Return the execution plan of the statement. :param args: Query arguments. :param analyze: If ``True``, the statement will be executed and the run time statitics added to the return value. :return: An object representing the execution plan. This valu
(self, *args, analyze=False)
| 124 | |
| 125 | @connresource.guarded |
| 126 | async def explain(self, *args, analyze=False): |
| 127 | """Return the execution plan of the statement. |
| 128 | |
| 129 | :param args: Query arguments. |
| 130 | :param analyze: If ``True``, the statement will be executed and |
| 131 | the run time statitics added to the return value. |
| 132 | |
| 133 | :return: An object representing the execution plan. This value |
| 134 | is actually a deserialized JSON output of the SQL |
| 135 | ``EXPLAIN`` command. |
| 136 | """ |
| 137 | query = 'EXPLAIN (FORMAT JSON, VERBOSE' |
| 138 | if analyze: |
| 139 | query += ', ANALYZE) ' |
| 140 | else: |
| 141 | query += ') ' |
| 142 | query += self._state.query |
| 143 | |
| 144 | if analyze: |
| 145 | # From PostgreSQL docs: |
| 146 | # Important: Keep in mind that the statement is actually |
| 147 | # executed when the ANALYZE option is used. Although EXPLAIN |
| 148 | # will discard any output that a SELECT would return, other |
| 149 | # side effects of the statement will happen as usual. If you |
| 150 | # wish to use EXPLAIN ANALYZE on an INSERT, UPDATE, DELETE, |
| 151 | # MERGE, CREATE TABLE AS, or EXECUTE statement without letting |
| 152 | # the command affect your data, use this approach: |
| 153 | # BEGIN; |
| 154 | # EXPLAIN ANALYZE ...; |
| 155 | # ROLLBACK; |
| 156 | tr = self._connection.transaction() |
| 157 | await tr.start() |
| 158 | try: |
| 159 | data = await self._connection.fetchval(query, *args) |
| 160 | finally: |
| 161 | await tr.rollback() |
| 162 | else: |
| 163 | data = await self._connection.fetchval(query, *args) |
| 164 | |
| 165 | return json.loads(data) |
| 166 | |
| 167 | @connresource.guarded |
| 168 | async def fetch(self, *args, timeout=None): |