diff --git a/Cargo.lock b/Cargo.lock
index 8fb82b7..4639fb2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,10 +2,10 @@
 # It is not intended for manual editing.
 [[package]]
 name = "aho-corasick"
-version = "0.7.9"
+version = "0.7.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "memchr 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -26,12 +26,12 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.26"
+version = "1.0.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "arc-swap"
-version = "0.4.4"
+version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -47,8 +47,8 @@ name = "atty"
 version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hermit-abi 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -88,7 +88,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "chrono"
-version = "0.4.10"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "num-integer 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -99,7 +99,7 @@ dependencies = [
 [[package]]
 name = "clap"
 version = "3.0.0-beta.1"
-source = "git+https://github.com/clap-rs/clap/#20cdc8384f9830bbca7bfcbf4cd2ffdfc96e4eca"
+source = "git+https://github.com/clap-rs/clap/#7a652054dc4f89f3b1831dfe69aad7fba6a99309"
 dependencies = [
  "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -116,13 +116,13 @@ dependencies = [
 [[package]]
 name = "clap_derive"
 version = "3.0.0-beta.1"
-source = "git+https://github.com/clap-rs/clap/#20cdc8384f9830bbca7bfcbf4cd2ffdfc96e4eca"
+source = "git+https://github.com/clap-rs/clap/#7a652054dc4f89f3b1831dfe69aad7fba6a99309"
 dependencies = [
  "heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro-error 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-error 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -153,7 +153,7 @@ dependencies = [
  "crossbeam-utils 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "maybe-uninit 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "memoffset 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memoffset 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "scopeguard 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -202,7 +202,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "futures-core"
-version = "0.3.3"
+version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -215,10 +215,10 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.6"
+version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -234,7 +234,7 @@ name = "iovec"
 version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -258,7 +258,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "libc"
-version = "0.2.66"
+version = "0.2.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -282,7 +282,7 @@ name = "matchers"
 version = "0.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "regex-automata 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-automata 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -292,29 +292,29 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "memchr"
-version = "2.3.0"
+version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "memoffset"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "mini-redis"
 version = "0.1.0"
 dependencies = [
- "anyhow 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anyhow 1.0.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "atoi 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytes 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 3.0.0-beta.1 (git+https://github.com/clap-rs/clap/)",
- "tokio 0.2.11 (git+https://github.com/tokio-rs/tokio)",
+ "tokio 0.2.13 (git+https://github.com/tokio-rs/tokio)",
  "tracing 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "tracing-futures 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "tracing-subscriber 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tracing-subscriber 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -327,7 +327,7 @@ dependencies = [
  "fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "miow 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -352,7 +352,7 @@ version = "0.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -382,7 +382,7 @@ version = "0.2.33"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -408,8 +408,8 @@ name = "num_cpus"
 version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hermit-abi 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -429,7 +429,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -449,9 +449,9 @@ name = "pin-project-internal"
 version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -461,31 +461,31 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "proc-macro-error"
-version = "0.4.8"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro-error-attr 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustversion 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-error-attr 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "proc-macro-error-attr"
-version = "0.4.8"
+version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustversion 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn-mid 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.8"
+version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -493,10 +493,10 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -506,28 +506,27 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "regex"
-version = "1.3.4"
+version = "1.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "aho-corasick 0.7.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "aho-corasick 0.7.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.6.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "regex-automata"
-version = "0.1.8"
+version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "byteorder 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "utf8-ranges 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.6.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.16"
+version = "0.6.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -538,19 +537,9 @@ dependencies = [
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "rustversion"
-version = "1.0.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "ryu"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -573,7 +562,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "serde"
-version = "1.0.104"
+version = "1.0.105"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -582,8 +571,8 @@ version = "1.0.48"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "itoa 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "ryu 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ryu 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -599,8 +588,8 @@ name = "signal-hook-registry"
 version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "arc-swap 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arc-swap 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -627,7 +616,7 @@ version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -639,11 +628,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "1.0.14"
+version = "1.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -652,9 +641,9 @@ name = "syn-mid"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -678,7 +667,7 @@ name = "time"
 version = "0.1.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -708,16 +697,16 @@ dependencies = [
 
