For a several days I’ve played with Apache Phoenix. Instead of playing with HBase directly, Phoenix helped me simplify HBase query (well, just a bit). What I want to tell you now is not about Phoenix in general but the difference between Timestamp and Date in Phoenix.
I have 2 column which have different format. I thought that both column should have different data type as well. Those format is like this:
1. yyyy-MM-dd HH:mm:ss 2. yyyy-MM-dd
When I use Date type for the 1st format, it doesn’t show me the right result. It only shows me year, month, and day of the data like this: 2015-01-31. But in Timestamp, it shows me the right result. So, my assumption is I should be using Timestamp when I want to include the time (hour, minute, and second) of the data, and the rest should be use Date type.
Unfortunately, I found that my data in HBase is inconsistent. It has 7 hours difference with the actual data. The culprit is the difference of data type. The documentation says that I should include format type and timezone when I want to insert the date with Phoenix (in timestamp). So, instead of to_date(‘2015-01-31 13:17:14’), I should use to_date(‘2015-01-31 13:17:14’, ‘yyyy-MM-dd HH:mm:ss’, ‘GMT+7’). But that is a bit long and there is too many code to change, also I should remember which column have Timestamp and Date type.
At last, after hundreds thousand data insertion (wrong data of course), I found that I can also use Date type in every column as long as I explicitly write the format when I try to get the data with Phoenix.
That’s all I wanna share, I hope it’s useful.