Remove redundant CAST to String for LowCardinality/Enum/UUID (#262)

Author: azat

Cargo.lock

@@ -34,6 +34,8 @@ libc = { version = "*", default-features = false }
 size = { version = "*", default-features = false, features = ["std"] }
 tempfile = { version = "*", default-features = false }
 url = { version = "*", default-features = false }
+# Must match clickhouse-rs (read UUID columns)
+uuid = { version = "*", default-features = false }
 humantime = { version = "*", default-features = false }
 backtrace = { version = "*", default-features = false, features = ["std"] }
 futures = { version = "*", default-features = false, features = ["std"] }

Cargo.toml

@@ -10,7 +10,7 @@ use chrono::{DateTime, Local};
 use chrono_tz::Tz;
 use clickhouse_rs::{
     Block, Options, Pool,
-    types::{ColumnType, Complex, FromSql},
+    types::{ColumnType, Complex, Enum8, Enum16, FromSql, SqlType},
 };
 use futures_util::StreamExt;
 use std::collections::HashMap;
@@ -23,6 +23,30 @@ use std::str::FromStr;
 
 pub type Columns = Block<Complex>;
 
+// clickhouse-rs reads an Enum column as its bare integer (FromSql drops the name mapping) and a
+// UUID as uuid::Uuid, so block.get::<String> fails on both; resolve the enum name from the Vec
+// carried by the column type and format the UUID. String and LowCardinality(String) fall through
+// to a plain String read (get coerces LC).
+pub fn column_as_string<K: ColumnType>(block: &Block<K>, row: usize, name: &str) -> Result<String> {
+    let column = block
+        .columns()
+        .iter()
+        .find(|c| c.name() == name)
+        .ok_or_else(|| Error::msg(format!("Cannot get {name} column")))?;
+    fn name_of<T: PartialEq + ToString>(values: &[(String, T)], v: T) -> String {
+        values
+            .iter()
+            .find(|(_, k)| *k == v)
+            .map_or_else(|| v.to_string(), |(name, _)| name.clone())
+    }
+    Ok(match column.sql_type() {
+        SqlType::Enum8(values) => name_of(&values, block.get::<Enum8, _>(row, name)?.internal()),
+        SqlType::Enum16(values) => name_of(&values, block.get::<Enum16, _>(row, name)?.internal()),
+        SqlType::Uuid => block.get::<uuid::Uuid, _>(row, name)?.to_string(),
+        _ => block.get::<String, _>(row, name)?,
+    })
+}
+
 pub struct ClickHouse {
     pub quirks: ClickHouseQuirks,
     // Server has use_shared_merge_tree_log_pipeline enabled (SharedMergeTree-backed system.*_log).
@@ -532,7 +556,7 @@ impl ClickHouse {
                         elapsed / {q} AS elapsed,
                         user,
                         initial_user,
-                        ''::String AS exception,
+                        '' AS exception,
                         is_initial_query,
                         is_cancelled,
                         initial_query_id,
@@ -1029,9 +1053,9 @@ impl ClickHouse {
                         event_time,
                         event_time_microseconds,
                         thread_id,
-                        level::String AS level,
-                        logger_name::String AS logger_name,
-                        query_id::String AS query_id,
+                        level,
+                        logger_name,
+                        query_id,
                         message
                     FROM {}
                     WHERE
@@ -1458,7 +1482,7 @@ impl ClickHouse {
                         fromUnixTimestamp64Nano({start}) AS start_,
                         fromUnixTimestamp64Nano({end}) AS end_
                     SELECT
-                        event_type::String AS event_type,
+                        event_type,
                         event_time_microseconds,
                         duration_ms,
                         database,
@@ -1532,7 +1556,7 @@ impl ClickHouse {
                     {with}
                     SELECT
                         event_time_microseconds,
-                        trace_type::String AS trace_type,
+                        trace_type,
                         cityHash64(trace) AS stack_hash,
                         {host_expr} AS host_name
                     FROM {dbtable}
@@ -1602,8 +1626,8 @@ impl ClickHouse {
                         fromUnixTimestamp64Nano({end}) AS end_
                     SELECT
                         event_time_microseconds,
-                        level::String AS level,
-                        logger_name::String AS logger_name,
+                        level,
+                        logger_name,
                         message,
                         query_id,
                         {host_expr} AS host_name
@@ -1867,7 +1891,7 @@ impl ClickHouse {
                         database,
                         table,
                         format,
-                        status::String AS status,
+                        status,
                         bytes,
                         exception,
                         event_time_microseconds,
@@ -1934,7 +1958,7 @@ impl ClickHouse {
                     SELECT
                         file_name,
                         rows_processed,
-                        status::String AS status,
+                        status,
                         processing_start_time,
                         processing_end_time,
                         exception
@@ -1966,7 +1990,7 @@ impl ClickHouse {
                         table,
                         file_name,
                         rows_processed,
-                        status::String AS status,
+                        status,
                         processing_start_time,
                         processing_end_time,
                         exception
@@ -1997,7 +2021,7 @@ impl ClickHouse {
                         fromUnixTimestamp64Nano({start}) AS start_,
                         fromUnixTimestamp64Nano({end}) AS end_
                     SELECT
-                        event_type::String AS event_type,
+                        event_type,
                         query_id,
                         disk_name,
                         bucket,
@@ -2069,11 +2093,11 @@ impl ClickHouse {
                         fromUnixTimestamp64Nano({start}) AS start_,
                         fromUnixTimestamp64Nano({end}) AS end_
                     SELECT
-                        type::String AS type,
+                        type,
                         -- user/auth_type are Nullable
                         coalesce(user, '') AS user,
-                        coalesce(auth_type::String, '') AS auth_type,
-                        interface::String AS interface,
+                        coalesce(auth_type, '') AS auth_type,
+                        interface,
                         toString(client_address) AS client_address,
                         client_name,
                         failure_reason,
@@ -2106,7 +2130,7 @@ impl ClickHouse {
                         event_time,
                         session_id,
                         parent_path,
-                        operation::String AS operation,
+                        operation,
                         count::UInt64 AS count,
                         mapKeys(errors) AS error_names,
                         mapValues(errors) AS error_counts,

