# -*- coding: utf-8 -*- # Copyright 2014-2016 OpenMarket Ltd # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # 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 logging from synapse.api.errors import StoreError from synapse.util.logcontext import LoggingContext, PreserveLoggingContext from synapse.util.caches import CACHE_SIZE_FACTOR from synapse.util.caches.dictionary_cache import DictionaryCache from synapse.util.caches.descriptors import Cache from synapse.storage.engines import PostgresEngine import synapse.metrics from twisted.internet import defer import sys import time import threading logger = logging.getLogger(__name__) sql_logger = logging.getLogger("synapse.storage.SQL") transaction_logger = logging.getLogger("synapse.storage.txn") perf_logger = logging.getLogger("synapse.storage.TIME") metrics = synapse.metrics.get_metrics_for("synapse.storage") sql_scheduling_timer = metrics.register_distribution("schedule_time") sql_query_timer = metrics.register_distribution("query_time", labels=["verb"]) sql_txn_timer = metrics.register_distribution("transaction_time", labels=["desc"]) class LoggingTransaction(object): """An object that almost-transparently proxies for the 'txn' object passed to the constructor. Adds logging and metrics to the .execute() method.""" __slots__ = [ "txn", "name", "database_engine", "after_callbacks", "final_callbacks", ] def __init__(self, txn, name, database_engine, after_callbacks, final_callbacks): object.__setattr__(self, "txn", txn) object.__setattr__(self, "name", name) object.__setattr__(self, "database_engine", database_engine) object.__setattr__(self, "after_callbacks", after_callbacks) object.__setattr__(self, "final_callbacks", final_callbacks) def call_after(self, callback, *args, **kwargs): """Call the given callback on the main twisted thread after the transaction has finished. Used to invalidate the caches on the correct thread. """ self.after_callbacks.append((callback, args, kwargs)) def call_finally(self, callback, *args, **kwargs): self.final_callbacks.append((callback, args, kwargs)) def __getattr__(self, name): return getattr(self.txn, name) def __setattr__(self, name, value): setattr(self.txn, name, value) def __iter__(self): return self.txn.__iter__() def execute(self, sql, *args): self._do_execute(self.txn.execute, sql, *args) def executemany(self, sql, *args): self._do_execute(self.txn.executemany, sql, *args) def _make_sql_one_line(self, sql): "Strip newlines out of SQL so that the loggers in the DB are on one line" return " ".join(l.strip() for l in sql.splitlines() if l.strip()) def _do_execute(self, func, sql, *args): sql = self._make_sql_one_line(sql) # TODO(paul): Maybe use 'info' and 'debug' for values? sql_logger.debug("[SQL] {%s} %s", self.name, sql) sql = self.database_engine.convert_param_style(sql) if args: try: sql_logger.debug( "[SQL values] {%s} %r", self.name, args[0] ) except: # Don't let logging failures stop SQL from working pass start = time.time() * 1000 try: return func( sql, *args ) except Exception as e: logger.debug("[SQL FAIL] {%s} %s", self.name, e) raise finally: msecs = (time.time() * 1000) - start sql_logger.debug("[SQL time] {%s} %f", self.name, msecs) sql_query_timer.inc_by(msecs, sql.split()[0]) class PerformanceCounters(object): def __init__(self): self.current_counters = {} self.previous_counters = {} def update(self, key, start_time, end_time=None): if end_time is None: end_time = time.time() * 1000 duration = end_time - start_time count, cum_time = self.current_counters.get(key, (0, 0)) count += 1 cum_time += duration self.current_counters[key] = (count, cum_time) return end_time def interval(self, interval_duration, limit=3): counters = [] for name, (count, cum_time) in self.current_counters.iteritems(): prev_count, prev_time = self.previous_counters.get(name, (0, 0)) counters.append(( (cum_time - prev_time) / interval_duration, count - prev_count, name )) self.previous_counters = dict(self.current_counters) counters.sort(reverse=True) top_n_counters = ", ".join( "%s(%d): %.3f%%" % (name, count, 100 * ratio) for ratio, count, name in counters[:limit] ) return top_n_counters class SQLBaseStore(object): _TXN_ID = 0 def __init__(self, hs): self.hs = hs self._clock = hs.get_clock() self._db_pool = hs.get_db_pool() self._previous_txn_total_time = 0 self._current_txn_total_time = 0 self._previous_loop_ts = 0 # TODO(paul): These can eventually be removed once the metrics code # is running in mainline, and we have some nice monitoring frontends # to watch it self._txn_perf_counters = PerformanceCounters() self._get_event_counters = PerformanceCounters() self._get_event_cache = Cache("*getEvent*", keylen=3, max_entries=hs.config.event_cache_size) self._state_group_cache = DictionaryCache( "*stateGroupCache*", 100000 * CACHE_SIZE_FACTOR ) self._event_fetch_lock = threading.Condition() self._event_fetch_list = [] self._event_fetch_ongoing = 0 self._pending_ds = [] self.database_engine = hs.database_engine def start_profiling(self): self._previous_loop_ts = self._clock.time_msec() def loop(): curr = self._current_txn_total_time prev = self._previous_txn_total_time self._previous_txn_total_time = curr time_now = self._clock.time_msec() time_then = self._previous_loop_ts self._previous_loop_ts = time_now ratio = (curr - prev) / (time_now - time_then) top_three_counters = self._txn_perf_counters.interval( time_now - time_then, limit=3 ) top_3_event_counters = self._get_event_counters.interval( time_now - time_then, limit=3 ) perf_logger.info( "Total database time: %.3f%% {%s} {%s}", ratio * 100, top_three_counters, top_3_event_counters ) self._clock.looping_call(loop, 10000) def _new_transaction(self, conn, desc, after_callbacks, final_callbacks, logging_context, func, *args, **kwargs): start = time.time() * 1000 txn_id = self._TXN_ID # We don't really need these to be unique, so lets stop it from # growing really large. self._TXN_ID = (self._TXN_ID + 1) % (sys.maxint - 1) name = "%s-%x" % (desc, txn_id, ) transaction_logger.debug("[TXN START] {%s}", name) try: i = 0 N = 5 while True: try: txn = conn.cursor() txn = LoggingTransaction( txn, name, self.database_engine, after_callbacks, final_callbacks, ) r = func(txn, *args, **kwargs) conn.commit() return r except self.database_engine.module.OperationalError as e: # This can happen if the database disappears mid # transaction. logger.warn( "[TXN OPERROR] {%s} %s %d/%d", name, e, i, N ) if i < N: i += 1 try: conn.rollback() except self.database_engine.module.Error as e1: logger.warn( "[TXN EROLL] {%s} %s", name, e1, ) continue raise except self.database_engine.module.DatabaseError as e: if self.database_engine.is_deadlock(e): logger.warn("[TXN DEADLOCK] {%s} %d/%d", name, i, N) if i < N: i += 1 try: conn.rollback() except self.database_engine.module.Error as e1: logger.warn( "[TXN EROLL] {%s} %s", name, e1, ) continue raise except Exception as e: logger.debug("[TXN FAIL] {%s} %s", name, e) raise finally: end = time.time() * 1000 duration = end - start if logging_context is not None: logging_context.add_database_transaction(duration) transaction_logger.debug("[TXN END] {%s} %f", name, duration) self._current_txn_total_time += duration self._txn_perf_counters.update(desc, start, end) sql_txn_timer.inc_by(duration, desc) @defer.inlineCallbacks def runInteraction(self, desc, func, *args, **kwargs): """Wraps the .runInteraction() method on the underlying db_pool.""" current_context = LoggingContext.current_context() start_time = time.time() * 1000 after_callbacks = [] final_callbacks = [] def inner_func(conn, *args, **kwargs): with LoggingContext("runInteraction") as context: sql_scheduling_timer.inc_by(time.time() * 1000 - start_time) if self.database_engine.is_connection_closed(conn): logger.debug("Reconnecting closed database connection") conn.reconnect() current_context.copy_to(context) return self._new_transaction( conn, desc, after_callbacks, final_callbacks, current_context, func, *args, **kwargs ) try: with PreserveLoggingContext(): result = yield self._db_pool.runWithConnection( inner_func, *args, **kwargs ) for after_callback, after_args, after_kwargs in after_callbacks: after_callback(*after_args, **after_kwargs) finally: for after_callback, after_args, after_kwargs in final_callbacks: after_callback(*after_args, **after_kwargs) defer.returnValue(result) @defer.inlineCallbacks def runWithConnection(self, func, *args, **kwargs): """Wraps the .runInteraction() method on the underlying db_pool.""" current_context = LoggingContext.current_context() start_time = time.time() * 1000 def inner_func(conn, *args, **kwargs): with LoggingContext("runWithConnection") as context: sql_scheduling_timer.inc_by(time.time() * 1000 - start_time) if self.database_engine.is_connection_closed(conn): logger.debug("Reconnecting closed database connection") conn.reconnect() current_context.copy_to(context) return func(conn, *args, **kwargs) with PreserveLoggingContext(): result = yield self._db_pool.runWithConnection( inner_func, *args, **kwargs ) defer.returnValue(result) @staticmethod def cursor_to_dict(cursor): """Converts a SQL cursor into an list of dicts. Args: cursor : The DBAPI cursor which has executed a query. Returns: A list of dicts where the key is the column header. """ col_headers = list(intern(column[0]) for column in cursor.description) results = list( dict(zip(col_headers, row)) for row in cursor ) return results def _execute(self, desc, decoder, query, *args): """Runs a single query for a result set. Args: decoder - The function which can resolve the cursor results to something meaningful. query - The query string to execute *args - Query args. Returns: The result of decoder(results) """ def interaction(txn): txn.execute(query, args) if decoder: return decoder(txn) else: return txn.fetchall() return self.runInteraction(desc, interaction) # "Simple" SQL API methods that operate on a single table with no JOINs, # no complex WHERE clauses, just a dict of values for columns. @defer.inlineCallbacks def _simple_insert(self, table, values, or_ignore=False, desc="_simple_insert"): """Executes an INSERT query on the named table. Args: table : string giving the table name values : dict of new column names and values for them Returns: bool: Whether the row was inserted or not. Only useful when `or_ignore` is True """ try: yield self.runInteraction( desc, self._simple_insert_txn, table, values, ) except self.database_engine.module.IntegrityError: # We have to do or_ignore flag at this layer, since we can't reuse # a cursor after we receive an error from the db. if not or_ignore: raise defer.returnValue(False) defer.returnValue(True) @staticmethod def _simple_insert_txn(txn, table, values): keys, vals = zip(*values.items()) sql = "INSERT INTO %s (%s) VALUES(%s)" % ( table, ", ".join(k for k in keys), ", ".join("?" for _ in keys) ) txn.execute(sql, vals) def _simple_insert_many(self, table, values, desc): return self.runInteraction( desc, self._simple_insert_many_txn, table, values ) @staticmethod def _simple_insert_many_txn(txn, table, values): if not values: return # This is a *slight* abomination to get a list of tuples of key names # and a list of tuples of value names. # # i.e. [{"a": 1, "b": 2}, {"c": 3, "d": 4}] # => [("a", "b",), ("c", "d",)] and [(1, 2,), (3, 4,)] # # The sort is to ensure that we don't rely on dictionary iteration # order. keys, vals = zip(*[ zip( *(sorted(i.items(), key=lambda kv: kv[0])) ) for i in values if i ]) for k in keys: if k != keys[0]: raise RuntimeError( "All items must have the same keys" ) sql = "INSERT INTO %s (%s) VALUES(%s)" % ( table, ", ".join(k for k in keys[0]), ", ".join("?" for _ in keys[0]) ) txn.executemany(sql, vals) def _simple_upsert(self, table, keyvalues, values, insertion_values={}, desc="_simple_upsert", lock=True): """ Args: table (str): The table to upsert into keyvalues (dict): The unique key tables and their new values values (dict): The nonunique columns and their new values insertion_values (dict): key/values to use when inserting Returns: Deferred(bool): True if a new entry was created, False if an existing one was updated. """ return self.runInteraction( desc, self._simple_upsert_txn, table, keyvalues, values, insertion_values, lock ) def _simple_upsert_txn(self, txn, table, keyvalues, values, insertion_values={}, lock=True): # We need to lock the table :(, unless we're *really* careful if lock: self.database_engine.lock_table(txn, table) # Try to update sql = "UPDATE %s SET %s WHERE %s" % ( table, ", ".join("%s = ?" % (k,) for k in values), " AND ".join("%s = ?" % (k,) for k in keyvalues) ) sqlargs = values.values() + keyvalues.values() txn.execute(sql, sqlargs) if txn.rowcount == 0: # We didn't update and rows so insert a new one allvalues = {} allvalues.update(keyvalues) allvalues.update(values) allvalues.update(insertion_values) sql = "INSERT INTO %s (%s) VALUES (%s)" % ( table, ", ".join(k for k in allvalues), ", ".join("?" for _ in allvalues) ) txn.execute(sql, allvalues.values()) return True else: return False def _simple_select_one(self, table, keyvalues, retcols, allow_none=False, desc="_simple_select_one"): """Executes a SELECT query on the named table, which is expected to return a single row, returning a single column from it. Args: table : string giving the table name keyvalues : dict of column names and values to select the row with retcols : list of strings giving the names of the columns to return allow_none : If true, return None instead of failing if the SELECT statement returns no rows """ return self.runInteraction( desc, self._simple_select_one_txn, table, keyvalues, retcols, allow_none, ) def _simple_select_one_onecol(self, table, keyvalues, retcol, allow_none=False, desc="_simple_select_one_onecol"): """Executes a SELECT query on the named table, which is expected to return a single row, returning a single column from it. Args: table : string giving the table name keyvalues : dict of column names and values to select the row with retcol : string giving the name of the column to return """ return self.runInteraction( desc, self._simple_select_one_onecol_txn, table, keyvalues, retcol, allow_none=allow_none, ) @classmethod def _simple_select_one_onecol_txn(cls, txn, table, keyvalues, retcol, allow_none=False): ret = cls._simple_select_onecol_txn( txn, table=table, keyvalues=keyvalues, retcol=retcol, ) if ret: return ret[0] else: if allow_none: return None else: raise StoreError(404, "No row found") @staticmethod def _simple_select_onecol_txn(txn, table, keyvalues, retcol): if keyvalues: where = "WHERE %s" % " AND ".join("%s = ?" % k for k in keyvalues.iterkeys()) else: where = "" sql = ( "SELECT %(retcol)s FROM %(table)s %(where)s" ) % { "retcol": retcol, "table": table, "where": where, } txn.execute(sql, keyvalues.values()) return [r[0] for r in txn] def _simple_select_onecol(self, table, keyvalues, retcol, desc="_simple_select_onecol"): """Executes a SELECT query on the named table, which returns a list comprising of the values of the named column from the selected rows. Args: table (str): table name keyvalues (dict): column names and values to select the rows with retcol (str): column whos value we wish to retrieve. Returns: Deferred: Results in a list """ return self.runInteraction( desc, self._simple_select_onecol_txn, table, keyvalues, retcol ) def _simple_select_list(self, table, keyvalues, retcols, desc="_simple_select_list"): """Executes a SELECT query on the named table, which may return zero or more rows, returning the result as a list of dicts. Args: table (str): the table name keyvalues (dict[str, Any] | None): column names and values to select the rows with, or None to not apply a WHERE clause. retcols (iterable[str]): the names of the columns to return Returns: defer.Deferred: resolves to list[dict[str, Any]] """ return self.runInteraction( desc, self._simple_select_list_txn, table, keyvalues, retcols ) @classmethod def _simple_select_list_txn(cls, txn, table, keyvalues, retcols): """Executes a SELECT query on the named table, which may return zero or more rows, returning the result as a list of dicts. Args: txn : Transaction object table (str): the table name keyvalues (dict[str, T] | None): column names and values to select the rows with, or None to not apply a WHERE clause. retcols (iterable[str]): the names of the columns to return """ if keyvalues: sql = "SELECT %s FROM %s WHERE %s" % ( ", ".join(retcols), table, " AND ".join("%s = ?" % (k, ) for k in keyvalues) ) txn.execute(sql, keyvalues.values()) else: sql = "SELECT %s FROM %s" % ( ", ".join(retcols), table ) txn.execute(sql) return cls.cursor_to_dict(txn) @defer.inlineCallbacks def _simple_select_many_batch(self, table, column, iterable, retcols, keyvalues={}, desc="_simple_select_many_batch", batch_size=100): """Executes a SELECT query on the named table, which may return zero or more rows, returning the result as a list of dicts. Filters rows by if value of `column` is in `iterable`. Args: table : string giving the table name