New short-term goal: get facets and suggested facets to execute in parallel with the main query. Generate a trace graph that proves that is happening using datasette-pretty-traces.

I wrote code to execute those in parallel using asyncio.gather() - which seems to work but causes the SQL run inside the parallel async def functions not to show up in the trace graph at all.

```diff diff --git a/datasette/views/table.py b/datasette/views/table.py index 9808fd2..ec9db64 100644 --- a/datasette/views/table.py +++ b/datasette/views/table.py @@ -1,3 +1,4 @@ +import asyncio import urllib import itertools import json @@ -615,44 +616,37 @@ class TableView(RowTableShared): if request.args.get("_timelimit"): extra_args["custom_time_limit"] = int(request.args.get("_timelimit"))

• Execute the main query!

• results = await db.execute(sql, params, truncate=True, **extra_args)

• Calculate the total count for this query

• filtered_table_rows_count = None
• if (
• not db.is_mutable
• and self.ds.inspect_data
• and count_sql == f"select count(*) from {table} "
• ):

• We can use a previously cached table row count

• try:
• filtered_table_rows_count = self.ds.inspect_data[database]["tables"][
• table
• ]["count"]
• except KeyError:

• pass

• Otherwise run a select count(*) ...

• if count_sql and filtered_table_rows_count is None and not nocount:
• try:
• count_rows = list(await db.execute(count_sql, from_sql_params))
• filtered_table_rows_count = count_rows[0][0]
• except QueryInterrupted:

• pass

• Faceting

• if not self.ds.setting("allow_facet") and any(
• arg.startswith("_facet") for arg in request.args
• ):
• raise BadRequest("_facet= is not allowed")
• async def execute_count():

• Calculate the total count for this query

• filtered_table_rows_count = None
• if (
• not db.is_mutable
• and self.ds.inspect_data
• and count_sql == f"select count(*) from {table} "
• ):

• We can use a previously cached table row count

• try:
• filtered_table_rows_count = self.ds.inspect_data[database][
• "tables"
• ][table]["count"]
• except KeyError:
• pass +
• if count_sql and filtered_table_rows_count is None and not nocount:
• try:
• count_rows = list(await db.execute(count_sql, from_sql_params))
• filtered_table_rows_count = count_rows[0][0]
• except QueryInterrupted:
• pass +
• return filtered_table_rows_count +

• filtered_table_rows_count = await execute_count()

   # pylint: disable=no-member
   facet_classes = list(
       itertools.chain.from_iterable(pm.hook.register_facet_classes())
   )
  

  • facet_results = {}
  • facets_timed_out = [] facet_instances = [] for klass in facet_classes: facet_instances.append( @@ -668,33 +662,58 @@ class TableView(RowTableShared): ) )

• if not nofacet:

• for facet in facet_instances:
• (
• instance_facet_results,
• instance_facets_timed_out,
• ) = await facet.facet_results()
• for facet_info in instance_facet_results:
• base_key = facet_info["name"]
• key = base_key
• i = 1
• while key in facet_results:
• i += 1
• key = f"{base_key}_{i}"
• facet_results[key] = facet_info

• facets_timed_out.extend(instance_facets_timed_out)

• Calculate suggested facets

• suggested_facets = []
• if (
• self.ds.setting("suggest_facets")
• and self.ds.setting("allow_facet")
• and not _next
• and not nofacet
• and not nosuggest
• ):
• for facet in facet_instances:
• suggested_facets.extend(await facet.suggest())
• async def execute_suggested_facets():

• Calculate suggested facets

• suggested_facets = []
• if (
• self.ds.setting("suggest_facets")
• and self.ds.setting("allow_facet")
• and not _next
• and not nofacet
• and not nosuggest
• ):
• for facet in facet_instances:
• suggested_facets.extend(await facet.suggest())
• return suggested_facets +
• async def execute_facets():
• facet_results = {}
• facets_timed_out = []
• if not self.ds.setting("allow_facet") and any(
• arg.startswith("_facet") for arg in request.args
• ):
• raise BadRequest("_facet= is not allowed") +
• if not nofacet:
• for facet in facet_instances:
• (
• instance_facet_results,
• instance_facets_timed_out,
• ) = await facet.facet_results()
• for facet_info in instance_facet_results:
• base_key = facet_info["name"]
• key = base_key
• i = 1
• while key in facet_results:
• i += 1
• key = f"{base_key}_{i}"
• facet_results[key] = facet_info
• facets_timed_out.extend(instance_facets_timed_out) +
• return facet_results, facets_timed_out +

• Execute the main query, facets and facet suggestions in parallel:

• (
• results,
• suggested_facets,
• (facet_results, facets_timed_out),
• ) = await asyncio.gather(
• db.execute(sql, params, truncate=True, **extra_args),
• execute_suggested_facets(),
• execute_facets(),
• ) +
• results = await db.execute(sql, params, truncate=True, **extra_args)

   # Figure out columns and rows for the query
   columns = [r[0] for r in results.description]
  

  `` Here's the trace forhttp://127.0.0.1:4422/fixtures/compound_three_primary_keys?_trace=1&_facet=pk1&_facet=pk2` with the missing facet and facet suggestion queries: