Port hook path to C

CMakeLists.txt

@@ -60,7 +60,7 @@ set(BUILD_BENCHMARK OFF CACHE BOOL "Disable clickhouse-cpp benchmarks" FORCE)
 add_subdirectory(third_party/clickhouse-cpp EXCLUDE_FROM_ALL)
 
 # Collect source files
-file(GLOB_RECURSE SOURCES src/*.cc)
+file(GLOB_RECURSE SOURCES src/*.cc src/*.c)
 
 # Build shared library
 add_library(pg_stat_ch SHARED ${SOURCES})

docker/init/00-schema.sql

@@ -53,6 +53,8 @@ CREATE TABLE pg_stat_ch.events_raw
 
     query_id Int64 COMMENT '64-bit hash identifying normalized queries. Queries differing only in constants share the same query_id. Use for aggregating statistics across similar queries.',
 
+    parent_query_id UInt64 COMMENT 'query_id of the calling query (e.g. the plpgsql function that issued this SPI statement). 0 for top-level queries. Use WHERE parent_query_id = 0 to restrict aggregations to top-level queries and avoid double-counting CPU and duration.',
+
     cmd_type LowCardinality(String) COMMENT 'Command type: SELECT, INSERT, UPDATE, DELETE, MERGE, UTILITY, or UNKNOWN. Use for workload characterization (read-heavy vs write-heavy).',
 
     rows UInt64 COMMENT 'Rows returned (SELECT) or affected (INSERT/UPDATE/DELETE). HIGH: large result sets or bulk operations. LOW: point queries. Watch for unexpected HIGH values indicating missing WHERE clauses.',

migrations/001_add_parent_query_id.sql

@@ -0,0 +1,12 @@
+-- Migration: add parent_query_id column
+--
+-- Introduced in pg_stat_ch 0.4.x. Each event now carries the query_id of its
+-- calling query (e.g. the plpgsql function that issued an SPI statement).
+-- Top-level queries emit 0. Use WHERE parent_query_id = 0 in aggregations to
+-- avoid double-counting CPU and duration across nested calls.
+--
+-- Run against your ClickHouse instance before upgrading the extension:
+--   clickhouse-client < migrations/001_add_parent_query_id.sql
+
+ALTER TABLE pg_stat_ch.events_raw
+    ADD COLUMN IF NOT EXISTS parent_query_id UInt64 DEFAULT 0;

src/config/guc.cc → src/config/guc.c

@@ -1,27 +1,23 @@
 // pg_stat_ch GUC (Grand Unified Configuration) implementation
 
-extern "C" {
 #include "postgres.h"
 
 #include "utils/guc.h"
-}
-
-#include <array>
 
 #include "config/guc.h"
 
 // GUC variable storage
 bool psch_enabled = true;
 bool psch_use_otel = false;
-char* psch_clickhouse_host = nullptr;
+char* psch_clickhouse_host = NULL;
 int psch_clickhouse_port = 9000;
-char* psch_clickhouse_user = nullptr;
-char* psch_clickhouse_password = nullptr;
-char* psch_clickhouse_database = nullptr;
+char* psch_clickhouse_user = NULL;
+char* psch_clickhouse_password = NULL;
+char* psch_clickhouse_database = NULL;
 bool psch_clickhouse_use_tls = false;
 bool psch_clickhouse_skip_tls_verify = false;
-char* psch_otel_endpoint = nullptr;
-char* psch_hostname = nullptr;
+char* psch_otel_endpoint = NULL;
+char* psch_hostname = NULL;
 int psch_queue_capacity = 131072;
 int psch_flush_interval_ms = 200;
 int psch_batch_max = 200000;
@@ -35,7 +31,7 @@ bool psch_debug_force_locked_overflow = false;
 
