PR #98820 - spanconfig: enable range coalescing by default

[cockroach-teamcity]

Exalate commented:

Related PR: cockroachdb/cockroach#98820
Commit: cockroachdb/cockroach@7a57e7e
Fixes: CRDB-15400
Informs: CRDB-7866

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Release note (general change): CockroachDB would previously use separate
ranges for each table, index, or partition. This is no longer true --
it's possible now to have multiple tables, indexes, and partitions to
get packed into the same range. For users with many such "schema
objects", this will reduce the total range count in their clusters. This
is especially true if individual tables, indexes, or partitions are
smaller than the default configured maximum range size (controlled using
zone configs, specifically the range_max_bytes parameter).
We made this change to improve scalability with respect to the number of
schema objects, since the underlying range count now no longer a
bottleneck. Users upgrading from 22.2, once finalizing their upgrade,
may observe a round of range merges and snapshot transfers (to power
said range merges) as a result of this change. If users want to opt-out
of this optimization, they can use the following cluster setting:

SET CLUSTER SETTING spanconfig.storage_coalesce_adjacent.enabled = false;

Jira Issue: DOC-7605