What changed?

--- 9.1
+++ 9.2
@@ -1,7 +1,7 @@
 vartype: string
 context: user
-boot_val: None
+boot_val: GMT
 unit: None
 enumvals: None
 
-Sets the time zone for displaying and interpreting time stamps. If not explicitly set, the server initializes this variable to the time zone specified by its system environment. See Section 8.5.3 for more information.
+Sets the time zone for displaying and interpreting time stamps. The built-in default is GMT, but that is typically overridden in postgresql.conf; initdb will install a setting there corresponding to its system environment. See Section 8.5.3 for more information.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Controls whether the server should run the autovacuum launcher daemon. This is on by default; however, track_counts must also be enabled for autovacuum to work. This parameter can only be set in the postgresql.conf file or on the server command line. Note that even when this parameter is disabled, the system will launch autovacuum processes if necessary to prevent transaction ID wraparound. See Section 23.1.4 for more information.
+Controls whether the server should run the autovacuum launcher daemon. This is on by default; however, track_counts must also be enabled for autovacuum to work. This parameter can only be set in the postgresql.conf file or on the server command line. Note that even when this parameter is disabled, the system will launch autovacuum processes if necessary to prevent transaction ID wraparound. See Section 23.1.5 for more information.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Specifies the maximum age (in transactions) that a table's pg_class.relfrozenxid field can attain before a VACUUM operation is forced to prevent transaction ID wraparound within the table. Note that the system will launch autovacuum processes to prevent wraparound even when autovacuum is otherwise disabled. Vacuum also allows removal of old files from the pg_clog subdirectory, which is why the default is a relatively low 200 million transactions. This parameter can only be set at server start, but the setting can be reduced for individual tables by changing storage parameters. For more information see Section 23.1.4.
+Specifies the maximum age (in transactions) that a table's pg_class.relfrozenxid field can attain before a VACUUM operation is forced to prevent transaction ID wraparound within the table. Note that the system will launch autovacuum processes to prevent wraparound even when autovacuum is otherwise disabled. Vacuum also allows removal of old files from the pg_clog subdirectory, which is why the default is a relatively low 200 million transactions. This parameter can only be set at server start, but the setting can be reduced for individual tables by changing storage parameters. For more information see Section 23.1.5.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: ms
 enumvals: None
 
-Specifies the delay between activity rounds for the background writer. In each round the writer issues writes for some number of dirty buffers (controllable by the following parameters). It then sleeps for bgwriter_delay milliseconds, and repeats. The default value is 200 milliseconds (200ms). Note that on many systems, the effective resolution of sleep delays is 10 milliseconds; setting bgwriter_delay to a value that is not a multiple of 10 might have the same results as setting it to the next higher multiple of 10. This parameter can only be set in the postgresql.conf file or on the server command line.
+Specifies the delay between activity rounds for the background writer. In each round the writer issues writes for some number of dirty buffers (controllable by the following parameters). It then sleeps for bgwriter_delay milliseconds, and repeats. When there are no dirty buffers in the buffer pool, though, it goes into a longer sleep regardless of bgwriter_delay. The default value is 200 milliseconds (200ms). Note that on many systems, the effective resolution of sleep delays is 10 milliseconds; setting bgwriter_delay to a value that is not a multiple of 10 might have the same results as setting it to the next higher multiple of 10. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-In each round, no more than this many buffers will be written by the background writer. Setting this to zero disables background writing (except for checkpoint activity). The default value is 100 buffers. This parameter can only be set in the postgresql.conf file or on the server command line.
+In each round, no more than this many buffers will be written by the background writer. Setting this to zero disables background writing. (Note that checkpoints, which are managed by a separate, dedicated auxiliary process, are unaffected.) The default value is 100 buffers. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -1,7 +0,0 @@
-vartype: string
-context: sighup
-boot_val: None
-unit: None
-enumvals: None
-
-This variable specifies one or several class names to be used for custom variables, in the form of a comma-separated list. A custom variable is a variable not normally known to PostgreSQL proper but used by some add-on module. Such variables must have names consisting of a class name, a dot, and a variable name. custom_variable_classes specifies all the class names in use in a particular installation. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -1,7 +1,7 @@
 vartype: integer
-context: sighup
+context: superuser
 boot_val: 1000
 unit: ms
 enumvals: None
 
