To flush inmemory layer eventually when no new data arrives, which helps
safekeepers to suspend activity (stop pushing to the broker). Default 10m should
be ok.
Reorganize existing READMEs and other documentation files into mdbook
format. The resulting Table of Contents is a mix of placeholders for
docs that we should write, and documentation files that we already had,
dropped into the most appropriate place.
Update the Pageserver overview diagram. Add sections on thread
management and WAL redo processes.
Add all the RFCs to the mdbook Table of Content too.
Per github issue #1979
+ neondatabase/cloud#1103
This adds a couple of control endpoints to simplify compute state
discovery for control-plane. For example, now we may figure out
that Postgres wasn't able to start or basebackup failed within
seconds instead of just blindly polling the compute readiness
for a minute or two.
Also we now expose startup metrics (time of the each step: basebackup,
sync safekeepers, config, total). Console grabs them after each
successful start and report as histogram to prometheus and grafana.
OpenAPI spec is added and up-tp date, but is not currently used in the
console yet.
Commit edba2e97 renamed pageserver/README to pageserver/README.md, but
forgot to update links to it. Fix.
Rename libs/postgres_ffi/README and safekeeper/README files to also
have the the .md extension, so that github can render them nicely.
Quote ascii-diagram in safekeeper/README.md so that it renders
correctly.
workspace_hack is needed to avoid recompilation when different crates
inside the workspace depend on the same packages but with different
features being enabled. Problem occurs when you build crates separately
one by one. So this is irrelevant to our CI setup because there we build
all binaries at once, but it may be relevant for local development.
this also changes cargo's resolver version to 2
This is a backwards-incompatible change. The new pageserver cannot
read repositories created with an old pageserver binary, or vice
versa.
Simplify Repository to a value-store
------------------------------------
Move the responsibility of tracking relation metadata, like which
relations exist and what are their sizes, from Repository to a new
module, pgdatadir_mapping.rs. The interface to Repository is now a
simple key-value PUT/GET operations.
It's still not any old key-value store though. A Repository is still
responsible from handling branching, and every GET operation comes
with an LSN.
Mapping from Postgres data directory to keys/values
---------------------------------------------------
All the data is now stored in the key-value store. The
'pgdatadir_mapping.rs' module handles mapping from PostgreSQL objects
like relation pages and SLRUs, to key-value pairs.
The key to the Repository key-value store is a Key struct, which
consists of a few integer fields. It's wide enough to store a full
RelFileNode, fork and block number, and to distinguish those from
metadata keys.
'pgdatadir_mapping.rs' is also responsible for maintaining a
"partitioning" of the keyspace. Partitioning means splitting the
keyspace so that each partition holds a roughly equal number of keys.
The partitioning is used when new image layer files are created, so
that each image layer file is roughly the same size.
The partitioning is also responsible for reclaiming space used by
deleted keys. The Repository implementation doesn't have any explicit
support for deleting keys. Instead, the deleted keys are simply
omitted from the partitioning, and when a new image layer is created,
the omitted keys are not copied over to the new image layer. We might
want to implement tombstone keys in the future, to reclaim space
faster, but this will work for now.
Changes to low-level layer file code
------------------------------------
The concept of a "segment" is gone. Each layer file can now store an
arbitrary range of Keys.
Checkpointing, compaction
-------------------------
The background tasks are somewhat different now. Whenever
checkpoint_distance is reached, the WAL receiver thread "freezes" the
current in-memory layer, and creates a new one. This is a quick
operation and doesn't perform any I/O yet. It then launches a
background "layer flushing thread" to write the frozen layer to disk,
as a new L0 delta layer. This mechanism takes care of durability. It
replaces the checkpointing thread.
Compaction is a new background operation that takes a bunch of L0
delta layers, and reshuffles the data in them. It runs in a separate
compaction thread.
Deployment
----------
This also contains changes to the ansible scripts that enable having
multiple different pageservers running at the same time in the staging
environment. We will use that to keep an old version of the pageserver
running, for clusters created with the old version, at the same time
with a new pageserver with the new binary.
Author: Heikki Linnakangas
Author: Konstantin Knizhnik <knizhnik@zenith.tech>
Author: Andrey Taranik <andrey@zenith.tech>
Reviewed-by: Matthias Van De Meent <matthias@zenith.tech>
Reviewed-by: Bojan Serafimov <bojan@zenith.tech>
Reviewed-by: Konstantin Knizhnik <knizhnik@zenith.tech>
Reviewed-by: Anton Shyrabokau <antons@zenith.tech>
Reviewed-by: Dhammika Pathirana <dham@zenith.tech>
Reviewed-by: Kirill Bulatov <kirill@zenith.tech>
Reviewed-by: Anastasia Lubennikova <anastasia@zenith.tech>
Reviewed-by: Alexey Kondratov <alexey@zenith.tech>
This patch includes attach/detach http endpoints in pageservers. Some
changes in callmemaybe handling inside safekeeper and an integrational
test to check migration with and without load. There are still some
rough edges that will be addressed in follow up patches
Mainly because it has better support for installing the packages from
different python versions.
It also has better dependency resolver than Pipenv. And supports modern
standard for python dependency management. This includes usage of
pyproject.toml for project specific configuration instead of per
tool conf files. See following links for details:
https://pip.pypa.io/en/stable/reference/build-system/pyproject-toml/https://www.python.org/dev/peps/pep-0518/
* Rename wal_acceptor binary to safekeeper
* Rename wal_acceptor.pid and wal_acceptor.log to safekeeper.pid and safekeeper.log
* Change some mentions of WAL acceptor to safekeeper
* Dockerfile: alias wal_acceptor to safekeeper temporarily until internal scripts are updated
- Change hardcoded OLDEST_INMEM_DISTANCE value to pageserver config option checkpoint_distance.
- Get rid of 'force' flag in checkpoint_internal(). Use checkpoint_distance=0 instead.
