On 20 Oct 2019, at 12:36pm, Peng Yu wrote:
> I am on Mac OS X. Is there anything equivalent? Thanks.
Have the database stored on a Flash Drive. Eject (or unmount) the Flash Drive.
Works on all versions of all operating systems.
___
sqlite-users
> You can try clearing Linux file system cache to convince
> yourself that cache misses contributes to performance drop.
>
> Run this as root:
>
> # sync; echo 3 > /proc/sys/vm/drop_caches
I am on Mac OS X. Is there anything equivalent? Thanks.
--
Regards,
Peng
On 20 Oct 2019, at 1:54am, Peng Yu wrote:
> How to prove the large time difference of sqlite3 is indeed due to
> cache and where is the cache?
Keep the database on an external drive (e.g. USB Flash drive). Unmount the
drive to be sure that the cache has been cleared.
> Why the caching used
Peng Yu wrote:
I have never seen such a dramatic difference in non-sqlite3
> operations. For example, cat has some difference but is ~13%.
>
> $ time cat file.sqa > /dev/null
>
> real0m7.282s
> user0m0.067s
> sys0m2.371s
> $ time cat file.sqa > /dev/null
>
> real0m6.316s
> user
On Saturday, 19 October, 2019 18:55, Peng Yu wrote:
>I have never seen such a dramatic difference in non-sqlite3
>operations. For example, cat has some difference but is ~13%.
Have you been looking?
>$ time cat file.sqa > /dev/null
>
>real0m7.282s
>user0m0.067s
>sys0m2.371s
>$
I have never seen such a dramatic difference in non-sqlite3
operations. For example, cat has some difference but is ~13%.
$ time cat file.sqa > /dev/null
real0m7.282s
user0m0.067s
sys0m2.371s
$ time cat file.sqa > /dev/null
real0m6.316s
user0m0.062s
sys0m2.319s
How to
On Saturday, 19 October, 2019 18:05, Peng Yu wrote:
Looks like the difference between reading from disk and reading from cache.
>I see that sqlite3 can be very different in terms of run time.
>$ time sqlite3 file.sqa -Atv > /dev/null
>
>real0m3.259s
>user0m0.193s
>sys0m0.704s
>$
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