-This is the amount of time, in milliseconds, to wait on a lock before checking to see if there is a deadlock condition. The check for deadlock is relatively expensive, so the server doesn't run it every time it waits for a lock. We optimistically assume that deadlocks are not common in production applications and just wait on the lock for a while before checking for a deadlock. Increasing this value reduces the amount of time wasted in needless deadlock checks, but slows down reporting of real deadlock errors. The default is one second (1s), which is probably about the smallest value you would want in practice. On a heavily loaded server you might want to raise it. Ideally the setting should exceed your typical transaction time, so as to improve the odds that a lock will be released before the waiter decides to check for deadlock. When log_lock_waits is set, this parameter also determines the length of time to wait before a log message is issued about the lock wait. If you are trying to investigate locking delays you might want to set a shorter than normal deadlock_timeout.
+This is the amount of time, in milliseconds, to wait on a lock before checking to see if there is a deadlock condition. The check for deadlock is relatively expensive, so the server doesn't run it every time it waits for a lock. We optimistically assume that deadlocks are not common in production applications and just wait on the lock for a while before checking for a deadlock. Increasing this value reduces the amount of time wasted in needless deadlock checks, but slows down reporting of real deadlock errors. The default is one second (1s), which is probably about the smallest value you would want in practice. On a heavily loaded server you might want to raise it. Ideally the setting should exceed your typical transaction time, so as to improve the odds that a lock will be released before the waiter decides to check for deadlock. Only superusers can change this setting. When log_lock_waits is set, this parameter also determines the length of time to wait before a log message is issued about the lock wait. If you are trying to investigate locking delays you might want to set a shorter than normal deadlock_timeout.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: bool
+context: user
+boot_val: on
+unit: None
+enumvals: None
+
+Enables or disables the query planner's use of index-only-scan plan types. The default is on.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: string
+context: postmaster
+boot_val: PostgreSQL
+unit: None
+enumvals: None
+
+When logging to event log is enabled, this parameter determines the program name used to identify PostgreSQL messages in the log. The default is PostgreSQL. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Soft upper limit of the size of the set returned by GIN index scans. For more information see Section 54.4.
+Soft upper limit of the size of the set returned by GIN index scans. For more information see Section 55.4.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Specifies whether or not a hot standby will send feedback to the primary about queries currently executing on the standby. This parameter can be used to eliminate query cancels caused by cleanup records, but can cause database bloat on the primary for some workloads. Feedback messages will not be sent more frequently than once per wal_receiver_status_interval. The default value is off. This parameter can only be set in the postgresql.conf file or on the server command line.
+Specifies whether or not a hot standby will send feedback to the primary or upstream standby about queries currently executing on the standby. This parameter can be used to eliminate query cancels caused by cleanup records, but can cause database bloat on the primary for some workloads. Feedback messages will not be sent more frequently than once per wal_receiver_status_interval. The default value is off. This parameter can only be set in the postgresql.conf file or on the server command line. If cascaded replication is in use the feedback is passed upstream until it eventually reaches the primary. Standbys make no other use of feedback they receive other than to pass upstream.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Specifies the configuration file for Section 19.2 user name mapping (customarily called pg_ident.conf). This parameter can only be set at server start.
+Specifies the configuration file for user name mapping (customarily called pg_ident.conf). This parameter can only be set at server start. See also Section 19.2.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-PostgreSQL supports several methods for logging server messages, including stderr, csvlog and syslog. On Windows, eventlog is also supported. Set this parameter to a list of desired log destinations separated by commas. The default is to log to stderr only. This parameter can only be set in the postgresql.conf file or on the server command line. If csvlog is included in log_destination, log entries are output in "comma separated value" (CSV) format, which is convenient for loading logs into programs. See Section 18.8.4 for details. logging_collector must be enabled to generate CSV-format log output. Note: On most Unix systems, you will need to alter the configuration of your system's syslog daemon in order to make use of the syslog option for log_destination. PostgreSQL can log to syslog facilities LOCAL0 through LOCAL7 (see syslog_facility), but the default syslog configuration on most platforms will discard all such messages. You will need to add something like: local0.* /var/log/postgresql to the syslog daemon's configuration file to make it work.
