We use this so that we can add prefix matching, which isn't something - that is supported by default. +@dataclass +class Phrase: + phrase: List[str] + + +class SearchToken(enum.Enum): + Not = enum.auto() + Or = enum.auto() + And = enum.auto() + + +Token = Union[str, Phrase, SearchToken] +TokenList = List[Token] + + +def _is_stop_word(word: str) -> bool: + # TODO Pull these out of the dictionary: + # https://github.com/postgres/postgres/blob/master/src/backend/snowball/stopwords/english.stop + return word in {"the", "a", "you", "me", "and", "but"} + + +def _tokenize_query(query: str) -> TokenList: + """ + Convert the user-supplied `query` into a TokenList, which can be translated into + some DB-specific syntax. + + The following constructs are supported: + + - phrase queries using "double quotes" + - case-insensitive `or` and `and` operators + - negation of a keyword via unary `-` + - unary hyphen to denote NOT e.g. 'include -exclude' + + The following differs from websearch_to_tsquery: + + - Stop words are not removed. + - Unclosed phrases are treated differently. + + """ + tokens: TokenList = [] + + # Find phrases. + in_phrase = False + parts = deque(query.split('"')) + for i, part in enumerate(parts): + # The contents inside double quotes is treated as a phrase, a trailing + # double quote is not implied. + in_phrase = bool(i % 2) and i != (len(parts) - 1) + + # Pull out the individual words, discarding any non-word characters. + words = deque(re.findall(r"([\w\-]+)", part, re.UNICODE)) + + # Phrases have simplified handling of words. + if in_phrase: + # Skip stop words. + phrase = [word for word in words if not _is_stop_word(word)] + + # Consecutive words are implicitly ANDed together. + if tokens and tokens[-1] not in (SearchToken.Not, SearchToken.Or): + tokens.append(SearchToken.And) + + # Add the phrase. + tokens.append(Phrase(phrase)) + continue + + # Otherwise, not in a phrase. + while words: + word = words.popleft() + + if word.startswith("-"): + tokens.append(SearchToken.Not) + + # If there's more word, put it back to be processed again. + word = word[1:] + if word: + words.appendleft(word) + elif word.lower() == "or": + tokens.append(SearchToken.Or) + else: + # Skip stop words. + if _is_stop_word(word): + continue + + # Consecutive words are implicitly ANDed together. + if tokens and tokens[-1] not in (SearchToken.Not, SearchToken.Or): + tokens.append(SearchToken.And) + + # Add the search term. + tokens.append(word) + + return tokens + + +def _tokens_to_sqlite_match_query(tokens: TokenList) -> str: + """ + Convert the list of tokens to a string suitable for passing to sqlite's MATCH. + Assume sqlite was compiled with enhanced query syntax. + + Ref: https://www.sqlite.org/fts3.html#full_text_index_queries """ + match_query = [] + for token in tokens: + if isinstance(token, str): + match_query.append(token) + elif isinstance(token, Phrase): + match_query.append('"' + " ".join(token.phrase) + '"') + elif token == SearchToken.Not: + # TODO: SQLite treats NOT as a *binary* operator. Hopefully a search + # term has already been added before this. + match_query.append(" NOT ") + elif token == SearchToken.Or: + match_query.append(" OR ") + elif token == SearchToken.And: + match_query.append(" AND ") + else: + raise ValueError(f"unknown token {token}") + + return "".join(match_query) - # Pull out the individual words, discarding any non-word characters. - results = re.findall(r"([\w\-]+)", search_term, re.UNICODE) - if isinstance(database_engine, PostgresEngine): - return " & ".join(result + ":*" for result in results) - elif isinstance(database_engine, Sqlite3Engine): - return " & ".join(result + "*" for result in results) - else: - # This should be unreachable. - raise Exception("Unrecognized database engine") +def _parse_query_for_sqlite(search_term: str) -> str: + """Takes a plain unicode string from the user and converts it into a form + that can be passed to sqllite's matchinfo(). + """ + return _tokens_to_sqlite_match_query(_tokenize_query(search_term)) |