>> These numbers have varied wildly, from being off by 2-3 between subsequent scans to 40 row increases, followed by a drop of 70 rows. When you say there is a variation in the number of rows retrieved - the 40 rows that got increased - are those rows in the expected time range? Or is the system retrieving some rows which are not in the specified time range?
And when the rows drop by 70, are you using any row which was needed to be retrieved got missed out? Any filters in your scan? Regards Ram On Wed, Feb 25, 2015 at 8:31 AM, Ted Yu <[email protected]> wrote: > What's the TTL setting for your table ? > > Which hbase release are you using ? > > Was there compaction in between the scans ? > > Thanks > > > > On Feb 24, 2015, at 2:32 PM, Stephen Durfey <[email protected]> wrote: > > > > I have some code that accepts a time range and looks for data written to > an HBase table during that range. If anything has been written for that row > during that range, the row key is saved off, and sometime later in the > pipeline those row keys are used to extract the entire row. I’m testing > against a fixed time range, at some point in the past. This is being done > as part of a Map/Reduce job (using Apache Crunch). I have some job counters > setup to keep track of the number of rows extracted. Since the time range > is fixed, I would expect the scan to return the same number of rows with > data in the provided time range. However, I am seeing this number vary from > scan to scan (bouncing between increasing and decreasing). > > > > I’ve eliminated the possibility that data is being pulled in from > outside the time range. I did this by scanning for one column qualifier > (and only using this as the qualifier for if a row had data in the time > range), getting the timestamp on the cell for each returned row and > compared it against the begin and end times for the scan, and I didn’t find > any that satisfied that criteria. I’ve observed some row keys show up in > the 1st scan, then drop out in the 2nd scan, only to show back up again in > the 3rd scan (all with the exact same Scan object). These numbers have > varied wildly, from being off by 2-3 between subsequent scans to 40 row > increases, followed by a drop of 70 rows. > > > > I’m kind of looking for ideas to try to track down what could be causing > this to happen. The code itself is pretty simple, it creates a Scan object, > scans the table, and then in the map phase, extract out the row key, and at > the end, it dumps them to a directory in hdfs. >
