ui: fix bug where "Drop Unused Index" recommendations are not populated on...

... Schema Insights

When hard refreshing on the Schema Index tab of the insights page, "Drop Unused
Index" recommendations don't populate. This is happening due to a race
condition in db console, where db console needs cluster settings from the redux
store to query for unused indexes. On a hard refresh, the cluster settings
aren't in the redux store when querying for these indexes, so it uses the
default cluster setting. To fix, the query no longer depends on cluster
settings from the reduxstore. Instead, thequery joins on
crdb_internal.cluster_settings.

Epic: CC-30965
Fixes: CC-31265
Release note (ui change): Fix bug where "Drop Unused Index" recommendations are
not populated on the schema index page.

Author: kyle-a-wong

pkg/ui/workspaces/cluster-ui/src/api/schemaInsightsApi.ts

@@ -8,7 +8,7 @@ import {
   InsightType,
   recommendDropUnusedIndex,
 } from "../insights";
-import { HexStringToInt64String, indexUnusedDuration } from "../util";
+import { HexStringToInt64String } from "../util";
 
 import { QuoteIdentifier } from "./safesql";
 import {
@@ -142,8 +142,7 @@ function createIndexRecommendationsToSchemaInsight(
 // and want to return the most used ones as a priority.
 const dropUnusedIndexQuery: SchemaInsightQuery<ClusterIndexUsageStatistic> = {
   name: "DropIndex",
-  query: (csIndexUnusedDuration: string) => {
-    csIndexUnusedDuration = csIndexUnusedDuration ?? indexUnusedDuration;
+  query: (_: string) => {
     return `SELECT * FROM (SELECT us.table_id,
                           us.index_id,
                           us.last_read,
@@ -154,14 +153,16 @@ const dropUnusedIndexQuery: SchemaInsightQuery<ClusterIndexUsageStatistic> = {
                           t.parent_id as database_id,
                           t.database_name,
                           t.schema_name,
-                          '${csIndexUnusedDuration}' as unused_threshold,
-                          '${csIndexUnusedDuration}'::interval as interval_threshold, 
+                          cs.value as unused_threshold,
+                          cs.value::interval as interval_threshold, 
                           now() - COALESCE(us.last_read AT TIME ZONE 'UTC', COALESCE(ti.created_at, '0001-01-01')) as unused_interval
                    FROM "".crdb_internal.index_usage_statistics AS us
                             JOIN "".crdb_internal.table_indexes as ti
                                  ON us.index_id = ti.index_id AND us.table_id = ti.descriptor_id
                             JOIN "".crdb_internal.tables as t
                                  ON t.table_id = ti.descriptor_id and t.name = ti.descriptor_name
+                            JOIN "".crdb_internal.cluster_settings cs
+                                 ON cs.variable = 'sql.index_recommendation.drop_unused_duration'
                    WHERE t.database_name != 'system' AND ti.is_unique IS false)
           WHERE unused_interval > interval_threshold
           ORDER BY total_reads DESC;`;