Thanks, Erzsebet and Markus. Tuning the number of map tasks can be a reasonal solution here, and I'll try that. As Sqoop 1 is a MapReduce job, I think it's hard to have both (1) many small queries and (2) limited concurrent executing queries.
-Wei On Thu, Jun 30, 2016 at 3:50 PM, Erzsebet Szilagyi < [email protected]> wrote: > Hi Wei, > Markus (in CC) offered the following explanation: > > " > The Sqoop1 default is 4 map tasks. When working with customers I usually > start with 1 and double the number of map tasks (e.g. 1, 2, 4, 8) until > finding a performance sweet spot while keeping in mind the potential rdbms > impact. > > Estimating the real rdbms impact is often challenging for some of the > following reasons: > 1. DBAs are often not present > 2. Jobs are often reviewed in isolation (excluding other simultaneous > Sqoop or non-sqoop workloads) > 3. Tests are often performed against smaller data volumes and/or virtual > resources than what will be in production (includes rdbms, network and had > pop cluster) > 4. There is not a uniform way to monitor/analyze impact across rdbms > vendors. > 4.1. I have not really tried to review Sqoop console debug from a dB > impact context, perhaps it could be used. > 5. Once deployed production job volumes often change > > Thanks, Markus > " > > On Wed, Jun 29, 2016 at 7:35 PM, Wei Yan <[email protected]> wrote: > >> Hi, >> >> Would like to check whether Sqoop supports this type of ingestion: >> consider we have records with range [1,12], and we have 3 mappers. So in >> default, the 3 mappers will be assigned [1,4], [5, 8], [9, 12]. >> >> Not sure whether we can split the range to smaller one, like, [1], [2], >> [3], ..., [12]. But still using 3 mappers instead of 12 mappers. We want >> this feature because: (1) if configured smaller mapper number, each mapper >> will be assigned a larger range and take much longer time to finish, and >> the infra may kill long running query; (2) But if we configured a larger >> mapper number, each mapper has a smaller range, but meanwhile we generates >> lots of network traffic to the database, which will also be bad. One good >> way we want is: still 12 ranges, but 3 mappers, and at most 3 concurrent >> connections at most. >> >> Appreciate any help here. >> >> -Wei >> > > > > -- > Erzsebet Szilagyi > Software Engineer > [image: www.cloudera.com] <http://www.cloudera.com> >