 [[package]]
 name = "tokio"
-version = "0.2.11"
-source = "git+https://github.com/tokio-rs/tokio#55b5e1b6adcc3f85a35d16444e496b203648c99d"
+version = "0.2.13"
+source = "git+https://github.com/tokio-rs/tokio#57ba37c97854d32e691ea68006c8d69d58c79b23"
 dependencies = [
  "bytes 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "futures-core 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures-core 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-named-pipes 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-uds 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -725,7 +714,7 @@ dependencies = [
  "pin-project-lite 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "signal-hook-registry 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "tokio-macros 0.2.4 (git+https://github.com/tokio-rs/tokio)",
+ "tokio-macros 0.2.5 (git+https://github.com/tokio-rs/tokio)",
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -779,12 +768,12 @@ dependencies = [
 
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-version = "0.2.4"
-source = "git+https://github.com/tokio-rs/tokio#55b5e1b6adcc3f85a35d16444e496b203648c99d"
+version = "0.2.5"
+source = "git+https://github.com/tokio-rs/tokio#57ba37c97854d32e691ea68006c8d69d58c79b23"
 dependencies = [
- "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -876,7 +865,7 @@ dependencies = [
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  "iovec 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
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@@ -900,8 +889,8 @@ name = "tracing-attributes"
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 dependencies = [
- "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -937,21 +926,21 @@ name = "tracing-serde"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.105 (registry+https://github.com/rust-lang/crates.io-index)",
  "tracing-core 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
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-version = "0.2.2"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
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- "chrono 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
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- "regex 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.104 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
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@@ -976,13 +965,13 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "utf8-ranges"
-version = "1.0.4"
+name = "vec_map"
+version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "vec_map"
-version = "0.8.1"
+name = "version_check"
+version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
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-"checksum tokio 0.2.11 (git+https://github.com/tokio-rs/tokio)" = "<none>"
+"checksum tokio 0.2.13 (git+https://github.com/tokio-rs/tokio)" = "<none>"
 "checksum tokio-codec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "25b2998660ba0e70d18684de5d06b70b70a3a747469af9dea7618cc59e75976b"
 "checksum tokio-current-thread 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "b1de0e32a83f131e002238d7ccde18211c0a5397f60cbfffcb112868c2e0e20e"
 "checksum tokio-executor 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "fb2d1b8f4548dbf5e1f7818512e9c406860678f29c300cdf0ebac72d1a3a1671"
 "checksum tokio-fs 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "297a1206e0ca6302a0eed35b700d292b275256f596e2f3fea7729d5e629b6ff4"
 "checksum tokio-io 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "57fc868aae093479e3131e3d165c93b1c7474109d13c90ec0dda2a1bbfff0674"
-"checksum tokio-macros 0.2.4 (git+https://github.com/tokio-rs/tokio)" = "<none>"
+"checksum tokio-macros 0.2.5 (git+https://github.com/tokio-rs/tokio)" = "<none>"
 "checksum tokio-reactor 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "09bc590ec4ba8ba87652da2068d150dcada2cfa2e07faae270a5e0409aa51351"
 "checksum tokio-sync 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "edfe50152bc8164fcc456dab7891fa9bf8beaf01c5ee7e1dd43a397c3cf87dee"
 "checksum tokio-tcp 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "98df18ed66e3b72e742f185882a9e201892407957e45fbff8da17ae7a7c51f72"
@@ -1127,12 +1115,12 @@ dependencies = [
 "checksum tracing-futures 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "58b0b7fd92dc7b71f29623cc6836dd7200f32161a2313dd78be233a8405694f6"
 "checksum tracing-log 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5e0f8c7178e13481ff6765bd169b33e8d554c5d2bbede5e32c356194be02b9b9"
 "checksum tracing-serde 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b6ccba2f8f16e0ed268fc765d9b7ff22e965e7185d32f8f1ec8294fe17d86e79"
-"checksum tracing-subscriber 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "feffc1a97b3515cfef0780b5c9542f7e75983e591e730f96aa2ecd0503197111"
+"checksum tracing-subscriber 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "dedebcf5813b02261d6bab3a12c6a8ae702580c0405a2e8ec16c3713caf14c20"
 "checksum unicode-segmentation 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e83e153d1053cbb5a118eeff7fd5be06ed99153f00dbcd8ae310c5fb2b22edc0"
 "checksum unicode-width 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "caaa9d531767d1ff2150b9332433f32a24622147e5ebb1f26409d5da67afd479"
 "checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"
-"checksum utf8-ranges 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b4ae116fef2b7fea257ed6440d3cfcff7f190865f170cdad00bb6465bf18ecba"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
+"checksum version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
diff --git a/src/bin/server.rs b/src/bin/server.rs
index 0fdf9cf..58865f3 100644
--- a/src/bin/server.rs
+++ b/src/bin/server.rs
@@ -7,7 +7,7 @@ pub async fn main() -> Result<()> {
     // enable logging
     // see https://docs.rs/tracing for more info
     tracing_subscriber::fmt::try_init().map_err(|e| anyhow!("{:?}", e))?;
-    
+
     let cli = Cli::parse();
     let port = cli.port.unwrap_or(DEFAULT_PORT.to_string());
     server::run(&port).await
diff --git a/src/cmd/get.rs b/src/cmd/get.rs
index 77f9da1..3a36d10 100644
--- a/src/cmd/get.rs
+++ b/src/cmd/get.rs
@@ -1,4 +1,4 @@
-use crate::{Connection, Frame, Kv, Parse, ParseError};
+use crate::{Connection, Frame, Db, Parse, ParseError};
 
