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disaggregated-oltp

compute/storage-separated OLTP: log-is-the-database page servers, quorum storage, branching, serverless compute

Aurora, Neon, AlloyDB, Azure SQL Hyperscale

SystemTechniques · 26Primitives · 62 disaggregated-oltp Anti-entropy repairdistributed · medium: Replicas compare hash trees of a key range, descend only into differing subtrees and stream just those ranges, healing silent divergence in the background.›Cell based architecturedistributed · medium: Independent full-stack cells with a thin router to bound blast radiusDeterministic simulation testingdistributed · medium: Run the whole system in one thread under a seeded scheduler with simulated network, disk and clock, so every failure replays from its seed.›Linearizable readsdistributed · medium: ReadIndex and leader-lease reads without writing to the logPartitioned commit logdistributed · medium: A topic split into replicated append-only partitions: key hash keeps per-key order, offsets give position, and a high watermark limits readers to fully replicated records.›Primary-backup replicationdistributed · medium: One node orders all writes and ships them to standbys; the acknowledgement rule (none, one, all) sets what a crash loses, and an external arbiter decides who takes over.›Quorum replicationdistributed · medium: Leaderless replication: write to W of N replicas, read from R; overlap (R + W > N) makes reads see the latest completed write.›Leasesdistributed · low: A lock that expires on its own: bounded-time ownership that survives crashes and partitions, given bounded clock drift and fencing tokens on writes.›Write-ahead logstorage · low: Append each change to a checksummed sequential log and fsync it before touching data pages; the basis of crash durability in nearly every database.›B+ treestorage · low: Balanced high-fanout search tree with all values in linked leaves; the default on-disk index for point lookups and range scans.›CRC32C checksumshardware-os · low: The Castagnoli CRC-32 with dedicated instructions on x86 (SSE4.2) and ARMv8. It is the standard fast integrity check for storage blocks, logs and network frames.›Object storagecloud · low: S3-compatible blob storage at cents per GB-month with 11 nines durability; pick by egress price, request price and latency, not by storage price alone.›Hdr histogramdata-structures · low: Log-linear bucketed histograms with bounded relative error for latency percentilesFencing tokensdistributed · low: A number that grows with every lock grant and is checked by the protected resource, so a paused ex-holder's late write is rejected.›Process supervisionhardware-os · low: A parent process starts services, reaps their exits and restarts them under a delay and burst-limit policy, then stops them with SIGTERM before SIGKILL.›Mutual TLSsecurity · low: TLS where the client also proves a certificate key, so every connection carries a verified, rotatable machine identity.›Group commitstorage · low: Let concurrent committers share one log write and fsync; throughput grows with concurrency while each commit still waits at most about two fsyncs.›Read write splittingstorage · low: Route reads to replicas and writes to the primary with lag-aware consistencySlotted pagesstorage · low: Fixed-size page layout for variable-length records, with a slot array growing from the front and data from the back; stable record IDs despite compaction.›Connection poolingsystems · low: Reuse and multiplex backend connections with bounded pools, checkout queues and health evictionGraceful drainingsystems · low: On a termination signal, stop taking new work, finish in-flight work until a deadline, tell clients to reconnect elsewhere, then exit; clients resume from a token.›Merkle treedata-structures · low: Hash tree for verifying and diffing large datasets with logarithmic proofsRange partitioningdistributed · low: Cut the sorted key space into contiguous half-open ranges kept in a boundary map; split hot or big ranges, merge small ones, move ranges between nodes.›+ 19 more techniques+ 46 more primitives

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In-house systems

Named systems of this kind at large companies, with their paper or write-up.

AuroraAmazonSocrates (Azure SQL Hyperscale)MicrosoftPolarDBAlibaba Group