From 6cf7750a6dfa5db56b7595430e6df62eba850166 Mon Sep 17 00:00:00 2001 From: Jelte Fennema-Nio Date: Tue, 18 Mar 2025 01:31:57 +0100 Subject: [PATCH] Allow logging backtraces in more cases We previously only had the backtrace_functions GUC to control when backtraces were logged. Based on mailinglist discussion there were two common cases that people wanted backtraces that were not covered by this GUC though: 1. Logging backtraces for all internal errors 2. Logging backtraces for all errors To support those two usecases, as well as to allow users to continue to log backtraces for specific warnings using `backtrace_functions`, this modifies the GUCs in the following way: 1. Adds a `log_backtrace` GUC, which can be set to `none` (default), `internal_error` and `all` to log different types of backtraces. 2. Change `backtrace_functions` to behave as an additional filter on top of `log_backtrace`. The empty string (the default) is now interpreted as doing no filtering based on function name. 3. Add a `backtrace_min_level` GUC, which limits for which log entries backtraces are written, based on their log level. This defaults to ERROR. This does mean that setting `backtrace_functions=some_func` alone is not enough to get backtraces for some_func. You now need to combine that with `log_backtrace_mode=all` and if you want to get backtraces for non-errors (which you previously got), you also need to change backtrace_min_level to whichever level you want backtraces for. --- doc/src/sgml/config.sgml | 82 +++++++++++++++++-- src/backend/utils/error/elog.c | 30 ++++++- src/backend/utils/misc/guc_tables.c | 50 +++++++++++ src/backend/utils/misc/postgresql.conf.sample | 1 + src/include/utils/elog.h | 8 ++ src/include/utils/guc.h | 1 + 6 files changed, 161 insertions(+), 11 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index fd6e3e028907..930c4df65b92 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -7435,6 +7435,44 @@ local0.* /var/log/postgresql + + log_backtrace_mode (boolean) + + log_backtrace_mode configuration parameter + + + + + If this parameter is set to all then for all log + entries a backtrace is written to the server log together with the log + message. If this parameter is set to internal_error then + such a backtrace is only written for logs with error code XX000 + (internal error; see also ). + This can be used to debug such internal errors (which should normally + not happen in production). Finally, if this parameter is set to + none (the default), no backtraces are ever written + to the server log. + + + + The logs for which a backtrace is written can be further restricted + using (default: + ERROR) and + (default: empty string, meaning all). + + + + Backtrace support is not available on all platforms, and the quality + of the backtraces depends on compilation options. + + + + Only superusers and users with the appropriate SET + privilege can change this setting. + + + + log_checkpoints (boolean) @@ -12088,16 +12126,45 @@ dynamic_library_path = '/usr/local/lib/postgresql:$libdir' - This parameter contains a comma-separated list of C function names. - If an error is raised and the name of the internal C function where - the error happens matches a value in the list, then a backtrace is - written to the server log together with the error message. This can - be used to debug specific areas of the source code. + This parameter can contain a comma-separated list of C function names, + which can be used to filter for which logs a backtrace is written to + the server log. + If a log entry is raised and the name of the + internal C function where the error happens does not match any of the + values in the list, then no backtrace is written to the server log. + This can be used to only debug specific areas of the source