 // Log level options (matches PostgreSQL's server_message_level_options pattern)
 // clang-format off
-static const std::array<config_enum_entry, 13> log_elevel_options = {{
+static const struct config_enum_entry log_elevel_options[] = {
     {"debug5",  DEBUG5,  false},
     {"debug4",  DEBUG4,  false},
     {"debug3",  DEBUG3,  false},
@@ -48,16 +44,15 @@ static const std::array<config_enum_entry, 13> log_elevel_options = {{
     {"error",   ERROR,   false},
     {"fatal",   FATAL,   false},
     {"panic",   PANIC,   false},
-    {nullptr,   0,       false},
-}};
+    {NULL,      0,       false},
+};
 // clang-format on
 
-extern "C" {
-
 // Check hook to ensure queue_capacity is a power of 2.
 // Parameters follow PostgreSQL GUC check hook signature.
-static bool check_psch_queue_capacity(int* newval, void** extra [[maybe_unused]],
-                                      GucSource source [[maybe_unused]]) {
+static bool check_psch_queue_capacity(int* newval, void** extra, GucSource source) {
+  (void)extra;
+  (void)source;
   // Check if value is positive and a power of 2
   if (*newval <= 0) {
     GUC_check_errdetail("pg_stat_ch.queue_capacity must be positive.");
@@ -81,12 +76,12 @@ void PschInitGuc(void) {
   DefineCustomBoolVariable(
       "pg_stat_ch.enabled",                                   // name
       "Enable or disable pg_stat_ch query telemetry collection.",  // short_desc
-      nullptr,                                                // long_desc
+      NULL,                                                   // long_desc
       &psch_enabled,                                          // valueAddr
       true,                                                   // bootValue
       PGC_SIGHUP,                                             // context
       0,                                                      // flags
-      nullptr, nullptr, nullptr);                             // hooks
+      NULL, NULL, NULL);                                      // hooks
 
   DefineCustomBoolVariable(
       "pg_stat_ch.use_otel",
@@ -96,131 +91,131 @@ void PschInitGuc(void) {
       false,
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomStringVariable(
       "pg_stat_ch.clickhouse_host",
       "ClickHouse server hostname.",
-      nullptr,
+      NULL,
       &psch_clickhouse_host,
       "localhost",
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.clickhouse_port",
       "ClickHouse server native protocol port.",
-      nullptr,
+      NULL,
       &psch_clickhouse_port,
       9000,           // bootValue
       1, 65535,       // min, max
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomStringVariable(
       "pg_stat_ch.clickhouse_user",
       "ClickHouse user name.",
-      nullptr,
+      NULL,
       &psch_clickhouse_user,
       "default",
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomStringVariable(
       "pg_stat_ch.clickhouse_password",
       "ClickHouse user password.",
-      nullptr,
+      NULL,
       &psch_clickhouse_password,
       "",
       PGC_POSTMASTER,
       GUC_SUPERUSER_ONLY,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomStringVariable(
       "pg_stat_ch.clickhouse_database",
       "ClickHouse database name for telemetry storage.",
-      nullptr,
+      NULL,
       &psch_clickhouse_database,
       "pg_stat_ch",
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomBoolVariable(
       "pg_stat_ch.clickhouse_use_tls",
       "Enable TLS for ClickHouse connections.",
-      nullptr,
+      NULL,
       &psch_clickhouse_use_tls,
       false,
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomBoolVariable(
       "pg_stat_ch.clickhouse_skip_tls_verify",
       "Skip TLS certificate verification (insecure, for testing only).",
-      nullptr,
+      NULL,
       &psch_clickhouse_skip_tls_verify,
       false,
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomStringVariable(
       "pg_stat_ch.otel_endpoint",
       "OpenTelemetry gRPC endpoint (host:port).",
-      nullptr,
+      NULL,
       &psch_otel_endpoint,
       "localhost:4317",
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomStringVariable(
       "pg_stat_ch.hostname",
       "Override the hostname of the current machine.",
-      nullptr,
+      NULL,
       &psch_hostname,
       "",
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.queue_capacity",
       "Maximum number of events in the shared memory queue (must be a power of 2).",
-      nullptr,
+      NULL,
       &psch_queue_capacity,
       131072,             // bootValue
       1024, 4194304,      // min, max
       PGC_POSTMASTER,
       0,
-      check_psch_queue_capacity, nullptr, nullptr);
+      check_psch_queue_capacity, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.flush_interval_ms",
       "Interval in milliseconds between ClickHouse export batches.",
-      nullptr,
+      NULL,
       &psch_flush_interval_ms,
       200,            // bootValue
       100, 60000,     // min, max
       PGC_SIGHUP,
       GUC_UNIT_MS,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.batch_max",
       "Maximum number of events per ClickHouse insert batch.",
-      nullptr,
+      NULL,
       &psch_batch_max,
       200000,           // bootValue
       1, 1000000,       // min, max
       PGC_SIGHUP,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.otel_log_queue_size",
@@ -232,7 +227,7 @@ void PschInitGuc(void) {
       512, 1048576,       // min, max
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.otel_log_batch_size",
@@ -244,7 +239,7 @@ void PschInitGuc(void) {
       1, 131072,          // min, max
       PGC_POSTMASTER,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.otel_log_max_bytes",
@@ -257,7 +252,7 @@ void PschInitGuc(void) {
       65536, 64 * 1024 * 1024,  // min: 64 KiB, max: 64 MiB
       PGC_POSTMASTER,
       GUC_UNIT_BYTE,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.otel_log_delay_ms",
@@ -269,7 +264,7 @@ void PschInitGuc(void) {
       10, 60000,          // min, max
       PGC_POSTMASTER,
       GUC_UNIT_MS,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomIntVariable(
       "pg_stat_ch.otel_metric_interval_ms",
@@ -281,7 +276,7 @@ void PschInitGuc(void) {
       100, 300000,         // min, max (100ms to 5min)
       PGC_POSTMASTER,
       GUC_UNIT_MS,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
 