src/interpreter/clickhouse.rs

@@ -1,5 +1,5 @@
 use crate::interpreter::Query;
-use crate::interpreter::clickhouse::{MetricLogRow, QueryMetricRow};
+use crate::interpreter::clickhouse::{MetricLogRow, QueryMetricRow, column_as_string};
 use anyhow::Result;
 use chrono::{DateTime, Local};
 use chrono_tz::Tz;
@@ -614,7 +614,7 @@ impl PerfettoTraceBuilder {
         let process_uuid = self.process_track_uuid("Part Log");
 
         for i in 0..columns.row_count() {
-            let event_type: String = columns.get(i, "event_type").unwrap_or_default();
+            let event_type: String = column_as_string(columns, i, "event_type").unwrap_or_default();
             let event_time: DateTime<Tz> = match columns.get(i, "event_time_microseconds") {
                 Ok(v) => v,
                 Err(e) => {
@@ -740,7 +740,7 @@ impl PerfettoTraceBuilder {
         };
 
         for i in 0..columns.row_count() {
-            let level: String = columns.get(i, "level").unwrap_or_default();
+            let level: String = column_as_string(columns, i, "level").unwrap_or_default();
             let logger_name: String = columns.get(i, "logger_name").unwrap_or_default();
             let message: String = columns.get(i, "message").unwrap_or_default();
             let query_id: String = columns.get(i, "query_id").unwrap_or_default();
@@ -854,7 +854,7 @@ impl PerfettoTraceBuilder {
             let database: String = columns.get(i, "database").unwrap_or_default();
             let table: String = columns.get(i, "table").unwrap_or_default();
             let format: String = columns.get(i, "format").unwrap_or_default();
-            let status: String = columns.get(i, "status").unwrap_or_default();
+            let status: String = column_as_string(columns, i, "status").unwrap_or_default();
             let bytes: u64 = columns.get(i, "bytes").unwrap_or(0);
             let exception: String = columns.get(i, "exception").unwrap_or_default();
             let query_id: String = columns.get(i, "query_id").unwrap_or_default();
@@ -945,7 +945,7 @@ impl PerfettoTraceBuilder {
         for i in 0..columns.row_count() {
             let file_name: String = columns.get(i, "file_name").unwrap_or_default();
             let rows_processed: u64 = columns.get(i, "rows_processed").unwrap_or(0);
-            let status: String = columns.get(i, "status").unwrap_or_default();
+            let status: String = column_as_string(columns, i, "status").unwrap_or_default();
             let exception: String = columns.get(i, "exception").unwrap_or_default();
 
             let start_ns: u64 = match columns.get::<DateTime<Tz>, _>(i, "processing_start_time") {
@@ -983,7 +983,7 @@ impl PerfettoTraceBuilder {
             let table: String = columns.get(i, "table").unwrap_or_default();
             let file_name: String = columns.get(i, "file_name").unwrap_or_default();
             let rows_processed: u64 = columns.get(i, "rows_processed").unwrap_or(0);
-            let status: String = columns.get(i, "status").unwrap_or_default();
+            let status: String = column_as_string(columns, i, "status").unwrap_or_default();
             let exception: String = columns.get(i, "exception").unwrap_or_default();
 
             let start_ns: u64 = match columns.get::<DateTime<Tz>, _>(i, "processing_start_time") {
@@ -1020,7 +1020,7 @@ impl PerfettoTraceBuilder {
         let process_uuid = self.process_track_uuid("Blob Storage");
 
         for i in 0..columns.row_count() {
-            let event_type: String = columns.get(i, "event_type").unwrap_or_default();
+            let event_type: String = column_as_string(columns, i, "event_type").unwrap_or_default();
             let query_id: String = columns.get(i, "query_id").unwrap_or_default();
             let disk_name: String = columns.get(i, "disk_name").unwrap_or_default();
             let bucket: String = columns.get(i, "bucket").unwrap_or_default();
@@ -1113,10 +1113,10 @@ impl PerfettoTraceBuilder {
         let process_uuid = self.process_track_uuid("Sessions");
 
