diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 0fc4e57..41144cb 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -4169,6 +4169,12 @@ SELECT * FROM parent WHERE key = 2400; server log + When logs are written to the file-system their paths, names, and + types are recorded in + the file. This provides + a convenient way to find and access log content without establishing a + database connection. + diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index eca98df..47ca846 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -15444,6 +15444,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n); + pg_current_logfile() + text + primary log file name in use by the logging collector + + + + pg_current_logfile(text) + text + log file name, of log in the requested format, in use by the + logging collector + + + pg_my_temp_schema() oid OID of session's temporary schema, or 0 if none @@ -15661,6 +15674,39 @@ SET search_path TO schema , schema, .. the time when the postmaster process re-read the configuration files.) + + pg_current_logile + + + + Logging + pg_current_logfile function + + + + pg_current_logfile returns, as text, + the path of either the csv or stderr log file currently in use by the + logging collector. This is a path including the + directory and the log file name. + Log collection must be active or the return value + is NULL. When multiple logfiles exist, each in a + different format, pg_current_logfile called + without arguments returns the path of the file having the first format + found in the ordered + list: stderr, csvlog. + NULL is returned when no log file has any of these + formats. To request a specific file format supply, + as text, either csvlog + or stderr as the value of the optional parameter. The + return value is NULL when the log format requested + is not a configured . + + pg_current_logfiles reflects the content of the + file. All caveats + regards current_logfiles content are applicable + to pg_current_logfiles' return value. + + pg_my_temp_schema diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml index 5c52824..928133c 100644 --- a/doc/src/sgml/storage.sgml +++ b/doc/src/sgml/storage.sgml @@ -60,6 +60,79 @@ Item Subdirectory containing per-database subdirectories + + + + current_logfiles + + + Logging + current_logfiles file + + current_logfiles + + + A file recording the log file(s) currently written to by the syslogger + and the file's log formats, stderr + or csvlog. Each line of the file is a space separated list of + two elements: the log format and the full path to the log file including the + value of . The log format must be present + in to be listed in + current_logfiles. + + + + pg_ctl + and current_logfiles + + + stderr + and current_logfiles + + + log_destination configuration parameter + and current_logfiles + + + Although logs directed to stderr may be written + to the filesystem, when the writing of stderr is + managed outside of the PostgreSQL database + server the location of such files in the filesystem is not reflected in + the content of current_logfiles. One such case is + when the pg_ctl command is used to start + the postgres database server, capture + the stderr output of the server, and direct it to a + file. + + There are other notable situations related + to stderr logging. + Non-PostgreSQL log sources, such as 3rd party + libraries, which deliver error messages directly + to stderr are always logged + by PostgreSQL + to stderr. Stderr is also the + destination for any incomplete log messages produced by + PostgreSQL. When + stderr is not in + , + current_logfiles does not not contain the name of the + file where these sorts of log messages are written. + + + The current_logfiles file + is present only when is + activated and when at least one of stderr or + csvlog value is present in + . + + On a busy system current_logfiles might not be + updated immediately upon logfile rotation. On an extremely busy system it + is possible, although highly unlikely, for a logfile to be "skipped" and + never appear in current_logfiles. + + + + global Subdirectory containing cluster-wide tables, such as diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c index fd62d66..ea812e0 100644 --- a/src/backend/postmaster/syslogger.c +++ b/src/backend/postmaster/syslogger.c @@ -146,6 +146,8 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix); static void set_next_rotation_time(void); static void sigHupHandler(SIGNAL_ARGS); static void sigUsr1Handler(SIGNAL_ARGS); +static bool rm_log_metainfo(void); +static void logfile_writename(void); /* @@ -348,6 +350,14 @@ SysLoggerMain(int argc, char *argv[]) rotation_disabled = false; rotation_requested = true; } + + /* + * Force rewriting last log filename when reloading configuration, + * even if rotation_requested is false, log_destination may have + * been changed and we don't want to wait the next file rotation. + */ + if (!rm_log_metainfo()) + logfile_writename(); } if (Log_RotationAge > 0 && !rotation_disabled) @@ -511,10 +521,14 @@ int SysLogger_Start(void) { pid_t sysloggerPid; - char *filename; - if (!Logging_collector) + if (!Logging_collector) { + /* Logging collector is not enabled. We don't know where messages are + * logged. Remove outdated file holding the current log filenames. + */ + unlink(LOG_METAINFO_DATAFILE); return 0; + } /* * If first time through, create the pipe which will