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MCOL-786 Redistribute: Round robin target dbroots

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This commit is contained in:
David Hall
2017-09-18 12:45:41 -05:00
parent 4954a42825
commit de919c7f05
1 changed files with 18 additions and 3 deletions
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21
writeengine/redistribute/we_redistributecontrolthread.cpp
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@ -393,6 +393,14 @@ int RedistributeControlThread::makeRedistributePlan()
// It's possible that a source that is "removed" on the command line is not empty. // It's possible that a source that is "removed" on the command line is not empty.
// This can happen if a partition exists on all dbroots. // This can happen if a partition exists on all dbroots.
// WCOL-786: use nextDbroot to start the loop looking for a suitible target
// where we left off with the previous partition. This gives each target
// an opportunity to get some of the data. In the case of dbroot removal,
// there is often the same number of partitions on each remaining dbroot.
// This logic tends to roundrobin which dbroot gets the next batch.
set<int>::iterator nextDbroot = targetDbroots.begin();
set<int>::iterator targetDbroot;
int targetCnt = (int)targetDbroots.size();
// Loop through the sources, looking for dbroots that are not targets that also still contain partitions // Loop through the sources, looking for dbroots that are not targets that also still contain partitions
for (set<int>::iterator sourceDbroot = sourceDbroots.begin(); for (set<int>::iterator sourceDbroot = sourceDbroots.begin();
sourceDbroot != sourceDbroots.end(); sourceDbroot != sourceDbroots.end();
@ -416,15 +424,22 @@ int RedistributeControlThread::makeRedistributePlan()
// the partition. // the partition.
uint64_t partCount = std::numeric_limits<uint64_t>::max(); uint64_t partCount = std::numeric_limits<uint64_t>::max();
int tdbroot = 0; int tdbroot = 0;
for (set<int>::iterator targetDbroot = targetDbroots.begin(); targetDbroot = nextDbroot;
targetDbroot != targetDbroots.end(); // MCOL-786. Start at targetDbroot and loop around back to the same spot.
++targetDbroot) for (int tbd=0; tbd < targetCnt; ++tbd)
{ {
if (targetDbroot == targetDbroots.end())
{
targetDbroot == targetDbroots.begin();
}
if (dbPartVec[*targetDbroot].size() < partCount) if (dbPartVec[*targetDbroot].size() < partCount)
{ {
tdbroot = *targetDbroot; tdbroot = *targetDbroot;
partCount = dbPartVec[*targetDbroot].size(); partCount = dbPartVec[*targetDbroot].size();
nextDbroot = targetDbroot;
++nextDbroot;
} }
++targetDbroot;
} }
if (tdbroot == 0) if (tdbroot == 0)
{ {