From 91cfc397d2d559bce4b68157a5a69bdd7cd29084 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Wed, 5 Mar 2025 18:05:19 -0500 Subject: [PATCH v13 2/2] Add connection establishment duration logging Add log_connections option 'durations' which logs durations of several key parts of connection establishment and backend setup. For an incoming connection, starting from when the postmaster gets a socket from accept() and ending when the forked child backend is first ready for query, there are multiple steps that could each take longer than expected due to external factors. This logging provides visibility into authentication and fork duration as well as the end-to-end connection establishment and initialization time. To make this portable, the timings captured in the postmaster (socket creation time, fork initiation time) are passed through the BackendStartupData instead of simply saved in backend local memory. Author: Melanie Plageman Reviewed-by: Bertrand Drouvot Reviewed-by: Fujii Masao Reviewed-by: Jelte Fennema-Nio Reviewed-by: Jacob Champion Reviewed-by: Guillaume Lelarge Discussion: https://postgr.es/m/flat/CAAKRu_b_smAHK0ZjrnL5GRxnAVWujEXQWpLXYzGbmpcZd3nLYw%40mail.gmail.com --- doc/src/sgml/config.sgml | 10 ++++ src/backend/postmaster/launch_backend.c | 31 +++++++++++++ src/backend/postmaster/postmaster.c | 6 +++ src/backend/tcop/backend_startup.c | 4 ++ src/backend/tcop/postgres.c | 35 ++++++++++++++ src/backend/utils/init/postinit.c | 6 +++ src/include/miscadmin.h | 7 +++ src/include/tcop/backend_startup.h | 56 +++++++++++++++++++++-- src/include/utils/timestamp.h | 9 ++++ src/test/authentication/t/001_password.pl | 18 +++++++- src/tools/pgindent/typedefs.list | 1 + 11 files changed, 179 insertions(+), 4 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 52f5a115391..b7180ccfffb 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7366,6 +7366,16 @@ local0.* /var/log/postgresql + + durations + + Logs the time spent establishing the connection and setting up the + backend at the time the connection is ready for use. The log + message includes the total setup duration as well as several + component durations, including process creation and authentication. + + + all diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c index 47375e5bfaa..74b0c33adaa 100644 --- a/src/backend/postmaster/launch_backend.c +++ b/src/backend/postmaster/launch_backend.c @@ -232,6 +232,10 @@ postmaster_child_launch(BackendType child_type, int child_slot, Assert(IsPostmasterEnvironment && !IsUnderPostmaster); + /* Capture time Postmaster initiates process creation for logging */ + if (IsConnectionBackend(child_type)) + ((BackendStartupData *) startup_data)->fork_started = GetCurrentTimestamp(); + #ifdef EXEC_BACKEND pid = internal_forkexec(child_process_kinds[child_type].name, child_slot, startup_data, startup_data_len, client_sock); @@ -240,6 +244,16 @@ postmaster_child_launch(BackendType child_type, int child_slot, pid = fork_process(); if (pid == 0) /* child */ { + /* Capture and transfer timings that may be needed for logging */ + if (IsConnectionBackend(child_type)) + { + conn_timing.socket_create = + ((BackendStartupData *) startup_data)->socket_created; + conn_timing.fork_start = + ((BackendStartupData *) startup_data)->fork_started; + conn_timing.fork_end = GetCurrentTimestamp(); + } + /* Close the postmaster's sockets */ ClosePostmasterPorts(child_type == B_LOGGER); @@ -586,11 +600,18 @@ SubPostmasterMain(int argc, char *argv[]) char *child_kind; BackendType child_type; bool found = false; + TimestampTz fork_end; /* In EXEC_BACKEND case we will not have inherited these settings */ IsPostmasterEnvironment = true; whereToSendOutput = DestNone; + /* + * Capture the end of process creation