html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app
https://github.com/simonw/datasette/issues/1513#issuecomment-970855084,https://api.github.com/repos/simonw/datasette/issues/1513,970855084,IC_kwDOBm6k_c453hKs,9599,simonw,2021-11-16T23:41:46Z,2021-11-16T23:41:46Z,OWNER,Conclusion: using a giant convoluted CTE and UNION ALL query to attempt to calculate facets at the same time as retrieving rows is a net LOSS for performance! Very surprised to see that.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1055469073,Research: CTEs and union all to calculate facets AND query at the same time,
https://github.com/simonw/datasette/issues/1513#issuecomment-970853917,https://api.github.com/repos/simonw/datasette/issues/1513,970853917,IC_kwDOBm6k_c453g4d,9599,simonw,2021-11-16T23:41:01Z,2021-11-16T23:41:01Z,OWNER,"One very interesting difference between the two: on the single giant query page:
```json
{
""request_duration_ms"": 376.4317020000476,
""sum_trace_duration_ms"": 370.0828700000329,
""num_traces"": 5
}
```
And on the page that uses separate queries:
```json
{
""request_duration_ms"": 819.012272000009,
""sum_trace_duration_ms"": 201.52852100000018,
""num_traces"": 19
}
```
The separate pages page takes 819ms total to render the page, but spends 201ms across 19 SQL queries.
The single big query takes 376ms total to render the page, spending 370ms in 5 queries
Those 5 queries, if you're interested
```sql
select database_name, schema_version from databases
PRAGMA schema_version
PRAGMA schema_version
explain with cte as (\r\n select rowid, date, county, state, fips, cases, deaths\r\n from ny_times_us_counties\r\n),\r\ntruncated as (\r\n select null as _facet, null as facet_name, null as facet_count, rowid, date, county, state, fips, cases, deaths\r\n from cte order by date desc limit 4\r\n),\r\nstate_facet as (\r\n select 'state' as _facet, state as facet_name, count(*) as facet_count,\r\n null, null, null, null, null, null, null\r\n from cte group by facet_name order by facet_count desc limit 3\r\n),\r\nfips_facet as (\r\n select 'fips' as _facet, fips as facet_name, count(*) as facet_count,\r\n null, null, null, null, null, null, null\r\n from cte group by facet_name order by facet_count desc limit 3\r\n),\r\ncounty_facet as (\r\n select 'county' as _facet, county as facet_name, count(*) as facet_count,\r\n null, null, null, null, null, null, null\r\n from cte group by facet_name order by facet_count desc limit 3\r\n)\r\nselect * from truncated\r\nunion all select * from state_facet\r\nunion all select * from fips_facet\r\nunion all select * from county_facet
with cte as (\r\n select rowid, date, county, state, fips, cases, deaths\r\n from ny_times_us_counties\r\n),\r\ntruncated as (\r\n select null as _facet, null as facet_name, null as facet_count, rowid, date, county, state, fips, cases, deaths\r\n from cte order by date desc limit 4\r\n),\r\nstate_facet as (\r\n select 'state' as _facet, state as facet_name, count(*) as facet_count,\r\n null, null, null, null, null, null, null\r\n from cte group by facet_name order by facet_count desc limit 3\r\n),\r\nfips_facet as (\r\n select 'fips' as _facet, fips as facet_name, count(*) as facet_count,\r\n null, null, null, null, null, null, null\r\n from cte group by facet_name order by facet_count desc limit 3\r\n),\r\ncounty_facet as (\r\n select 'county' as _facet, county as facet_name, count(*) as facet_count,\r\n null, null, null, null, null, null, null\r\n from cte group by facet_name order by facet_count desc limit 3\r\n)\r\nselect * from truncated\r\nunion all select * from state_facet\r\nunion all select * from fips_facet\r\nunion all select * from county_facet
```