 use std::io;
 use tracing::{debug, instrument};
@@ -27,8 +27,8 @@ impl Get {
     }
 
     #[instrument]
-    pub(crate) async fn apply(self, kv: &Kv, dst: &mut Connection) -> io::Result<()> {
-        let response = if let Some(value) = kv.get(&self.key) {
+    pub(crate) async fn apply(self, db: &Db, dst: &mut Connection) -> io::Result<()> {
+        let response = if let Some(value) = db.get(&self.key) {
             Frame::Bulk(value)
         } else {
             Frame::Null
diff --git a/src/cmd/mod.rs b/src/cmd/mod.rs
index 7e5cd97..8bfaf32 100644
--- a/src/cmd/mod.rs
+++ b/src/cmd/mod.rs
@@ -10,7 +10,7 @@ pub use set::Set;
 mod subscribe;
 pub use subscribe::{Subscribe, Unsubscribe};
 
-use crate::{Connection, Frame, Kv, Parse, ParseError, Shutdown};
+use crate::{Connection, Frame, Db, Parse, ParseError, Shutdown};
 
 use std::io;
 
@@ -44,17 +44,17 @@ impl Command {
 
     pub(crate) async fn apply(
         self,
-        kv: &Kv,
+        db: &Db,
         dst: &mut Connection,
         shutdown: &mut Shutdown,
     ) -> io::Result<()> {
         use Command::*;
 
         match self {
-            Get(cmd) => cmd.apply(kv, dst).await,
-            Publish(cmd) => cmd.apply(kv, dst).await,
-            Set(cmd) => cmd.apply(kv, dst).await,
-            Subscribe(cmd) => cmd.apply(kv, dst, shutdown).await,
+            Get(cmd) => cmd.apply(db, dst).await,
+            Publish(cmd) => cmd.apply(db, dst).await,
+            Set(cmd) => cmd.apply(db, dst).await,
+            Subscribe(cmd) => cmd.apply(db, dst, shutdown).await,
             // `Unsubscribe` cannot be applied. It may only be received from the
             // context of a `Subscribe` command.
             Unsubscribe(_) => unimplemented!(),
diff --git a/src/cmd/publish.rs b/src/cmd/publish.rs
index 423af99..4c72377 100644
--- a/src/cmd/publish.rs
+++ b/src/cmd/publish.rs
@@ -1,4 +1,4 @@
-use crate::{Connection, Frame, Kv, Parse, ParseError};
+use crate::{Connection, Frame, Db, Parse, ParseError};
 
 use bytes::Bytes;
 use std::io;
@@ -17,9 +17,9 @@ impl Publish {
         Ok(Publish { channel, message })
     }
 