+PostgreSQL supports several methods for logging server messages, including stderr, csvlog and syslog. On Windows, eventlog is also supported. Set this parameter to a list of desired log destinations separated by commas. The default is to log to stderr only. This parameter can only be set in the postgresql.conf file or on the server command line. If csvlog is included in log_destination, log entries are output in "comma separated value" (CSV) format, which is convenient for loading logs into programs. See Section 18.8.4 for details. logging_collector must be enabled to generate CSV-format log output. Note: On most Unix systems, you will need to alter the configuration of your system's syslog daemon in order to make use of the syslog option for log_destination. PostgreSQL can log to syslog facilities LOCAL0 through LOCAL7 (see syslog_facility), but the default syslog configuration on most platforms will discard all such messages. You will need to add something like: local0.* /var/log/postgresql to the syslog daemon's configuration file to make it work. On Windows, when you use the eventlog option for log_destination, you should register an event source and its library with the operating system so that the Windows Event Viewer can display event log messages cleanly. See Section 17.11 for details.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-This is a printf-style string that is output at the beginning of each log line. % characters begin "escape sequences" that are replaced with status information as outlined below. Unrecognized escapes are ignored. Other characters are copied straight to the log line. Some escapes are only recognized by session processes, and are ignored by background processes such as the main server process. This parameter can only be set in the postgresql.conf file or on the server command line. The default is an empty string. Escape Effect Session only %a Application name yes %u User name yes %d Database name yes %r Remote host name or IP address, and remote port yes %h Remote host name or IP address yes %p Process ID no %t Time stamp without milliseconds no %m Time stamp with milliseconds no %i Command tag: type of session's current command yes %e SQLSTATE error code no %c Session ID: see below no %l Number of the log line for each session or process, starting at 1 no %s Process start time stamp no %v Virtual transaction ID (backendID/localXID) no %x Transaction ID (0 if none is assigned) no %q Produces no output, but tells non-session processes to stop at this point in the string; ignored by session processes no %% Literal % no The %c escape prints a quasi-unique session identifier, consisting of two 4-byte hexadecimal numbers (without leading zeros) separated by a dot. The numbers are the process start time and the process ID, so %c can also be used as a space saving way of printing those items. For example, to generate the session identifier from pg_stat_activity, use this query: SELECT to_hex(EXTRACT(EPOCH FROM backend_start)::integer) || '.' || to_hex(procpid) FROM pg_stat_activity; Tip: If you set a nonempty value for log_line_prefix, you should usually make its last character be a space, to provide visual separation from the rest of the log line. A punctuation character can be used too. Tip: Syslog produces its own time stamp and process ID information, so you probably do not want to include those escapes if you are logging to syslog.
+This is a printf-style string that is output at the beginning of each log line. % characters begin "escape sequences" that are replaced with status information as outlined below. Unrecognized escapes are ignored. Other characters are copied straight to the log line. Some escapes are only recognized by session processes, and are ignored by background processes such as the main server process. This parameter can only be set in the postgresql.conf file or on the server command line. The default is an empty string. Escape Effect Session only %a Application name yes %u User name yes %d Database name yes %r Remote host name or IP address, and remote port yes %h Remote host name or IP address yes %p Process ID no %t Time stamp without milliseconds no %m Time stamp with milliseconds no %i Command tag: type of session's current command yes %e SQLSTATE error code no %c Session ID: see below no %l Number of the log line for each session or process, starting at 1 no %s Process start time stamp no %v Virtual transaction ID (backendID/localXID) no %x Transaction ID (0 if none is assigned) no %q Produces no output, but tells non-session processes to stop at this point in the string; ignored by session processes no %% Literal % no The %c escape prints a quasi-unique session identifier, consisting of two 4-byte hexadecimal numbers (without leading zeros) separated by a dot. The numbers are the process start time and the process ID, so %c can also be used as a space saving way of printing those items. For example, to generate the session identifier from pg_stat_activity, use this query: SELECT to_hex(EXTRACT(EPOCH FROM backend_start)::integer) || '.' || to_hex(pid) FROM pg_stat_activity; Tip: If you set a nonempty value for log_line_prefix, you should usually make its last character be a space, to provide visual separation from the rest of the log line. A punctuation character can be used too. Tip: Syslog produces its own time stamp and process ID information, so you probably do not want to include those escapes if you are logging to syslog.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Controls whether a log message is produced when a session waits longer than deadlock_timeout to acquire a lock. This is useful in determining if lock waits are causing poor performance. The default is off.
+Controls whether a log message is produced when a session waits longer than deadlock_timeout to acquire a lock. This is useful in determining if lock waits are causing poor performance. The default is off. Only superusers can change this setting.

