Tuple missing in secondary index if DML races with DDL

[locker]

Version: 2.9.0-166-g71a67913af75

The following script

fiber = require('fiber')
yaml = require('yaml')

box.cfg{memtx_use_mvcc_engine = true}

s = box.schema.space.create('test')
s:create_index('pk')

ch1 = fiber.channel()
ch2 = fiber.channel()

fiber.create(function()
    box.begin()
    s:insert{1, 1}
    ch1:get()
    box.commit()
    ch2:put(true)
end)

s:create_index('sk', {parts = {{2, 'unsigned'}}})

ch1:put(true)
ch2:get()

print('Primary:')
print(yaml.encode(s.index.pk:select()))

print('Secondary:')
print(yaml.encode(s.index.sk:select()))

os.exit(0)

prints the following

Primary:
---
- [1, 1]
...

Secondary:
--- []
...

That is, a tuple present in the space is not visible via the secondary index.

Vinyl fixes this problem by aborting all pending transactions before proceeding to building an index.

The same bug probably affects space format change. Please check.