There are several system tables with strict durability requirements.
This means that if we have written to such a table, we want to be sure
that the write won't be lost in case of node failure. We currently
accomplish this by accompanying each write to these tables with
`db.flush()` on all shards. This is expensive, since it causes all the
memtables to be written to sstables, which causes a lot of disk writes.
This overheads can become painful during node startup, when we write the
current boot state to `system.local`/`system.scylla_local` or during
topology change, when `update_peer_info`/`update_tokens` write to
`system.peers`.
In this series we remove flushes on writes to the `system.local`,
`system.peers`, `system.scylla_local` and `system.cdc_local` tables and
start using schema commitlog for durability.
Fixes: #15133Closes#15279
* github.com:scylladb/scylladb:
system_keyspace: switch CDC_LOCAL to schema commitlog
system_keyspace: scylla_local: use schema commitlog
database.cc: make _uses_schema_commitlog optional
system_keyspace: drop load phases
database.hh: add_column_family: add readonly parameter
schema_tables: merge_tables_and_views: delay events until tables/views are created on all shards
system_keyspace: switch system.peers to schema commitlog
system_keyspace: switch system.local to schema commitlog
main.cc: move schema commitlog replay earlier
sstables_format_selector: extract listener
sstables_format_selector: wrap when_enabled with seastar::async
main.cc: inline and split system_keyspace.setup
system_keyspace: refactor save_system_schema function
system_keyspace: move initialize_virtual_tables into virtual_tables.hh
system_keyspace: remove unused parameter
config.cc: drop db::config::host_id
main.cc:: extract local_info initialization into function
schema.cc: check static_props for sanity
system_keyspace: set null sharder when configuring schema commitlog
system_keyspace: rename static variables
system_keyspace: remove redundant wait_for_sync_to_commitlog
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