--- 9.1
+++ 9.2
@@ -1,7 +1,7 @@
 vartype: string
 context: sighup
-boot_val: None
+boot_val: GMT
 unit: None
 enumvals: None
 
-Sets the time zone used for timestamps written in the server log. Unlike timezone, this value is cluster-wide, so that all sessions will report timestamps consistently. If not explicitly set, the server initializes this variable to the time zone specified by its system environment. See Section 8.5.3 for more information. This parameter can only be set in the postgresql.conf file or on the server command line.
+Sets the time zone used for timestamps written in the server log. Unlike TimeZone, this value is cluster-wide, so that all sessions will report timestamps consistently. The built-in default is GMT, but that is typically overridden in postgresql.conf; initdb will install a setting there corresponding to its system environment. See Section 8.5.3 for more information. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Sets the planner's estimate of the cost of a non-sequentially-fetched disk page. The default is 4.0. This value can be overridden for a particular tablespace by setting the tablespace parameter of the same name (see ALTER TABLESPACE). Reducing this value relative to seq_page_cost will cause the system to prefer index scans; raising it will make index scans look relatively more expensive. You can raise or lower both values together to change the importance of disk I/O costs relative to CPU costs, which are described by the following parameters. Tip: Although the system will let you set random_page_cost to less than seq_page_cost, it is not physically sensible to do so. However, setting them equal makes sense if the database is entirely cached in RAM, since in that case there is no penalty for touching pages out of sequence. Also, in a heavily-cached database you should lower both values relative to the CPU parameters, since the cost of fetching a page already in RAM is much smaller than it would normally be.
+Sets the planner's estimate of the cost of a non-sequentially-fetched disk page. The default is 4.0. This value can be overridden for tables and indexes in a particular tablespace by setting the tablespace parameter of the same name (see ALTER TABLESPACE). Reducing this value relative to seq_page_cost will cause the system to prefer index scans; raising it will make index scans look relatively more expensive. You can raise or lower both values together to change the importance of disk I/O costs relative to CPU costs, which are described by the following parameters. Random access to mechanical disk storage is normally much more expensive than four-times sequential access. However, a lower default is used (4.0) because the majority of random accesses to disk, such as indexed reads, are assumed to be in cache. The default value can be thought of as modeling random access as 40 times slower than sequential, while expecting 90% of random reads to be cached. If you believe a 90% cache rate is an incorrect assumption for your workload, you can increase random_page_cost to better reflect the true cost of random storage reads. Correspondingly, if your data is likely to be completely in cache, such as when the database is smaller than the total server memory, decreasing random_page_cost can be appropriate. Storage that has a low random read cost relative to sequential, e.g. solid-state drives, might also be better modeled with a lower value for random_page_cost. Tip: Although the system will let you set random_page_cost to less than seq_page_cost, it is not physically sensible to do so. However, setting them equal makes sense if the database is entirely cached in RAM, since in that case there is no penalty for touching pages out of sequence. Also, in a heavily-cached database you should lower both values relative to the CPU parameters, since the cost of fetching a page already in RAM is much smaller than it would normally be.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: ms
 enumvals: None
 