-    pub(crate) async fn apply(self, kv: &Kv, dst: &mut Connection) -> io::Result<()> {
+    pub(crate) async fn apply(self, db: &Db, dst: &mut Connection) -> io::Result<()> {
         // Set the value
-        let num_subscribers = kv.publish(&self.channel, self.message);
+        let num_subscribers = db.publish(&self.channel, self.message);
 
         let response = Frame::Integer(num_subscribers as u64);
         dst.write_frame(&response).await
diff --git a/src/cmd/set.rs b/src/cmd/set.rs
index e8fcd3e..38e1806 100644
--- a/src/cmd/set.rs
+++ b/src/cmd/set.rs
@@ -1,5 +1,5 @@
 use crate::cmd::{Parse, ParseError};
-use crate::{Connection, Frame, Kv};
+use crate::{Connection, Frame, Db};
 
 use bytes::Bytes;
 use std::io;
@@ -42,9 +42,9 @@ impl Set {
     }
 
     #[instrument]
-    pub(crate) async fn apply(self, kv: &Kv, dst: &mut Connection) -> io::Result<()> {
+    pub(crate) async fn apply(self, db: &Db, dst: &mut Connection) -> io::Result<()> {
         // Set the value
-        kv.set(self.key, self.value, self.expire);
+        db.set(self.key, self.value, self.expire);
 
         let response = Frame::Simple("OK".to_string());
         debug!(?response);
diff --git a/src/cmd/subscribe.rs b/src/cmd/subscribe.rs
index bb711ce..2ef8fad 100644
--- a/src/cmd/subscribe.rs
+++ b/src/cmd/subscribe.rs
@@ -1,5 +1,5 @@
 use crate::cmd::{Parse, ParseError};
-use crate::{Command, Connection, Frame, Kv, Shutdown};
+use crate::{Command, Connection, Frame, Db, Shutdown};
 
 use bytes::Bytes;
 use std::io;
@@ -45,7 +45,7 @@ impl Subscribe {
     /// [here]: https://redis.io/topics/pubsub
     pub(crate) async fn apply(
         mut self,
-        kv: &Kv,
+        db: &Db,
         dst: &mut Connection,
         shutdown: &mut Shutdown,
     ) -> io::Result<()> {
@@ -71,7 +71,7 @@ impl Subscribe {
                 response.push_bulk(Bytes::copy_from_slice(channel.as_bytes()));
 
                 // Subscribe to channel
-                let rx = kv.subscribe(channel.clone());
+                let rx = db.subscribe(channel.clone());
 
