Fix sqlite syntax for upserts.

[clokep]

Fixes the backfill script given in #13394. I missed parentheses for sqlite.

[DMRobertson]

(Any reason for not using one of the upsert helpers here?)

[clokep]

(Any reason for not using one of the upsert helpers here?)

They can't be used: they don't support providing both keys and values, but doing nothing on conflict. (They assume that you want to apply the new values on conflict.)

[DMRobertson]

(Any reason for not using one of the upsert helpers here?)

They can't be used: they don't support providing both keys and values, but doing nothing on conflict. (They assume that you want to apply the new values on conflict.)

Are you sure? This comment (err, which I wrote) suggests otherwise:

synapse/synapse/storage/database.py

Lines 1144 to 1148 in 328b991

	If (values) is empty, the resulting query is slighlty simpler:
	INSERT INTO table VALUES (insertion_values)
	ON CONFLICT (keyvalues)
	DO NOTHING; -- do not overwrite any columns

Will gladly amend the comment if it is wrong.

[clokep]

Are you sure? This comment (err, which I wrote) suggests otherwise:

The comment is correct: in this case we do want to pass values, but we don't want to use them to update, only to insert.

I'm fairly certain this isn't possible with the current API since if you pass values it tries to update on conflict.

[DMRobertson]

Note that there are three dictionaries by which you can provide column/value pairs: keybalues, values and insertion_values. I might be missing something, but I think

simple_upsert(
    table="threads",
    keyvalues={"room_id": ..., "thread_id": ... },
    values={},
    insertion_values={"topological_ordering": ..., "stream_ordering": ..., "latest_event_id": ...},
)

would work?

(I'm not saying we should write it this way. If anything, I'm advocating for the opposite: the manually written sql is probably clearer, and the fact that we're not in agreement about the helper suggests that its behaviour is confusing.)

[clokep]

Note that there are three dictionaries by which you can provide column/value pairs: keybalues, values and insertion_values. I might be missing something, but I think

This would need to use simple_upsert_many which does not offer this functionality:

synapse/synapse/storage/database.py

Lines 1401 to 1410 in b4ec4f5

	async def simple_upsert_many(
	self,
	table: str,
	key_names: Collection[str],
	key_values: Collection[Collection[Any]],
	value_names: Collection[str],
	value_values: Collection[Collection[Any]],
	desc: str,
	lock: bool = True,
	) -> None:

[DMRobertson]

Ahh thanks, I'd missed that you were upserting multiple rows in one query.

[clokep]

I updated the changelog of this in 5a983cc to match the changes done in #14175.