code. - Backtrace support is not available on all platforms, and the quality - of the backtraces depends on compilation options. + The empty string (the default) disables any such filtering. So for any + logs that match both and + a backtrace is + written to the server log. + + + + + + backtrace_min_level (string) + + backtrace_min_level configuration parameter + + + + + Controls which message + levels cause backtraces to be written to the log, for log + messages that match both and + . + Valid values are DEBUG5, DEBUG4, + DEBUG3, DEBUG2, DEBUG1, + LOG, INFO, NOTICE, + WARNING, ERROR, FATAL, + and PANIC. Each level includes all the levels that + follow it. The later the level, the fewer messages result in a + backtrace. The default is ERROR. Note that + LOG has a different rank here than in + . @@ -12130,6 +12197,7 @@ dynamic_library_path = '/usr/local/lib/postgresql:$libdir' + debug_discard_caches (integer) diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c index 47af743990fe..58b721989e98 100644 --- a/src/backend/utils/error/elog.c +++ b/src/backend/utils/error/elog.c @@ -110,6 +110,7 @@ int Log_error_verbosity = PGERROR_DEFAULT; char *Log_line_prefix = NULL; /* format for extra log line info */ int Log_destination = LOG_DESTINATION_STDERR; char *Log_destination_string = NULL; +int log_backtrace = LOGBACKTRACE_NONE; bool syslog_sequence_numbers = true; bool syslog_split_messages = true; @@ -178,6 +179,7 @@ static void set_stack_entry_domain(ErrorData *edata, const char *domain); static void set_stack_entry_location(ErrorData *edata, const char *filename, int lineno, const char *funcname); +static bool matches_backtrace_gucs(ErrorData *edata); static bool matches_backtrace_functions(const char *funcname); static pg_noinline void set_backtrace(ErrorData *edata, int num_skip); static void set_errdata_field(MemoryContextData *cxt, char **ptr, const char *str); @@ -493,10 +495,7 @@ errfinish(const char *filename, int lineno, const char *funcname) oldcontext = MemoryContextSwitchTo(ErrorContext); /* Collect backtrace, if enabled and we didn't already */ - if (!edata->backtrace && - edata->funcname && - backtrace_functions && - matches_backtrace_functions(edata->funcname)) + if (!edata->backtrace && matches_backtrace_gucs(edata)) set_backtrace(edata, 2); /* @@ -816,6 +815,26 @@ set_stack_entry_location(ErrorData *edata, edata->funcname = funcname; } +/* + * matches_backtrace_gucs --- checks whether the log entry matches + * log_backtrace_mode, backtrace_min_level and backtrace_functions. + */ +static bool +matches_backtrace_gucs(ErrorData *edata) +{ + if (log_backtrace == LOGBACKTRACE_NONE) + return false; + + if (log_backtrace == LOGBACKTRACE_INTERNAL_ERROR && + edata->sqlerrcode != ERRCODE_INTERNAL_ERROR) + return false; + + if (backtrace_min_level > edata->elevel) + return false; + + return matches_backtrace_functions(edata->funcname); +} + /* * matches_backtrace_functions --- checks whether the given funcname matches * backtrace_functions @@ -827,6 +846,9 @@ matches_backtrace_functions(const char *funcname) { const char *p; + if (!backtrace_functions || backtrace_functions[0] == '\0') + return true; + if (!backtrace_function_list || funcname == NULL || funcname[0] == '\0') return false; diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c index 2f8cbd867599..766b33a59253 100644 --- a/src/backend/utils/misc/guc_tables.c +++ b/src/backend/utils/misc/guc_tables.c @@ -163,6 +163,23 @@ static const struct config_enum_entry server_message_level_options[] = { {NULL, 0, false} }; +static const struct config_enum_entry backtrace_level_options[] = { + {"debug5", DEBUG5, false}, + {"debug4", DEBUG4, false}, + {"debug3", DEBUG3, false}, + {"debug2", DEBUG2, false}, + {"debug1", DEBUG1, false}, + {"debug", DEBUG2, true}, + {"log", LOG, false}, + {"info", INFO, true}, + {"notice", NOTICE, false}, + {"warning", WARNING, false}, + {"error", ERROR, false}, + {"fatal", FATAL, false}, + {"panic", PANIC, false}, + {NULL, 