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480 lines
16 KiB

package engine
import (
"context"
"strconv"
"strings"
"testing"
)
// TestParseSQL_OFFSET_EdgeCases tests edge cases for OFFSET parsing
func TestParseSQL_OFFSET_EdgeCases(t *testing.T) {
tests := []struct {
name string
sql string
wantErr bool
validate func(t *testing.T, stmt Statement, err error)
}{
{
name: "Valid LIMIT OFFSET with WHERE",
sql: "SELECT * FROM users WHERE age > 18 LIMIT 10 OFFSET 5",
wantErr: false,
validate: func(t *testing.T, stmt Statement, err error) {
selectStmt := stmt.(*SelectStatement)
if selectStmt.Limit == nil {
t.Fatal("Expected LIMIT clause, got nil")
}
if selectStmt.Limit.Offset == nil {
t.Fatal("Expected OFFSET clause, got nil")
}
if selectStmt.Where == nil {
t.Fatal("Expected WHERE clause, got nil")
}
},
},
{
name: "LIMIT OFFSET with mixed case",
sql: "select * from users limit 5 offset 3",
wantErr: false,
validate: func(t *testing.T, stmt Statement, err error) {
selectStmt := stmt.(*SelectStatement)
offsetVal := selectStmt.Limit.Offset.(*SQLVal)
if string(offsetVal.Val) != "3" {
t.Errorf("Expected offset value '3', got '%s'", string(offsetVal.Val))
}
},
},
{
name: "LIMIT OFFSET with extra spaces",
sql: "SELECT * FROM users LIMIT 10 OFFSET 20 ",
wantErr: false,
validate: func(t *testing.T, stmt Statement, err error) {
selectStmt := stmt.(*SelectStatement)
limitVal := selectStmt.Limit.Rowcount.(*SQLVal)
offsetVal := selectStmt.Limit.Offset.(*SQLVal)
if string(limitVal.Val) != "10" {
t.Errorf("Expected limit value '10', got '%s'", string(limitVal.Val))
}
if string(offsetVal.Val) != "20" {
t.Errorf("Expected offset value '20', got '%s'", string(offsetVal.Val))
}
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
stmt, err := ParseSQL(tt.sql)
if tt.wantErr {
if err == nil {
t.Errorf("Expected error, but got none")
}
return
}
if err != nil {
t.Errorf("Unexpected error: %v", err)
return
}
if tt.validate != nil {
tt.validate(t, stmt, err)
}
})
}
}
// TestSQLEngine_OFFSET_EdgeCases tests edge cases for OFFSET execution
func TestSQLEngine_OFFSET_EdgeCases(t *testing.T) {
engine := NewTestSQLEngine()
t.Run("OFFSET larger than result set", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT * FROM user_events LIMIT 5 OFFSET 100")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// Should return empty result set
if len(result.Rows) != 0 {
t.Errorf("Expected 0 rows when OFFSET > total rows, got %d", len(result.Rows))
}
})
t.Run("OFFSET with LIMIT 0", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT * FROM user_events LIMIT 0 OFFSET 2")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// LIMIT 0 should return no rows regardless of OFFSET
if len(result.Rows) != 0 {
t.Errorf("Expected 0 rows with LIMIT 0, got %d", len(result.Rows))
}
})
t.Run("High OFFSET with small LIMIT", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT * FROM user_events LIMIT 1 OFFSET 3")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// In clean mock environment, we have 4 live_log rows from unflushed messages
// LIMIT 1 OFFSET 3 should return the 4th row (0-indexed: rows 0,1,2,3 -> return row 3)
if len(result.Rows) != 1 {
t.Errorf("Expected 1 row with LIMIT 1 OFFSET 3 (4th live_log row), got %d", len(result.Rows))
}
})
}
// TestSQLEngine_OFFSET_ErrorCases tests error conditions for OFFSET
func TestSQLEngine_OFFSET_ErrorCases(t *testing.T) {
engine := NewTestSQLEngine()
// Test negative OFFSET - should be caught during execution
t.Run("Negative OFFSET value", func(t *testing.T) {
// Note: This would need to be implemented as validation in the execution engine
// For now, we test that the parser accepts it but execution might handle it
