Merge branch 'check-clean-expired' into 'master'

fix test case

See merge request paas/zanredisdb!29

Merge branch 'check-clean-expired' into 'master'

adjust log

See merge request paas/zanredisdb!22

Merge branch 'check-clean-expired' into 'master'

fix: avoid wait future proposal response twice on chan

See merge request !18

Merge branch 'check-clean-expired' into 'master'

fix scan namespaces and use magic code to handle the deleted namespace

See merge request !15

Merge branch 'optimize-storage' into 'master'

add memory engine

See merge request !10

Merge pull request #70 from youzan/upgrade-rocksdb-6.4.6

update the rocksdb to v6.4.6

Merge pull request #66 from youzan/absolute8511-patch-action

Create go.yml

bump version

bump version

Merge pull request #60 from youzan/optimize-latency

Optimize cluster syncer and write latency