From b99dc5c1c549921ed2ac054db4e8c5398543dfc4 Mon Sep 17 00:00:00 2001 From: benoit Date: Tue, 8 Oct 2024 12:39:41 +0200 Subject: [PATCH 1/5] Add a guc for parallel worker logging The new guc log_parallel_workers controls whether a log message is produced to display information on the number of workers spawned when a parallel query or utility is executed. The default value is `none` which disables logging. `all` displays information for all parallel queries, whereas `shortage` displays information only when the number of workers launched is lower than the number of planned workers. This new parameter can help database administrators and developers diagnose performance issues related to parallelism and optimize the configuration of the system accordingly. --- doc/src/sgml/config.sgml | 18 ++++++++++++++++++ src/backend/access/transam/parallel.c | 15 +++++++++++++++ src/backend/utils/misc/guc_tables.c | 12 ++++++++++++ src/backend/utils/misc/postgresql.conf.sample | 1 + src/include/access/parallel.h | 19 +++++++++++++++++++ 5 files changed, 65 insertions(+) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index a8866292d46..095bb751183 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7611,6 +7611,24 @@ log_line_prefix = '%m [%p] %q%u@%d/%a ' + + log_parallel_workers (enum) + + log_parallel_workers configuration parameter + + + + + Controls whether a log message about the number of workers is produced during the + execution of a parallel query or utility statement. The default value is + none which disables logging. all displays + information for all parallel queries or utilities, whereas shortage + displays information only when the number of workers launched is lower than the number + of planned workers. + + + + log_parameter_max_length (integer) diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c index 7817bedc2ef..d5b630e055b 100644 --- a/src/backend/access/transam/parallel.c +++ b/src/backend/access/transam/parallel.c @@ -1659,3 +1659,18 @@ LookupParallelWorkerFunction(const char *libraryname, const char *funcname) return (parallel_worker_main_type) load_external_function(libraryname, funcname, true, NULL); } + +/* + * The function determines if information about workers should + * be logged. +*/ +bool +LoggingParallelWorkers(int log_parallel_workers, + int parallel_workers_to_launch, + int parallel_workers_launched) +{ + return ((log_parallel_workers == LOG_PARALLEL_WORKERS_ALL && + parallel_workers_to_launch > 0) || + (log_parallel_workers == LOG_PARALLEL_WORKERS_SHORTAGE && + parallel_workers_to_launch != parallel_workers_launched)); +} diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c index 38cb9e970d5..fe38758fd57 100644 --- a/src/backend/utils/misc/guc_tables.c +++ b/src/backend/utils/misc/guc_tables.c @@ -482,6 +482,7 @@ extern const struct config_enum_entry archive_mode_options[]; extern const struct config_enum_entry recovery_target_action_options[]; extern const struct config_enum_entry wal_sync_method_options[]; extern const struct config_enum_entry dynamic_shared_memory_options[]; +extern const struct config_enum_entry log_parallel_workers_options[]; /* * GUC option variables that are exported from this module @@ -526,6 +527,7 @@ int log_min_duration_statement = -1; int log_parameter_max_length = -1; int log_parameter_max_length_on_error = 0; int log_temp_files = -1; +int log_parallel_workers = LOG_PARALLEL_WORKERS_NONE; double log_statement_sample_rate = 1.0; double log_xact_sample_rate = 0; char *backtrace_functions; @@ -5236,6 +5238,16 @@ struct config_enum ConfigureNamesEnum[] = NULL, NULL, NULL }, + { + {"log_parallel_workers", PGC_SUSET, LOGGING_WHAT, + gettext_noop("Log information about parallel worker usage"), + NULL + }, + &log_parallel_workers, + LOG_PARALLEL_WORKERS_NONE, log_parallel_workers_options, + NULL, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, 0, NULL, NULL, NULL, NULL diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 079efa1baa7..94da28977cc 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -614,6 +614,7 @@ #log_temp_files = -1 # log temporary files equal or larger # than the specified size in kilobytes; # -1 disables, 0 logs all temp files +#log_parallel_workers = none # none, all, shortage #log_timezone = 'GMT' # - Process Title - diff --git a/src/include/access/parallel.h b/src/include/access/parallel.h index 8811618acb7..46df6e7de65 100644 --- a/src/include/access/parallel.h +++ b/src/include/access/parallel.h @@ -19,6 +19,20 @@ #include "postmaster/bgworker.h" #include "storage/shm_mq.h" #include "storage/shm_toc.h" +#include "utils/guc.h" + +typedef enum log_parallel_workers_option_list { + LOG_PARALLEL_WORKERS_NONE=0, + LOG_PARALLEL_WORKERS_ALL, + LOG_PARALLEL_WORKERS_SHORTAGE, +} log_parallel_workers_option_list; + +static const struct config_enum_entry log_parallel_workers_options[] = { + {"none", LOG_PARALLEL_WORKERS_NONE, false}, + {"all", LOG_PARALLEL_WORKERS_ALL, false}, + {"shortage", LOG_PARALLEL_WORKERS_SHORTAGE, false}, + {NULL, 0, false} +}; typedef void (*parallel_worker_main_type) (dsm_segment *seg, shm_toc *toc); @@ -56,6 +70,7 @@ typedef struct ParallelWorkerContext extern PGDLLIMPORT volatile sig_atomic_t ParallelMessagePending; extern PGDLLIMPORT int ParallelWorkerNumber; extern PGDLLIMPORT bool InitializingParallelWorker; +extern PGDLLEXPORT int log_parallel_workers; #define IsParallelWorker() (ParallelWorkerNumber >= 0) @@ -78,4 +93,8 @@ extern void ParallelWorkerReportLastRecEnd(XLogRecPtr last_xlog_end); extern void ParallelWorkerMain(Datum main_arg); +extern bool LoggingParallelWorkers(int log_parallel_workers, + int parallel_workers_to_launch, + int parallel_workers_launched); + #endif /* PARALLEL_H */ -- 2.47.0