_, err := ParseSQL("SELECT * FROM users LIMIT 10 OFFSET -5")
if err != nil {
t.Logf("Parser rejected negative OFFSET (this is expected): %v", err)
} else {
// Parser accepts it, execution should handle validation
t.Logf("Parser accepts negative OFFSET, execution should validate")
}
})
// Test very large OFFSET
t.Run("Very large OFFSET value", func(t *testing.T) {
largeOffset := "2147483647" // Max int32
sql := "SELECT * FROM user_events LIMIT 1 OFFSET " + largeOffset
result, err := engine.ExecuteSQL(context.Background(), sql)
if err != nil {
// Large OFFSET might cause parsing or execution errors
if strings.Contains(err.Error(), "out of valid range") {
t.Logf("Large OFFSET properly rejected: %v", err)
} else {
t.Errorf("Unexpected error for large OFFSET: %v", err)
}
} else if result.Error != nil {
if strings.Contains(result.Error.Error(), "out of valid range") {
t.Logf("Large OFFSET properly rejected during execution: %v", result.Error)
} else {
t.Errorf("Unexpected execution error for large OFFSET: %v", result.Error)
}
} else {
// Should return empty result for very large offset
if len(result.Rows) != 0 {
t.Errorf("Expected 0 rows for very large OFFSET, got %d", len(result.Rows))
}
}
})
}
// TestSQLEngine_OFFSET_Consistency tests that OFFSET produces consistent results
func TestSQLEngine_OFFSET_Consistency(t *testing.T) {
engine := NewTestSQLEngine()
// Get all rows first
allResult, err := engine.ExecuteSQL(context.Background(), "SELECT * FROM user_events")
if err != nil {
t.Fatalf("Failed to get all rows: %v", err)
}
if allResult.Error != nil {
t.Fatalf("Failed to get all rows: %v", allResult.Error)
}
totalRows := len(allResult.Rows)
if totalRows == 0 {
t.Skip("No data available for consistency test")
}
// Test that OFFSET + remaining rows = total rows
for offset := 0; offset < totalRows; offset++ {
t.Run("OFFSET_"+strconv.Itoa(offset), func(t *testing.T) {
sql := "SELECT * FROM user_events LIMIT 100 OFFSET " + strconv.Itoa(offset)
result, err := engine.ExecuteSQL(context.Background(), sql)
if err != nil {
t.Fatalf("Error with OFFSET %d: %v", offset, err)
}
if result.Error != nil {
t.Fatalf("Query error with OFFSET %d: %v", offset, result.Error)
}
expectedRows := totalRows - offset
if len(result.Rows) != expectedRows {
t.Errorf("OFFSET %d: expected %d rows, got %d", offset, expectedRows, len(result.Rows))
}
})
}
}
// TestSQLEngine_LIMIT_OFFSET_BugFix tests the specific bug fix for LIMIT with OFFSET
// This test addresses the issue where LIMIT 10 OFFSET 5 was returning 5 rows instead of 10
func TestSQLEngine_LIMIT_OFFSET_BugFix(t *testing.T) {
engine := NewTestSQLEngine()
// Test the specific scenario that was broken: LIMIT 10 OFFSET 5 should return 10 rows
t.Run("LIMIT 10 OFFSET 5 returns correct count", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT id, user_id, id+user_id FROM user_events LIMIT 10 OFFSET 5")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// The bug was that this returned 5 rows instead of 10
// After fix, it should return up to 10 rows (limited by available data)
actualRows := len(result.Rows)
if actualRows > 10 {
t.Errorf("LIMIT 10 violated: got %d rows", actualRows)
}
t.Logf("LIMIT 10 OFFSET 5 returned %d rows (within limit)", actualRows)
// Verify we have the expected columns
expectedCols := 3 // id, user_id, id+user_id
if len(result.Columns) != expectedCols {
t.Errorf("Expected %d columns, got %d columns: %v", expectedCols, len(result.Columns), result.Columns)
}
})
// Test various LIMIT and OFFSET combinations to ensure correct row counts
testCases := []struct {
name string
limit int
offset int
allowEmpty bool // Whether 0 rows is acceptable (for large offsets)
