Improve docs and add more tests

http_integration_test.go

@@ -87,3 +87,38 @@ func (suite *integrationTestSuite) TestE2ESuccessfulHttpBasicAuthWithTlsProxy()
 		return reflect.DeepEqual(expected, data)
 	}, eventualDataTimeout, 100*time.Millisecond)
 }
+
+func (suite *integrationTestSuite) TestServerSideError() {
+	if testing.Short() {
+		suite.T().Skip("skipping integration test")
+	}
+
+	ctx := context.Background()
+
+	var (
+		sender qdb.LineSender
+		err    error
+	)
+
+	questdbC, err := setupQuestDB(ctx, noAuth)
+	assert.NoError(suite.T(), err)
+
+	sender, err = qdb.NewLineSender(ctx, qdb.WithHttp(), qdb.WithAddress(questdbC.httpAddress))
+	assert.NoError(suite.T(), err)
+
+	err = sender.Table(testTable).Int64Column("long_col", 42).AtNow(ctx)
+	assert.NoError(suite.T(), err)
+	err = sender.Flush(ctx)
+	assert.NoError(suite.T(), err)
+
+	// Now, use wrong type for the long_col.
+	err = sender.Table(testTable).StringColumn("long_col", "42").AtNow(ctx)
+	assert.NoError(suite.T(), err)
+	err = sender.Flush(ctx)
+	assert.Error(suite.T(), err)
+	assert.ErrorContains(suite.T(), err, "my_test_table, column: long_col; cast error from protocol type: STRING to column type")
+	assert.ErrorContains(suite.T(), err, "line: 1")
+
+	sender.Close(ctx)
+	questdbC.Stop(ctx)
+}

http_sender_test.go

@@ -143,6 +143,14 @@ func TestHttpPathologicalCasesFromConf(t *testing.T) {
 	}
 }
 
+func TestErrorWhenSenderTypeIsNotSpecified(t *testing.T) {
+	ctx := context.Background()
+
+	_, err := qdb.NewLineSender(ctx)
+	assert.Error(t, err)
+	assert.ErrorContains(t, err, "sender type is not specified: use WithHttp or WithTcp")
+}
+
 func TestHttpErrorWhenMaxBufferSizeIsReached(t *testing.T) {
 	ctx := context.Background()
 

sender.go

@@ -407,7 +407,7 @@ func WithAutoFlushInterval(interval time.Duration) LineSenderOption {
 // http(s) and tcp(s):
 // -------------------
 // addr:           hostname/port of QuestDB endpoint
-// init_buf_size:  initial growable ILP buffer size in bytes (defaults to 64KiB)
+// init_buf_size:  initial growable ILP buffer size in bytes (defaults to 128KiB)
 // tls_verify:     determines if TLS certificates should be validated (defaults to "on", can be set to "unsafe_off")
 //
 // http(s)-only
@@ -420,13 +420,12 @@ func WithAutoFlushInterval(interval time.Duration) LineSenderOption {
 // request_min_throughput: bytes per second, used to calculate each request's timeout (defaults to 100KiB/s)
 // request_timeout:        minimum request timeout in milliseconds (defaults to 10 seconds)
 // retry_timeout:          cumulative maximum millisecond duration spent in retries (defaults to 10 seconds)
-// max_buf_size:           buffer growth limit in bytes. client errors if breached (default is 100MiB)
+// max_buf_size:           buffer growth limit in bytes. Client errors if breached (default is 100MiB)
 //
 // tcp(s)-only
 // -----------
 // username:  KID (key ID) for ECDSA authentication
 // token:     Secret K (D) for ECDSA authentication
-
 func LineSenderFromConf(ctx context.Context, conf string) (LineSender, error) {
 	c, err := confFromStr(conf)
 	if err != nil {