Zaumseil Ren? wrote: > I have a separate table for each parameter with time stamp and value. > The time stamp is used as "integer primary key asc". > [...] > It is also possible to go back in time and then start from there. > Currently I remove all values from the tables after the specified time. > New values can be added after this. > With larger backtrack intervals I have performance problems. > > Can I speed up the deletion?
How exactly are you doing the deletion? Are you using a single transaction? > I will only read the data with a second program on another computer. > I have read it is not possible to use sqlite in wal mode over a network. > Is it so in my scenario? If "on another computer" means that you are using a network file system (and not copying the DB files to the other computer's local disk), then WAL will not work correctly. > Would it be possible if I can stop the writing for the duration of the > read? Updates of memory-mapped files are not guaranteed to be seen on remote computers (this might corrupt data). But if everything happens on a single computer, it should work. Using WAL mode appears not to be a good idea, but I guess you need the read/write concurrency. In that case, consider using a client/server database. > Diese Nachricht (inkl. Anhaenge) beinhaltet moeglicherweise vertrauliche ... This e-mail contains public information intended for any subscriber of this mailing list and for anybody else who bothers to read it; it will be copied, disclosed and distributed to the public. If you think you are not the intended recipient, please commit suicide immediately. These terms apply also to any e-mails quoted in, referenced from, or answering this e-mail, and supersede any confidentiality notices in those e-mails. Additionally, confidentiality notices in those e-mails will incur legal processing fees of $42 per line; you have agreed to this by reading this confidentiality notice. Regards, Clemens