}{
{"LIMIT 5 OFFSET 0", 5, 0, false},
{"LIMIT 5 OFFSET 2", 5, 2, false},
{"LIMIT 8 OFFSET 3", 8, 3, false},
{"LIMIT 15 OFFSET 1", 15, 1, false},
{"LIMIT 3 OFFSET 7", 3, 7, true}, // Large offset may exceed data
{"LIMIT 12 OFFSET 4", 12, 4, true}, // Large offset may exceed data
}
for _, tc := range testCases {
t.Run(tc.name, func(t *testing.T) {
sql := "SELECT id, user_id FROM user_events LIMIT " + strconv.Itoa(tc.limit) + " OFFSET " + strconv.Itoa(tc.offset)
result, err := engine.ExecuteSQL(context.Background(), sql)
if err != nil {
t.Fatalf("Expected no error for %s, got %v", tc.name, err)
}
if result.Error != nil {
t.Fatalf("Expected no query error for %s, got %v", tc.name, result.Error)
}
actualRows := len(result.Rows)
// Verify LIMIT is never exceeded
if actualRows > tc.limit {
t.Errorf("%s: LIMIT violated - returned %d rows, limit was %d", tc.name, actualRows, tc.limit)
}
// Check if we expect rows
if !tc.allowEmpty && actualRows == 0 {
t.Errorf("%s: expected some rows but got 0 (insufficient test data or early termination bug)", tc.name)
}
t.Logf("%s: returned %d rows (within limit %d)", tc.name, actualRows, tc.limit)
})
}
}
// TestSQLEngine_OFFSET_DataCollectionBuffer tests that the enhanced data collection buffer works
func TestSQLEngine_OFFSET_DataCollectionBuffer(t *testing.T) {
engine := NewTestSQLEngine()
// Test scenarios that specifically stress the data collection buffer enhancement
t.Run("Large OFFSET with small LIMIT", func(t *testing.T) {
// This scenario requires collecting more data upfront to handle the offset
result, err := engine.ExecuteSQL(context.Background(), "SELECT * FROM user_events LIMIT 2 OFFSET 8")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// Should either return 2 rows or 0 (if offset exceeds available data)
// The bug would cause early termination and return 0 incorrectly
actualRows := len(result.Rows)
if actualRows != 0 && actualRows != 2 {
t.Errorf("Expected 0 or 2 rows for LIMIT 2 OFFSET 8, got %d", actualRows)
}
})
t.Run("Medium OFFSET with medium LIMIT", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT id, user_id FROM user_events LIMIT 6 OFFSET 4")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// With proper buffer enhancement, this should work correctly
actualRows := len(result.Rows)
if actualRows > 6 {
t.Errorf("LIMIT 6 should never return more than 6 rows, got %d", actualRows)
}
})
t.Run("Progressive OFFSET test", func(t *testing.T) {
// Test that increasing OFFSET values work consistently
baseSQL := "SELECT id FROM user_events LIMIT 3 OFFSET "
for offset := 0; offset <= 5; offset++ {
sql := baseSQL + strconv.Itoa(offset)
result, err := engine.ExecuteSQL(context.Background(), sql)
if err != nil {
t.Fatalf("Error at OFFSET %d: %v", offset, err)
}
if result.Error != nil {
t.Fatalf("Query error at OFFSET %d: %v", offset, result.Error)
}
actualRows := len(result.Rows)
// Each should return at most 3 rows (LIMIT 3)
if actualRows > 3 {
t.Errorf("OFFSET %d: LIMIT 3 returned %d rows (should be ≤ 3)", offset, actualRows)
}
t.Logf("OFFSET %d: returned %d rows", offset, actualRows)
}
})
}
// TestSQLEngine_LIMIT_OFFSET_ArithmeticExpressions tests LIMIT/OFFSET with arithmetic expressions
func TestSQLEngine_LIMIT_OFFSET_ArithmeticExpressions(t *testing.T) {
engine := NewTestSQLEngine()
// Test the exact scenario from the user's example
t.Run("Arithmetic expressions with LIMIT OFFSET", func(t *testing.T) {
// First query: LIMIT 10 (should return 10 rows)
result1, err := engine.ExecuteSQL(context.Background(), "SELECT id, user_id, id+user_id FROM user_events LIMIT 10")
if err != nil {
t.Fatalf("Expected no error for first query, got %v", err)
}
