From a0c4cd7dec7db574e3a89b496cecdbddcdc5e8df Mon Sep 17 00:00:00 2001
From: slinkydeveloper <me@slinkydeveloper.com>
Date: Tue, 10 Nov 2026 17:25:17 +0100
Subject: [PATCH 1/2] Sessions: large databases' checkpoints in an object store
 (RESTATE_SQL_OBJECT_STORE)

Upgrade restate-sdk-shared-core to 8.5.0, with its object store backends.
Set RESTATE_SQL_OBJECT_STORE to `s3://bucket/path`, `gs://bucket/path`,
`az://container/path` or `file:///a/directory`, and a database whose packs
in Restate pass 4 MiB moves them to the object store in one upload.
Credentials come from the provider's variables (`AWS_*`, `GOOGLE_*`,
`AZURE_*`); MinIO or R2 is `s3://` with `AWS_ENDPOINT`. Unset, every pack
stays in Restate, as before.

The store is shared-core's `state::ObjectStoreL1`, made once per process;
each namespace gets its own directory. Its requests are reqwest's, which
need a tokio runtime, and a session's calls are polled on the asyncio
loop's thread: the store's futures alone are polled inside
pyo3-async-runtimes' runtime (`InRuntime`). Without it, the first request
panics with "there is no reactor running".

Crypto: `aws_lc_rs` instead of `rust_crypto`. The object stores' backends
are aws-lc; with it, the tunnel's TLS and request identity use aws-lc too,
and ring is no longer built.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Cargo.lock                     | 809 ++++++++++++++++++---------------
 Cargo.toml                     |  12 +-
 src/sessions.rs                |  72 ++-
 tests/sessions_object_store.py | 126 +++++
 4 files changed, 659 insertions(+), 360 deletions(-)
 create mode 100644 tests/sessions_object_store.py

diff --git a/Cargo.lock b/Cargo.lock
index dfad8881..cb9f9040 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -158,10 +158,28 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f2032f911046de80f0a198e0901378627c33f59ea0ac00e363d481118bd70a53"
 
 [[package]]
-name = "base16ct"
-version = "0.2.0"
+name = "aws-lc-rs"
+version = "1.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "048006790404103c488e6c5616b3e7e702a71292aadda08e8f7698a9e0d2eb53"
+dependencies = [
+ "aws-lc-sys",
+ "untrusted 0.7.1",
+ "zeroize",
+]
+
+[[package]]
+name = "aws-lc-sys"
+version = "0.47.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c7f02d4ea65f2c1853089ffd8d2787bdbc63de2f0d29dedbcf8ccdfa0ccd4cf"
+checksum = "8bfbe32ac36b3c428696ce315464181bc4029d689fd58e3f2a4e58c252242f52"
+dependencies = [
+ "cc",
+ "cmake",
+ "dunce",
+ "fs_extra",
+ "pkg-config",
+]
 
 [[package]]
 name = "base64"
@@ -170,10 +188,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72b3254f16251a8381aa12e40e3c4d2f0199f8c6508fbecb9d91f575e0fbb8c6"
 
 [[package]]
-name = "base64ct"
-version = "1.8.3"
+name = "base64"
+version = "0.23.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2af50177e190e07a26ab74f8b1efbfe2ef87da2116221318cb1c2e82baf7de06"
+checksum = "ac07cdecf99051d9a5238b80f35af32cdeba5b336e55d957b318b50137e18da5"
 
 [[package]]
 name = "bigdecimal"
@@ -206,15 +224,6 @@ dependencies = [
  "wyz",
 ]
 
-[[package]]
-name = "block-buffer"
-version = "0.10.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
-dependencies = [
- "generic-array",
-]
-
 [[package]]
 name = "block-buffer"
 version = "0.12.1"
@@ -340,6 +349,7 @@ dependencies = [
  "iana-time-zone",
  "js-sys",
  "num-traits",
+ "serde",
  "wasm-bindgen",
  "windows-link",
 ]
@@ -354,6 +364,15 @@ dependencies = [
  "inout",
 ]
 
+[[package]]
+name = "cmake"
+version = "0.1.58"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0f78a02292a74a88ac736019ab962ece0bc380e3f977bf72e376c5d78ff0678"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "cmsketch"
 version = "0.2.4"
@@ -379,12 +398,6 @@ dependencies = [
  "crossbeam-utils",
 ]
 
-[[package]]
-name = "const-oid"
-version = "0.9.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c2459377285ad874054d797f3ccebf984978aa39129f6eafde5cdc8315b612f8"
-
 [[package]]
 name = "const-oid"
 version = "0.10.2"
@@ -446,6 +459,16 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "crc-fast"
+version = "1.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e75b2483e97a5a7da73ac68a05b629f9c53cff58d8ed1c77866079e18b00dba5"
+dependencies = [
+ "digest 0.10.7",
+ "spin",
+]
+
 [[package]]
 name = "crc32c"
 version = "0.6.9"
@@ -485,18 +508,6 @@ version = "0.8.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a31eee39dddec8330830986fcd7625edb5a24ec90ea038215273bbc3adb08ac6"
 
-[[package]]
-name = "crypto-bigint"
-version = "0.5.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0dc92fb57ca44df6db8059111ab3af99a63d5d0f8375d9972e319a379c6bab76"
-dependencies = [
- "generic-array",
- "rand_core 0.6.4",
- "subtle",
- "zeroize",
-]
-
 [[package]]
 name = "crypto-common"
 version = "0.1.7"
@@ -526,60 +537,19 @@ dependencies = [
  "cipher",
 ]
 
