Sergey Petrunya 763af1a8a3 MDEV-4240: mariadb 5.3.12 using more memory than MySQL 5.1 for an inefficient query ...

- Let index_merge allocate table handlers on quick select's MEM_ROOT,
  not on statement's MEM_ROOT. 
  This is crucial for big "range checked for each record" queries, where 
  index_merge can be created and deleted many times during query exection. 
  We should not make O(#rows) allocations on statement's MEM_ROOT.

2013-04-01 18:03:14 +04:00

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