Dear list,
sorry to just come up with another performance question. I build a yet small
database with one table. It has about 650.000 rows, 75 columns and
has at the moment about 650 Mb. It runs on a Intel Pentium M with 2 GHz. The
Laptop runs Suse 10.2 and does basicly nothing but this database.
sqlite3 -version is 3.3.8
This is the schema:
CREATE TABLE 'data'('nr' INTEGER PRIMARY KEY,
'year' INTEGER,
'month' INTEGER,
'day' INTEGER,
'sec' REAL,
'campId' TEXT,
'flightNr' INTEGER,
'1' REAL,
...
'71' REAL
);
CREATE INDEX sec on data(year,month,day,sec);
I experience a big variability of time a query needs:
~database> time sqlite3 data.db 'select "14" from data where
campId="polstar98" and "14">-9999;' >/dev/null
real 0m3.115s
user 0m1.748s
sys 0m1.368s
~/database> time sqlite3 data.db 'select "14" from data where
campId="polstar98" and "14">-9999;' >/dev/null
real 0m3.139s
user 0m1.756s
sys 0m1.380s
~/database> time sqlite3 data.db 'select "42" from data where
campId="stream94" and "14">-9999;' >/dev/null
real 0m50.227s
user 0m4.692s
sys 0m3.028s
I've tried it with and without index and at different times. Most of the
time such simple queries take about 35 sec. Why is that so and what can be done?
I can live with 3 sec of response but not up to one minute and the
database is still not complete. Would pytables with hdf5 be an alternative?
Knowing that this is probably not the right place to ask...
Tips, suggestions, recommendation are gratefuly appreciated!
Thanks in advance
Hubertus
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