[stats]: fix panic for empty table stats with one root chunk

dolthub · Feb 16, 2024 · 732127d · 732127d
1 parent 3419237
commit 732127d
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Showing 4 changed files with 73 additions and 3 deletions.
diff --git a/go/libraries/doltcore/sqle/enginetest/dolt_engine_test.go b/go/libraries/doltcore/sqle/enginetest/dolt_engine_test.go
@@ -2110,7 +2110,11 @@ func TestStatsFunctions(t *testing.T) {
 	harness.configureStats = true
 	for _, test := range StatProcTests {
 		t.Run(test.Name, func(t *testing.T) {
-			enginetest.TestScript(t, harness, test)
+			// reset engine so provider statistics are clean
+			harness.engine = nil
+			e := mustNewEngine(t, harness)
+			defer e.Close()
+			enginetest.TestScriptWithEngine(t, e, harness, test)
 		})
 	}
 }

diff --git a/go/libraries/doltcore/sqle/enginetest/dolt_harness.go b/go/libraries/doltcore/sqle/enginetest/dolt_harness.go
@@ -247,7 +247,7 @@ func (d *DoltHarness) NewEngine(t *testing.T) (enginetest.QueryEngine, error) {
 	// Get a fresh session if we are reusing the engine
 	if !initializeEngine {
 		var err error
-		d.session, err = dsess.NewDoltSession(enginetest.NewBaseSession(), d.provider, d.multiRepoEnv.Config(), d.branchControl, nil)
+		d.session, err = dsess.NewDoltSession(enginetest.NewBaseSession(), d.provider, d.multiRepoEnv.Config(), d.branchControl, d.statsPro)
 		require.NoError(t, err)
 	}
 

diff --git a/go/libraries/doltcore/sqle/enginetest/stats_queries.go b/go/libraries/doltcore/sqle/enginetest/stats_queries.go
@@ -404,6 +404,69 @@ var DoltStatsIOTests = []queries.ScriptTest{
 }
 
 var StatProcTests = []queries.ScriptTest{
+	{
+		Name: "deleting stats removes information_schema access point",
+		SetUpScript: []string{
+			"CREATE table xy (x bigint primary key, y int, z varchar(500), key(y,z));",
+			"insert into xy values (0,0,0)",
+		},
+		Assertions: []queries.ScriptTestAssertion{
+			{
+				Query: "analyze table xy",
+			},
+			{
+				Query:    "select count(*) from information_schema.column_statistics",
+				Expected: []sql.Row{{2}},
+			},
+			{
+				Query: "call dolt_stats_drop()",
+			},
+			{
+				Query:    "select count(*) from information_schema.column_statistics",
+				Expected: []sql.Row{{0}},
+			},
+		},
+	},
+	{
+		Name: "restart empty stats panic",
+		SetUpScript: []string{
+			"CREATE table xy (x bigint primary key, y int, z varchar(500), key(y,z));",
+		},
+		Assertions: []queries.ScriptTestAssertion{
+			{
+				Query: "analyze table xy",
+			},
+			{
+				Query:    "select count(*) from dolt_statistics",
+				Expected: []sql.Row{{0}},
+			},
+			{
+				Query:    "set @@GLOBAL.dolt_stats_auto_refresh_threshold = 0",
+				Expected: []sql.Row{{}},
+			},
+			{
+				Query:    "set @@GLOBAL.dolt_stats_auto_refresh_interval = 0",
+				Expected: []sql.Row{{}},
+			},
+			{
+				// don't panic
+				Query: "call dolt_stats_restart()",
+			},
+			{
+				Query: "select sleep(.1)",
+			},
+			{
+				Query: "insert into xy values (0,0,0)",
+			},
+			{
+				Query: "select sleep(.1)",
+			},
+			{
+				Query:    "select count(*) from dolt_statistics",
+				Expected: []sql.Row{{2}},
+			},
+		},
+	},
 	{
 		Name: "basic start, status, stop loop",
 		SetUpScript: []string{

diff --git a/go/libraries/doltcore/sqle/stats/update.go b/go/libraries/doltcore/sqle/stats/update.go
@@ -80,7 +80,6 @@ func updateStats(ctx *sql.Context, sqlTable sql.Table, dTab *doltdb.Table, index
 		} else if cnt == 0 {
 			// table is empty
 			ret[meta.qual] = NewDoltStats()
-			ret[meta.qual].chunks = meta.allAddrs
 			ret[meta.qual].CreatedAt = time.Now()
 			ret[meta.qual].Columns = meta.cols
 			ret[meta.qual].Types = types
@@ -192,6 +191,10 @@ func mergeStatUpdates(newStats *DoltStats, idxMeta indexMeta) *DoltStats {
 		}
 	}
 
+	if len(mergeHist) == 0 {
+		return newStats
+	}
+
 	newStats.Histogram = mergeHist
 	newStats.chunks = idxMeta.allAddrs
 	newStats.updateActive()