   DefineCustomEnumVariable(
       "pg_stat_ch.log_min_elevel",
@@ -290,10 +285,10 @@ void PschInitGuc(void) {
       "'error' for errors only, or 'debug5' for all messages.",
       &psch_log_min_elevel,
       WARNING,
-      log_elevel_options.data(),
+      log_elevel_options,
       PGC_SUSET,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
   DefineCustomBoolVariable(
       "pg_stat_ch.debug_force_locked_overflow",
       "Force HandleOverflow in locked path (debug/test only).",
@@ -303,10 +298,8 @@ void PschInitGuc(void) {
       false,
       PGC_SUSET,
       0,
-      nullptr, nullptr, nullptr);
+      NULL, NULL, NULL);
   // clang-format on
 
   EmitWarningsOnPlaceholders("pg_stat_ch");
 }
-
-}  // extern "C"

src/export/stats_exporter.cc

@@ -93,6 +93,7 @@ void ExportEventStats(const std::vector<PschEvent>& events, StatsExporter* expor
   auto col_username = exporter->DbUserColumn();
   auto col_pid = exporter->RecordInt32("pid");
   auto col_query_id = exporter->RecordInt64("query_id");
+  auto col_parent_query_id = exporter->RecordUInt64("parent_query_id");
   auto col_cmd_type = exporter->DbOperationColumn();
   auto col_rows = exporter->MetricUInt64("rows");
   auto col_query = exporter->DbQueryTextColumn();
@@ -148,6 +149,7 @@ void ExportEventStats(const std::vector<PschEvent>& events, StatsExporter* expor
     col_username->Append(std::string(ev.username, ev.username_len));
     col_pid->Append(ev.pid);
     col_query_id->Append(static_cast<int64_t>(ev.queryid));
+    col_parent_query_id->Append(static_cast<int64_t>(ev.parent_query_id));
     col_cmd_type->Append(CmdTypeToString(ev.cmd_type));
     col_rows->Append(ev.rows);