diff --git a/Cargo.lock b/Cargo.lock
index a516320d..975a9c3c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -49,6 +49,12 @@ dependencies = [
  "gimli",
 ]
 
+[[package]]
+name = "adler32"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "567b077b825e468cc974f0020d4082ee6e03132512f207ef1a02fd5d00d1f32d"
+
 [[package]]
 name = "ahash"
 version = "0.3.8"
@@ -152,9 +158,9 @@ checksum = "c17772156ef2829aadc587461c7753af20b7e8db1529bc66855add962a3b35d3"
 
 [[package]]
 name = "async-trait"
-version = "0.1.35"
+version = "0.1.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89cb5d814ab2a47fd66d3266e9efccb53ca4c740b7451043b8ffcf9a6208f3f8"
+checksum = "a265e3abeffdce30b2e26b7a11b222fe37c6067404001b434101457d0385eb92"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -195,13 +201,14 @@ checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
 
 [[package]]
 name = "backtrace"
-version = "0.3.48"
+version = "0.3.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0df2f85c8a2abbe3b7d7e748052fdd9b76a0458fdeb16ad4223f5eca78c7c130"
+checksum = "05100821de9e028f12ae3d189176b41ee198341eb8f369956407fea2f5cc666c"
 dependencies = [
  "addr2line",
  "cfg-if",
  "libc",
+ "miniz_oxide",
  "object",
  "rustc-demangle",
 ]
@@ -229,9 +236,9 @@ checksum = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 
 [[package]]
 name = "base64"
-version = "0.12.1"
+version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53d1ccbaf7d9ec9537465a97bf19edc1a4e158ecb49fc16178202238c569cc42"
+checksum = "e223af0dc48c96d4f8342ec01a4974f139df863896b316681efd36742f22cc67"
 
 [[package]]
 name = "bigdecimal"
@@ -239,7 +246,7 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1374191e2dd25f9ae02e3aa95041ed5d747fc77b3c102b49fe2dd9a8117a6244"
 dependencies = [
- "num-bigint",
+ "num-bigint 0.2.6",
  "num-integer",
  "num-traits",
 ]
@@ -294,6 +301,19 @@ dependencies = [
  "byte-tools",
 ]
 
+[[package]]
+name = "blocking"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d17efb70ce4421e351d61aafd90c16a20fb5bfe339fcdc32a86816280e62ce0"
+dependencies = [
+ "futures-channel",
+ "futures-util",
+ "once_cell",
+ "parking",
+ "waker-fn",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.4.0"
@@ -325,9 +345,18 @@ dependencies = [
 
 [[package]]
 name = "bytes"
-version = "0.5.4"
+version = "0.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "130aac562c0dd69c56b3b1cc8ffd2e17be31d0b6c25b61c96b76231aa23e39e1"
+checksum = "118cf036fbb97d0816e3c34b2d7a1e8cfc60f68fcf63d550ddbe9bd5f59c213b"
+dependencies = [
+ "loom",
+]
+
+[[package]]
+name = "cache-padded"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24508e28c677875c380c20f4d28124fab6f8ed4ef929a1397d7b1a31e92f1005"
 
 [[package]]
 name = "cargo_metadata"
@@ -401,6 +430,15 @@ dependencies = [
  "bitflags",
 ]
 
+[[package]]
+name = "concurrent-queue"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f83c06aff61f2d899eb87c379df3cbf7876f14471dcab474e0b6dc90ab96c080"
+dependencies = [
+ "cache-padded",
+]
+
 [[package]]
 name = "console"
 version = "0.10.3"
@@ -542,9 +580,9 @@ checksum = "72aa14c04dfae8dd7d8a2b1cb7ca2152618cd01336dbfe704b8dcbf8d41dbd69"
 
 [[package]]
 name = "derive_more"
-version = "0.99.7"
+version = "0.99.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2127768764f1556535c01b5326ef94bd60ff08dcfbdc544d53e69ed155610f5d"
+checksum = "bc655351f820d774679da6cdc23355a93de496867d8203496675162e17b1d671"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -642,6 +680,12 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
 
+[[package]]
+name = "fastrand"
+version = "1.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a64b0126b293b050395b37b10489951590ed024c03d7df4f249d219c8ded7cbf"
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -802,6 +846,19 @@ dependencies = [
  "tokio-io",
 ]
 
