Hey Alexey, I think your explanation makes sense from an implementation perspective. But, I think we should treat this behavior as a bug. From the user perspective, such an error is a per-row data issue and should only affect the row with the problem, not some arbitrary subset of rows in the batch which happened to share a partition.
Does anyone disagree? Todd On Fri, Nov 16, 2018, 9:28 PM Alexey Serbin <[email protected] wrote: > Hi Boris, > > Kudu clients (both Java and C++ ones) send write operations to > corresponding tablet servers in batches when using the AUTO_FLUSH_BACKGROUND > and MANUAL_FLUSH modes. When a tablet server receives a Write RPC > (WriteRequestPB is the corresponding type of the parameter), it decodes the > operations from the batch: > https://github.com/apache/kudu/blob/master/src/kudu/tablet/local_tablet_writer.h#L97 > > While decoding operations from a batch, various constraints are being > checked. One of those is checking for nulls in non-nullable columns. If > there is a row in the batch that violates the non-nullable constraint, the > whole batch is rejected. > > That's exactly what happened in your example: a batch to one tablet > consisted of 3 rows one of which had a row with violation of the > non-nullable constraint for the dt_tm column, so the whole batch of 3 > operations was rejected. You can play with different partition schemes: > e.g., in case of 10 hashed partitions it might happen that only 2 > operations would be rejected, in case of 30 partitions -- just the single > key==2 row could be rejected. > > BTW, that might also happen if using the MANUAL_FLUSH mode. However, with > the AUTO_FLUSH_SYNC mode, the client sends operations in batches of size 1. > > > Kind regards, > > Alexey > > On Fri, Nov 16, 2018 at 7:24 PM Boris Tyukin <[email protected]> > wrote: > >> Hi Todd, >> >> We are on Kudu 1.5 still and I used Kudu client 1.7 >> >> Thanks, >> Boris >> >> On Fri, Nov 16, 2018, 17:07 Todd Lipcon <[email protected] wrote: >> >>> Hi Boris, >>> >>> This is interesting. Just so we're looking at the same code, what >>> version of the kudu-client dependency have you specified, and what version >>> of the server? >>> >>> -Todd >>> >>> On Fri, Nov 16, 2018 at 1:12 PM Boris Tyukin <[email protected]> >>> wrote: >>> >>>> Hey guys, >>>> >>>> I am playing with Kudu Java client (wow it is fast), using mostly code >>>> from Kudu Java example. >>>> >>>> While learning about exceptions during rows inserts, I stumbled upon >>>> something I could not explain. >>>> >>>> If I insert 10 rows into a brand new Kudu table (AUTO_FLUSH_BACKGROUND >>>> mode) and I make one row to be "bad" intentionally (one column cannot be >>>> NULL), I actually get 3 rows that cannot be inserted into Kudu, not 1 as I >>>> was expected. >>>> >>>> But if I do session.flush() after every single insert, I get only one >>>> error row (but this ruins the purpose of AUTO_FLUSH_BACKGROUND mode). >>>> >>>> Any ideas one? We cannot afford losing data and need to track all rows >>>> which cannot be inserted. >>>> >>>> AUTO_FLUSH mode works much better and I do not have an issue like >>>> above, but then it is way slower than AUTO_FLUSH_BACKGROUND. >>>> >>>> My code is below. It is in Groovy, but I think you will get an idea :) >>>> https://gist.github.com/boristyukin/8703d2c6ec55d6787843aa133920bf01 >>>> >>>> Here is output from my test code that hopefully illustrates my >>>> confusion - out of 10 rows inserted, 9 should be good and 1 bad, but it >>>> turns out Kudu flagged 3 as bad: >>>> >>>> Created table kudu_groovy_example >>>> Inserting 10 rows in AUTO_FLUSH_BACKGROUND flush mode ... >>>> (int32 key=1, string value="value 1", unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.469000Z) >>>> (int32 key=2, string value=NULL) BAD ROW >>>> (int32 key=3, string value="value 3", unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.595000Z) >>>> (int32 key=4, string value=NULL, unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.596000Z) >>>> (int32 key=5, string value="value 5", unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.597000Z) >>>> (int32 key=6, string value=NULL, unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.597000Z) >>>> (int32 key=7, string value="value 7", unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.598000Z) >>>> (int32 key=8, string value=NULL, unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.602000Z) >>>> (int32 key=9, string value="value 9", unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.603000Z) >>>> (int32 key=10, string value=NULL, unixtime_micros >>>> dt_tm=2018-11-16T20:57:03.603000Z) >>>> 3 errors inserting rows - why 3???? only 1 expected to be bad... >>>> there were errors inserting rows to Kudu >>>> the first few errors follow: >>>> ??? key 1 and 6 supposed to be fine! >>>> Row error for primary key=[-128, 0, 0, 1], tablet=null, server=null, >>>> status=Invalid argument: No value provided for required column: >>>> dt_tm[unixtime_micros NOT NULL] (error 0) >>>> Row error for primary key=[-128, 0, 0, 2], tablet=null, server=null, >>>> status=Invalid argument: No value provided for required column: >>>> dt_tm[unixtime_micros NOT NULL] (error 0) >>>> Row error for primary key=[-128, 0, 0, 6], tablet=null, server=null, >>>> status=Invalid argument: No value provided for required column: >>>> dt_tm[unixtime_micros NOT NULL] (error 0) >>>> Rows counted in 485 ms >>>> Table has 7 rows - ??? supposed to be 9! >>>> INT32 key=4, STRING value=NULL, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.596000Z >>>> INT32 key=8, STRING value=NULL, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.602000Z >>>> INT32 key=9, STRING value=value 9, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.603000Z >>>> INT32 key=3, STRING value=value 3, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.595000Z >>>> INT32 key=10, STRING value=NULL, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.603000Z >>>> INT32 key=5, STRING value=value 5, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.597000Z >>>> INT32 key=7, STRING value=value 7, UNIXTIME_MICROS >>>> dt_tm=2018-11-16T20:57:03.598000Z >>>> >>>> >>>> >>>> >>>> >>> >>> -- >>> Todd Lipcon >>> Software Engineer, Cloudera >>> >>