-[[package]]
-name = "curve25519-dalek"
-version = "4.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97fb8b7c4503de7d6ae7b42ab72a5a59857b4c937ec27a3d4539dba95b5ab2be"
-dependencies = [
- "cfg-if",
- "cpufeatures 0.2.17",
- "curve25519-dalek-derive",
- "digest 0.10.7",
- "fiat-crypto",
- "rustc_version",
- "subtle",
- "zeroize",
-]
-
-[[package]]
-name = "curve25519-dalek-derive"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f46882e17999c6cc590af592290432be3bce0428cb0d5f8b6715e4dc7b383eb3"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn 2.0.119",
-]
-
 [[package]]
 name = "data-encoding"
 version = "2.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4583a4551df46e2792f82ceeac45e850d2e2d5debba0b91f102385cda5b11f06"
 
-[[package]]
-name = "der"
-version = "0.7.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e7c1832837b905bbfb5101e07cc24c8deddf52f93225eee6ead5f4d63d53ddcb"
-dependencies = [
- "const-oid 0.9.6",
- "pem-rfc7468",
- "zeroize",
-]
-
 [[package]]
 name = "digest"
 version = "0.10.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
 dependencies = [
- "block-buffer 0.10.4",
- "const-oid 0.9.6",
  "crypto-common 0.1.7",
- "subtle",
 ]
 
 [[package]]
@@ -588,8 +558,8 @@ version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f1dd6dbb5841937940781866fa1281a1ff7bd3bf827091440879f9994983d5c2"
 dependencies = [
- "block-buffer 0.12.1",
- "const-oid 0.10.2",
+ "block-buffer",
+ "const-oid",
  "crypto-common 0.2.2",
 ]
 
@@ -605,42 +575,10 @@ dependencies = [
 ]
 
 [[package]]
-name = "ecdsa"
-version = "0.16.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee27f32b5c5292967d2d4a9d7f1e0b0aed2c15daded5a60300e4abb9d8020bca"
-dependencies = [
- "der",
- "digest 0.10.7",
- "elliptic-curve",
- "rfc6979",
- "signature",
- "spki",
-]
-
-[[package]]
-name = "ed25519"
-version = "2.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "115531babc129696a58c64a4fef0a8bf9e9698629fb97e9e40767d235cfbcd53"
-dependencies = [
- "pkcs8",
- "signature",
-]
-
-[[package]]
-name = "ed25519-dalek"
-version = "2.2.0"
+name = "dunce"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70e796c081cee67dc755e1a36a0a172b897fab85fc3f6bc48307991f64e4eca9"
-dependencies = [
- "curve25519-dalek",
- "ed25519",
- "serde",
- "sha2 0.10.9",
- "subtle",
- "zeroize",
-]
+checksum = "92773504d58c093f6de2459af4af33faa518c13451eb8f2b5698ed3d36e7c813"
 
 [[package]]
 name = "either"
@@ -648,27 +586,6 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0e9c71c2167ca323c882b99918929403426e2373ea17242ff5653e0d5e1058be"
 
-[[package]]
-name = "elliptic-curve"
-version = "0.13.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5e6043086bf7973472e0c7dff2142ea0b680d30e18d9cc40f267efbf222bd47"
-dependencies = [
- "base16ct",
- "crypto-bigint",
- "digest 0.10.7",
- "ff",
- "generic-array",
- "group",
- "hkdf",
- "pem-rfc7468",
- "pkcs8",
- "rand_core 0.6.4",
- "sec1",
- "subtle",
- "zeroize",
-]
-
 [[package]]
 name = "equivalent"
 version = "1.0.3"
@@ -718,22 +635,6 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "da7c62ceae207dd37ea5b845da6a0696c799f85e97da1ab5b7910be3c1c80223"
 
-[[package]]
-name = "ff"
-version = "0.13.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c0b50bfb653653f9ca9095b427bed08ab8d75a137839d9ad64eb11810d5b6393"
-dependencies = [
- "rand_core 0.6.4",
- "subtle",
-]
-
-[[package]]
-name = "fiat-crypto"
-version = "0.2.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28dea519a9695b9977216879a3ebfddf92f1c08c05d984f8996aecd6ecdc811d"
-
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.15"
@@ -882,6 +783,12 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "fs_extra"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42703706b716c37f96a77aea830392ad231f44c9e9a67872fa5548707e11b11c"
+
 [[package]]
 name = "funty"
 version = "2.0.0"
@@ -999,7 +906,6 @@ checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
 dependencies = [
  "typenum",
  "version_check",
- "zeroize",
 ]
 
 [[package]]
@@ -1053,17 +959,6 @@ dependencies = [
  "polyval",
 ]
 
-[[package]]
-name = "group"
-version = "0.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0f9ef7462f7c099f518d754361858f86d8a07af53ba9af0fe635bbccb151a63"
-dependencies = [
- "ff",
- "rand_core 0.6.4",
- "subtle",
-]
-
 [[package]]
 name = "h2"
 version = "0.4.20"
@@ -1188,24 +1083,6 @@ dependencies = [
  "tracing",
 ]
 
-[[package]]
-name = "hkdf"
-version = "0.12.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b5f8eb2ad728638ea2c7d47a21db23b7b58a72ed6a38256b8a1849f15fbbdf7"
-dependencies = [
- "hmac",
-]
-
-[[package]]
-name = "hmac"
-version = "0.12.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c49c37c09c17a53d937dfbb742eb3a961d65a994e6bcdcf37e7399d0cc8ab5e"
-dependencies = [
- "digest 0.10.7",
-]
-
 [[package]]
 name = "hostname"
 version = "0.4.2"
@@ -1250,12 +1127,24 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "httparse"
+version = "1.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6dbf3de79e51f3d586ab4cb9d5c3e2c14aa28ed23d180cf89b4df0454a69cc87"
+
 [[package]]
 name = "httpdate"
 version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
 
