On 01/06/2017 12:56 AM, Simone Mosciatti wrote:
Hi all,
I am writing a small Redis module that embeds SQLite [1]
I am facing some performance issues and I wonder if the behaviour I am
seeing is expected or if I am doing something completely wrong.
However I am finding some issues on the performance of the in memory
database, and I see the insert performance decrease, quite fast, as
more and more tuple are added. I run some test and I would like to
understand if this behaviour is expected.
I collect the result of my benchmark on a github issues [2] where you
can see that the performance decrease in a more than linear way from
roughly 24.000 inserts per second to stabilize at roughly 4.000
inserts per second.
The actual number of inserts per second is pretty pointless, it
depends on the hardware, on the resource of the machine, etc... what
leaves me wonder is the fact that I was expecting a logarithmic
decrease in performance and not a (at least) linear decrease.
Can somebody confirm that this is normal?
Can you describe the performance test you are running?
If I create a table in an in-memory database with:
CREATE TABLE test (a INT, b INT, c INT);
Then run this:
INSERT INTO test VALUES(random(), random(), random())
10,000,000 times, I get a fairly stable 330,000 inserts per second or
so. Tcl code to do this below. What is your test doing differently?
Dan.
########## START TCL CODE
package require sqlite3
sqlite3 db :memory:
db eval { CREATE TABLE test (a INT, b INT, c INT); }
proc insert_n_rows {n} {
for {set i 0} {$i<$n} {incr i} {
db eval { INSERT INTO test VALUES(random(), random(), random()) }
}
}
set nStep 100000
for {set i 0} {$i < 100} {incr i} {
set us [lindex [time { insert_n_rows $nStep }] 0]
puts "[expr $i*$nStep] [format %.2f [expr (1000000.0 * $nStep) /
$us]]/sec"
}
########## END TCL CODE
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