if result1.Error != nil {
t.Fatalf("Expected no query error for first query, got %v", result1.Error)
}
// Second query: LIMIT 10 OFFSET 5 (should return 10 rows, not 5)
result2, err := engine.ExecuteSQL(context.Background(), "SELECT id, user_id, id+user_id FROM user_events LIMIT 10 OFFSET 5")
if err != nil {
t.Fatalf("Expected no error for second query, got %v", err)
}
if result2.Error != nil {
t.Fatalf("Expected no query error for second query, got %v", result2.Error)
}
// Verify column structure is correct
expectedColumns := []string{"id", "user_id", "id+user_id"}
if len(result2.Columns) != len(expectedColumns) {
t.Errorf("Expected %d columns, got %d", len(expectedColumns), len(result2.Columns))
}
// The key assertion: LIMIT 10 OFFSET 5 should return 10 rows (if available)
// This was the specific bug reported by the user
rows1 := len(result1.Rows)
rows2 := len(result2.Rows)
t.Logf("LIMIT 10: returned %d rows", rows1)
t.Logf("LIMIT 10 OFFSET 5: returned %d rows", rows2)
if rows1 >= 15 { // If we have enough data for the test to be meaningful
if rows2 != 10 {
t.Errorf("LIMIT 10 OFFSET 5 should return 10 rows when sufficient data available, got %d", rows2)
}
} else {
t.Logf("Insufficient data (%d rows) to fully test LIMIT 10 OFFSET 5 scenario", rows1)
}
// Verify multiplication expressions work in the second query
if len(result2.Rows) > 0 {
for i, row := range result2.Rows {
if len(row) >= 3 { // Check if we have the id+user_id column
idVal := row[0].ToString() // id column
userIdVal := row[1].ToString() // user_id column
sumVal := row[2].ToString() // id+user_id column
t.Logf("Row %d: id=%s, user_id=%s, id+user_id=%s", i, idVal, userIdVal, sumVal)
}
}
}
})
// Test multiplication specifically
t.Run("Multiplication expressions", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT id, id*2 FROM user_events LIMIT 3")
if err != nil {
t.Fatalf("Expected no error for multiplication test, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error for multiplication test, got %v", result.Error)
}
if len(result.Columns) != 2 {
t.Errorf("Expected 2 columns for multiplication test, got %d", len(result.Columns))
}
if len(result.Rows) == 0 {
t.Error("Expected some rows for multiplication test")
}
// Check that id*2 column has values (not empty)
for i, row := range result.Rows {
if len(row) >= 2 {
idVal := row[0].ToString()
doubledVal := row[1].ToString()
if doubledVal == "" || doubledVal == "0" {
t.Errorf("Row %d: id*2 should not be empty, id=%s, id*2=%s", i, idVal, doubledVal)
} else {
t.Logf("Row %d: id=%s, id*2=%s ✓", i, idVal, doubledVal)
}
}
}
})
}
// TestSQLEngine_OFFSET_WithAggregation tests OFFSET with aggregation queries
func TestSQLEngine_OFFSET_WithAggregation(t *testing.T) {
engine := NewTestSQLEngine()
// Note: Aggregation queries typically return single rows, so OFFSET behavior is different
t.Run("COUNT with OFFSET", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT COUNT(*) FROM user_events LIMIT 1 OFFSET 0")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// COUNT typically returns 1 row, so OFFSET 0 should return that row
if len(result.Rows) != 1 {
t.Errorf("Expected 1 row for COUNT with OFFSET 0, got %d", len(result.Rows))
}
})
t.Run("COUNT with OFFSET 1", func(t *testing.T) {
result, err := engine.ExecuteSQL(context.Background(), "SELECT COUNT(*) FROM user_events LIMIT 1 OFFSET 1")
if err != nil {
t.Fatalf("Expected no error, got %v", err)
}
if result.Error != nil {
t.Fatalf("Expected no query error, got %v", result.Error)
}
// COUNT returns 1 row, so OFFSET 1 should return 0 rows
if len(result.Rows) != 0 {
t.Errorf("Expected 0 rows for COUNT with OFFSET 1, got %d", len(result.Rows))
}
})
}