0, false} +}; + static const struct config_enum_entry intervalstyle_options[] = { {"postgres", INTSTYLE_POSTGRES, false}, {"postgres_verbose", INTSTYLE_POSTGRES_VERBOSE, false}, @@ -200,6 +217,16 @@ static const struct config_enum_entry log_error_verbosity_options[] = { StaticAssertDecl(lengthof(log_error_verbosity_options) == (PGERROR_VERBOSE + 2), "array length mismatch"); +static const struct config_enum_entry log_backtrace_options[] = { + {"none", LOGBACKTRACE_NONE, false}, + {"internal_error", LOGBACKTRACE_INTERNAL_ERROR, false}, + {"all", LOGBACKTRACE_ALL, false}, + {NULL, 0, false} +}; + +StaticAssertDecl(lengthof(log_backtrace_options) == (LOGBACKTRACE_ALL + 2), + "array length mismatch"); + static const struct config_enum_entry log_statement_options[] = { {"none", LOGSTMT_NONE, false}, {"ddl", LOGSTMT_DDL, false}, @@ -546,6 +573,7 @@ int log_temp_files = -1; double log_statement_sample_rate = 1.0; double log_xact_sample_rate = 0; char *backtrace_functions; +int backtrace_min_level = ERROR; int temp_file_limit = -1; @@ -5004,6 +5032,18 @@ struct config_enum ConfigureNamesEnum[] = NULL, NULL, NULL }, + { + {"backtrace_min_level", PGC_SUSET, DEVELOPER_OPTIONS, + gettext_noop("Sets the message levels that create backtraces when log_backtrace is configured."), + gettext_noop("Each level includes all the levels that follow it. The later" + " the level, the fewer backtraces are created."), + GUC_NOT_IN_SAMPLE + }, + &backtrace_min_level, + ERROR, backtrace_level_options, + NULL, NULL, NULL + }, + { {"bytea_output", PGC_USERSET, CLIENT_CONN_STATEMENT, gettext_noop("Sets the output format for bytea."), @@ -5100,6 +5140,16 @@ struct config_enum ConfigureNamesEnum[] = NULL, NULL, NULL }, + { + {"log_backtrace", PGC_SUSET, LOGGING_WHAT, + gettext_noop("Sets if logs should include a backtrace."), + NULL + }, + &log_backtrace, + LOGBACKTRACE_NONE, log_backtrace_options, + NULL, NULL, NULL + }, + { {"log_error_verbosity", PGC_SUSET, LOGGING_WHAT, gettext_noop("Sets the verbosity of logged messages."), diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 34826d01380b..3e5d20fe5023 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -594,6 +594,7 @@ # their durations, > 0 logs only # actions running at least this number # of milliseconds. +#log_backtrace = 'none' #log_checkpoints = on #log_connections = '' # log aspects of connection setup # options include receipt, authentication, authorization, diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h index 5eac0e16970c..522f8e1dfe89 100644 --- a/src/include/utils/elog.h +++ b/src/include/utils/elog.h @@ -487,9 +487,17 @@ typedef enum PGERROR_VERBOSE, /* all the facts, ma'am */ } PGErrorVerbosity; +enum +{ + LOGBACKTRACE_NONE, /* no backtrace */ + LOGBACKTRACE_INTERNAL_ERROR, /* backtrace for internal error code */ + LOGBACKTRACE_ALL, /* backtrace for all logs */ +}; + extern PGDLLIMPORT int Log_error_verbosity; extern PGDLLIMPORT char *Log_line_prefix; extern PGDLLIMPORT int Log_destination; +extern PGDLLIMPORT int log_backtrace; extern PGDLLIMPORT char *Log_destination_string; extern PGDLLIMPORT bool syslog_sequence_numbers; extern PGDLLIMPORT bool syslog_split_messages; diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h index f619100467df..2150328191b9 100644 --- a/src/include/utils/guc.h +++ b/src/include/utils/guc.h @@ -279,6 +279,7 @@ extern PGDLLIMPORT int log_temp_files; extern PGDLLIMPORT double log_statement_sample_rate; extern PGDLLIMPORT double log_xact_sample_rate; extern PGDLLIMPORT char *backtrace_functions; +extern PGDLLIMPORT int backtrace_min_level; extern PGDLLIMPORT int temp_file_limit;