id,page,ref,title,content,breadcrumbs,references
performance:performance,performance,performance,Performance and caching,"Datasette runs on top of SQLite, and SQLite has excellent performance.  For small databases almost any query should return in just a few milliseconds, and larger databases (100s of MBs or even GBs of data) should perform extremely well provided your queries make sensible use of database indexes. 
         That said, there are a number of tricks you can use to improve Datasette's performance.",[],[]
performance:performance-immutable-mode,performance,performance-immutable-mode,Immutable mode,"If you can be certain that a SQLite database file will not be changed by another process you can tell Datasette to open that file in  immutable mode . 
             Doing so will disable all locking and change detection, which can result in improved query performance. 
             This also enables further optimizations relating to HTTP caching, described below. 
             To open a file in immutable mode pass it to the datasette command using the  -i  option: 
             datasette -i data.db 
             When you open a file in immutable mode like this Datasette will also calculate and cache the row counts for each table in that database when it first starts up, further improving performance.","[""Performance and caching""]",[]
performance:performance-inspect,performance,performance-inspect,"Using ""datasette inspect""","Counting the rows in a table can be a very expensive operation on larger databases. In immutable mode Datasette performs this count only once and caches the results, but this can still cause server startup time to increase by several seconds or more. 
             If you know that a database is never going to change you can precalculate the table row counts once and store then in a JSON file, then use that file when you later start the server. 
             To create a JSON file containing the calculated row counts for a database, use the following: 
             datasette inspect data.db --inspect-file=counts.json 
             Then later you can start Datasette against the  counts.json  file and use it to skip the row counting step and speed up server startup: 
             datasette -i data.db --inspect-file=counts.json 
             You need to use the  -i  immutable mode against the database file here or the counts from the JSON file will be ignored. 
             You will rarely need to use this optimization in every-day use, but several of the  datasette publish  commands described in  Publishing data  use this optimization for better performance when deploying a database file to a hosting provider.","[""Performance and caching""]",[]