receive stderr @@ -570,11 +584,13 @@ SysLogger_Start(void) * a time-based rotation. */ first_syslogger_file_time = time(NULL); - filename = logfile_getname(first_syslogger_file_time, NULL); + last_file_name = logfile_getname(first_syslogger_file_time, NULL); - syslogFile = logfile_open(filename, "a", false); + syslogFile = logfile_open(last_file_name, "a", false); - pfree(filename); + if (!rm_log_metainfo()) + logfile_writename(); + pfree(last_file_name); #ifdef EXEC_BACKEND switch ((sysloggerPid = syslogger_forkexec())) @@ -1098,6 +1114,8 @@ open_csvlogfile(void) pfree(last_csv_file_name); last_csv_file_name = filename; + + logfile_writename(); } /* @@ -1151,9 +1169,11 @@ static void logfile_rotate(bool time_based_rotation, int size_rotation_for) { char *filename; - char *csvfilename = NULL; + char *csvfilename; pg_time_t fntime; FILE *fh; + bool rotate_csvlog; + bool rotate_stderr; rotation_requested = false; @@ -1166,9 +1186,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for) fntime = next_rotation_time; else fntime = time(NULL); - filename = logfile_getname(fntime, NULL); - if (csvlogFile != NULL) - csvfilename = logfile_getname(fntime, ".csv"); /* * Decide whether to overwrite or append. We can overwrite if (a) @@ -1178,8 +1195,12 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for) * * Note: last_file_name should never be NULL here, but if it is, append. */ - if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR)) + rotate_stderr = time_based_rotation || + (size_rotation_for & LOG_DESTINATION_STDERR); + if (rotate_stderr) { + filename = logfile_getname(fntime, NULL); + if (Log_truncate_on_rotation && time_based_rotation && last_file_name != NULL && strcmp(filename, last_file_name) != 0) @@ -1202,10 +1223,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for) rotation_disabled = true; } - if (filename) - pfree(filename); - if (csvfilename) - pfree(csvfilename); + pfree(filename); return; } @@ -1216,14 +1234,16 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for) if (last_file_name != NULL) pfree(last_file_name); last_file_name = filename; - filename = NULL; } /* Same as above, but for csv file. */ - - if (csvlogFile != NULL && - (time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG))) + rotate_csvlog = csvlogFile != NULL && + (time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)); + if (rotate_csvlog) { + if (csvlogFile != NULL) + csvfilename = logfile_getname(fntime, ".csv"); + if (Log_truncate_on_rotation && time_based_rotation && last_csv_file_name != NULL && strcmp(csvfilename, last_csv_file_name) != 0) @@ -1246,10 +1266,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for) rotation_disabled = true; } - if (filename) - pfree(filename); - if (csvfilename) - pfree(csvfilename); + pfree(csvfilename); return; } @@ -1260,13 +1277,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for) if (last_csv_file_name != NULL) pfree(last_csv_file_name); last_csv_file_name = csvfilename; - csvfilename = NULL; } - if (filename) - pfree(filename); - if (csvfilename) - pfree(csvfilename); + if (rotate_stderr || rotate_csvlog) + logfile_writename(); set_next_rotation_time(); } @@ -1365,3 +1379,77 @@ sigUsr1Handler(SIGNAL_ARGS) errno = save_errno; } + +/* + * Store the name of the file(s) where the log collector, when enabled, writes + * log messages. Useful for finding the name(s) of the current log file(s) + * when there is time-based logfile rotation. Filenames are stored in a + * temporary file and renamed into the final destination for atomicity. + */ +static void +logfile_writename() +{ + FILE *fh; + char tempfn[MAXPGPATH]; + + snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE); + + if ((fh = logfile_open(tempfn, "w", true) ) == NULL) + { + if (errno == ENFILE || errno == EMFILE) + ereport(LOG, + (errmsg("system is too busy to write logfile meta info, %s will be updated on next rotation (or use SIGHUP to retry)", LOG_METAINFO_DATAFILE))); + return; + } + if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR)) + { + if (fprintf(fh, "stderr %s\n", last_file_name) < 0) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not write stderr log file path \"%s\": %m", + tempfn))); + fclose(fh); + return; + } + } + + if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG)) + { + if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not write csvlog log file path \"%s\": %m", + tempfn))); + fclose(fh); + return; + } + } + fclose(fh); + + if (rename(tempfn, LOG_METAINFO_DATAFILE) != 0) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\": %m", + tempfn))); + return; + } + +} + +/* + * Delete the LOG_METAINFO_DATAFILE if it's not going to be used. + */ +static bool +rm_log_metainfo(void) +{ + if (!(Log_destination & LOG_DESTINATION_STDERR) + && !