-Terminate replication connections that are inactive longer than the specified number of milliseconds. This is useful for the primary server to detect a standby crash or network outage. A value of zero disables the timeout mechanism. This parameter can only be set in the postgresql.conf file or on the server command line. The default value is 60 seconds. To prevent connections from being terminated prematurely, wal_receiver_status_interval must be enabled on the standby, and its value must be less than the value of replication_timeout.
+Terminate replication connections that are inactive longer than the specified number of milliseconds. This is useful for the sending server to detect a standby crash or network outage. A value of zero disables the timeout mechanism. This parameter can only be set in the postgresql.conf file or on the server command line. The default value is 60 seconds. To prevent connections from being terminated prematurely, wal_receiver_status_interval must be enabled on the standby, and its value must be less than the value of replication_timeout.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-This variable specifies the order in which schemas are searched when an object (table, data type, function, etc.) is referenced by a simple name with no schema specified. When there are objects of identical names in different schemas, the one found first in the search path is used. An object that is not in any of the schemas in the search path can only be referenced by specifying its containing schema with a qualified (dotted) name. The value for search_path must be a comma-separated list of schema names. If one of the list items is the special value $user, then the schema having the name returned by SESSION_USER is substituted, if there is such a schema. (If not, $user is ignored.) The system catalog schema, pg_catalog, is always searched, whether it is mentioned in the path or not. If it is mentioned in the path then it will be searched in the specified order. If pg_catalog is not in the path then it will be searched before searching any of the path items. Likewise, the current session's temporary-table schema, pg_temp_nnn, is always searched if it exists. It can be explicitly listed in the path by using the alias pg_temp. If it is not listed in the path then it is searched first (even before pg_catalog). However, the temporary schema is only searched for relation (table, view, sequence, etc) and data type names. It is never searched for function or operator names. When objects are created without specifying a particular target schema, they will be placed in the first schema listed in the search path. An error is reported if the search path is empty. The default value for this parameter is '"$user", public' (where the second part will be ignored if there is no schema named public). This supports shared use of a database (where no users have private schemas, and all share use of public), private per-user schemas, and combinations of these. Other effects can be obtained by altering the default search path setting, either globally or per-user. The current effective value of the search path can be examined via the SQL function current_schemas (see Section 9.23). This is not quite the same as examining the value of search_path, since current_schemas shows how the items appearing in search_path were resolved. For more information on schema handling, see Section 5.7.
+This variable specifies the order in which schemas are searched when an object (table, data type, function, etc.) is referenced by a simple name with no schema specified. When there are objects of identical names in different schemas, the one found first in the search path is used. An object that is not in any of the schemas in the search path can only be referenced by specifying its containing schema with a qualified (dotted) name. The value for search_path must be a comma-separated list of schema names. Any name that is not an existing schema, or is a schema for which the user does not have USAGE permission, is silently ignored. If one of the list items is the special name $user, then the schema having the name returned by SESSION_USER is substituted, if there is such a schema and the user has USAGE permission for it. (If not, $user is ignored.) The system catalog schema, pg_catalog, is always searched, whether it is mentioned in the path or not. If it is mentioned in the path then it will be searched in the specified order. If pg_catalog is not in the path then it will be searched before searching any of the path items. Likewise, the current session's temporary-table schema, pg_temp_nnn, is always searched if it exists. It can be explicitly listed in the path by using the alias pg_temp. If it is not listed in the path then it is searched first (even before pg_catalog). However, the temporary schema is only searched for relation (table, view, sequence, etc) and data type names. It is never searched for function or operator names. When objects are created without specifying a particular target schema, they will be placed in the first valid schema named in search_path. An error is reported if the search path is empty. The default value for this parameter is "$user", public. This setting supports shared use of a database (where no users have private schemas, and all share use of public), private per-user schemas, and combinations of these. Other effects can be obtained by altering the default search path setting, either globally or per-user. The current effective value of the search path can be examined via the SQL function current_schemas (see Section 9.25). This is not quite the same as examining the value of search_path, since current_schemas shows how the items appearing in search_path were resolved. For more information on schema handling, see Section 5.7.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Sets the planner's estimate of the cost of a disk page fetch that is part of a series of sequential fetches. The default is 1.0. This value can be overridden for a particular tablespace by setting the tablespace parameter of the same name (see ALTER TABLESPACE).
+Sets the planner's estimate of the cost of a disk page fetch that is part of a series of sequential fetches. The default is 1.0. This value can be overridden for tables and indexes in a particular tablespace by setting the tablespace parameter of the same name (see ALTER TABLESPACE).

--- 9.1
+++ 9.2
@@ -1,6 +1,6 @@
 vartype: string
 context: internal
-boot_val: 9.1.24
+boot_val: 9.2.23
 unit: None
 enumvals: None
 

--- 9.1
+++ 9.2
@@ -1,6 +1,6 @@
 vartype: integer
 context: internal
-boot_val: 90124
+boot_val: 90223
 unit: 
 enumvals: None
 