column : column name to test for inclusion against `iterable` iterable : list keyvalues : dict of column names and values to select the rows with retcols : list of strings giving the names of the columns to return """ results = [] if not iterable: defer.returnValue(results) chunks = [ iterable[i:i + batch_size] for i in xrange(0, len(iterable), batch_size) ] for chunk in chunks: rows = yield self.runInteraction( desc, self._simple_select_many_txn, table, column, chunk, keyvalues, retcols ) results.extend(rows) defer.returnValue(results) @classmethod def _simple_select_many_txn(cls, txn, table, column, iterable, keyvalues, retcols): """Executes a SELECT query on the named table, which may return zero or more rows, returning the result as a list of dicts. Filters rows by if value of `column` is in `iterable`. Args: txn : Transaction object table : string giving the table name column : column name to test for inclusion against `iterable` iterable : list keyvalues : dict of column names and values to select the rows with retcols : list of strings giving the names of the columns to return """ if not iterable: return [] sql = "SELECT %s FROM %s" % (", ".join(retcols), table) clauses = [] values = [] clauses.append( "%s IN (%s)" % (column, ",".join("?" for _ in iterable)) ) values.extend(iterable) for key, value in keyvalues.iteritems(): clauses.append("%s = ?" % (key,)) values.append(value) if clauses: sql = "%s WHERE %s" % ( sql, " AND ".join(clauses), ) txn.execute(sql, values) return cls.cursor_to_dict(txn) def _simple_update_one(self, table, keyvalues, updatevalues, desc="_simple_update_one"): """Executes an UPDATE query on the named table, setting new values for columns in a row matching the key values. Args: table : string giving the table name keyvalues : dict of column names and values to select the row with updatevalues : dict giving column names and values to update retcols : optional list of column names to return If present, retcols gives a list of column names on which to perform a SELECT statement *before* performing the UPDATE statement. The values of these will be returned in a dict. These are performed within the same transaction, allowing an atomic get-and-set. This can be used to implement compare-and-set by putting the update column in the 'keyvalues' dict as well. """ return self.runInteraction( desc, self._simple_update_one_txn, table, keyvalues, updatevalues, ) @staticmethod def _simple_update_one_txn(txn, table, keyvalues, updatevalues): if keyvalues: where = "WHERE %s" % " AND ".join("%s = ?" % k for k in keyvalues.iterkeys()) else: where = "" update_sql = "UPDATE %s SET %s %s" % ( table, ", ".join("%s = ?" % (k,) for k in updatevalues), where, ) txn.execute( update_sql, updatevalues.values() + keyvalues.values() ) if txn.rowcount == 0: raise StoreError(404, "No row found") if txn.rowcount > 1: raise StoreError(500, "More than one row matched") @staticmethod def _simple_select_one_txn(txn, table, keyvalues, retcols, allow_none=False): select_sql = "SELECT %s FROM %s WHERE %s" % ( ", ".join(retcols), table, " AND ".join("%s = ?" % (k,) for k in keyvalues) ) txn.execute(select_sql, keyvalues.values()) row = txn.fetchone() if not row: if allow_none: return None raise StoreError(404, "No row found") if txn.rowcount > 1: raise StoreError(500, "More than one row matched") return dict(zip(retcols, row)) def _simple_delete_one(self, table, keyvalues, desc="_simple_delete_one"): """Executes a DELETE query on the named table, expecting to delete a single row. Args: table : string giving the table name keyvalues : dict of column names and values to select the row with """ return self.runInteraction( desc, self._simple_delete_one_txn, table, keyvalues ) @staticmethod def _simple_delete_one_txn(txn, table, keyvalues): """Executes a DELETE query on the named table, expecting to delete a single row. Args: table : string giving the table name keyvalues : dict of column names and values to select the row with """ sql = "DELETE FROM %s WHERE %s" % ( table, " AND ".join("%s = ?" % (k, ) for k in keyvalues) ) txn.execute(sql, keyvalues.values()) if txn.rowcount == 0: raise StoreError(404, "No row found") if txn.rowcount > 1: raise StoreError(500, "more than one row matched") def _simple_delete(self, table, keyvalues, desc): return self.runInteraction( desc, self._simple_delete_txn, table, keyvalues ) @staticmethod def _simple_delete_txn(txn, table, keyvalues): sql = "DELETE FROM %s WHERE %s" % ( table, " AND ".join("%s = ?" % (k, ) for k in keyvalues) ) return txn.execute(sql, keyvalues.values()) def _simple_delete_many(self, table, column, iterable, keyvalues, desc): return self.runInteraction( desc, self._simple_delete_many_txn, table, column, iterable, keyvalues ) @staticmethod def _simple_delete_many_txn(txn, table, column, iterable, keyvalues): """Executes a DELETE query on the named table. Filters rows by if value of `column` is in `iterable`. Args: txn : Transaction object table : string giving the table name column : column name to test for inclusion against `iterable` iterable : list keyvalues : dict of column names and values to select the rows with """ if not iterable: return sql = "DELETE FROM %s" % table clauses = [] values = [] clauses.append( "%s IN (%s)" % (column, ",".join("?" for _ in iterable)) ) values.extend(iterable) for key, value in keyvalues.iteritems(): clauses.append("%s = ?" % (key,)) values.append(value) if clauses: sql = "%s WHERE %s" % ( sql, " AND ".join(clauses), ) return txn.execute(sql, values) def _get_cache_dict(self, db_conn, table, entity_column, stream_column, max_value, limit=100000): # Fetch a mapping of room_id -> max stream position for "recent" rooms. # It doesn't really matter how many we get, the StreamChangeCache will # do the right thing to ensure it respects the max size of cache. sql = ( "SELECT %(entity)s, MAX(%(stream)s) FROM %(table)s" " WHERE %(stream)s > ? - %(limit)s" " GROUP BY %(entity)s" ) % { "table": table, "entity": entity_column, "stream": stream_column, "limit": limit, } sql = self.database_engine.convert_param_style(sql) txn = db_conn.cursor() txn.execute(sql, (int(max_value),)) cache = { row[0]: int(row[1]) for row in txn } txn.close() if cache: min_val = min(cache.itervalues()) else: min_val = max_value return cache, min_val def _invalidate_cache_and_stream(self, txn, cache_func, keys): """Invalidates the cache and adds it to the cache stream so slaves will know to invalidate their caches. This should only be used to invalidate caches where slaves won't otherwise know from other replication streams that the cache should be invalidated. """ txn.call_after(cache_func.invalidate, keys) if isinstance(self.database_engine, PostgresEngine): # get_next() returns a context manager which is designed to wrap # the transaction. However, we want to only get an ID when we want # to use it, here, so we need to call __enter__ manually, and have # __exit__ called after the transaction finishes. ctx = self._cache_id_gen.get_next() stream_id = ctx.__enter__() txn.call_finally(ctx.__exit__, None, None, None) txn.call_after(self.hs.get_notifier().on_new_replication_data) self._simple_insert_txn( txn, table="cache_invalidation_stream", values={ "stream_id": stream_id, "cache_func": cache_func.__name__, "keys": list(keys), "invalidation_ts": self.clock.time_msec(), } ) def get_all_updated_caches(self, last_id, current_id, limit): if last_id == current_id: return defer.succeed([]) def get_all_updated_caches_txn(txn): # We purposefully don't bound by the current token, as we want to # send across cache invalidations as quickly as possible. Cache # invalidations are idempotent, so duplicates are fine. sql = ( "SELECT stream_id, cache_func, keys, invalidation_ts" " FROM cache_invalidation_stream" " WHERE stream_id > ? ORDER BY stream_id ASC LIMIT ?" ) txn.execute(sql, (last_id, limit,)) return txn.fetchall() return self.runInteraction( "get_all_updated_caches", get_all_updated_caches_txn ) def get_cache_stream_token(self): if self._cache_id_gen: return self._cache_id_gen.get_current_token() else: return 0 def _simple_select_list_paginate(self, table, keyvalues, pagevalues, retcols, desc="_simple_select_list_paginate"): """Executes a SELECT query on the named table with start and limit, of row numbers, which may return zero or number of rows from start to limit, returning the result as a list of dicts. Args: table (str): the table name keyvalues (dict[str, Any] | None): column names and values to select the rows with, or