(Log_destination & LOG_DESTINATION_CSVLOG)) + { + unlink(LOG_METAINFO_DATAFILE); + return true; + } + return false; +} diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c index 0da051a..2da40b2 100644 --- a/src/backend/utils/adt/misc.c +++ b/src/backend/utils/adt/misc.c @@ -19,6 +19,7 @@ #include #include #include +#include #include "access/sysattr.h" #include "catalog/pg_authid.h" @@ -892,3 +893,141 @@ parse_ident(PG_FUNCTION_ARGS) PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext)); } + +/* + * Report current log file used by log collector + */ +Datum +pg_current_logfile(PG_FUNCTION_ARGS) +{ + FILE *fd; + char lbuffer[MAXPGPATH]; + char log_filepath[MAXPGPATH]; + text *fmt; + char *logfmt; + struct stat stat_buf; + + /* The log format parameter is optional */ + if (PG_NARGS() == 1) { + fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0); + if (fmt != NULL) { + logfmt = text_to_cstring(fmt); + if ( (strcmp(logfmt, "stderr") != 0) && + (strcmp(logfmt, "csvlog") != 0) ) { + ereport(ERROR, + (errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt))); + PG_RETURN_NULL(); + } + } + } else { + logfmt = NULL; + } + + if (!Logging_collector) + PG_RETURN_NULL(); + + /* Check if current log file is present */ + if (stat(LOG_METAINFO_DATAFILE, &stat_buf) != 0) + PG_RETURN_NULL(); + + fd = AllocateFile(LOG_METAINFO_DATAFILE, "r"); + if (fd == NULL) + { + if (errno != ENOENT) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", + LOG_METAINFO_DATAFILE))); + PG_RETURN_NULL(); + } + + /* + * Read the file to gather current log filename(s) registered + * by the syslogger. + */ + while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) { + char log_format[10]; + int i = 0, space_pos = 0; + + /* Check for a read error. */ + if (ferror(fd)) { + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read file \"%s\": %m", LOG_METAINFO_DATAFILE))); + FreeFile(fd); + break; + } + + /* remove trailing newline */ + if (strchr(lbuffer, '\n') != NULL) + *strchr(lbuffer, '\n') = '\0'; + + /* extract log format and log file path from the line */ + for (i = 0; lbuffer[i] != '\0'; i++) + { + if ((space_pos == 0) && (isspace(lbuffer[i]) != 0)) + { + log_format[i] = '\0'; + space_pos = i; + } + else if (space_pos > 0) + log_filepath[i-space_pos-1] = lbuffer[i]; + else + log_format[i] = lbuffer[i]; + } + log_filepath[i] = '\0'; + if ((space_pos != (int)strlen("stderr")) && + (space_pos != (int)strlen("csvlog"))) + { + ereport(ERROR, + (errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE))); + break; + } + + /* + * When no log format is provided as argument always reports + * the first registered log file in LOG_METAINFO_DATAFILE. + */ + if (logfmt == NULL) + break; + + /* report the entry corresponding to the requested format */ + if (strcmp(logfmt, log_format) == 0) + break; + } + /* Close the current log filename file. */ + if (FreeFile(fd)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not close file \"%s\": %m", LOG_METAINFO_DATAFILE))); + + + + if (lbuffer[0] == '\0') + PG_RETURN_NULL(); + + /* Return null when csvlog is requested but we have a stderr log */ + if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0) + && !(Log_destination & LOG_DESTINATION_CSVLOG) ) + PG_RETURN_NULL(); + + /* Return null when stderr is requested but we have a csv log */ + if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0) + && !(Log_destination & LOG_DESTINATION_STDERR) ) + PG_RETURN_NULL(); + + PG_RETURN_TEXT_P(cstring_to_text(log_filepath)); +} + +/* + * Report current log file used by log collector (1 argument version) + * + * note: this wrapper is necessary to pass the sanity check in opr_sanity, + * which checks that all built-in functions that share the implementing C + * function take the same number of arguments + */ +Datum +pg_current_logfile_1arg(PG_FUNCTION_ARGS) +{ + return pg_current_logfile(fcinfo); +} diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h index 047a1ce..26db448 100644 --- a/src/include/catalog/pg_proc.h +++ b/src/include/catalog/pg_proc.h @@ -3181,6 +3181,10 @@ DATA(insert OID = 2621 ( pg_reload_conf PGNSP PGUID 12 1 0 0 0 f f f f t f v s DESCR("reload configuration files"); DATA(insert OID = 2622 ( pg_rotate_logfile PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ )); DESCR("rotate log file"); +DATA(insert OID = 3800 ( pg_current_logfile PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ )); +DESCR("current logging collector file location"); +DATA(insert OID = 3801 ( pg_current_logfile PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile_1arg _null_ _null_ _null_ )); +DESCR("current logging collector file location"); DATA(insert OID = 2623 ( pg_stat_file PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ )); DESCR("get information about file"); diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h index 999440f..afc636f 100644 --- a/src/include/miscadmin.h +++ b/src/include/miscadmin.h @@ -467,4 +467,13 @@ extern bool has_rolreplication(Oid roleid); extern bool BackupInProgress(void); extern void CancelBackup(void); +/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */ +/* + * Name of file holding the paths, names, and types of the files where current + * log messages are written, when the log collector is enabled. Useful + * outside of Postgres when finding the name of the current log file in the + * case of time-based log rotation. + */ +#define LOG_METAINFO_DATAFILE "current_logfiles" + #endif /* MISCADMIN_H */ diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h index 90f5132..e532022 100644 --- a/src/include/utils/builtins.h +++ b/src/include/utils/builtins.h @@ -522,6 +522,8 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS); extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS); extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS); extern Datum parse_ident(PG_FUNCTION_ARGS); +extern Datum pg_current_logfile(PG_FUNCTION_ARGS); +extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS); /* oid.c */ extern Datum oidin(PG_FUNCTION_ARGS);