+[[package]]
+name = "humantime"
+version = "2.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "15cdd26707701c53297e2fa6afb323d55fbc1d0810c3aec078ae3ef0424c3c15"
+
 [[package]]
 name = "hybrid-array"
 version = "0.4.15"
@@ -1278,10 +1167,28 @@ dependencies = [
  "h2",
  "http",
  "http-body",
+ "httparse",
  "httpdate",
+ "itoa",
  "pin-project-lite",
  "smallvec",
  "tokio",
+ "want",
+]
+
+[[package]]
+name = "hyper-rustls"
+version = "0.27.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dfa8e654703247911e29c23fbeaa261834bd9bb74efba2f9acddc37bfb127f53"
+dependencies = [
+ "http",
+ "hyper",
+ "hyper-util",
+ "rustls",
+ "tokio",
+ "tokio-rustls",
+ "tower-service",
 ]
 
 [[package]]
@@ -1290,12 +1197,22 @@ version = "0.1.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ddc03d96684f9226b8a787cdb71488417b53ab5ea8fdb1dac946cb9431cc8bff"
 dependencies = [
+ "base64 0.23.1",
  "bytes",
+ "futures-channel",
+ "futures-util",
  "http",
  "http-body",
+ "httparse",
  "hyper",
+ "ipnet",
+ "libc",
+ "percent-encoding",
  "pin-project-lite",
+ "socket2",
  "tokio",
+ "tower-service",
+ "tracing",
 ]
 
 [[package]]
@@ -1659,18 +1576,12 @@ version = "10.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eba32bfb4ffdeaca3e34431072faf01745c9b26d25504aa7a6cf5684334fc4fc"
 dependencies = [
- "base64",
- "ed25519-dalek",
+ "aws-lc-rs",
+ "base64 0.22.1",
  "getrandom 0.2.17",
- "hmac",
  "js-sys",
- "p256",
- "p384",
- "rand 0.8.8",
- "rsa",
  "serde",
  "serde_json",
- "sha2 0.10.9",
  "signature",
  "zeroize",
 ]
@@ -1680,9 +1591,6 @@ name = "lazy_static"
 version = "1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "20870f649af7073d53e38067b2a84312175d56ea15217e1b15bc83506ec50afb"
-dependencies = [
- "spin",
-]
 
 [[package]]
 name = "libc"
@@ -1766,6 +1674,12 @@ dependencies = [
  "tracing-subscriber",
 ]
 
+[[package]]
+name = "lru-slab"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4050469837a6ff301cd14c1f8f24f88549e6d548f24f64e2148eb0f72cebc51f"
+
 [[package]]
 name = "lz4"
 version = "1.28.1"
@@ -1794,6 +1708,16 @@ dependencies = [
  "regex-automata",
 ]
 
+[[package]]
+name = "md-5"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69b6441f590336821bb897fb28fc622898ccceb1d6cea3fde5ea86b090c4de98"
+dependencies = [
+ "cfg-if",
+ "digest 0.11.3",
+]
+
 [[package]]
 name = "mea"
 version = "0.6.7"
@@ -1885,6 +1809,18 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "27b02d87554356db9e9a873add8782d4ea6e3e58ea071a9adb9a2e8ddb884a8b"
 
+[[package]]
+name = "nix"
+version = "0.31.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf20d2fde8ff38632c426f1165ed7436270b44f199fc55284c38276f9db47c3d"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+]
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.50.3"
@@ -1904,22 +1840,6 @@ dependencies = [
  "num-traits",
 ]
 
-[[package]]
-name = "num-bigint-dig"
-version = "0.8.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e661dda6640fad38e827a6d4a310ff4763082116fe217f279885c97f511bb0b7"
-dependencies = [
- "lazy_static",
- "libm",
- "num-integer",
- "num-iter",
- "num-traits",
- "rand 0.8.8",
- "smallvec",
- "zeroize",
-]
-
 [[package]]
 name = "num-integer"
 version = "0.1.47"
@@ -1929,16 +1849,6 @@ dependencies = [
  "num-traits",
 ]
 
-[[package]]
-name = "num-iter"
-version = "0.1.46"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c92800bd69a1eac91786bcfe9da64a897eb72911b8dc3095decbd07429e8048b"
-dependencies = [
- "num-integer",
- "num-traits",
-]
-
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -1946,7 +1856,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
 dependencies = [
  "autocfg",
- "libm",
 ]
 
 [[package]]
@@ -1959,6 +1868,49 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "object_store"
+version = "0.14.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1796bc93603f78c5760a69f2d58badc9618d22adade0a95385bb2adbae4eb94"
+dependencies = [
+ "async-trait",
+ "aws-lc-rs",
+ "base64 0.23.1",
+ "bytes",
+ "chrono",
+ "crc-fast",
+ "form_urlencoded",
+ "futures-channel",
+ "futures-core",
+ "futures-util",
+ "http",
+ "http-body-util",
+ "httparse",
+ "humantime",
+ "hyper",
+ "itertools 0.15.0",
+ "md-5",
+ "nix",
+ "parking_lot",
+ "percent-encoding",
+ "quick-xml",
+ "rand 0.10.3",
+ "reqwest",
+ "rustls-pki-types",
+ "serde",
+ "serde_json",
+ "serde_urlencoded",
+ "thiserror",
+ "tokio",
+ "tracing",
+ "url",
+ "walkdir",
+ "wasm-bindgen-futures",
+ "web-time",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -1987,30 +1939,6 @@ version = "3.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c1b04fb49957986fdce4d6ee7a65027d55d4b6d2265e5848bbb507b58ccfdb6f"
 