+[[package]]
+name = "generator"
+version = "0.6.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "add72f17bb81521258fcc8a7a3245b1e184e916bfbe34f0ea89558f440df5c68"
+dependencies = [
+ "cc",
+ "libc",
+ "log",
+ "rustc_version",
+ "winapi 0.3.8",
+]
+
 [[package]]
 name = "generic-array"
 version = "0.12.3"
@@ -877,9 +934,9 @@ dependencies = [
 
 [[package]]
 name = "hashbrown"
-version = "0.7.2"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "96282e96bfcd3da0d3aa9938bedf1e50df3269b6db08b4876d2da0bb1a0841cf"
+checksum = "ab9b7860757ce258c89fd48d28b68c41713e597a7b09e793f6c6a6e2ea37c827"
 dependencies = [
  "ahash",
  "autocfg 1.0.0",
@@ -896,9 +953,9 @@ dependencies = [
 
 [[package]]
 name = "hermit-abi"
-version = "0.1.13"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91780f809e750b0a89f5544be56617ff6b1227ee485bcb06ebe10cdf89bd3b71"
+checksum = "b9586eedd4ce6b3c498bc3b4dd92fc9f11166aa908a914071953768066c67909"
 dependencies = [
  "libc",
 ]
@@ -1069,9 +1126,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.5"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
+checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
 [[package]]
 name = "js-sys"
@@ -1166,6 +1223,17 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "loom"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ecc775857611e1df29abba5c41355cdf540e7e9d4acfdf0f355eefee82330b7"
+dependencies = [
+ "cfg-if",
+ "generator",
+ "scoped-tls 0.1.2",
+]
+
 [[package]]
 name = "maplit"
 version = "1.0.2"
@@ -1216,6 +1284,15 @@ version = "0.3.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2a60c7ce501c71e03a9c9c0d35b861413ae925bd979cc7a4e30d060069aaac8d"
 
+[[package]]
+name = "miniz_oxide"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "791daaae1ed6889560f8c4359194f56648355540573244a5448a83ba1ecc7435"
+dependencies = [
+ "adler32",
+]
+
 [[package]]
 name = "mio"
 version = "0.6.22"
@@ -1320,6 +1397,17 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "num-bigint"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b7f3fc75e3697059fb1bc465e3d8cca6cf92f56854f201158b3f9c77d5a3cfa0"
+dependencies = [
+ "autocfg 1.0.0",
+ "num-integer",
+ "num-traits",
+]
+
 [[package]]
 name = "num-bigint-dig"
 version = "0.6.0"
@@ -1381,9 +1469,9 @@ dependencies = [
 
 [[package]]
 name = "object"
-version = "0.19.0"
+version = "0.20.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9cbca9424c482ee628fa549d9c812e2cd22f1180b9222c9200fdfa6eb31aecb2"
+checksum = "1ab52be62400ca80aa00285d25253d7f7c437b7375c4de678f5405d3afe82ca5"
 
 [[package]]
 name = "once_cell"
@@ -1430,6 +1518,12 @@ dependencies = [
  "vcpkg",
 ]
 
+[[package]]
+name = "parking"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a7fad362df89617628a7508b3e9d588ade1b0ac31aa25de168193ad999c2dd4"
+
 [[package]]
 name = "parking_lot"
 version = "0.9.0"
@@ -1535,7 +1629,7 @@ version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "59698ea79df9bf77104aefd39cc3ec990cb9693fb59c3b0a70ddf2646fdffb4b"
 dependencies = [
- "base64 0.12.1",
+ "base64 0.12.2",
  "once_cell",
  "regex",
 ]
@@ -1598,18 +1692,18 @@ dependencies = [
 
 [[package]]
 name = "pin-project"
-version = "0.4.21"
+version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b044170ce52ac41b78bdf855a045f6fe6ba72c293a33a2e3f654642127680563"
+checksum = "12e3a6cdbfe94a5e4572812a0201f8c0ed98c1c452c7b8563ce2276988ef9c17"
 dependencies = [
  "pin-project-internal",
 ]
 
