Problem summery:
-----------------------
Simple queries sometimes take ~400 ms
Analysis:
-----------
- A php script runs the same SQL query several times in different places
(in different transactions).
Some of the queries take around 400ms while the others (identical
queries) takes only 4-20ms.
(The timings are consistent for the same php script.)
- Testing showed that when adding multiple identical queries after a
"problematic" query run very fast, I.e.: ...
- time measurement is done with explode(' ', microtime());
Test script:
---------------
A Test script shows that the first query take long time, but the others
are quick.
It happens also not in the first query, but we don't have a simple test
script that reproduces that yet.
Script output:
<p>DB is sqlite:/usr/local/web/443/lbaProvDB<p>oneOpenTest:
<br> 0.66058707 SELECT * FROM MediaGateway
<br> 0.00106287 SELECT * FROM MediaGateway
<br> 0.00017715 SELECT * FROM MediaGateway
<br> 0.12085819 SELECT * FROM GeneralPlatformProperties
<br> 0.00016093 SELECT * FROM GeneralPlatformProperties WHERE 1
<br> 0.0649929 SELECT * FROM ClassOfRestriction WHERE id IS NULL
<br> 0.05895591 SELECT * FROM ClassOfRestriction
<br> 0.05869102 SELECT * From BriefHuntGroupList ORDER BY huntGroupName
COLLATE NOCASE
Second run:
<br> 0.04814911 SELECT * FROM MediaGateway
<br> 0.00015306 SELECT * FROM MediaGateway
<br> 0.00019789 SELECT * FROM MediaGateway
<br> 0.00516605 SELECT * FROM GeneralPlatformProperties
<br> 0.000175 SELECT * FROM GeneralPlatformProperties WHERE 1
<br> 0.02837396 SELECT * FROM ClassOfRestriction WHERE id IS NULL
<br> 0.00037098 SELECT * FROM ClassOfRestriction
<br> 0.05728984 SELECT * From BriefHuntGroupList ORDER BY huntGroupName
COLLATE NOCASE
Questrions:
-------------------
What can explain the long procces time for the first query?
What can explain log proccessing time for queries whic are not the first
?
Thanks,
Erez.
