sql/delegate: pick up new 21.2 columns in SHOW JOBS

New columns were added to `crdb_internal.jobs` to expose retry and
exponential backoff state. This commit exposes them in `SHOW JOBS`.

No need for a version gate because the virtual table is local and will
just populate the columns with NULL in the mixed version state.

Fixes #70765.

Release note (sql change): `SHOW JOBS` will now include the newly added
columns from `crdb_internal.jobs` (`last_run`, `next_run`, `num_runs`,
and `execution_errors`). The columns capture state related to retries,
failures, and exponential backoff.

pkg/sql/delegate/show_jobs.go

@@ -32,10 +32,12 @@ SHOW JOBS SELECT id FROM system.jobs WHERE created_by_type='%s' and created_by_i
  sqltelemetry.IncrementShowCounter(sqltelemetry.Jobs)
 
  const (
- selectClause = `SELECT job_id, job_type, description, statement, user_name, status,
- running_status, created, started, finished, modified,
- fraction_completed, error, coordinator_id, trace_id
- FROM crdb_internal.jobs`
+ selectClause = `
+SELECT job_id, job_type, description, statement, user_name, status,
+ running_status, created, started, finished, modified,
+ fraction_completed, error, coordinator_id, trace_id, last_run,
+ next_run, num_runs, execution_errors
+ FROM crdb_internal.jobs`
  )
  var typePredicate, whereClause, orderbyClause string
  if n.Jobs == nil {

pkg/sql/logictest/testdata/logic_test/show_source

@@ -415,10 +415,10 @@ SELECT * FROM [SHOW COMPACT TRACE FOR SESSION] LIMIT 0
 ----
 age message tag operation
 
-query ITTTTTTTTTTRTII colnames
+query ITTTTTTTTTTRTIITTIT colnames
 SELECT * FROM [SHOW JOBS] LIMIT 0
 ----
-job_id job_type description statement user_name status running_status created started finished modified fraction_completed error coordinator_id trace_id
+job_id job_type description statement user_name status running_status created started finished modified fraction_completed error coordinator_id trace_id last_run next_run num_runs execution_errors
 
 query TT colnames
 SELECT * FROM [SHOW SYNTAX 'select 1; select 2']