From bc028beb166b704d3c3028961dd6905772bf3a2d Mon Sep 17 00:00:00 2001 From: Neil Conway Date: Tue, 6 Jan 2004 17:26:23 +0000 Subject: [PATCH] Make the 'wal_debug' GUC variable a boolean (rather than an integer), and hide it behind #ifdef WAL_DEBUG blocks. --- doc/src/sgml/ref/show.sgml | 4 ++-- doc/src/sgml/runtime.sgml | 9 ++++++--- doc/src/sgml/wal.sgml | 21 ++++++++++---------- src/backend/access/transam/xlog.c | 18 +++++++++++++++-- src/backend/utils/misc/guc.c | 33 +++++++++++++++++-------------- src/include/access/xlog.h | 6 ++++-- src/include/pg_config_manual.h | 8 +++++++- 7 files changed, 63 insertions(+), 36 deletions(-) diff --git a/doc/src/sgml/ref/show.sgml b/doc/src/sgml/ref/show.sgml index 3087c92d9e..85dbfdcedc 100644 --- a/doc/src/sgml/ref/show.sgml +++ b/doc/src/sgml/ref/show.sgml @@ -1,5 +1,5 @@ @@ -172,7 +172,7 @@ SHOW ALL; . . . - wal_debug | 0 + wal_debug | off wal_sync_method | fdatasync (94 rows) diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml index 6caf5dd93a..5ec155d24d 100644 --- a/doc/src/sgml/runtime.sgml +++ b/doc/src/sgml/runtime.sgml @@ -1,5 +1,5 @@ @@ -2667,10 +2667,13 @@ dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir' - wal_debug (integer) + wal_debug (boolean) - If nonzero, turn on WAL-related debugging output. + If true, emit WAL-related debugging output. This option is + only available if the WAL_DEBUG macro was + defined when PostgreSQL was + compiled. diff --git a/doc/src/sgml/wal.sgml b/doc/src/sgml/wal.sgml index 0883f20242..8d0127b9f9 100644 --- a/doc/src/sgml/wal.sgml +++ b/doc/src/sgml/wal.sgml @@ -1,4 +1,4 @@ - + Write-Ahead Logging (<acronym>WAL</acronym>) @@ -19,10 +19,10 @@ transaction processing. Briefly, WAL's central concept is that changes to data files (where tables and indexes reside) must be written only after those changes have been logged, - that is, when log records have been flushed to permanent - storage. If we follow this procedure, we do not need to flush - data pages to disk on every transaction commit, because we know - that in the event of a crash we will be able to recover the + that is, when log records describing the changes have been flushed + to permanent storage. If we follow this procedure, we do not need + to flush data pages to disk on every transaction commit, because we + know that in the event of a crash we will be able to recover the database using the log: any changes that have not been applied to the data pages will first be redone from the log records (this is roll-forward recovery, also known as REDO) and then changes made by @@ -187,7 +187,7 @@ There will be at least one 16 MB segment file, and will normally not be more than 2 * checkpoint_segments + 1 - files. You can use this to estimate space requirements for WAL. + files. You can use this to estimate space requirements for WAL. Ordinarily, when old log segment files are no longer needed, they are recycled (renamed to become the next segments in the numbered sequence). If, due to a short-term peak of log output rate, there @@ -254,7 +254,7 @@ The wal_sync_method parameter determines how PostgreSQL will ask the kernel to force - WAL updates out to disk. + WAL updates out to disk. All the options should be the same as far as reliability goes, but it's quite platform-specific which one will be the fastest. Note that this parameter is irrelevant if fsync @@ -262,11 +262,10 @@ - Setting the wal_debug parameter to any nonzero - value will result in each LogInsert and + Enabling the wal_debug configuration parameter + will result in each LogInsert and LogFlush WAL call being - logged to the server log. At present, it makes no difference what - the nonzero value is. This option may be replaced by a more + logged to the server log. This option may be replaced by a more general mechanism in the future. diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 1f8eb50795..f630fca7d7 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.129 2003/12/20 17:31:20 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.130 2004/01/06 17:26:23 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -86,12 +86,15 @@ /* User-settable parameters */ int CheckPointSegments = 3; int XLOGbuffers = 8; -int XLOG_DEBUG = 0; char *XLOG_sync_method = NULL; const char XLOG_sync_method_default[] = DEFAULT_SYNC_METHOD_STR; char XLOG_archive_dir[MAXPGPATH]; /* null string means * delete 'em */ +#ifdef WAL_DEBUG +bool XLOG_DEBUG = false; +#endif + /* * XLOGfileslop is used in the code as the allowed "fuzz" in the number of * preallocated XLOG segments --- we try to have at least XLOGfiles advance @@ -766,6 +769,7 @@ begin:; MyProc->logRec = RecPtr; } +#ifdef WAL_DEBUG if (XLOG_DEBUG) { char buf[8192]; @@ -779,6 +783,7 @@ begin:; } elog(LOG, "%s", buf); } +#endif /* Record begin of record in appropriate places */ if (!no_tran) @@ -1074,8 +1079,10 @@ XLogWrite(XLogwrtRqst WriteRqst) openLogSeg >= (RedoRecPtr.xrecoff / XLogSegSize) + (uint32) CheckPointSegments)) { +#ifdef WAL_DEBUG if (XLOG_DEBUG) elog(LOG, "time for a checkpoint, signaling postmaster"); +#endif SendPostmasterSignal(PMSIGNAL_DO_CHECKPOINT); } } @@ -1214,11 +1221,13 @@ XLogFlush(XLogRecPtr record) if (XLByteLE(record, LogwrtResult.Flush)) return; +#ifdef WAL_DEBUG if (XLOG_DEBUG) elog(LOG, "xlog flush request %X/%X; write %X/%X; flush %X/%X", record.xlogid, record.xrecoff, LogwrtResult.Write.xlogid, LogwrtResult.Write.xrecoff, LogwrtResult.Flush.xlogid, LogwrtResult.Flush.xrecoff); +#endif START_CRIT_SECTION(); @@ -2613,8 +2622,10 @@ StartupXLOG(void) /* This is just to allow attaching to startup process with a debugger */ #ifdef XLOG_REPLAY_DELAY +#ifdef WAL_DEBUG if (XLOG_DEBUG && ControlFile->state != DB_SHUTDOWNED) sleep(60); +#endif #endif /* @@ -2742,6 +2753,8 @@ StartupXLOG(void) ShmemVariableCache->nextXid = record->xl_xid; TransactionIdAdvance(ShmemVariableCache->nextXid); } + +#ifdef WAL_DEBUG if (XLOG_DEBUG) { char buf[8192]; @@ -2755,6 +2768,7 @@ StartupXLOG(void) record->xl_info, XLogRecGetData(record)); elog(LOG, "%s", buf); } +#endif if (record->xl_info & XLR_BKP_BLOCK_MASK) RestoreBkpBlocks(record, EndRecPtr); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 705dd166e4..f0a0a88dd6 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -10,7 +10,7 @@ * Written by Peter Eisentraut . * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.175 2003/12/03 18:52:00 joe Exp $ + * $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.176 2004/01/06 17:26:23 neilc Exp $ * *-------------------------------------------------------------------- */ @@ -336,17 +336,18 @@ const char *const config_type_names[] = * TO ADD AN OPTION: * * 1. Declare a global variable of type bool, int, double, or char* - * and make use of it. + * and make use of it. * * 2. Decide at what times it's safe to set the option. See guc.h for - * details. + * details. * * 3. Decide on a name, a default value, upper and lower bounds (if - * applicable), etc. + * applicable), etc. * * 4. Add a record below. * - * 5. Add it to src/backend/utils/misc/postgresql.conf.sample. + * 5. Add it to src/backend/utils/misc/postgresql.conf.sample, if + * appropriate * * 6. Add it to src/bin/psql/tab-complete.c, if it's a USERSET option. * @@ -862,6 +863,18 @@ static struct config_bool ConfigureNamesBool[] = #endif }, +#ifdef WAL_DEBUG + { + {"wal_debug", PGC_SUSET, DEVELOPER_OPTIONS, + gettext_noop("Emit WAL-related debugging output."), + NULL, + GUC_NOT_IN_SAMPLE + }, + &XLOG_DEBUG, + false, NULL, NULL + }, +#endif + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL @@ -1171,16 +1184,6 @@ static struct config_int ConfigureNamesInt[] = 8, 4, INT_MAX, NULL, NULL }, - { - {"wal_debug", PGC_SUSET, DEVELOPER_OPTIONS, - gettext_noop("If nonzero, WAL-related debugging output is logged."), - NULL, - GUC_NOT_IN_SAMPLE - }, - &XLOG_DEBUG, - 0, 0, 16, NULL, NULL - }, - { {"commit_delay", PGC_USERSET, WAL_CHECKPOINTS, gettext_noop("Sets the delay in microseconds between transaction commit and " diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h index 751e880320..e4f5b7182c 100644 --- a/src/include/access/xlog.h +++ b/src/include/access/xlog.h @@ -6,7 +6,7 @@ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.46 2003/12/12 18:45:10 petere Exp $ + * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.47 2004/01/06 17:26:23 neilc Exp $ */ #ifndef XLOG_H #define XLOG_H @@ -189,10 +189,12 @@ extern XLogRecPtr ProcLastRecEnd; extern int CheckPointSegments; extern int CheckPointWarning; extern int XLOGbuffers; -extern int XLOG_DEBUG; extern char *XLOG_sync_method; extern const char XLOG_sync_method_default[]; +#ifdef WAL_DEBUG +extern bool XLOG_DEBUG; +#endif extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata); extern void XLogFlush(XLogRecPtr RecPtr); diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index be80abfdc4..3722798cce 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -6,7 +6,7 @@ * for developers. If you edit any of these, be sure to do a *full* * rebuild (and an initdb if noted). * - * $PostgreSQL: pgsql/src/include/pg_config_manual.h,v 1.8 2003/11/29 22:40:53 pgsql Exp $ + * $PostgreSQL: pgsql/src/include/pg_config_manual.h,v 1.9 2004/01/06 17:26:23 neilc Exp $ *------------------------------------------------------------------------ */ @@ -224,6 +224,12 @@ */ /* #define LOCK_DEBUG */ +/* + * Enable debugging print statements for WAL-related operations; see + * also the wal_debug GUC var. + */ +/* #define WAL_DEBUG */ + /* * Other debug #defines (documentation, anyone?) */