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authorThomas Munro2022-01-14 08:27:44 +0000
committerThomas Munro2022-01-14 11:09:24 +0000
commit7170f2159fb21b62c263acd458d781e2f3c3f8bb (patch)
treebd02aef0987a575154e87b2c75bef4b65a061342
parentc4cc2850f4d16092c2b7b39964c097260935a72c (diff)
Allow "in place" tablespaces.
Provide a developer-only GUC allow_in_place_tablespaces, disabled by default. When enabled, tablespaces can be created with an empty LOCATION string, meaning that they should be created as a directory directly beneath pg_tblspc. This can be used for new testing scenarios, in a follow-up patch. Not intended for end-user usage, since it might confuse backup tools that expect symlinks. Reviewed-by: Andres Freund <[email protected]> Reviewed-by: Michael Paquier <[email protected]> Discussion: https://postgr.es/m/CA%2BhUKGKpRWQ9SxdxxDmTBCJoR0YnFpMBe7kyzY8SUQk%2BHeskxg%40mail.gmail.com
-rw-r--r--doc/src/sgml/config.sgml19
-rw-r--r--src/backend/commands/tablespace.c39
-rw-r--r--src/backend/utils/misc/guc.c12
-rw-r--r--src/include/commands/tablespace.h2
4 files changed, 65 insertions, 7 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index afbb6c35e30..d098a33a17f 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -10433,6 +10433,25 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
</para>
<variablelist>
+ <varlistentry id="guc-allow-in-place-tablespaces" xreflabel="allow_in_place_tablespaces">
+ <term><varname>allow_in_place_tablespaces</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>allow_in_place_tablespaces</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Allows tablespaces to be created as directories inside
+ <filename>pg_tblspc</filename>, when an empty location string
+ is provided to the <command>CREATE TABLESPACE</command> command. This
+ is intended to allow testing replication scenarios where primary and
+ standby servers are running on the same machine. Such directories
+ are likely to confuse backup tools that expect to find only symbolic
+ links in that location. Only superusers can change this setting.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-allow-system-table-mods" xreflabel="allow_system_table_mods">
<term><varname>allow_system_table_mods</varname> (<type>boolean</type>)
<indexterm>
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 3e154ec1056..7123b4069b4 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -87,6 +87,7 @@
/* GUC variables */
char *default_tablespace = NULL;
char *temp_tablespaces = NULL;
+bool allow_in_place_tablespaces = false;
static void create_tablespace_directories(const char *location,
@@ -241,6 +242,7 @@ CreateTableSpace(CreateTableSpaceStmt *stmt)
char *location;
Oid ownerId;
Datum newOptions;
+ bool in_place;
/* Must be superuser */
if (!superuser())
@@ -266,12 +268,15 @@ CreateTableSpace(CreateTableSpaceStmt *stmt)
(errcode(ERRCODE_INVALID_NAME),
errmsg("tablespace location cannot contain single quotes")));
+ in_place = allow_in_place_tablespaces && strlen(location) == 0;
+
/*
* Allowing relative paths seems risky
*
- * this also helps us ensure that location is not empty or whitespace
+ * This also helps us ensure that location is not empty or whitespace,
+ * unless specifying a developer-only in-place tablespace.
*/
- if (!is_absolute_path(location))
+ if (!in_place && !is_absolute_path(location))
ereport(ERROR,
(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
errmsg("tablespace location must be an absolute path")));
@@ -590,16 +595,36 @@ create_tablespace_directories(const char *location, const Oid tablespaceoid)
char *linkloc;
char *location_with_version_dir;
struct stat st;
+ bool in_place;
linkloc = psprintf("pg_tblspc/%u", tablespaceoid);
- location_with_version_dir = psprintf("%s/%s", location,
+
+ /*
+ * If we're asked to make an 'in place' tablespace, create the directory
+ * directly where the symlink would normally go. This is a developer-only
+ * option for now, to facilitate regression testing.
+ */
+ in_place = strlen(location) == 0;
+
+ if (in_place)
+ {
+ if (MakePGDirectory(linkloc) < 0 && errno != EEXIST)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not create directory \"%s\": %m",
+ linkloc)));
+ }
+
+ location_with_version_dir = psprintf("%s/%s", in_place ? linkloc : location,
TABLESPACE_VERSION_DIRECTORY);
/*
* Attempt to coerce target directory to safe permissions. If this fails,
- * it doesn't exist or has the wrong owner.
+ * it doesn't exist or has the wrong owner. Not needed for in-place mode,
+ * because in that case we created the directory with the desired
+ * permissions.
*/
- if (chmod(location, pg_dir_create_mode) != 0)
+ if (!in_place && chmod(location, pg_dir_create_mode) != 0)
{
if (errno == ENOENT)
ereport(ERROR,
@@ -648,13 +673,13 @@ create_tablespace_directories(const char *location, const Oid tablespaceoid)
/*
* In recovery, remove old symlink, in case it points to the wrong place.
*/
- if (InRecovery)
+ if (!in_place && InRecovery)
remove_tablespace_symlink(linkloc);
/*
* Create the symlink under PGDATA
*/
- if (symlink(location, linkloc) < 0)
+ if (!in_place && symlink(location, linkloc) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not create symbolic link \"%s\": %m",
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 85752817f83..effb9d03a03 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -46,6 +46,7 @@
#include "catalog/storage.h"
#include "commands/async.h"
#include "commands/prepare.h"
+#include "commands/tablespace.h"
#include "commands/trigger.h"
#include "commands/user.h"
#include "commands/vacuum.h"
@@ -1962,6 +1963,17 @@ static struct config_bool ConfigureNamesBool[] =
},
{
+ {"allow_in_place_tablespaces", PGC_SUSET, DEVELOPER_OPTIONS,
+ gettext_noop("Allows tablespaces directly inside pg_tblspc, for testing."),
+ NULL,
+ GUC_NOT_IN_SAMPLE
+ },
+ &allow_in_place_tablespaces,
+ false,
+ NULL, NULL, NULL
+ },
+
+ {
{"lo_compat_privileges", PGC_SUSET, COMPAT_OPTIONS_PREVIOUS,
gettext_noop("Enables backward compatibility mode for privilege checks on large objects."),
gettext_noop("Skips privilege checks when reading or modifying large objects, "
diff --git a/src/include/commands/tablespace.h b/src/include/commands/tablespace.h
index 97b0be35e52..323528ebb83 100644
--- a/src/include/commands/tablespace.h
+++ b/src/include/commands/tablespace.h
@@ -19,6 +19,8 @@
#include "lib/stringinfo.h"
#include "nodes/parsenodes.h"
+extern bool allow_in_place_tablespaces;
+
/* XLOG stuff */
#define XLOG_TBLSPC_CREATE 0x00
#define XLOG_TBLSPC_DROP 0x10