-[[package]]
-name = "p256"
-version = "0.13.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c9863ad85fa8f4460f9c48cb909d38a0d689dba1f6f6988a5e3e0d31071bcd4b"
-dependencies = [
- "ecdsa",
- "elliptic-curve",
- "primeorder",
- "sha2 0.10.9",
-]
-
-[[package]]
-name = "p384"
-version = "0.13.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe42f1670a52a47d448f14b6a5c61dd78fce51856e68edaa38f7ae3a46b8d6b6"
-dependencies = [
- "ecdsa",
- "elliptic-curve",
- "primeorder",
- "sha2 0.10.9",
-]
-
 [[package]]
 name = "pack1"
 version = "1.1.0"
@@ -2055,15 +1983,6 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2ee67f1008b1ba2321834326597b8e186293b049a023cdef258527550b9935b4"
 
-[[package]]
-name = "pem-rfc7468"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88b39c9bfcfc231068454382784bb460aae594343fb030d46e9f50a645418412"
-dependencies = [
- "base64ct",
-]
-
 [[package]]
 name = "percent-encoding"
 version = "2.3.2"
@@ -2096,27 +2015,6 @@ version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
 
-[[package]]
-name = "pkcs1"
-version = "0.7.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8ffb9f10fa047879315e6625af03c164b16962a5368d724ed16323b68ace47f"
-dependencies = [
- "der",
- "pkcs8",
- "spki",
-]
-
-[[package]]
-name = "pkcs8"
-version = "0.10.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f950b2377845cebe5cf8b5165cb3cc1a5e0fa5cfa3e1f7f55707d8fd82e0a7b7"
-dependencies = [
- "der",
- "spki",
-]
-
 [[package]]
 name = "pkg-config"
 version = "0.3.34"
@@ -2186,15 +2084,6 @@ dependencies = [
  "num-traits",
 ]
 
-[[package]]
-name = "primeorder"
-version = "0.13.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "353e1ca18966c16d9deb1c69278edbc5f194139612772bd9537af60ac231e1e6"
-dependencies = [
- "elliptic-curve",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.107"
@@ -2298,6 +2187,73 @@ dependencies = [
  "syn 3.0.9",
 ]
 
+[[package]]
+name = "quick-xml"
+version = "0.41.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e660451e55124f798a69a5af3f49ccfbefbd41910eefd25caf2393e1f3473ec1"
+dependencies = [
+ "memchr",
+ "serde",
+]
+
+[[package]]
+name = "quinn"
+version = "0.11.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4051e23e9185c255a7e33ef59cdbca87a22d359052eecd22fc6b901fb37d9d11"
+dependencies = [
+ "bytes",
+ "cfg_aliases",
+ "pin-project-lite",
+ "quinn-proto",
+ "quinn-udp",
+ "rustc-hash",
+ "rustls",
+ "socket2",
+ "thiserror",
+ "tokio",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-proto"
+version = "0.11.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e750cca55fe4f0439a15d0bb529da9651e79993e8e72c61a899a36d462befbe"
+dependencies = [
+ "aws-lc-rs",
+ "bytes",
+ "getrandom 0.4.3",
+ "lru-slab",
+ "rand 0.10.3",
+ "rand_pcg 0.10.2",
+ "ring",
+ "rustc-hash",
+ "rustls",
+ "rustls-pki-types",
+ "slab",
+ "thiserror",
+ "tinyvec",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-udp"
+version = "0.5.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af66907df18639dcf4db56ca65490cabc4b27a97dbadd96f2926cca73298f016"
+dependencies = [
+ "cfg_aliases",
+ "libc",
+ "once_cell",
+ "socket2",
+ "tracing",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.47"
@@ -2410,6 +2366,15 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "rand_pcg"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "caa0f4137e1c0a72f4c651489402276c8e8e1cf081f3b0ba156d2cbeef09e86a"
+dependencies = [
+ "rand_core 0.10.1",
+]
+
 [[package]]
 name = "rapidhash"
 version = "4.5.1"
@@ -2457,6 +2422,45 @@ version = "0.8.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6f6ff9a378485b298a5286656da665ba74413d36db0979633275d2e708145d4"
 
+[[package]]
+name = "reqwest"
+version = "0.13.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "16a1cfa75cc186dd73d5818e510e042e40927bccc9c236b061cea97e1eb08029"
+dependencies = [
+ "base64 0.23.1",
+ "bytes",
+ "futures-core",
+ "futures-util",
+ "h2",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-rustls",
+ "hyper-util",
+ "js-sys",
+ "log",
+ "percent-encoding",
+ "pin-project-lite",
+ "quinn",
+ "rustls",
+ "rustls-pki-types",
+ "rustls-platform-verifier",
+ "sync_wrapper",
+ "tokio",
+ "tokio-rustls",
+ "tokio-util",
+ "tower",
+ "tower-http",
+ "tower-service",
+ "url",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "wasm-streams",
+ "web-sys",
+]
+
 [[package]]
 name = "resolv-conf"
 version = "0.7.6"
@@ -2486,11 +2490,11 @@ dependencies = [
 
 [[package]]
 name = "restate-sdk-shared-core"
-version = "8.4.0"
+version = "8.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08cd57336afa55c59eb52b63a9d46608677718332f2a813014c37acad74f9fe4"
+checksum = "3a955c21a0cd1d0cebbad2878355c9c954282f43f46a9bf37caf10afd36b1a17"
 dependencies = [
- "base64",
+ "base64 0.22.1",
  "bs58",
  "bytes",
  "bytes-utils",
@@ -2509,6 +2513,7 @@ dependencies = [
  "hyper",
  "hyper-util",
  "jsonwebtoken",
+ "object_store",
  "parking_lot",
  "pastey",
  "prost",
@@ -2516,7 +2521,7 @@ dependencies = [
  "rustls",
  "rustls-native-certs",
  "serde",
- "sha2 0.11.1",
+ "sha2",
  "socket2",
  "strum 0.27.2",
  "thiserror",
@@ -2525,20 +2530,11 @@ dependencies = [
  "tokio-util",
  "tracing",
  "turso_core",
+ "url",
  "uuid",
  "zstd-safe",
 ]
 
