* Vladimir Davydov <vdavydov.dev@xxxxxxxxx> [18/07/27 16:55]:
When executing a REPLACE or DELETE request for a vinyl space, we need to
delete the old tuple from secondary indexes if any, e.g. if there's a
space with the primary index over field 1 and a secondary index over
field 2 and there's REPLACE{1, 10} in the space, then REPLACE{1, 20} has
to generate DELETE{10, 1} in order to overwrite REPLACE{10, 1} before
inserting REPLACE{20, 1} into the secondary index. Currently, we
generate DELETEs for secondary indexes immediately on request execution,
which makes REPLACE/DELETE operations disk-bound in case the space has
secondary indexes, because in order to delete the old tuple we have to
look it up in the primary index first.
