What is the goal, though? Your app knows your data and performance needs, so if you find yourself running the same query to read off the same result set over and over, change your app to do the right thing.
If it's somehow more convenient to have SQLite do it, populate a temporary table and pull the data from that, which doesn't require any new API at all. -scott On Thu, Mar 23, 2017 at 6:23 AM, Domingo Alvarez Duarte <mingo...@gmail.com> wrote: > Hello Richard ! > > Yes I do see "because the implementation parsing the JSON anew each time" > and this is a recurring pattern in some sqlite functions, would be nice if > we could have a "session/query/row" storage space to store query > information that can be reused, for example on the json functions we could > reuse an already parsed json field several times, another example we could > have session/query/row variables. > > We could have something like "sqlite3_set_auxdata" but with granularity > for row/query/session and as a bonus would be nice to have session > variables like https://dev.mysql.com/doc/refman/5.7/en/user-variables.html > . > > Cheers ! > > On 23/03/17 08:30, Richard Hipp wrote: > >> On 3/22/17, Domingo Alvarez Duarte <mingo...@gmail.com> wrote: >> >>> Hello Richard ! >>> >>> I noticed that sqlite do not use any memoization in json1 functions. >>> >>> For example jsonExtractFunc and others parse the json string every time >>> it's called even when the json string is the same. >>> >>> minimal example : "select json_extract(json, '$.name') name, >>> json_extract(json, '$.address') name from some_table;" >>> >>> Could be possible to have some kind of memoization as a general option >>> for any sqlite functions ?' >>> >> In paragraph 3.0 of https://www.sqlite.org/json1.html: "All json1 >> functions currently throw an error if any of their arguments are BLOBs >> because BLOBs are reserved for a future enhancement in which BLOBs >> will store the binary encoding for JSON." >> >> But let me ask this: Have you actually measured a performance >> problem? Or are you just assuming that because the implementation >> parses the JSON anew each time it see it that it must therefore be >> inefficient? >> >> > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