-[[package]]
-name = "rfc6979"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8dd2a808d456c4a54e300a23e9f5a67e122c3024119acbfd73e3bf664491cb2"
-dependencies = [
- "hmac",
- "subtle",
-]
-
 [[package]]
 name = "ring"
 version = "0.17.14"
@@ -2549,7 +2545,7 @@ dependencies = [
  "cfg-if",
  "getrandom 0.2.17",
  "libc",
- "untrusted",
+ "untrusted 0.9.0",
  "windows-sys 0.52.0",
 ]
 
@@ -2563,26 +2559,6 @@ dependencies = [
  "byteorder",
 ]
 
-[[package]]
-name = "rsa"
-version = "0.9.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8573f03f5883dcaebdfcf4725caa1ecb9c15b2ef50c43a07b816e06799bb12d"
-dependencies = [
- "const-oid 0.9.6",
- "digest 0.10.7",
- "num-bigint-dig",
- "num-integer",
- "num-traits",
- "pkcs1",
- "pkcs8",
- "rand_core 0.6.4",
- "signature",
- "spki",
- "subtle",
- "zeroize",
-]
-
 [[package]]
 name = "rustc-hash"
 version = "2.1.3"
@@ -2627,8 +2603,8 @@ version = "0.23.46"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "48e13bd8c0e9365c43cfa5c9e8f9ad49d3c8444926c9aac819e0e4dc503c8fdf"
 dependencies = [
+ "aws-lc-rs",
  "once_cell",
- "ring",
  "rustls-pki-types",
  "rustls-webpki",
  "subtle",
@@ -2653,18 +2629,47 @@ version = "1.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2f4925028c7eb5d1fcdaf196971378ed9d2c1c4efc7dc5d011256f76c99c0a96"
 dependencies = [
+ "web-time",
  "zeroize",
 ]
 
+[[package]]
+name = "rustls-platform-verifier"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1167586491e2b18b8bfbb293e8180ec17c201c4f076d7cb3070ca964e7598f98"
+dependencies = [
+ "core-foundation 0.10.1",
+ "core-foundation-sys",
+ "jni",
+ "log",
+ "once_cell",
+ "rustls",
+ "rustls-native-certs",
+ "rustls-platform-verifier-android",
+ "rustls-webpki",
+ "security-framework",
+ "security-framework-sys",
+ "webpki-root-certs",
+ "windows-sys 0.61.2",
+]
+
+[[package]]
+name = "rustls-platform-verifier-android"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eec689c0bc40ff2458a5977b6619cb718087084a18e02a131c599b62d05e1a5f"
+
 [[package]]
 name = "rustls-webpki"
 version = "0.103.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4443b1b6d39d7c663139942cc4558262562d2c84123bb6282ef177009ca8b281"
 dependencies = [
+ "aws-lc-rs",
  "ring",
  "rustls-pki-types",
- "untrusted",
+ "untrusted 0.9.0",
 ]
 
 [[package]]
@@ -2709,20 +2714,6 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
-[[package]]
-name = "sec1"
-version = "0.7.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d3e97a565f76233a6003f9f5c54be1d9c5bdfa3eccfb189469f11ec4901c47dc"
-dependencies = [
- "base16ct",
- "der",
- "generic-array",
- "pkcs8",
- "subtle",
- "zeroize",
-]
-
 [[package]]
 name = "security-framework"
 version = "3.7.0"
@@ -2796,21 +2787,22 @@ dependencies = [
 ]
 
 [[package]]
-name = "sha1_smol"
-version = "1.0.1"
+name = "serde_urlencoded"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbfa15b3dddfee50a0fff136974b3e1bde555604ba463834a7eb7deb6417705d"
+checksum = "d3491c14715ca2294c4d6a88f15e84739788c1d030eed8c110436aafdaa2f3fd"
+dependencies = [
+ "form_urlencoded",
+ "itoa",
+ "ryu",
+ "serde",
+]
 
 [[package]]
-name = "sha2"
-version = "0.10.9"
+name = "sha1_smol"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7507d819769d01a365ab707794a4084392c824f54a7a6a7862f8c3d0892b283"
-dependencies = [
- "cfg-if",
- "cpufeatures 0.2.17",
- "digest 0.10.7",
-]
+checksum = "bbfa15b3dddfee50a0fff136974b3e1bde555604ba463834a7eb7deb6417705d"
 
 [[package]]
 name = "sha2"
@@ -2852,7 +2844,7 @@ dependencies = [
  "owo-colors",
  "rand 0.8.8",
  "rand_core 0.6.4",
- "rand_pcg",
+ "rand_pcg 0.3.1",
  "scoped-tls",
  "smallvec",
  "tracing",
@@ -2864,7 +2856,6 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77549399552de45a898a580c1b41d445bf730df867cc44e6c0233bbc4b8329de"
 dependencies = [
- "digest 0.10.7",
  "rand_core 0.6.4",
 ]
 
@@ -2926,19 +2917,9 @@ checksum = "c4fdfe13e1c42e45f497416afb8dc4e783bf0e25b7be9077c1c77c5fb14cb998"
 
 [[package]]
 name = "spin"
-version = "0.9.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3763264f6b73151db08c50ff20d7d8a0b8796e021cdea7ceedad07b80155fa0e"
-
-[[package]]
-name = "spki"
-version = "0.7.3"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d91ed6c858b01f942cd56b37a94b3e0a1798290327d1236e4d9cf4eaca44d29d"
-dependencies = [
- "base64ct",
- "der",
-]
+checksum = "023a211cb3138dbc438680b32560ad89f699977624c9f8dbb95a47d5b4c07dd3"
 