                 // Track subscription in this client's subscription set.
                 subscriptions.insert(channel, rx);
diff --git a/src/db.rs b/src/db.rs
new file mode 100644
index 0000000..5404289
--- /dev/null
+++ b/src/db.rs
@@ -0,0 +1,201 @@
+use tokio::sync::{broadcast, Notify};
+use tokio::time::{self, Duration, Instant};
+
+use bytes::Bytes;
+use std::collections::{BTreeMap, HashMap};
+use std::sync::{Arc, Mutex};
+
+#[derive(Debug, Clone)]
+pub(crate) struct Db {
+    shared: Arc<Shared>,
+}
+
+#[derive(Debug)]
+struct Shared {
+    state: Mutex<State>,
+
+    /// Notifies the task handling entry expiration
+    expire_task: Notify,
+}
+
+#[derive(Debug)]
+struct State {
+    /// The key-value data
+    entries: HashMap<String, Entry>,
+
+    /// The pub/sub key-space
+    pub_sub: HashMap<String, broadcast::Sender<Bytes>>,
+
+    /// Tracks key TTLs.
+    expirations: BTreeMap<(Instant, u64), String>,
+
+    /// Identifier to use for the next expiration.
+    next_id: u64,
+}
+
+/// Entry in the key-value store
+#[derive(Debug)]
+struct Entry {
+    /// Uniquely identifies this entry.
+    id: u64,
+
+    /// Stored data
+    data: Bytes,
+
+    /// Instant at which the entry expires and should be removed from the
+    /// database.
+    expires_at: Option<Instant>,
+}
+
+impl Db {
+    pub(crate) fn new() -> Db {
+        let shared = Arc::new(Shared {
+            state: Mutex::new(State {
+                entries: HashMap::new(),
+                pub_sub: HashMap::new(),
+                expirations: BTreeMap::new(),
+                next_id: 0,
+            }),
+            expire_task: Notify::new(),
+        });
+
+        // Start the background task.
+        tokio::spawn(purge_expired_tasks(shared.clone()));
+
+        Db { shared }
+    }
+
+    pub(crate) fn get(&self, key: &str) -> Option<Bytes> {
+        let state = self.shared.state.lock().unwrap();
+        state.entries.get(key).map(|entry| entry.data.clone())
+    }
+
+    pub(crate) fn set(&self, key: String, value: Bytes, expire: Option<Duration>) {
+        let mut state = self.shared.state.lock().unwrap();
+
+        // Get and increment the next insertion ID.
+        let id = state.next_id;
+        state.next_id += 1;
+
+        // By default, no notification is needed
+        let mut notify = false;
+
+        let expires_at = expire.map(|duration| {
+            let when = Instant::now() + duration;
+
+            // Only notify the worker task if the newly inserted expiration is the
+            // **next** key to evict. In this case, the worker needs to be woken up
+            // to update its state.
+            notify = state.next_expiration()
+                .map(|expiration| expiration > when)
+                .unwrap_or(true);
+
+            state.expirations.insert((when, id), key.clone());
+            when
+        });
+
+        // Insert the entry.
+        let prev = state.entries.insert(key, Entry {
+            id,
+            data: value,
+            expires_at,
+        });
+
+        if let Some(prev) = prev {
+            if let Some(when) = prev.expires_at {
+                // clear expiration
+                state.expirations.remove(&(when, prev.id));
+            }
+        }
+
+        drop(state);
+
+        if notify {
+            self.shared.expire_task.notify();
+        }
+    }
+
+    pub(crate) fn subscribe(&self, key: String) -> broadcast::Receiver<Bytes> {
+        use std::collections::hash_map::Entry;
+
+        let mut state = self.shared.state.lock().unwrap();
+
+        match state.pub_sub.entry(key) {
+            Entry::Occupied(e) => e.get().subscribe(),
+            Entry::Vacant(e) => {
+                let (tx, rx) = broadcast::channel(1028);
+                e.insert(tx);
+                rx
+            }
+        }
+    }
+
+    /// Publish a message to the channel. Returns the number of subscribers
+    /// listening on the channel.
+    pub(crate) fn publish(&self, key: &str, value: Bytes) -> usize {
+        let state = self.shared.state.lock().unwrap();
+
+        state
+            .pub_sub
+            .get(key)
+            // On a successful message send on the broadcast channel, the number
+            // of subscribers is returned. An error indicates there are no
+            // receivers, in which case, `0` should be returned.
+            .map(|tx| tx.send(value).unwrap_or(0))
+            // If there is no entry for the channel key, then there are no
+            // subscribers. In this case, return `0`.
+            .unwrap_or(0)
+    }
+}
+
+impl Shared {
+    fn purge_expired_keys(&self) -> Option<Instant> {
+        let mut state = self.state.lock().unwrap();
+
+        // This is needed to make the borrow checker happy. In short, `lock()`
+        // returns a `MutexGuard` and not a `&mut State`. The borrow checker is
+        // not able to see "through" the mutex guard and determine that it is
+        // safe to access both `state.expirations` and `state.entries` mutably,
+        // so we get a "real" mutable reference to `State` outside of the loop.
+        let state = &mut *state;
+
+        // Find all keys scheduled to expire **before** now.
+        let now = Instant::now();
+
+        while let Some((&(when, id), key)) = state.expirations.iter().next() {
+            if when > now {
+                // Done purging, `when` is the instant at which the next key
+                // expires. The worker task will wait until this instant.
+                return Some(when);
+            }
+
+            // The key expired, remove it
+            state.entries.remove(key);
+            state.expirations.remove(&(when, id));
+        }
+
+        None
+    }
+}
+
+impl State {
+    fn next_expiration(&self) -> Option<Instant> {
+        self.expirations.keys().next().map(|expiration| expiration.0)
+    }
+}
+
+async fn purge_expired_tasks(shared: Arc<Shared>) {
+    loop {
+        // Purge all keys that are expired. The function returns the instant at
+        // which the **next** key will expire. The worker should wait until the
+        // instant has passed then purge again.
+        if let Some(when) = shared.purge_expired_keys() {
+            tokio::select! {
+                _ = time::delay_until(when) => {}
+                _ = shared.expire_task.notified() => {}
+            }
+        } else {
+            shared.expire_task.notified().await;
+        }
+    }
+}
diff --git a/src/kv.rs b/src/kv.rs
deleted file mode 100644
index b170248..0000000
--- a/src/kv.rs
+++ /dev/null
@@ -1,65 +0,0 @@
-use bytes::Bytes;
-use std::collections::HashMap;
-use std::sync::{Arc, Mutex};
-use std::time::Duration;
-use tokio::sync::broadcast;
-
-#[derive(Debug, Clone)]
-pub(crate) struct Kv {
-    shared: Arc<Mutex<Shared>>,
-}
-
-#[derive(Debug)]
-struct Shared {
-    // The key-value data
-    data: HashMap<String, Bytes>,
-
-    // The pub/sub key-space
-    pub_sub: HashMap<String, broadcast::Sender<Bytes>>,
-}
-
-impl Kv {
-    pub(crate) fn new() -> Kv {
-        Kv {
-            shared: Arc::new(Mutex::new(Shared {
-                data: HashMap::new(),
-                pub_sub: HashMap::new(),
-            })),
-        }
-    }
-
-    pub(crate) fn get(&self, key: &str) -> Option<Bytes> {
-        let shared = self.shared.lock().unwrap();
-        shared.data.get(key).map(|data| data.clone())
-    }
-
-    pub(crate) fn set(&self, key: String, value: Bytes, _expire: Option<Duration>) {
-        let mut shared = self.shared.lock().unwrap();
-        shared.data.insert(key, value);
-    }
-
-    pub(crate) fn subscribe(&self, key: String) -> broadcast::Receiver<Bytes> {
-        use std::collections::hash_map::Entry;
-
-        let mut shared = self.shared.lock().unwrap();
-
-        match shared.pub_sub.entry(key) {
-            Entry::Occupied(e) => e.get().subscribe(),
-            Entry::Vacant(e) => {
-                let (tx, rx) = broadcast::channel(1028);
-                e.insert(tx);
-                rx
-            }
-        }
-    }
-
-    pub(crate) fn publish(&self, key: &str, value: Bytes) -> usize {
-        let shared = self.shared.lock().unwrap();
-
-        shared
-            .pub_sub
-            .get(key)
-            .map(|tx| tx.send(value).unwrap_or(0))
-            .unwrap_or(0)
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index 8d79814..9e7dc87 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,8 +11,8 @@ use conn::Connection;
 mod frame;
 use frame::Frame;
 
