Partition Pruning

[Scott Watson]

Hello,

I am trying to understand partition pruning. The problem is that partition pruning is working when I was expecting it to not work. So I believe I have either misunderstood the documentation or something is happening that I am not aware of.

mysql> select version();
+------------+
| version() |
+------------+
| 5.5.17-log |
+------------+
1 row in set (0.01 sec)

So my understanding was that partition pruning is only supported on date, datetime columns when you use the YEAR or the TO_DAYS function. ( FROM THE DOC: In MySQL 5.5, partition pruning is supported for the TO_DAYS(), TO_SECONDS(), and YEAR() functions.) However, I used the DAYOFWEEK function so that I have 7 partitions since I only need to keep 5 days worth of data in a rolling fashion. Did I misread the doc or is it the case that DAYOFWEEK works with partition pruning but is just not supported? I have tried simple selects and joins and it seem to prune as long as I supply a date value. I will not be using ranges of dates.


Thanks
Scott.