 [[package]]
 name = "stable_deref_trait"
@@ -3017,6 +2998,15 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "sync_wrapper"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
+dependencies = [
+ "futures-core",
+]
+
 [[package]]
 name = "synstructure"
 version = "0.14.0"
@@ -3188,6 +3178,51 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "tower"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ebe5ef63511595f1344e2d5cfa636d973292adc0eec1f0ad45fae9f0851ab1d4"
+dependencies = [
+ "futures-core",
+ "futures-util",
+ "pin-project-lite",
+ "sync_wrapper",
+ "tokio",
+ "tower-layer",
+ "tower-service",
+]
+
+[[package]]
+name = "tower-http"
+version = "0.6.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4cfcf7e2740e6fc6d4d688b4ef00650406bb94adf4731e43c096c3a19fe40840"
+dependencies = [
+ "bitflags",
+ "bytes",
+ "futures-util",
+ "http",
+ "http-body",
+ "pin-project-lite",
+ "tower",
+ "tower-layer",
+ "tower-service",
+ "url",
+]
+
+[[package]]
+name = "tower-layer"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "121c2a6cda46980bb0fcd1647ffaf6cd3fc79a013de288782836f6df9c48780e"
+
+[[package]]
+name = "tower-service"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8df9b6e13f2d32c91b9bd719c00d1958837bc7dec474d94952798cc8e69eeec3"
+
 [[package]]
 name = "tracing"
 version = "0.1.44"
@@ -3249,6 +3284,12 @@ dependencies = [
  "tracing-log",
 ]
 
+[[package]]
+name = "try-lock"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
+
 [[package]]
 name = "turso_core"
 version = "0.8.2"
@@ -3403,6 +3444,12 @@ dependencies = [
  "subtle",
 ]
 
+[[package]]
+name = "untrusted"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
+
 [[package]]
 name = "untrusted"
 version = "0.9.0"
@@ -3479,6 +3526,15 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "want"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec4cdd0dd910afe868b7ef477227d8d538b46b3075031afee8a9f2acb0a2ed0b"
+dependencies = [
+ "try-lock",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"
@@ -3506,6 +3562,17 @@ dependencies = [
  "wasm-bindgen-shared",
 ]
 
+[[package]]
+name = "wasm-bindgen-futures"
+version = "0.4.80"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e14e0327cb5368ad60ccb22d04a9827a693c95a926d8d125e9fa39e0baec501"
+dependencies = [
+ "js-sys",
+ "tokio",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "wasm-bindgen-macro"
 version = "0.2.130"
@@ -3538,6 +3605,29 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "wasm-streams"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d1ec4f6517c9e11ae630e200b2b65d193279042e28edd4a2cda233e46670bbb"
+dependencies = [
+ "futures-util",
+ "js-sys",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+]
+
+[[package]]
+name = "web-sys"
+version = "0.3.107"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7d179596ff5ec0f6de4db64d54011bde6289cc49603d3a6e4ce3f329207ab88"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "web-time"
 version = "1.1.0"
@@ -3548,6 +3638,15 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "webpki-root-certs"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e49d0e65abc00c142e8f9428da991da9f1a250c39be97459901eb12b9b49f62a"
+dependencies = [
+ "rustls-pki-types",
+]
+
 [[package]]
 name = "widestring"
 version = "1.2.1"
diff --git a/Cargo.toml b/Cargo.toml
index 3ff17370..1569d04b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,13 +17,19 @@ pyo3-async-runtimes = { version = "0.30", features = ["tokio-runtime"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["fmt", "env-filter"] }
 # The feature `sql` is the sessions' storage: the SQLite-compatible database kept in an
-# object's state, with its page cache (foyer); `tunnel` is Restate Cloud's.
-restate-sdk-shared-core = { version = "8.4.0", features = [
+# object's state, with its page cache (foyer); `object_store_*`, the object stores its
+# checkpoints may outgrow Restate into (RESTATE_SQL_OBJECT_STORE: S3, GCS, Azure, or a
+# directory); `tunnel` is Restate Cloud's. `aws_lc_rs` is the crypto of all of them (the
+# tunnel's TLS, request identity's signatures), as the object stores' must be aws-lc.
+restate-sdk-shared-core = { version = "8.5.0", features = [
     "request_identity",
     "sha2_random_seed",
-    "rust_crypto",
+    "aws_lc_rs",
     "tunnel",
     "sql",
+    "object_store_aws",
+    "object_store_gcp",
+    "object_store_azure",
 ] }
 
 # ASGI bridge for the tunnel
diff --git a/src/sessions.rs b/src/sessions.rs
index f9fc8595..01cd9428 100644
--- a/src/sessions.rs
+++ b/src/sessions.rs
@@ -38,7 +38,10 @@
 //! in the order of the requests, so that a read sees the writes before it.
 //!
 //! Every database of the process is kept warm in one page cache
-//! ([`page_cache`]).
+//! ([`page_cache`]), and keeps the checkpoints it outgrows Restate with in
+//! the object store `RESTATE_SQL_OBJECT_STORE` names, if any
+//! ([`object_store`]). That store's requests are reqwest's, which need a
+//! tokio runtime: they alone are polled inside one ([`InRuntime`]).
 use crate::PyVM;
 use bytes::Bytes;
 use futures::channel::oneshot;
@@ -50,12 +53,15 @@ use pyo3::sync::PyOnceLock;
 use pyo3::types::{PyBool, PyByteArray, PyBytes, PyFloat, PyInt, PyList, PyString, PyTuple};
 use pyo3::IntoPyObjectExt;
 use restate_sdk_shared_core::sql::{self, Numeric, Value};
-use restate_sdk_shared_core::state::{self, KvStore, PageCache, PageCacheConfig};
+use restate_sdk_shared_core::state::{
+    self, BlobStore, KvStore, ObjectStoreBlobs, ObjectStoreL1, PageCache, PageCacheConfig,
+};
 use restate_sdk_shared_core::{Value as VmValue, VM};
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::future::Future;
 use std::io;
+use std::ops::Range;
 use std::pin::Pin;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{mpsc, Arc, Mutex, OnceLock};
@@ -594,7 +600,65 @@ fn cache_config() -> io::Result<Option<PageCacheConfig>> {
     }))
 }
 
