Hello, >author="Warren Young" >On Mar 28, 2018, at 3:28 AM, rene <RZaumseil@> wrote: >> >> My main goal is currently to reduce the startup time. > >That’s not what I understood from your first post. Are you moving the goalposts, or is indexed read of >stored data not actually the primary problem?
Both are related. I need a fast startup time and the access should be "reasonable" fast. >> 1. parsing time is nearly the same between "nlohmann::json::parse(..)" >> and >> "insert into data values(json(..))” > >That’s good to know, but not too surprising. It just means one particular C parser and one particular C++ >parser happen to be about the same speed. Yup. >> insert into arrayname select >> key,json_extract(value,'$.name'),json_extract(value,'$.id') from data, >> json_each(data.json,'$.arrayname’) > >I’m suggesting that you don’t use SQLite’s JSON features at all. Use this other C++ JSON parser you >have, then construct INSERT queries for each row from the parsed JSON data. Oh no. Either I use the C++ parser or I use sqlite. The C++ parser has no knobs to tune. So it is a fixed first option. Now I'm try to be faster with sqlite :) With this option I have more options in selecting data. >Also, be sure to use prepared queries and bound parameters for something like this. Don’t rebuild the SQL >query each time: > > https://www3.sqlite.org/c3ref/bind_blob.html > >Not only will it be faster, it’s also safer. I have done this. >> Necessary indexes are created after the insert statement. > >Good. > >> The database is ":memory:" and all commands are inside an transaction. > >Also good. I have done some more experiments with json_tree(). But these are not faster. It would be really cool if the json_extract() function could support a wildcard as array index and return all values p.e. json_extract(data.json,'$.arrayname[*].name') Oh, regarding json_extract(). If I do a "explain query .." on it, it always do a table scan. Is there a way to directly get values from json? At least there are some id's returned from json_tree(). May be a function with this id as argument. Thank you Rene -- Sent from: http://sqlite.1065341.n5.nabble.com/ _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
