*: rename SQL Stats

[Azhng]

Previously, SQL Stats refer to statement / transaction statistics. This is often confused with table statistics, which are used by the optimizer to better plan queries.

We need a better name to avoid terminology confusion.

Jira issue: CRDB-15788

[mgartner]

Can we make a thorough list of all the places that the statement / transcation statistics are named with some form of stats or statistics? A rough brainstorm:

• The job_type for stats compactions is AUTO SQL STATS COMPACTION
• session and cluster settings?
• packages

I think we should prioritize user-facing names like settings and job types/descriptions. Package names aren't see by a customer and will cause less confusion. They're also easier to switch in the future, whereas things like setting names are not.

[rafiss]

There's also the crdb_internal.reset_sql_stats builtin

[mgartner]

The cluster settings for SQL activity stats also use the same namespace, sql.stats, as table statistics cluster settings:

Table statistics:

Setting	Type	Default	Description
sql.stats.automatic_collection.enabled	boolean	true	automatic statistics collection mode
sql.stats.automatic_collection.fraction_stale_rows	float	0.2	target fraction of stale rows per table that will trigger a statistics refresh
sql.stats.automatic_collection.min_stale_rows	integer	500	target minimum number of stale rows per table that will trigger a statistics refresh
sql.stats.histogram_collection.enabled	boolean	true	histogram collection mode
sql.stats.multi_column_collection.enabled	boolean	true	multi-column statistics collection mode
sql.stats.post_events.enabled	boolean	false	if set, an event is logged for every CREATE STATISTICS job

SQL Activity Statistics:

Setting	Type	Default	Description
sql.stats.cleanup.recurrence	string	@hourly	cron-tab recurrence for SQL Stats cleanup job
sql.stats.flush.enabled	boolean	true	if set, SQL execution statistics are periodically flushed to disk
sql.stats.flush.interval	duration	10m0s	the interval at which SQL execution statistics are flushed to disk, this value must be less than or equal to sql.stats.aggregation.interval
sql.stats.persisted_rows.max	integer	1000000	maximum number of rows of statement and transaction statistics that will be persisted in the system tables
sql.stats.response.max	integer	20000	the maximum number of statements and transaction stats returned in a CombinedStatements request

We'll have to figure out a migration plan for the settings that causes as little annoyance for customers as possible.

More immediately, I think we should make the descriptions of these settings more clear in our documentation.

[mgartner]

This also affects metric names: https://github.com/cockroachdb/cockroach/blob/2fdc0a62df08829dd96901fffb5fb1fbb0b0997d/pkg/sql/exec_util.go#L1031-L1084

[maryliag]

No longer a priority

[michae2]

Reopening because there was confusion from a customer about this.