+/// The process's object store, the one `RESTATE_SQL_OBJECT_STORE` names
+/// ([`ObjectStoreL1::from_env`]: `s3://bucket/path`, `gs://bucket/path`,
+/// `az://container/path` or `file:///a/directory`, with the provider's own
+/// `AWS_*`, `GOOGLE_*` or `AZURE_*` variables), made once: `None` when it is
+/// unset or empty, and every pack stays in Restate. Its databases share it,
+/// and its HTTP client. A value that names no store fails every open, with
+/// its message, as a page cache size that is not one does. Once a database
+/// has moved packs to the store, every process that serves it needs the same
+/// value, or its opens fail.
+fn object_store() -> io::Result<Option<ObjectStoreL1>> {
+    static L1: Mutex<Option<Option<ObjectStoreL1>>> = Mutex::new(None);
+    let mut l1 = L1.lock().unwrap_or_else(|poisoned| poisoned.into_inner());
+    if let Some(l1) = &*l1 {
+        return Ok(l1.clone());
+    }
+    Ok(l1.insert(ObjectStoreL1::from_env()?).clone())
+}
+
+/// A database's packs in the object store, each request polled inside
+/// pyo3-async-runtimes' tokio runtime (the tunnel's too). The store's HTTP
+/// client, reqwest, takes its connections and timers from the current
+/// runtime, and a call is polled on the asyncio loop's thread, outside any
+/// ([`SqlTask`]); the runtime's threads drive them, and wake the call as
+/// any other thread does ([`TaskWaker`]). Nothing else is polled inside it.
+struct InRuntime(ObjectStoreBlobs);
+
+impl BlobStore for InRuntime {
+    fn get_range<'a>(
+        &'a self,
+        key: &'a str,
+        range: Range<u64>,
+    ) -> BoxFuture<'a, io::Result<Option<Bytes>>> {
+        in_runtime(self.0.get_range(key, range))
+    }
+
+    fn put<'a>(&'a self, key: &'a str, value: Bytes) -> BoxFuture<'a, io::Result<()>> {
+        in_runtime(self.0.put(key, value))
+    }
+
+    fn delete<'a>(&'a self, keys: &'a [String]) -> BoxFuture<'a, io::Result<()>> {
+        in_runtime(self.0.delete(keys))
+    }
+
+    fn list<'a>(&'a self, prefix: &'a str) -> BoxFuture<'a, io::Result<Vec<String>>> {
+        in_runtime(self.0.list(prefix))
+    }
+}
+
+/// `future`, each poll inside the runtime's context.
+fn in_runtime<'a, T: 'a>(mut future: BoxFuture<'a, T>) -> BoxFuture<'a, T> {
+    let runtime = pyo3_async_runtimes::tokio::get_runtime();
+    Box::pin(std::future::poll_fn(move |cx| {
+        let _entered = runtime.enter();
+        future.as_mut().poll(cx)
+    }))
+}
+
 /// Open the database of `namespace`, kept warm in the process's page cache,
+/// with its packs past L0 in the process's object store, if any ([`object_store`]),
 /// over the invocation's `vm` if given (with `name`, the key's database
 /// `name`), or else over the store behind `dispatch` (`lists_keys` if it has
 /// `keys`): see the module's doc. See [`sql::Open::reader`] for a `reader`.
@@ -630,6 +694,10 @@ pub(crate) fn sql_open<'py>(
         if let Some(cache) = &cache {
             open = open.cached(cache, &namespace);
         }
+        let l1 = object_store().map_err(|e| PyRuntimeError::new_err(e.to_string()))?;
+        if let Some(l1) = l1 {
+            open = open.checkpoints(Arc::new(InRuntime(l1.blobs(&namespace))));
+        }
         if reader {
             open = open.reader();
         }
diff --git a/tests/sessions_object_store.py b/tests/sessions_object_store.py
new file mode 100644
index 00000000..4f136f31
--- /dev/null
+++ b/tests/sessions_object_store.py
@@ -0,0 +1,126 @@
+#
+#  Copyright (c) 2023-2026 - Restate Software, Inc., Restate GmbH
+#
+#  This file is part of the Restate SDK for Python,
+#  which is released under the MIT license.
+#
+#  You can find a copy of the license in file LICENSE in the root
+#  directory of this repository or package, or at
+#  https://github.com/restatedev/sdk-typescript/blob/main/LICENSE
+#
+"""A database past L0 (4 MiB compressed): its checkpoints promote to the object
+store ``RESTATE_SQL_OBJECT_STORE`` names, here a directory, and read back from it.
+
+The variable is read at the process's first open, so the scenario runs in a
+process of its own, with the variable set before any; the page cache is off,
+so every session reads cold.
+"""
+
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+SCENARIO = """
+import asyncio, hashlib, os
+from pathlib import Path
+
+from restate.sessions._database import open
+from sessions_database import Backend, listing
+
+
+def files(path):
+    if not path.exists():
+        return []
+    return [str(f.relative_to(path)) for f in path.rglob("*") if f.is_file()]
+
+
+def store(backend):
+    request = backend.request()
+    request.keys = listing(backend)
+    return request
+
+
+async def main():
+    # Its directory: the namespace, escaped to one segment.
+    namespace = "Ledger/a%20b"
+    packs = Path(os.environ["PACKS"]) / "_4cedger_2fa_2520b"
+    backend = Backend()
+
+    written = hashlib.sha256()
+    db = await open(namespace, store(backend))
+    await db.execute("CREATE TABLE blobs (id INTEGER PRIMARY KEY, data BLOB NOT NULL)")
+    # 12 MiB that does not compress, 256 KiB a commit.
+    for i in range(48):
+        data = os.urandom(256 << 10)
+        written.update(data)
+        await db.execute("INSERT INTO blobs VALUES (?, ?)", [i, data])
+    await db.save()
+
+    promoted = files(packs)
+    assert promoted, "a pack in the object store"
+    assert all(f.startswith("l1/") for f in promoted), f"only L1's packs: {promoted}"
+    # Restate keeps no more than L0's few MiB, and the head, tail and manifests.
+    in_restate = sum(len(v) for v in backend.stored.values())
+    assert in_restate < 8 << 20, f"{in_restate} bytes in Restate"
+
+    # A cold session reads every row, from both tiers.
+    again = await open(namespace, store(backend))
+    read = hashlib.sha256()
+    for (data,) in await again.values("SELECT data FROM blobs ORDER BY id"):
+        read.update(data)
+    assert read.hexdigest() == written.hexdigest()
+    # So does a reader beside it.
+    reader = await open(namespace, backend.request(), reader=True)
+    assert await reader.values("SELECT count(*) FROM blobs") == [[48]]
+    await reader.close()
+
+    # Rewriting it all promotes again; the packs no checkpoint needs go.
+    for i in range(48):
+        await again.execute("UPDATE blobs SET data = ? WHERE id = ?", [os.urandom(256 << 10), i])
+    await again.save()
+    stored = sum((packs / f).stat().st_size for f in files(packs))
+    assert stored < 40 << 20, f"{stored} bytes in the object store for a 12 MiB database"
+
+
+asyncio.run(main())
+"""
+
+
+def test_a_database_past_l0_promotes_its_packs_to_the_object_store_and_reads_them_back(tmp_path: Path):
+    packs = tmp_path / "packs"
+    tests = Path(__file__).parent
+    env = {
+        **os.environ,
+        "RESTATE_SQL_OBJECT_STORE": f"file://{packs}",
+        "RESTATE_SQL_CACHE": "off",
+        "PACKS": str(packs),
+        "PYTHONPATH": os.pathsep.join(filter(None, [str(tests), os.environ.get("PYTHONPATH")])),
+    }
+    ran = subprocess.run([sys.executable, "-c", SCENARIO], env=env, capture_output=True, text=True, check=False)
+    assert ran.returncode == 0, ran.stdout + ran.stderr
+
+
+def test_an_object_store_the_build_cannot_serve_fails_the_open_with_its_message():
+    env = {
+        **os.environ,
+        "RESTATE_SQL_OBJECT_STORE": "memory:///",
+        "PYTHONPATH": os.pathsep.join(filter(None, [str(Path(__file__).parent), os.environ.get("PYTHONPATH")])),
+    }
+    scenario = """
+import asyncio
+from restate.sessions._database import open
+from sessions_database import Backend
+
+async def main():
+    try:
+        await open("Ledger/a", Backend().request())
+    except Exception as error:
+        assert "RESTATE_SQL_OBJECT_STORE=memory:///" in str(error), error
+    else:
+        raise AssertionError("the open succeeded")
+
+asyncio.run(main())
+"""
+    ran = subprocess.run([sys.executable, "-c", scenario], env=env, capture_output=True, text=True, check=False)
+    assert ran.returncode == 0, ran.stdout + ran.stderr

