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## Problem This PR is part of larger computes support activity: https://www.notion.so/neondatabase/Larger-computes-114f189e00478080ba01e8651ab7da90 Epic: https://github.com/neondatabase/cloud/issues/19010 In case of planned node restart, we are going to 1. create new read-only replica 2. capture LFC state at primary 3. use this state to prewarm replica 4. stop old primary 5. promote replica to primary Steps 1-3 are currently implemented and support from compute side. This PR provides compute level implementation of replica promotion. Support replica promotion ## Summary of changes Right now replica promotion is done in three steps: 1. Set safekeepers list (now it is empty for replica) 2. Call `pg_promote()` top promote replica 3. Update endpoint setting to that it ids not more treated as replica. May be all this three steps should be done by some function in compute_ctl. But right now this logic is only implement5ed in test. Postgres submodules PRs: https://github.com/neondatabase/postgres/pull/648 https://github.com/neondatabase/postgres/pull/649 https://github.com/neondatabase/postgres/pull/650 https://github.com/neondatabase/postgres/pull/651 --------- Co-authored-by: Matthias van de Meent <matthias@neon.tech> Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
neon extension consists of several parts:
shared preload library neon.so
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implements storage manager API and network communications with remote page server.
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walproposer: implements broadcast protocol between postgres and WAL safekeepers.
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control plane connector: Captures updates to roles/databases using ProcessUtility_hook and sends them to the control ProcessUtility_hook.
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remote extension server: Request compute_ctl to download extension files.
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file_cache: Local file cache is used to temporary store relations pages in local file system for better performance.
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relsize_cache: Relation size cache for better neon performance.
SQL functions in neon--*.sql
Utility functions to expose neon specific information to user and metrics collection. This extension is created in all databases in the cluster by default.