 [[package]]
 name = "pin-project-internal"
-version = "0.4.21"
+version = "0.4.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "babd76ce3c0d7c677fd01a3c3f9be24fa760adb73fd6db48f151662c1ec7eaba"
+checksum = "6a0ffd45cf79d88737d7cc85bfd5d2894bee1139b356e616fe85dc389c61aaf7"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1686,9 +1780,9 @@ checksum = "7e0456befd48169b9f13ef0f0ad46d492cf9d2dbb918bcf38e01eed4ce3ec5e4"
 
 [[package]]
 name = "proc-macro-nested"
-version = "0.1.5"
+version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0afe1bd463b9e9ed51d0e0f0b50b6b146aec855c56fd182bb242388710a9b6de"
+checksum = "eba180dafb9038b050a4c280019bbedf9f2467b61e5d892dcad585bb57aadc5a"
 
 [[package]]
 name = "proc-macro2"
@@ -1884,10 +1978,16 @@ dependencies = [
 ]
 
 [[package]]
-name = "scoped-tls-hkt"
+name = "scoped-tls"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c2e9d7eaddb227e8fbaaa71136ae0e1e913ca159b86c7da82f3e8f0044ad3a63"
+checksum = "332ffa32bf586782a3efaeb58f127980944bbc8c4d6913a86107ac2a5ab24b28"
+
+[[package]]
+name = "scoped-tls"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea6a9290e3c9cf0f18145ef7ffa62d68ee0bf5fcd651017e586dc7fd5da448c2"
 
 [[package]]
 name = "scopeguard"
@@ -1942,18 +2042,18 @@ checksum = "f638d531eccd6e23b980caf34876660d38e265409d8e99b397ab71eb3612fad0"
 
 [[package]]
 name = "serde"
-version = "1.0.111"
+version = "1.0.112"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9124df5b40cbd380080b2cc6ab894c040a3070d995f5c9dc77e18c34a8ae37d"
+checksum = "736aac72d1eafe8e5962d1d1c3d99b0df526015ba40915cb3c49d042e92ec243"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.111"
+version = "1.0.112"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f2c3ac8e6ca1e9c80b8be1023940162bf81ae3cffbb1809474152f2ce1eb250"
+checksum = "bf0343ce212ac0d3d6afd9391ac8e9c9efe06b533c8d33f660f6390cc4093f57"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2043,7 +2143,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b25ecba7165254f0c97d6c22a64b1122a03634b18d20a34daf21e18f892e618"
 dependencies = [
  "chrono",
- "num-bigint",
+ "num-bigint 0.2.6",
  "num-traits",
 ]
 
@@ -2076,20 +2176,20 @@ checksum = "c7cb5678e1615754284ec264d9bb5b4c27d2018577fd90ac0ceb578591ed5ee4"
 
 [[package]]
 name = "smol"
-version = "0.1.11"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "845f5e7db6b614a8f4f59e565c3035f0fab2f71c9537ff0119eddb60d866cae3"
+checksum = "2f50d21240d7045d848746d6244762b8cb96449b586b4200519719784859ef50"
 dependencies = [
  "async-task",
- "crossbeam-deque",
- "crossbeam-queue",
- "crossbeam-utils 0.7.2",
+ "blocking",
+ "concurrent-queue",
+ "fastrand",
  "futures-io",
  "futures-util",
  "libc",
  "once_cell",
  "piper",
- "scoped-tls-hkt",
+ "scoped-tls 1.0.0",
  "slab",
  "socket2",
  "wepoll-binding",
@@ -2171,11 +2271,11 @@ name = "sqlx-core"
 version = "0.4.0-pre"
 dependencies = [
  "atoi",
- "base64 0.12.1",
+ "base64 0.12.2",
  "bigdecimal",
  "bitflags",
  "byteorder",
- "bytes 0.5.4",
+ "bytes 0.5.5",
  "chrono",
  "crossbeam-channel",
  "crossbeam-queue",
@@ -2197,7 +2297,7 @@ dependencies = [
  "log",
  "md-5",
  "memchr",
- "num-bigint",
+ "num-bigint 0.3.0",
  "once_cell",
  "parking_lot 0.10.2",
  "percent-encoding 2.1.0",
@@ -2423,9 +2523,9 @@ checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 
 [[package]]
 name = "structopt"
-version = "0.3.14"
+version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "863246aaf5ddd0d6928dfeb1a9ca65f505599e4e1b399935ef7e75107516b4ef"
+checksum = "de2f5e239ee807089b62adce73e48c625e0ed80df02c7ab3f068f5db5281065c"
 dependencies = [
  "clap",
  "lazy_static",
@@ -2434,9 +2534,9 @@ dependencies = [
 