None to not apply a WHERE clause. retcols (iterable[str]): the names of the columns to return order (str): order the select by this column start (int): start number to begin the query from limit (int): number of rows to reterive Returns: defer.Deferred: resolves to list[dict[str, Any]] """ return self.runInteraction( desc, self._simple_select_list_paginate_txn, table, keyvalues, pagevalues, retcols ) @classmethod def _simple_select_list_paginate_txn(cls, txn, table, keyvalues, pagevalues, retcols): """Executes a SELECT query on the named table with start and limit, of row numbers, which may return zero or number of rows from start to limit, returning the result as a list of dicts. Args: txn : Transaction object table (str): the table name keyvalues (dict[str, T] | None): column names and values to select the rows with, or None to not apply a WHERE clause. pagevalues ([]): order (str): order the select by this column start (int): start number to begin the query from limit (int): number of rows to reterive retcols (iterable[str]): the names of the columns to return Returns: defer.Deferred: resolves to list[dict[str, Any]] """ if keyvalues: sql = "SELECT %s FROM %s WHERE %s ORDER BY %s" % ( ", ".join(retcols), table, " AND ".join("%s = ?" % (k,) for k in keyvalues), " ? ASC LIMIT ? OFFSET ?" ) txn.execute(sql, keyvalues.values() + pagevalues) else: sql = "SELECT %s FROM %s ORDER BY %s" % ( ", ".join(retcols), table, " ? ASC LIMIT ? OFFSET ?" ) txn.execute(sql, pagevalues) return cls.cursor_to_dict(txn) @defer.inlineCallbacks def get_user_list_paginate(self, table, keyvalues, pagevalues, retcols, desc="get_user_list_paginate"): """Get a list of users from start row to a limit number of rows. This will return a json object with users and total number of users in users list. Args: table (str): the table name keyvalues (dict[str, Any] | None): column names and values to select the rows with, or None to not apply a WHERE clause. pagevalues ([]): order (str): order the select by this column start (int): start number to begin the query from limit (int): number of rows to reterive retcols (iterable[str]): the names of the columns to return Returns: defer.Deferred: resolves to json object {list[dict[str, Any]], count} """ users = yield self.runInteraction( desc, self._simple_select_list_paginate_txn, table, keyvalues, pagevalues, retcols ) count = yield self.runInteraction( desc, self.get_user_count_txn ) retval = { "users": users, "total": count } defer.returnValue(retval) def get_user_count_txn(self, txn): """Get a total number of registerd users in the users list. Args: txn : Transaction object Returns: defer.Deferred: resolves to int """ sql_count = "SELECT COUNT(*) FROM users WHERE is_guest = 0;" txn.execute(sql_count) count = txn.fetchone()[0] defer.returnValue(count) def _simple_search_list(self, table, term, col, retcols, desc="_simple_search_list"): """Executes a SELECT query on the named table, which may return zero or more rows, returning the result as a list of dicts. Args: table (str): the table name term (str | None): term for searching the table matched to a column. col (str): column to query term should be matched to retcols (iterable[str]): the names of the columns to return Returns: defer.Deferred: resolves to list[dict[str, Any]] or None """ return self.runInteraction( desc, self._simple_search_list_txn, table, term, col, retcols ) @classmethod def _simple_search_list_txn(cls, txn, table, term, col, retcols): """Executes a SELECT query on the named table, which may return zero or more rows, returning the result as a list of dicts. Args: txn : Transaction object table (str): the table name term (str | None): term for searching the table matched to a column. col (str): column to query term should be matched to retcols (iterable[str]): the names of the columns to return Returns: defer.Deferred: resolves to list[dict[str, Any]] or None """ if term: sql = "SELECT %s FROM %s WHERE %s LIKE ?" % ( ", ".join(retcols), table, col ) termvalues = ["%%" + term + "%%"] txn.execute(sql, termvalues) else: return 0 return cls.cursor_to_dict(txn) class _RollbackButIsFineException(Exception): """ This exception is used to rollback a transaction without implying something went wrong. """ pass