From 722c8415da3a5221ffe3477279d004cf36feb7e5 Mon Sep 17 00:00:00 2001
From: slinkydeveloper <me@slinkydeveloper.com>
Date: Tue, 10 Nov 2026 17:37:59 +0100
Subject: [PATCH 2/2] Sessions: the object store's runtime wakes calls too
 (docs)

The module docs and `TaskWaker`'s said the page cache's disk tier is the
only other thread that wakes a call; with an object store, the tokio
runtime driving its requests does too, through the same `foreign_wakes`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 src/sessions.rs | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/sessions.rs b/src/sessions.rs
index 01cd9428..efb4884f 100644
--- a/src/sessions.rs
+++ b/src/sessions.rs
@@ -13,10 +13,12 @@
 //! task that polls it. A call that needs nothing it must wait for, such as SQL
 //! on cached pages or a statement inside a transaction, returns its value at
 //! once, or raises its error ([`answer`]); one that waits returns an asyncio
-//! future, and is polled again on the loop as what it waits for completes. The
-//! one other thread is the page cache's disk tier (foyer's runtime): its
-//! wake-ups reach the loop through a thread of their own, so that the cache
-//! never waits for the GIL.
+//! future, and is polled again on the loop as what it waits for completes.
+//! Two other kinds of thread wake a call: the page cache's disk tier
+//! (foyer's runtime), and, with an object store, the tokio runtime that
+//! drives its requests' connections and timers ([`InRuntime`]). Their
+//! wake-ups reach the loop through a thread of their own ([`foreign_wakes`]),
+//! so that neither ever waits for the GIL.
 //!
 //! # The store
 //!
@@ -180,9 +182,9 @@ fn poll(py: Python<'_>, task: &Py<SqlTask>) -> PyResult<()> {
 
 /// Wakes a [`SqlTask`]: a poll on its loop, scheduled once however often it
 /// is woken before it runs. Woken on the loop's thread, it schedules it
-/// there; woken on another (the page cache's disk tier), it hands the
-/// scheduling to [`foreign_wakes`], so that the waking thread never waits
-/// for the GIL.
+/// there; woken on another (the page cache's disk tier, or the object
+/// store's tokio runtime), it hands the scheduling to [`foreign_wakes`], so
+/// that the waking thread never waits for the GIL.
 struct TaskWaker(Py<SqlTask>);
 
 impl Wake for TaskWaker {