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Fix bgupdate error if index already exists (#2167)

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When creating a new table index in the background, guard against it existing already. Fixes
https://github.com/matrix-org/synapse/issues/2135.

Also, make sure we restore the autocommit flag when we're done, otherwise we
get more failures from other operations later on. Fixes
https://github.com/matrix-org/synapse/issues/1890 (hopefully).
This commit is contained in:
Richard van der Hoff 2017-04-27 15:27:48 +01:00 committed by GitHub
parent 380fb87ecc
commit c84770b877
1 changed files with 53 additions and 30 deletions
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83
synapse/storage/background_updates.py
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@ -228,46 +228,69 @@ class BackgroundUpdateStore(SQLBaseStore):
columns (list[str]): columns/expressions to include in index
"""
# if this is postgres, we add the indexes concurrently. Otherwise
# we fall back to doing it inline
if isinstance(self.database_engine, engines.PostgresEngine):
conc = True
else:
conc = False
# We don't use partial indices on SQLite as it wasn't introduced
# until 3.8, and wheezy has 3.7
where_clause = None
sql = (
"CREATE INDEX %(conc)s %(name)s ON %(table)s (%(columns)s)"
" %(where_clause)s"
) % {
"conc": "CONCURRENTLY" if conc else "",
"name": index_name,
"table": table,
"columns": ", ".join(columns),
"where_clause": "WHERE " + where_clause if where_clause else ""
}
def create_index_concurrently(conn):
def create_index_psql(conn):
conn.rollback()
# postgres insists on autocommit for the index
conn.set_session(autocommit=True)
c = conn.cursor()
c.execute(sql)
conn.set_session(autocommit=False)
def create_index(conn):
try:
c = conn.cursor()
# If a previous attempt to create the index was interrupted,
# we may already have a half-built index. Let's just drop it
# before trying to create it again.
sql = "DROP INDEX IF EXISTS %s" % (index_name,)
logger.debug("[SQL] %s", sql)
c.execute(sql)
sql = (
"CREATE INDEX CONCURRENTLY %(name)s ON %(table)s"
" (%(columns)s) %(where_clause)s"
) % {
"name": index_name,
"table": table,
"columns": ", ".join(columns),
"where_clause": "WHERE " + where_clause if where_clause else ""
}
logger.debug("[SQL] %s", sql)
c.execute(sql)
finally:
conn.set_session(autocommit=False)
def create_index_sqlite(conn):
# Sqlite doesn't support concurrent creation of indexes.
#
# We don't use partial indices on SQLite as it wasn't introduced
# until 3.8, and wheezy has 3.7
#
# We assume that sqlite doesn't give us invalid indices; however
# we may still end up with the index existing but the
# background_updates not having been recorded if synapse got shut
# down at the wrong moment - hance we use IF NOT EXISTS. (SQLite
# has supported CREATE TABLE|INDEX IF NOT EXISTS since 3.3.0.)
sql = (
"CREATE INDEX IF NOT EXISTS %(name)s ON %(table)s"
" (%(columns)s)"
) % {
"name": index_name,
"table": table,
"columns": ", ".join(columns),
}
c = conn.cursor()
logger.debug("[SQL] %s", sql)
c.execute(sql)
if isinstance(self.database_engine, engines.PostgresEngine):
runner = create_index_psql
else:
runner = create_index_sqlite
@defer.inlineCallbacks
def updater(progress, batch_size):
logger.info("Adding index %s to %s", index_name, table)
if conc:
yield self.runWithConnection(create_index_concurrently)
else:
yield self.runWithConnection(create_index)
yield self.runWithConnection(runner)
yield self._end_background_update(update_name)
defer.returnValue(1)