diff options
| -rw-r--r-- | doc/src/sgml/ref/postgres-ref.sgml | 11 | ||||
| -rw-r--r-- | src/backend/postmaster/postmaster.c | 50 | ||||
| -rw-r--r-- | src/backend/utils/misc/guc.c | 8 | ||||
| -rw-r--r-- | src/bin/pg_checksums/t/002_actions.pl | 22 | ||||
| -rw-r--r-- | src/include/utils/guc.h | 6 |
5 files changed, 83 insertions, 14 deletions
diff --git a/doc/src/sgml/ref/postgres-ref.sgml b/doc/src/sgml/ref/postgres-ref.sgml index 4aaa7abe1a2..f72c3b04e42 100644 --- a/doc/src/sgml/ref/postgres-ref.sgml +++ b/doc/src/sgml/ref/postgres-ref.sgml @@ -133,14 +133,21 @@ PostgreSQL documentation <listitem> <para> Prints the value of the named run-time parameter, and exits. - (See the <option>-c</option> option above for details.) This can - be used on a running server, and returns values from + (See the <option>-c</option> option above for details.) This + returns values from <filename>postgresql.conf</filename>, modified by any parameters supplied in this invocation. It does not reflect parameters supplied when the cluster was started. </para> <para> + This can be used on a running server for most parameters. However, + the server must be shut down for some runtime-computed parameters + (e.g., <xref linkend="guc-shared-memory-size"/> and + <xref linkend="guc-wal-segment-size"/>). + </para> + + <para> This option is meant for other programs that interact with a server instance, such as <xref linkend="app-pg-ctl"/>, to query configuration parameter values. User-facing applications should instead use <link diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index b2fe420c3cf..d16d881e570 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -896,15 +896,31 @@ PostmasterMain(int argc, char *argv[]) if (output_config_variable != NULL) { /* - * "-C guc" was specified, so print GUC's value and exit. No extra - * permission check is needed because the user is reading inside the - * data dir. + * If this is a runtime-computed GUC, it hasn't yet been initialized, + * and the present value is not useful. However, this is a convenient + * place to print the value for most GUCs because it is safe to run + * postmaster startup to this point even if the server is already + * running. For the handful of runtime-computed GUCs that we cannot + * provide meaningful values for yet, we wait until later in + * postmaster startup to print the value. We won't be able to use -C + * on running servers for those GUCs, but using this option now would + * lead to incorrect results for them. */ - const char *config_val = GetConfigOption(output_config_variable, - false, false); + int flags = GetConfigOptionFlags(output_config_variable, true); - puts(config_val ? config_val : ""); - ExitPostmaster(0); + if ((flags & GUC_RUNTIME_COMPUTED) == 0) + { + /* + * "-C guc" was specified, so print GUC's value and exit. No + * extra permission check is needed because the user is reading + * inside the data dir. + */ + const char *config_val = GetConfigOption(output_config_variable, + false, false); + + puts(config_val ? config_val : ""); + ExitPostmaster(0); + } } /* Verify that DataDir looks reasonable */ @@ -1034,6 +1050,26 @@ PostmasterMain(int argc, char *argv[]) InitializeShmemGUCs(); /* + * If -C was specified with a runtime-computed GUC, we held off printing + * the value earlier, as the GUC was not yet initialized. We handle -C + * for most GUCs before we lock the data directory so that the option may + * be used on a running server. However, a handful of GUCs are runtime- + * computed and do not have meaningful values until after locking the data + * directory, and we cannot safely calculate their values earlier on a + * running server. At this point, such GUCs should be properly + * initialized, and we haven't yet set up shared memory, so this is a good + * time to handle the -C option for these special GUCs. + */ + if (output_config_variable != NULL) + { + const char *config_val = GetConfigOption(output_config_variable, + false, false); + + puts(config_val ? config_val : ""); + ExitPostmaster(0); + } + + /* * Set up shared memory and semaphores. */ reset_shared(); diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 23236fa4c3d..a6e4fcc24ed 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -1983,7 +1983,7 @@ static struct config_bool ConfigureNamesBool[] = {"data_checksums", PGC_INTERNAL, PRESET_OPTIONS, gettext_noop("Shows whether data checksums are turned on for this cluster."), NULL, - GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE + GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_RUNTIME_COMPUTED }, &data_checksums, false, @@ -2342,7 +2342,7 @@ static struct config_int ConfigureNamesInt[] = {"shared_memory_size", PGC_INTERNAL, PRESET_OPTIONS, gettext_noop("Shows the size of the server's main shared memory area (rounded up to the nearest MB)."), NULL, - GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_UNIT_MB + GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_UNIT_MB | GUC_RUNTIME_COMPUTED }, &shared_memory_size_mb, 0, 0, INT_MAX, @@ -2407,7 +2407,7 @@ static struct config_int ConfigureNamesInt[] = "in the form accepted by the chmod and umask system " "calls. (To use the customary octal format the number " "must start with a 0 (zero).)"), - GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE + GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_RUNTIME_COMPUTED }, &data_directory_mode, 0700, 0000, 0777, @@ -3231,7 +3231,7 @@ static struct config_int ConfigureNamesInt[] = {"wal_segment_size", PGC_INTERNAL, PRESET_OPTIONS, gettext_noop("Shows the size of write ahead log segments."), NULL, - GUC_UNIT_BYTE | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE + GUC_UNIT_BYTE | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_RUNTIME_COMPUTED }, &wal_segment_size, DEFAULT_XLOG_SEG_SIZE, diff --git a/src/bin/pg_checksums/t/002_actions.pl b/src/bin/pg_checksums/t/002_actions.pl index a18c104a94d..2cc8b68c75f 100644 --- a/src/bin/pg_checksums/t/002_actions.pl +++ b/src/bin/pg_checksums/t/002_actions.pl @@ -10,7 +10,7 @@ use PostgresNode; use TestLib; use Fcntl qw(:seek); -use Test::More tests => 63; +use Test::More tests => 69; # Utility routine to create and check a table with corrupted checksums @@ -178,11 +178,31 @@ command_fails( [ 'pg_checksums', '--enable', '--filenode', '1234', '-D', $pgdata ], "fails when relfilenodes are requested and action is --enable"); +# Test postgres -C for an offline cluster. +# Run-time GUCs are safe to query here. Note that a lock file is created, +# then unlinked, leading to an extra LOG entry showing in stderr. +command_checks_all( + [ 'postgres', '-D', $pgdata, '-C', 'data_checksums' ], + 0, + [qr/^on$/], + # LOG entry when unlinking lock file. + [qr/database system is shut down/], + 'data_checksums=on is reported on an offline cluster'); + # Checks cannot happen with an online cluster $node->start; command_fails([ 'pg_checksums', '--check', '-D', $pgdata ], "fails with online cluster"); +# Test postgres -C on an online cluster. +command_fails_like( + [ 'postgres', '-D', $pgdata, '-C', 'data_checksums' ], + qr/lock file .* already exists/, + 'data_checksums is not reported on an online cluster'); +command_ok( + [ 'postgres', '-D', $pgdata, '-C', 'work_mem' ], + 'non-runtime parameter is reported on an online cluster'); + # Check corruption of table on default tablespace. check_relation_corruption($node, 'corrupt1', 'pg_default'); diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h index a7c3a4958e0..aa18d304ac0 100644 --- a/src/include/utils/guc.h +++ b/src/include/utils/guc.h @@ -229,6 +229,12 @@ typedef enum #define GUC_EXPLAIN 0x100000 /* include in explain */ +/* + * GUC_RUNTIME_COMPUTED is intended for runtime-computed GUCs that are only + * available via 'postgres -C' if the server is not running. + */ +#define GUC_RUNTIME_COMPUTED 0x200000 + #define GUC_UNIT (GUC_UNIT_MEMORY | GUC_UNIT_TIME) |