Sounds good to me
On 4/9/13 12:04 AM, "Jitendra Pandey" <jiten...@hortonworks.com> wrote: >I agree that we shouldn't wait too long before merging the branch. >We are targeting to have basic queries working within a month from now and >will definitely propose to merge the branch back into trunk at that point. >We will limit the scope of the work on the branch to just a few operators >and primitive datatypes. Does that sound reasonable? > >regards >jitendra > >On Wed, Apr 3, 2013 at 9:03 PM, Namit Jain <nj...@fb.com> wrote: > >> There is no right answer, but I feel if you go this path a long way, it >> will be very difficult >> to merge back. Given that this is not a new functionality, and >>improvement >> to existing code >> (which will also evolve), it will become difficult to maintain/review a >> big diff in the future. >> >> I haven't thought much about it, but can start by creating the >>high-level >> interfaces first, and then >> going from there. For e.g.: create interfaces for operators which take >>in >> an array of rows instead of >> a single row - initially the array size can always be 1. Now, proceed >>from >> there. >> >> What makes you think, merging a branch 6 months/1 year from now will be >> easier than working on the >> current branch ? >> >> Having said that, both approaches can be made to work - but I think you >> are just delaying the >> merging work instead of taking the hit upfront. >> >> Thanks, >> -namit >> >> >> >> On 4/4/13 2:40 AM, "Jitendra Pandey" <jiten...@hortonworks.com> wrote: >> >> > We did consider implementing these changes on the trunk. But, it >>would >> >take several patches in various parts of the code before a simple end >>to >> >end query can be executed on vectorized path. For example a patch for >> >vectorized expressions will be a significant amount of code, but will >>not >> >be used in a query until a vectorized operator is implemented and the >> >query >> >plan is modified to use the vectorized path. Vectorization of even >>basic >> >expressions becomes non trivial because we need to optimize for various >> >cases like chain of expressions, for non-null columns or repeating >>values >> >and also handle case for nullable columns, or short circuit >>optimization >> >etc. Careful handling of these is important for performance gains. >> > >> > Committing those intermediate patches in trunk without stabilizing >>them >> >in a branch first might be a cause of concern. >> > >> > A separate branch will let us make incremental changes to the system >>so >> >that each patch addresses a single feature or functionality and is >>small >> >enough to review. >> > We will make sure that the branch is frequently updated with the >> >changes >> >in the trunk to avoid conflicts at the time of the merge. >> > Also, we plan to propose merger of the branch as soon as a basic end >>to >> >end query begins to work and is sufficiently tested, instead of waiting >> >for >> >all operators to get vectorized. Initially our target is to make select >> >and >> >filter operators work with vectorized expressions for primitive types. >> > >> > We will have a single global configuration flag that can be used to >> >turn >> >off the entire vectorization code path and we will specifically test to >> >make sure that when this flag is off there is no regression on the >>current >> >system. When vectorization is turned on, we will have a validation >>step to >> >make sure the given query is supported on the vectorization path >>otherwise >> >it will fall back to current code path. >> > >> > Although, we intend to follow commit then review policy on the branch >> >for >> >speed of development, each patch will have an associated jira and will >>be >> >available for review and feedback. >> > >> >thanks >> >jitendra >> > >> >On Tue, Apr 2, 2013 at 8:37 PM, Namit Jain <nj...@fb.com> wrote: >> > >> >> It will be difficult to merge back the branch. >> >> Can you stage your changes incrementally ? >> >> >> >> I mean, start with the making the operators vectorized - it can be a >>for >> >> loop to >> >> start with ? I think it will be very difficult to merge it back if we >> >> diverge on this. >> >> I would recommend starting with simple interfaces for operators and >>then >> >> plugging them >> >> in slowly instead of a new branch, unless this approach is extremely >> >> difficult. >> >> >> >> >> >> Thanks, >> >> -namit >> >> >> >> On 4/3/13 1:52 AM, "Jitendra Pandey" <jiten...@hortonworks.com> >>wrote: >> >> >> >> >Hi Folks, >> >> > I want to propose for creation of a separate branch for >>HIVE-4160 >> >> >work. This is a significant amount of work, and support for very >>basic >> >> >functionality will need big chunks of code. It will also take some >> >>time to >> >> >stabilize and test. A separate dev branch will allow us to do this >>work >> >> >incrementally and collaboratively. We have already uploaded a design >> >> >document on the jira for comments/feedback. >> >> > >> >> >thanks >> >> >jitendra >> >> > >> >> > >> >> >-- >> >> ><http://hortonworks.com/download/> >> >> >> >> >> > >> > >> >-- >> ><http://hortonworks.com/download/> >> >> > > >-- ><http://hortonworks.com/download/>
