html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,issue,performed_via_github_app
https://github.com/simonw/datasette/issues/420#issuecomment-474407617,https://api.github.com/repos/simonw/datasette/issues/420,474407617,MDEyOklzc3VlQ29tbWVudDQ3NDQwNzYxNw==,9599,2019-03-19T14:55:51Z,2019-03-19T14:55:51Z,OWNER,"A microbenchmark against `fivethirtyeight.db` (415 tables):

    In [1]: import sqlite3                                                                                              
    In [2]: c = sqlite3.connect(""fivethirtyeight.db"")                                                                   
    In [3]: %timeit c.execute(""select name from sqlite_master where type = 'table'"").fetchall()                         
    283 µs ± 12.3 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)
    In [4]: tables = [r[0] for r in c.execute(""select name from sqlite_master where type = 'table'"").fetchall()]        
    In [5]: len(tables)                                                                                                 
    Out[5]: 415
    In [6]: %timeit [c.execute(""pragma foreign_keys([{}])"".format(t)).fetchall() for t in tables]                       
    1.81 ms ± 161 µs per loop (mean ± std. dev. of 7 runs, 1000 loops each)

So running `pragma foreign_keys()` against 415 tables only takes 1.81ms. This is going to be fine.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",421971339,
https://github.com/simonw/datasette/issues/420#issuecomment-474399630,https://api.github.com/repos/simonw/datasette/issues/420,474399630,MDEyOklzc3VlQ29tbWVudDQ3NDM5OTYzMA==,9599,2019-03-19T14:38:14Z,2019-03-19T14:38:14Z,OWNER,"Most of these can be replaced with relatively straight-forward direct introspection of the SQLite table.

The one exception is the incoming foreign keys: these can only be found by inspecting ALL of the other tables. 

This requires running `PRAGMA foreign_key_list([table_name])` against every other table in the database. How expensive is doing this on a database with hundreds of tables?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",421971339,
https://github.com/simonw/datasette/issues/420#issuecomment-474398127,https://api.github.com/repos/simonw/datasette/issues/420,474398127,MDEyOklzc3VlQ29tbWVudDQ3NDM5ODEyNw==,9599,2019-03-19T14:34:55Z,2019-03-19T14:34:55Z,OWNER,"I systematically reviewed the codebase for things that `.inspect()` is used for:

In `app.py`:

* `table_exists()` uses `table in self.inspect().get(database, {}).get(""tables"")`
* `.execute()` looks up the database name to get the `info[""file""]` (the correct filename with the `.db` extension)

In `cli.py`:

* The `datasette inspect` command dumps it to JSON
* `datasette skeleton` iterates over it
* `datasette serve` calls it on startup (to populate static cache of inspect data)

In `base.py`:

* `.database_url(database)` calls it to lookup the hash (if `hash_urls` config turned on)
* `.resolve_db_name()` uses it to lookup the hash

In `database.py`:

* `DatabaseView` uses it to find up the list of tables and views to display, plus the size of the DB file in bytes
* `DatabaseDownload` uses it to get the filepath for download

In `index.py`:

* `IndexView` uses it _extensively_ - to loop through every database and every table. This would make a good starting point for the refactor.

In `table.py`:

* `sortable_columns_for_table()` uses it to find the columns in a table
* `expandable_columns()` uses it to find foreign keys
* `expand_foreign_keys()` uses it to find foreign keys
* `display_columns_and_rows()` uses it to find primary keys and foreign keys... but also has access to a `cursor.description` which it uses to list the columns
* `TableView.data` uses it to lookup columns and primary keys and the `table_rows_count` (used if the thing isn't a view) and probably a few more things, this method is huge!
* `RowView.data` uses it for primary keys
* `foreign_key_tables()` uses it for foreign keys

In the tests it's used by `test_api.test_inspect_json()` and by a couple of tests in `test_inspect`.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",421971339,