-mod kv;
-use kv::Kv;
+mod db;
+use db::Db;
 
 mod parse;
 use parse::{Parse, ParseError};
diff --git a/src/parse.rs b/src/parse.rs
index 227a38b..5cfb571 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -54,8 +54,12 @@ impl Parse {
     }
 
     pub(crate) fn next_int(&mut self) -> Result<u64, ParseError> {
+        use atoi::atoi;
+
         match self.next()? {
             Frame::Integer(v) => Ok(v),
+            Frame::Simple(data) => atoi::<u64>(data.as_bytes()).ok_or(ParseError::Invalid),
+            Frame::Bulk(data) => atoi::<u64>(&data).ok_or(ParseError::Invalid),
             _ => Err(ParseError::Invalid),
         }
     }
diff --git a/src/server.rs b/src/server.rs
index 6fbd9be..0e2e661 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -1,4 +1,4 @@
-use crate::{Command, Connection, Kv, Shutdown};
+use crate::{Command, Connection, Db, Shutdown};
 
 use anyhow::Result;
 use tokio::io;
@@ -8,7 +8,7 @@ use tokio::sync::broadcast;
 
 struct Server {
     /// Database state
-    kv: Kv,
+    db: Db,
 
     /// TCP listener
     listener: TcpListener,
@@ -20,7 +20,7 @@ struct Server {
 /// Handles a connections
 struct Handler {
     /// Database state
-    kv: Kv,
+    db: Db,
 
     /// The TCP connection decorated with the redis protocol encoder / decoder
     connection: Connection,
@@ -35,7 +35,7 @@ pub async fn run(port: &str) -> Result<()> {
 
     let mut server = Server {
         listener: TcpListener::bind(&format!("127.0.0.1:{}", port)).await?,
-        kv: Kv::new(),
+        db: Db::new(),
         notify_shutdown,
     };
 
@@ -61,7 +61,7 @@ impl Server {
             let (socket, _) = self.listener.accept().await?;
 
             let mut handler = Handler {
-                kv: self.kv.clone(),
+                db: self.db.clone(),
                 connection: Connection::new(socket),
                 shutdown: Shutdown::new(self.notify_shutdown.subscribe()),
             };
@@ -92,7 +92,7 @@ impl Handler {
 
             let cmd = Command::from_frame(frame)?;
 
-            cmd.apply(&self.kv, &mut self.connection, &mut self.shutdown)
+            cmd.apply(&self.db, &mut self.connection, &mut self.shutdown)
                 .await?;
         }