for logging. We don't include the + * time spent copying data from shared memory and setting up the backend. + */ + fork_end = GetCurrentTimestamp(); + /* Setup essential subsystems (to ensure elog() behaves sanely) */ InitializeGUCOptions(); @@ -648,6 +669,16 @@ SubPostmasterMain(int argc, char *argv[]) /* Read in remaining GUC variables */ read_nondefault_variables(); + /* Capture and transfer timings that may be needed for log_connections */ + if (IsConnectionBackend(child_type)) + { + conn_timing.socket_create = + ((BackendStartupData *) startup_data)->socket_created; + conn_timing.fork_start = + ((BackendStartupData *) startup_data)->fork_started; + conn_timing.fork_end = fork_end; + } + /* * Check that the data directory looks valid, which will also check the * privileges on the data directory and update our umask and file/group diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index b4f34c57a1b..57155c00e01 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -3477,6 +3477,12 @@ BackendStartup(ClientSocket *client_sock) BackendStartupData startup_data; CAC_state cac; + /* + * Capture time that Postmaster got a socket from accept (for logging + * connection establishment and setup total duration). + */ + startup_data.socket_created = GetCurrentTimestamp(); + /* * Allocate and assign the child slot. Note we must do this before * forking, so that we can handle failures (out of memory or child-process diff --git a/src/backend/tcop/backend_startup.c b/src/backend/tcop/backend_startup.c index fb0baeb4a24..2dc838e7dc1 100644 --- a/src/backend/tcop/backend_startup.c +++ b/src/backend/tcop/backend_startup.c @@ -46,6 +46,9 @@ bool Trace_connection_negotiation = false; uint32 log_connections = 0; char *log_connections_string = NULL; +/* Other globals */ +ConnectionTiming conn_timing = {0}; + static void BackendInitialize(ClientSocket *client_sock, CAC_state cac); static int ProcessSSLStartup(Port *port); static int ProcessStartupPacket(Port *port, bool ssl_done, bool gss_done); @@ -999,6 +1002,7 @@ validate_log_connections_options(List *elemlist, uint32 *flags) {"receipt", LOG_CONNECTION_RECEIPT}, {"authentication", LOG_CONNECTION_AUTHENTICATION}, {"authorization", LOG_CONNECTION_AUTHORIZATION}, + {"durations", LOG_CONNECTION_DURATIONS}, {"all", LOG_CONNECTION_ALL}, }; diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c index 947ffb40421..0f140f41d80 100644 --- a/src/backend/tcop/postgres.c +++ b/src/backend/tcop/postgres.c @@ -66,6 +66,7 @@ #include "storage/proc.h" #include "storage/procsignal.h" #include "storage/sinval.h" +#include "tcop/backend_startup.h" #include "tcop/fastpath.h" #include "tcop/pquery.h" #include "tcop/tcopprot.h" @@ -4153,6 +4154,7 @@ PostgresMain(const char *dbname, const char *username) volatile bool send_ready_for_query = true; volatile bool idle_in_transaction_timeout_enabled = false; volatile bool idle_session_timeout_enabled = false; + bool reported_first_ready_for_query = false; Assert(dbname != NULL); Assert(username != NULL); @@ -4607,6 +4609,39 @@ PostgresMain(const char *dbname, const char *username) /* Report any recently-changed GUC options */ ReportChangedGUCOptions(); + /* + * The first time this backend is ready for query, log the + * durations of the different components of connection + * establishment and setup. + */ + if (!reported_first_ready_for_query && + (log_connections & LOG_CONNECTION_DURATIONS) && + IsConnectionBackend(MyBackendType)) + { + uint64 total_duration, + fork_duration, + auth_duration; + + conn_timing.ready_for_use = GetCurrentTimestamp(); + + total_duration = + TimestampDifferenceMicroseconds(conn_timing.socket_create, + conn_timing.ready_for_use); + fork_duration = + TimestampDifferenceMicroseconds(conn_timing.fork_start, + conn_timing.fork_end); + auth_duration = + TimestampDifferenceMicroseconds(conn_timing.auth_start, + conn_timing.auth_end); + + ereport(LOG, + errmsg("connection ready: total=%.3f ms, fork=%.3f ms, authentication=%.3f ms", + (double) total_duration / NS_PER_US, + (double) fork_duration / NS_PER_US, + (double) auth_duration / NS_PER_US)); + + reported_first_ready_for_query = true; + } ReadyForQuery(whereToSendOutput); send_ready_for_query = false; } diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 6c207e17768..4b2faf1ba9d 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -235,6 +235,9 @@ PerformAuthentication(Port *port) } #endif + /* Capture authentication start time for logging */ + conn_timing.auth_start = GetCurrentTimestamp(); + /* * Set up a timeout in case a buggy or malicious client fails to respond * during authentication. Since we're inside a transaction and might do @@ -253,6 +256,9 @@ PerformAuthentication(Port *port) */ disable_timeout(STATEMENT_TIMEOUT, false); + /* Capture authentication end time for logging */ + conn_timing.auth_end = GetCurrentTimestamp(); + if (log_connections & LOG_CONNECTION_AUTHORIZATION) { StringInfoData logmsg; diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h index a2b63495eec..312eb3f9529 100644 --- a/src/include/miscadmin.h +++ b/src/include/miscadmin.h @@ -394,6 +394,13 @@ extern PGDLLIMPORT BackendType MyBackendType; (AmAutoVacuumLauncherProcess() || \ AmLogicalSlotSyncWorkerProcess()) +/* + * Backend types that are spawned by the postmaster to serve a client + * or replication connection. + */ +#define IsConnectionBackend(backend_type) \ + (backend_type == B_BACKEND || backend_type == B_WAL_SENDER) + extern const char *GetBackendTypeDesc(BackendType backendType); extern void SetDatabasePath(const char *path); diff --git a/src/include/tcop/backend_startup.h b/src/include/tcop/backend_startup.h index b5a33a2b0e1..acc01461b76 100644 --- a/src/include/tcop/backend_startup.h +++ b/src/include/tcop/backend_startup.h @@ -14,11 +14,16 @@ #ifndef BACKEND_STARTUP_H #define BACKEND_STARTUP_H +#include "utils/timestamp.h" + /* GUCs */ extern PGDLLIMPORT bool Trace_connection_negotiation; extern PGDLLIMPORT uint32 log_connections; extern PGDLLIMPORT char *log_connections_string; +/* Other globals */ +extern PGDLLIMPORT struct ConnectionTiming conn_timing; + /* * CAC_state is passed from postmaster to the backend process, to indicate * whether the connection should be accepted, or if the process should just @@ -39,13 +44,26 @@ typedef enum CAC_state typedef struct BackendStartupData { CAC_state canAcceptConnections; + + /* + * Time at which the connection client socket is created. Only used for + * client and wal sender connections. + */ + TimestampTz socket_created; + + /* + * Time at which the postmaster initiates process creation -- either + * through fork or otherwise. Only used for client and wal sender + * connections. + */ + TimestampTz fork_started; } BackendStartupData; /* * Granular control over which messages to log for the log_connections GUC. * - * RECEIPT, AUTHENTICATION, and AUTHORIZATION are different aspects of - * connection establishment and backend setup for which we may emit a log + * RECEIPT, AUTHENTICATION, AUTHORIZATION, and DURATIONS are different aspects + * of connection establishment and backend setup for which we may emit a log * message. * * ALL is a convenience alias equivalent to all of the above aspects. @@ -58,14 +76,46 @@ typedef enum LogConnectionOption LOG_CONNECTION_RECEIPT = (1 << 0), LOG_CONNECTION_AUTHENTICATION = (1 << 1), LOG_CONNECTION_AUTHORIZATION = (1 << 2), + LOG_CONNECTION_DURATIONS = (1 << 3), LOG_CONNECTION_ON = LOG_CONNECTION_RECEIPT | LOG_CONNECTION_AUTHENTICATION | LOG_CONNECTION_AUTHORIZATION, LOG_CONNECTION_ALL = - LOG_CONNECTION_ON, + LOG_CONNECTION_ON | + LOG_CONNECTION_DURATIONS, } LogConnectionOption; +/* + * A collection of timings and durations of various stages of connection + * establishment and setup for client backends and WAL senders. + * + * Used to emit log messages according to the options specified in the + * log_connections GUC. + */ +typedef struct ConnectionTiming +{ + /* + * The time at which the client socket is created and the time at which + * the connection is fully set up and first ready for query. Together + * these represent the total connection establishment and setup time. + */ + TimestampTz socket_create; + TimestampTz ready_for_use; + + /* Time at which process creation was initiated */ + TimestampTz fork_start; + + /* Time at which process creation was completed */ + TimestampTz fork_end; + + /* Time at which authentication started */ + TimestampTz auth_start; + + /* Time at which authentication was finished */ + TimestampTz auth_end; +} ConnectionTiming; + extern void BackendMain(const void *startup_data, size_t startup_data_len) pg_attribute_noreturn(); #endif /* BACKEND_STARTUP_H */ diff --git a/src/include/utils/timestamp.h b/src/include/utils/timestamp.h index 9963bddc0ec..8c205859c3b 100644 --- a/src/include/utils/timestamp.h +++ b/src/include/utils/timestamp.h @@ -85,6 +85,15 @@ IntervalPGetDatum(const Interval *X) #define TimestampTzPlusMilliseconds(tz,ms) ((tz) + ((ms) * (int64) 1000)) #define TimestampTzPlusSeconds(tz,s) ((tz) + ((s) * (int64) 1000000)) +/* Helper for simple subtraction between two timestamps */ +static inline uint64 +TimestampDifferenceMicroseconds(TimestampTz start_time, + TimestampTz stop_time) +{ + if (start_time >= stop_time) + return 0; + return (uint64) stop_time - start_time; +} /* Set at postmaster start */ extern PGDLLIMPORT TimestampTz PgStartTime; diff --git a/src/test/authentication/t/001_password.pl b/src/test/authentication/t/001_password.pl index c83e4d5c20e..b4138a8f71d 100644 --- a/src/test/authentication/t/001_password.pl +++ b/src/test/authentication/t/001_password.pl @@ -72,8 +72,22 @@ $node->start; # other tests are added to this file in the future $node->safe_psql('postgres', "CREATE DATABASE test_log_connections"); +my $log_connections = $node->safe_psql('test_log_connections', q(SHOW log_connections;)); +is($log_connections, 'on', qq(check log connections has expected value 'on')); + +$node->connect_ok('test_log_connections', + qq(log_connections 'on' works as expected for backwards compatibility), + log_like => [ + qr/connection received/, + qr/connection authenticated/, + qr/connection authorized: user=\S+ database=test_log_connections/, + ], + log_unlike => [ + qr/connection ready/, + ],); + $node->safe_psql('test_log_connections', - q[ALTER SYSTEM SET log_connections = receipt,authorization; + q[ALTER SYSTEM SET log_connections = receipt,authorization,durations; SELECT pg_reload_conf();]); $node->connect_ok('test_log_connections', @@ -81,6 +95,7 @@ $node->connect_ok('test_log_connections', log_like => [ qr/connection received/, qr/connection authorized: user=\S+ database=test_log_connections/, + qr/connection ready/, ], log_unlike => [ qr/connection authenticated/, @@ -95,6 +110,7 @@ $node->connect_ok('test_log_connections', qr/connection received/, qr/connection authenticated/, qr/connection authorized: user=\S+ database=test_log_connections/, + qr/connection ready/, ],); # Authentication tests diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 29e52b64994..3da74999634 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -484,6 +484,7 @@ ConnParams ConnStatusType ConnType ConnectionStateEnum +ConnectionTiming ConsiderSplitContext Const ConstrCheck -- 2.34.1