zulip/zerver/lib/migrate.py

49 lines
1.5 KiB
Python

from psycopg2.extensions import cursor
from typing import List, TypeVar
import time
CursorObj = TypeVar('CursorObj', bound=cursor)
def do_batch_update(cursor: CursorObj,
table: str,
cols: List[str],
vals: List[str],
batch_size: int=10000,
sleep: float=0.1,
escape: bool=True) -> None: # nocoverage
# The string substitution below is complicated by our need to
# support multiple postgres versions.
stmt = '''
UPDATE %s
SET %s
WHERE id >= %%s AND id < %%s
''' % (table, ', '.join(['%s = %%s' % (col) for col in cols]))
cursor.execute("SELECT MIN(id), MAX(id) FROM %s" % (table,))
(min_id, max_id) = cursor.fetchall()[0]
if min_id is None:
return
print("\n Range of rows to update: [%s, %s]" % (min_id, max_id))
while min_id <= max_id:
lower = min_id
upper = min_id + batch_size
print(' Updating range [%s,%s)' % (lower, upper))
params = list(vals) + [lower, upper]
if escape:
cursor.execute(stmt, params=params)
else:
cursor.execute(stmt % tuple(params))
min_id = upper
time.sleep(sleep)
# Once we've finished, check if any new rows were inserted to the table
if min_id > max_id:
cursor.execute("SELECT MAX(id) FROM %s" % (table,))
max_id = cursor.fetchall()[0][0]
print(" Finishing...", end='')