 [[package]]
 name = "structopt-derive"
-version = "0.4.7"
+version = "0.4.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d239ca4b13aee7a2142e6795cbd69e457665ff8037aed33b3effdc430d2f927a"
+checksum = "510413f9de616762a4fbeab62509bf15c729603b72d7cd71280fbca431b1c118"
 dependencies = [
  "heck",
  "proc-macro-error",
@@ -2538,18 +2638,18 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "1.0.19"
+version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b13f926965ad00595dd129fa12823b04bbf866e9085ab0a5f2b05b850fbfc344"
+checksum = "7dfdd070ccd8ccb78f4ad66bf1982dc37f620ef696c6b5028fe2ed83dd3d0d08"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.19"
+version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "893582086c2f98cde18f906265a65b5030a074b1046c674ae898be6519a7f479"
+checksum = "bd80fc12f73063ac132ac92aceea36734f04a1d93c1240c6944e23a3b8841793"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2643,6 +2743,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tinyvec"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53953d2d3a5ad81d9f844a32f14ebb121f50b650cd59d0ee2a07cf13c617efed"
+
 [[package]]
 name = "tokio"
 version = "0.1.22"
@@ -2667,7 +2773,7 @@ version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d099fa27b9702bed751524694adbe393e18b36b204da91eb1cbbbbb4a5ee2d58"
 dependencies = [
- "bytes 0.5.4",
+ "bytes 0.5.5",
  "fnv",
  "futures-core",
  "iovec",
@@ -2837,9 +2943,9 @@ checksum = "e604eb7b43c06650e854be16a2a03155743d3752dd1c943f6829e26b7a36e382"
 
 [[package]]
 name = "trybuild"
-version = "1.0.29"
+version = "1.0.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70876fbb7e0d79e3e9bb1ecdffb94fde1963485b3cb4b51a4173907490f7afda"
+checksum = "bbe777c4e2060f44d83892be1189f96200be8ed3d99569d5c2d5ee26e62c0ea9"
 dependencies = [
  "glob",
  "lazy_static",
@@ -2866,11 +2972,11 @@ dependencies = [
 
 [[package]]
 name = "unicode-normalization"
-version = "0.1.12"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5479532badd04e128284890390c1e876ef7a993d0570b3597ae43dfa1d59afa4"
+checksum = "6fb19cf769fa8c6a80a162df694621ebeb4dafb606470b2b2fce0be40a98a977"
 dependencies = [
- "smallvec 1.4.0",
+ "tinyvec",
 ]
 
 [[package]]
@@ -2943,6 +3049,12 @@ version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 
+[[package]]
+name = "waker-fn"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9571542c2ce85ce642e6b58b3364da2fb53526360dfb7c211add4f5c23105ff7"
+
 [[package]]
 name = "want"
 version = "0.2.0"
diff --git a/sqlx-core/Cargo.toml b/sqlx-core/Cargo.toml
index ff12a0d3..7cf51853 100644
--- a/sqlx-core/Cargo.toml
+++ b/sqlx-core/Cargo.toml
@@ -54,7 +54,7 @@ futures-channel = { version = "0.3.5", default-features = false, features = [ "s
 futures-core = { version = "0.3.5", default-features = false }
 futures-util = { version = "0.3.5", features = [ "sink" ] }
 generic-array = { version = "0.14.2", default-features = false, optional = true }
-hashbrown = "0.7.2"
+hashbrown = "0.8.0"
 hex = "0.4.2"
 hmac = { version = "0.8.0", default-features = false, optional = true }
 itoa = "0.4.5"
@@ -64,7 +64,7 @@ libsqlite3-sys = { version = "0.18.0", optional = true, default-features = false
 log = { version = "0.4.8", default-features = false }
 md-5 = { version = "0.9.0", default-features = false, optional = true }
 memchr = { version = "2.3.3", default-features = false }
-num-bigint = { version = "0.2.6", default-features = false, optional = true, features = [ "std" ] }
+num-bigint = { version = "0.3.0", default-features = false, optional = true, features = [ "std" ] }
 once_cell = "1.4.0"
 percent-encoding = "2.1.0"
 parking_lot = "0.10.2"