Merge #33524

33524: opt: Add support for DELETE operator r=andy-kimball a=andy-kimball

This commit adds support for the DELETE operator to the cost-based
optimizer. The DELETE operator is similar to the UPDATE operator. It
fetches existing values from the deletion table using the clauses
specified in the DELETE statement:

  CREATE TABLE abc (a INT PRIMARY KEY, b INT, c INT)
  DELETE FROM abc WHERE b=10

Then an input expression equivalent to this would be built:

  SELECT a, b, c
  FROM abc
  WHERE b=10

At runtime, the Delete execution operator will iterate over each input
row and use its key to delete each row in turn.


Co-authored-by: Andrew Kimball <[email protected]>

docs/generated/settings/settings.html

@@ -62,7 +62,7 @@
 <tr><td><code>sql.defaults.default_int_size</code></td><td>integer</td><td><code>8</code></td><td>the size, in bytes, of an INT type</td></tr>
 <tr><td><code>sql.defaults.distsql</code></td><td>enumeration</td><td><code>1</code></td><td>default distributed SQL execution mode [off = 0, auto = 1, on = 2, 2.0-off = 3, 2.0-auto = 4]</td></tr>
 <tr><td><code>sql.defaults.experimental_automatic_statistics</code></td><td>boolean</td><td><code>false</code></td><td>default experimental automatic statistics mode</td></tr>
-<tr><td><code>sql.defaults.experimental_optimizer_updates</code></td><td>boolean</td><td><code>false</code></td><td>default experimental_optimizer_updates mode</td></tr>
+<tr><td><code>sql.defaults.experimental_optimizer_mutations</code></td><td>boolean</td><td><code>false</code></td><td>default experimental_optimizer_mutations mode</td></tr>
 <tr><td><code>sql.defaults.experimental_vectorize</code></td><td>enumeration</td><td><code>0</code></td><td>default experimental_vectorize mode [off = 0, on = 1, always = 2]</td></tr>
 <tr><td><code>sql.defaults.optimizer</code></td><td>enumeration</td><td><code>1</code></td><td>default cost-based optimizer mode [off = 0, on = 1, local = 2]</td></tr>
 <tr><td><code>sql.defaults.results_buffer.size</code></td><td>byte size</td><td><code>16 KiB</code></td><td>size of the buffer that accumulates results for a statement or a batch of statements before they are sent to the client. Note that auto-retries generally only happen while no results have been delivered to the client, so reducing this size can increase the number of retriable errors a client receives. On the other hand, increasing the buffer size can increase the delay until the client receives the first result row. Updating the setting only affects new connections. Setting to 0 disables any buffering.</td></tr>

pkg/sql/exec_util.go

@@ -127,11 +127,11 @@ var OptimizerClusterMode = settings.RegisterEnumSetting(
 	},
 )
 
-// OptimizerUpdatesClusterMode controls the cluster default for when the cost-
-// based optimizer is planning UPDATE statements.
-var OptimizerUpdatesClusterMode = settings.RegisterBoolSetting(
-	"sql.defaults.experimental_optimizer_updates",
-	"default experimental_optimizer_updates mode",
+// OptimizerMutationsClusterMode controls the cluster default for when the cost-
+// based optimizer is planning mutation statements.
+var OptimizerMutationsClusterMode = settings.RegisterBoolSetting(
+	"sql.defaults.experimental_optimizer_mutations",
+	"default experimental_optimizer_mutations mode",
 	false,
 )
 
@@ -1690,8 +1690,8 @@ func (m *sessionDataMutator) SetOptimizerMode(val sessiondata.OptimizerMode) {
 	m.data.OptimizerMode = val
 }
 
-func (m *sessionDataMutator) SetOptimizerUpdates(val bool) {
-	m.data.OptimizerUpdates = val
+func (m *sessionDataMutator) SetOptimizerMutations(val bool) {
+	m.data.OptimizerMutations = val
 }
 
 func (m *sessionDataMutator) SetSerialNormalizationMode(val sessiondata.SerialNormalizationMode) {

pkg/sql/logictest/logic.go

@@ -929,9 +929,9 @@ func (t *logicTest) setUser(user string) func() {
 			t.Fatal(err)
 		}
 
-		// Use the cost-based-optimizer for planning UPDATE statements.
+		// Use the cost-based-optimizer for planning mutation statements.
 		if optMode == "on" {
-			if _, err := db.Exec("SET experimental_optimizer_updates = true"); err != nil {
+			if _, err := db.Exec("SET experimental_optimizer_mutations = true"); err != nil {
 				t.Fatal(err)
 			}
 		}

pkg/sql/logictest/testdata/logic_test/delete

@@ -153,13 +153,13 @@ statement ok
 INSERT INTO unindexed VALUES (1, 9), (8, 2), (3, 7), (6, 4)
 
 query II
-DELETE FROM unindexed WHERE k > 1 AND v < 7 ORDER BY v DESC RETURNING v,k
+DELETE FROM unindexed WHERE k > 1 AND v < 7 ORDER BY v DESC LIMIT 2 RETURNING v,k
 ----
 4  6
 2  8
 
 query II
-DELETE FROM unindexed ORDER BY v RETURNING k,v
+DELETE FROM unindexed ORDER BY v LIMIT 2 RETURNING k,v
 ----
 3  7
 1  9