--- 9.1
+++ 9.2
@@ -1,7 +0,0 @@
-vartype: bool
-context: postmaster
-boot_val: off
-unit: None
-enumvals: None
-
-Runs the server silently. If this parameter is set, the server will automatically run in background and disassociate from the controlling terminal. This parameter can only be set at server start. Caution When this parameter is set, the server's standard output and standard error are redirected to the file postmaster.log within the data directory. There is no provision for rotating this file, so it will grow indefinitely unless server log output is redirected elsewhere by other settings. It is recommended that log_destination be set to syslog or that logging_collector be enabled when using this option. Even with those measures, errors reported early during startup may appear in postmaster.log rather than the normal log destination.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: string
+context: postmaster
+boot_val: 
+unit: None
+enumvals: None
+
+Specifies the name of the file containing the SSL server certificate authority (CA). The default is empty, meaning no CA file is loaded, and client certificate verification is not performed. (In previous releases of PostgreSQL, the name of this file was hard-coded as root.crt.) Relative paths are relative to the data directory. This parameter can only be set at server start.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: string
+context: postmaster
+boot_val: server.crt
+unit: None
+enumvals: None
+
+Specifies the name of the file containing the SSL server certificate. The default is server.crt. Relative paths are relative to the data directory. This parameter can only be set at server start.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: string
+context: postmaster
+boot_val: 
+unit: None
+enumvals: None
+
+Specifies the name of the file containing the SSL server certificate revocation list (CRL). The default is empty, meaning no CRL file is loaded. (In previous releases of PostgreSQL, the name of this file was hard-coded as root.crl.) Relative paths are relative to the data directory. This parameter can only be set at server start.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: string
+context: postmaster
+boot_val: server.key
+unit: None
+enumvals: None
+
+Specifies the name of the file containing the SSL server private key. The default is server.key. Relative paths are relative to the data directory. This parameter can only be set at server start.

--- 9.1
+++ 9.2
@@ -2,6 +2,6 @@
 context: user
 boot_val: on
 unit: None
-enumvals: ['local', 'on', 'off']
+enumvals: ['local', 'remote_write', 'on', 'off']
 
-Specifies whether transaction commit will wait for WAL records to be written to disk before the command returns a "success" indication to the client. Valid values are on, local, and off. The default, and safe, value is on. When off, there can be a delay between when success is reported to the client and when the transaction is really guaranteed to be safe against a server crash. (The maximum delay is three times wal_writer_delay.) Unlike fsync, setting this parameter to off does not create any risk of database inconsistency: an operating system or database crash might result in some recent allegedly-committed transactions being lost, but the database state will be just the same as if those transactions had been aborted cleanly. So, turning synchronous_commit off can be a useful alternative when performance is more important than exact certainty about the durability of a transaction. For more discussion see Section 29.3. If synchronous_standby_names is set, this parameter also controls whether or not transaction commit will wait for the transaction's WAL records to be flushed to disk and replicated to the standby server. The commit wait will last until a reply from the current synchronous standby indicates it has written the commit record of the transaction to durable storage. If synchronous replication is in use, it will normally be sensible either to wait both for WAL records to reach both the local and remote disks, or to allow the transaction to commit asynchronously. However, the special value local is available for transactions that wish to wait for local flush to disk, but not synchronous replication. This parameter can be changed at any time; the behavior for any one transaction is determined by the setting in effect when it commits. It is therefore possible, and useful, to have some transactions commit synchronously and others asynchronously. For example, to make a single multistatement transaction commit asynchronously when the default is the opposite, issue SET LOCAL synchronous_commit TO OFF within the transaction.
+Specifies whether transaction commit will wait for WAL records to be written to disk before the command returns a "success" indication to the client. Valid values are on, remote_write, local, and off. The default, and safe, setting is on. When off, there can be a delay between when success is reported to the client and when the transaction is really guaranteed to be safe against a server crash. (The maximum delay is three times wal_writer_delay.) Unlike fsync, setting this parameter to off does not create any risk of database inconsistency: an operating system or database crash might result in some recent allegedly-committed transactions being lost, but the database state will be just the same as if those transactions had been aborted cleanly. So, turning synchronous_commit off can be a useful alternative when performance is more important than exact certainty about the durability of a transaction. For more discussion see Section 29.3. If synchronous_standby_names is set, this parameter also controls whether or not transaction commits will wait for the transaction's WAL records to be replicated to the standby server. When set to on, commits will wait until a reply from the current synchronous standby indicates it has received the commit record of the transaction and flushed it to disk. This ensures the transaction will not be lost unless both primary and standby suffer corruption of their database storage. When set to remote_write, commits will wait until a reply from the current synchronous standby indicates it has received the commit record of the transaction and written it out to the standby's operating system, but the data has not necessarily reached stable storage on the standby. This setting is sufficient to ensure data preservation even if the standby instance of PostgreSQL were to crash, but not if the standby suffers an operating-system-level crash. When synchronous replication is in use, it will normally be sensible either to wait for both local flush to disk and replication of WAL records, or to allow the transaction to commit asynchronously. However, the setting local is available for transactions that wish to wait for local flush to disk, but not synchronous replication. If synchronous_standby_names is not set, the settings on, remote_write and local all provide the same synchronization level: transaction commits only wait for local flush to disk. This parameter can be changed at any time; the behavior for any one transaction is determined by the setting in effect when it commits. It is therefore possible, and useful, to have some transactions commit synchronously and others asynchronously. For example, to make a single multistatement transaction commit asynchronously when the default is the opposite, issue SET LOCAL synchronous_commit TO OFF within the transaction.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: None
 enumvals: None
 
