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Refs #28459 -- Improved performance of sql.compiler.cursor_iter().

This commit is contained in:
Sergey Fedoseev 2017-08-08 23:07:03 +05:00 committed by Tim Graham
parent 831358f23d
commit b8731c3fff
1 changed files with 3 additions and 2 deletions
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5
django/db/models/sql/compiler.py
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@ -51,6 +51,7 @@ class SQLCompiler:
order_by = self.get_order_by() order_by = self.get_order_by()
self.where, self.having = self.query.where.split_having() self.where, self.having = self.query.where.split_having()
extra_select = self.get_extra_select(order_by, self.select) extra_select = self.get_extra_select(order_by, self.select)
self.has_extra_select = bool(extra_select)
group_by = self.get_group_by(self.select + extra_select, order_by) group_by = self.get_group_by(self.select + extra_select, order_by)
return extra_select, order_by, group_by return extra_select, order_by, group_by
@ -1025,7 +1026,7 @@ class SQLCompiler:
result = cursor_iter( result = cursor_iter(
cursor, self.connection.features.empty_fetchmany_value, cursor, self.connection.features.empty_fetchmany_value,
self.col_count, self.col_count if self.has_extra_select else None,
chunk_size, chunk_size,
) )
if not chunked_fetch and not self.connection.features.can_use_chunked_reads: if not chunked_fetch and not self.connection.features.can_use_chunked_reads:
@ -1394,6 +1395,6 @@ def cursor_iter(cursor, sentinel, col_count, itersize):
""" """
try: try:
for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel): for rows in iter((lambda: cursor.fetchmany(itersize)), sentinel):
yield [r[0:col_count] for r in rows] yield rows if col_count is None else [r[:col_count] for r in rows]
finally: finally:
cursor.close() cursor.close()