android - Time required by some statements to execute not constant -

inside sqlite adapter class, android application, have following method. key key_was can either 0 or 1. method searches given name , given date in database (for given date there can 1 unique entry particular name in db). so, if such entry present, go inside if, otherwise was remains zero. finally, was returned.

public int washere(string name, string date) throws sqlexception {     log.d("washere", "begins, date = " + date);     cursor c = ourdatabase.query(database_table, all_keys, key_name             + "=" + "'" + name + "'" + " , " + key_date + "=" + "'"             + date + "'", null, null, null, null);     log.d("washere", "below cursor");     int = 0;     if(c.movetofirst()) {         log.d("washere", "inside if");         = c.getint(c.getcolumnindex(key_was));     }     lod.d("washere", "ends");     return was; } 

from log entries, pasting particular ones (you can ignore time between "begins" , "ends" depends on loop calling washere):

07-18 07:08:03.398: d/dbwas(29568): begins, date = 08 aug 2013 07-18 07:08:03.398: d/dbwas(29568): below cursor 07-18 07:08:03.398: d/dbwas(29568): ends  07-18 07:08:03.398: d/dbwas(29568): begins, date = 09 aug 2013 07-18 07:08:03.406: d/dbwas(29568): below cursor 07-18 07:08:03.406: d/dbwas(29568): ends  07-18 07:08:03.359: d/dbwas(29568): begins, date = 02 aug 2013 07-18 07:08:03.359: d/dbwas(29568): below cursor 07-18 07:08:03.367: d/dbwas(29568): inside if 07-18 07:08:03.367: d/dbwas(29568): ends  07-18 07:08:03.367: d/dbwas(29568): begins, date = 03 aug 2013 07-18 07:08:03.367: d/dbwas(29568): below cursor 07-18 07:08:03.375: d/dbwas(29568): inside if 07-18 07:08:03.375: d/dbwas(29568): ends  07-18 07:08:03.430: d/dbwas(29568): begins, date = 14 aug 2013 07-18 07:08:03.430: d/dbwas(29568): below cursor 07-18 07:08:03.430: d/dbwas(29568): inside if 07-18 07:08:03.430: d/dbwas(29568): ends 

my question regarding log times "begins" , "ends". can see above, among 5 log entries, 2 (8 aug , 14 aug) take 0 time "begins, date = ..." "ends".

9 aug takes 8 ms (.008 seconds) in executing cursor statement.

2 aug , 3 aug take 8 ms (.008 seconds) in executing if statement.

14 aug takes no time executing either of 2 above mentioned statements.

similarly, there many such discrepancies in "log". different dates, cursor , if statements randomly take 8 ms (and yes, time 8 ms).

now, executing "washere" method hundreds of times, hundreds of 8 milliseconds cost me time. why above discrepancies happening randomly. , there way remove (or maybe way of doing doing). [8 aug , 14 aug statement take 0 time should.]

on system, timer interrupt apparently runs @ 125 hz , happens every 8 ms. if function gets executed between 2 timer interrupts, see no change in timestamps, if timer interrupt happens while function executing, see jump of 8 ms.

there no discrepancy in actual execution times; timestamps in log not precise enough.