         for i in 0..columns.row_count() {
-            let session_type: String = columns.get(i, "type").unwrap_or_default();
+            let session_type: String = column_as_string(columns, i, "type").unwrap_or_default();
             let user: String = columns.get(i, "user").unwrap_or_default();
             let auth_type: String = columns.get(i, "auth_type").unwrap_or_default();
-            let interface: String = columns.get(i, "interface").unwrap_or_default();
+            let interface: String = column_as_string(columns, i, "interface").unwrap_or_default();
             let client_address: String = columns.get(i, "client_address").unwrap_or_default();
             let client_name: String = columns.get(i, "client_name").unwrap_or_default();
             let failure_reason: String = columns.get(i, "failure_reason").unwrap_or_default();
@@ -1159,7 +1159,7 @@ impl PerfettoTraceBuilder {
         let process_uuid = self.process_track_uuid("ZooKeeper");
 
         for i in 0..columns.row_count() {
-            let operation: String = columns.get(i, "operation").unwrap_or_default();
+            let operation: String = column_as_string(columns, i, "operation").unwrap_or_default();
             let count: u64 = columns.get(i, "count").unwrap_or(0);
             let average_latency: f64 = columns.get(i, "average_latency").unwrap_or(0.0);
             let parent_path: String = columns.get(i, "parent_path").unwrap_or_default();
@@ -1310,7 +1310,7 @@ impl PerfettoTraceBuilder {
     /// emitted by finalize_stack_traces() from build().
     pub fn add_stack_samples<K: ColumnType>(&mut self, samples: &Block<K>) {
         for i in 0..samples.row_count() {
-            let trace_type: String = samples.get(i, "trace_type").unwrap_or_default();
+            let trace_type: String = column_as_string(samples, i, "trace_type").unwrap_or_default();
             let stack_hash: u64 = samples.get(i, "stack_hash").unwrap_or_default();
             let host_name: String = samples.get(i, "host_name").unwrap_or_default();
 

src/interpreter/perfetto.rs

@@ -24,7 +24,7 @@ impl ViewProvider for BackupsViewProvider {
     fn show(&self, siv: &mut Cursive, context: ContextArc) {
         let columns = vec![
             "name",
-            "status::String status",
+            "status",
             "error",
             "start_time",
             "end_time",

src/view/providers/backups.rs

@@ -19,7 +19,7 @@ impl ViewProvider for DictionariesViewProvider {
     fn show(&self, siv: &mut Cursive, context: ContextArc) {
         let columns = vec![
             "name",
-            "status::String status",
+            "status",
             "source",
             "bytes_allocated memory",
             "query_count queries",

src/view/providers/dictionaries.rs

@@ -26,7 +26,7 @@ impl ViewProvider for ErrorLogViewProvider {
         }
 
         let columns = vec![
-            "error::String name",
+            "error name",
             "any(code) code",
             "sum(value) total",
             "total bar",

src/view/providers/error_log.rs

@@ -38,7 +38,7 @@ impl ViewProvider for LoggerNamesViewProvider {
         let end = view_options.end;
 
         let mut columns = vec![
-            "logger_name::String logger_name",
+            "logger_name",
             "count() count",
             "countIf(level = 'Fatal') fatal",
             "countIf(level = 'Critical') critical",

src/view/providers/logger_names.rs

@@ -38,7 +38,7 @@ fn get_columns(is_dialog: bool) -> Vec<&'static str> {
             "rows_written",
             "memory_usage memory",
             "now()-elapsed _create_time",
-            "tables.uuid::String _table_uuid",
+            "tables.uuid _table_uuid",
         ]
     } else {
         vec![
@@ -54,7 +54,7 @@ fn get_columns(is_dialog: bool) -> Vec<&'static str> {
             "rows_written",
             "memory_usage memory",
             "now()-elapsed _create_time",
-            "tables.uuid::String _table_uuid",
+            "tables.uuid _table_uuid",
         ]
     }
 }

src/view/providers/merges.rs

@@ -123,30 +123,30 @@ fn build_query(context: &ContextArc, filters: &FilterParams, is_dialog: bool) ->
 
     let select_clause = if is_dialog {
         r#"event_time,
-            event_type::String event_type,
+            event_type,
             part_name,
-            merge_algorithm::String merge_algorithm,
+            merge_algorithm,
             part_type,
             rows,
             size_in_bytes,
             duration_ms,
             peak_memory_usage,
             exception,
-            table_uuid::String _table_uuid"#
+            table_uuid _table_uuid"#
     } else {
         r#"event_time,
-            event_type::String event_type,
+            event_type,
             database,
             table,
             part_name,
-            merge_algorithm::String merge_algorithm,
+            merge_algorithm,
             part_type,
             rows,
             size_in_bytes,
             duration_ms,
             peak_memory_usage,
             exception,
-            table_uuid::String _table_uuid"#
+            table_uuid _table_uuid"#
     };
 
     format!(