space:truncate() (and sometimes even space:delete()) doesn't work when memtx_memory is reached

[dsamirov]

Tarantool version: 1.10.1-370-ge93dc30

OS version: centos 7

Bug description:

Sometimes when memtx_memory limit is reached space:truncate() doesn't work with error
Failed to allocate 21 bytes in slab allocator for memtx_tuple.

[dkuk]

Same for me Tarantool 1.9.2-7-g3736c3798
Ubuntu 16.10

Also reproduces in Tarantool 1.10.2-66-g2972cfcee, Ubuntu 18.04.1 LTS

Sometimes this bug affects space:delete() operation. It falls with same error. After instance being restarted delete becomes possible.

[no1seman]

Reproducer for truncate:
Tarantool 2.8.3-0-g01023dbc2
Target: Linux-x86_64-RelWithDebInfo

local yaml = require('yaml')

box.cfg({memtx_memory = 32*1024*1024})

local space = box.schema.space.create('test_space', { if_not_exists = true })
space:format({{ name = 'key', type = 'unsigned'}, { name = 'value', type = 'string'}})
space:create_index('primary', { parts = {{ field = 1, type = 'unsigned' }, { field = 2, type = 'string' }}, if_not_exists = true })
space:create_index('secondary', { parts = {{ field = 2, type = 'string' }}, if_not_exists = true })

local count = space:len()

while true do
    count = count + 1
    if not select(1, pcall(function() box.space.test_space:insert({count, 'Key number: '..tostring(count)}) end)) then
        break
    end
    if count % 10000 == 0 then
        print(count)
    end
end

print('"test_space" length: '.. tostring(box.space.test_space:len()))
print('Arena:\n'..yaml.encode(box.slab.info()))

print('Try to truncate space:')
box.space.test_space:truncate()

Log:
Try to truncate space:
2022-03-26 09:58:25.811 [2468] main memtx_engine.c:1320 !> SystemError Failed to allocate 19 bytes in slab allocator for memtx_tuple: Cannot allocate memory

[RunsFor]

Same issue at TEST stand on pretty huge (40gb) instance (and multiple replicasets). Used workaround was pretty time-consuming:

• space:pairs():take(100000):each(function(t) space:delete({t[1], t[2]}) end)
• box.snapshot() -- do this on replicas too
• restart replicasets and wait for it to become available
• space:truncate()