Take the 2-minute tour ×  I have a database that stores readings
from numerous gauges. Depending on the gauge, there may be data
for that gauge every 1-5 minutes with multiple readings (i.e.-
weather station and it stores 5 different readings).  I
currently store the data by date. I group everything for a
particular gauge for a single date together and store is as xml
in a text column.  Would it be more efficient to store this data
as individual rows?  I'm trying to decide which is the smartest
solution long term (i.e.- fewer rows with more data per row, or
many more rows, each being smaller).  It is a read heavy
environment.   By 'efficient' I am most concerned about speed
and resource usage (if I pull back a year's worth of data, which
would be least processor/memory intensive).  I almost
exclusively use this data to graph for clients. The number of
readings per timestamp is variable, from 1 to 6 readings.  The
database is currently an INNODB.   I'm looking more towards
keeping the data in MySQL for ease of