Merge #78184 #78195

78184: workload/schemachanger: primary index detection is incorrect r=fqazi a=fqazi

Fixes: #77885

Previously, the schemachanger workload incorrectly detected primary
indexes using their names checking for either the words
'pkey' or 'primary'. This approach was not correct and heuristic
in nature. To address this, this patch uses crdb_internal.table_indexes
to detect primary indexes.

Release note: None

78195: distsql: clean up the determination of txn type in mixed version r=yuzefovich a=yuzefovich

This commit cleans up the way we determine what txn type to use for
a particular flow.

Addresses: #78150.

Release note: None

Co-authored-by: Faizan Qazi <faizan@cockroachlabs.com>
Co-authored-by: Yahor Yuzefovich <yahor@cockroachlabs.com>

pkg/sql/distsql/BUILD.bazel

@@ -17,7 +17,6 @@ go_library(
         "//pkg/sql/execinfrapb",
         "//pkg/sql/faketreeeval",
         "//pkg/sql/flowinfra",
-        "//pkg/sql/row",
         "//pkg/sql/rowflow",
         "//pkg/sql/sem/tree",
         "//pkg/sql/sessiondata",

pkg/sql/distsql/server.go

@@ -27,7 +27,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/execinfrapb"
 	"github.com/cockroachdb/cockroach/pkg/sql/faketreeeval"
 	"github.com/cockroachdb/cockroach/pkg/sql/flowinfra"
-	"github.com/cockroachdb/cockroach/pkg/sql/row"
 	"github.com/cockroachdb/cockroach/pkg/sql/rowflow"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/sql/sessiondata"
@@ -407,24 +406,11 @@ func (ds *ServerImpl) setupFlow(
 	}
 
 	// Figure out what txn the flow needs to run in, if any. For gateway flows
-	// that have no remote flows and also no concurrency, the txn comes from
-	// localState.Txn. Otherwise, we create a txn based on the request's
-	// LeafTxnInputState.
-	useLeaf := false
-	if req.LeafTxnInputState != nil && row.CanUseStreamer(ctx, ds.Settings) {
-		for _, proc := range req.Flow.Processors {
-			if jr := proc.Core.JoinReader; jr != nil {
-				if jr.IsIndexJoin() {
-					// Index joins are executed via the Streamer API that has
-					// concurrency.
-					useLeaf = true
-					break
-				}
-			}
-		}
-	}
+	// that have no remote flows and also no concurrency, the (root) txn comes
+	// from localState.Txn if we haven't already created a leaf txn. Otherwise,
+	// we create, if necessary, a txn based on the request's LeafTxnInputState.
 	var txn *kv.Txn
-	if localState.IsLocal && !f.ConcurrentTxnUse() && !useLeaf {
+	if localState.IsLocal && !f.ConcurrentTxnUse() && leafTxn == nil {
 		txn = localState.Txn
 	} else {
 		// If I haven't created the leaf already, do it now.

pkg/workload/schemachange/error_screening.go

@@ -177,16 +177,22 @@ func (og *operationGenerator) colIsPrimaryKey(
 	ctx context.Context, tx pgx.Tx, tableName *tree.TableName, columnName string,
 ) (bool, error) {
 	primaryColumns, err := og.scanStringArray(ctx, tx,
-		`SELECT array_agg(column_name)
-		FROM (
-			SELECT DISTINCT column_name
-				FROM information_schema.statistics
-			WHERE (index_name = 'primary' OR index_name LIKE '%pkey%')
-				AND table_schema = $1
-				AND table_name = $2
-				AND storing = 'NO'
-		);
-	`, tableName.Schema(), tableName.Object())
+		`
+SELECT array_agg(column_name)
+  FROM (
+        SELECT DISTINCT column_name
+          FROM information_schema.statistics
+         WHERE index_name
+               IN (
+                  SELECT index_name
+                    FROM crdb_internal.table_indexes
+                   WHERE index_type = 'primary' AND descriptor_id = $3::REGCLASS
+                )
+               AND table_schema = $1
+               AND table_name = $2
+               AND storing = 'NO'
+       );
+	`, tableName.Schema(), tableName.Object(), tableName.String())
 	if err != nil {
 		return false, err
 	}
@@ -282,15 +288,18 @@ func (og *operationGenerator) tableHasPrimaryKeySwapActive(
 	indexName, err := og.scanStringArray(
 		ctx,
 		tx,
-		fmt.Sprintf(`
+		`
 SELECT array_agg(index_name)
   FROM (
-		SELECT index_name
-		  FROM [SHOW INDEXES FROM %s]
-		 WHERE index_name LIKE '%%_pkey%%'
-		 LIMIT 1
+SELECT
+	index_name
+FROM
+	crdb_internal.table_indexes
+WHERE
+	index_type = 'primary'
+	AND descriptor_id = $1::REGCLASS
        );
-	`, tableName.String()),
+	`, tableName.String(),
 	)
 	if err != nil {
 		return err