-Specifies a comma-separated list of standby names that can support synchronous replication, as described in Section 25.2.6. At any one time there will be at most one active synchronous standby; transactions waiting for commit will be allowed to proceed after this standby server confirms receipt of their data. The synchronous standby will be the first standby named in this list that is both currently connected and streaming data in real-time (as shown by a state of streaming in the pg_stat_replication view). Other standby servers appearing later in this list represent potential synchronous standbys. If the current synchronous standby disconnects for whatever reason, it will be replaced immediately with the next-highest-priority standby. Specifying more than one standby name can allow very high availability. The name of a standby server for this purpose is the application_name setting of the standby, as set in the primary_conninfo of the standby's walreceiver. There is no mechanism to enforce uniqueness. In case of duplicates one of the matching standbys will be chosen to be the synchronous standby, though exactly which one is indeterminate. The special entry * matches any application_name, including the default application name of walreceiver. If no synchronous standby names are specified here, then synchronous replication is not enabled and transaction commits will not wait for replication. This is the default configuration. Even when synchronous replication is enabled, individual transactions can be configured not to wait for replication by setting the synchronous_commit parameter to local or off. This parameter can only be set in the postgresql.conf file or on the server command line.
+Specifies a comma-separated list of standby names that can support synchronous replication, as described in Section 25.2.7. At any one time there will be at most one active synchronous standby; transactions waiting for commit will be allowed to proceed after this standby server confirms receipt of their data. The synchronous standby will be the first standby named in this list that is both currently connected and streaming data in real-time (as shown by a state of streaming in the pg_stat_replication view). Other standby servers appearing later in this list represent potential synchronous standbys. If the current synchronous standby disconnects for whatever reason, it will be replaced immediately with the next-highest-priority standby. Specifying more than one standby name can allow very high availability. The name of a standby server for this purpose is the application_name setting of the standby, as set in the primary_conninfo of the standby's walreceiver. There is no mechanism to enforce uniqueness. In case of duplicates one of the matching standbys will be chosen to be the synchronous standby, though exactly which one is indeterminate. The special entry * matches any application_name, including the default application name of walreceiver. If no synchronous standby names are specified here, then synchronous replication is not enabled and transaction commits will not wait for replication. This is the default configuration. Even when synchronous replication is enabled, individual transactions can be configured not to wait for replication by setting the synchronous_commit parameter to local or off. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Specifies the number of keepalive packets to send on an otherwise idle connection. A value of 0 uses the system default. This parameter is supported only on systems that support the TCP_KEEPCNT symbol; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero. Note: This parameter is not supported on Windows, and must be zero.
+Specifies the number of keepalive packets to send on an otherwise idle connection. A value of 0 uses the system default. This parameter is supported only on systems that support TCP_KEEPCNT or an equivalent socket option; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero. Note: This parameter is not supported on Windows, and must be zero.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: s
 enumvals: None
 
-Specifies the number of seconds before sending a keepalive packet on an otherwise idle connection. A value of 0 uses the system default. This parameter is supported only on systems that support the TCP_KEEPIDLE or TCP_KEEPALIVE symbols, and on Windows; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero. Note: On Windows, a value of 0 will set this parameter to 2 hours, since Windows does not provide a way to read the system default value.
+Specifies the number of seconds before sending a keepalive packet on an otherwise idle connection. A value of 0 uses the system default. This parameter is supported only on systems that support TCP_KEEPIDLE or an equivalent socket option, and on Windows; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero. Note: On Windows, a value of 0 will set this parameter to 2 hours, since Windows does not provide a way to read the system default value.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: s
 enumvals: None
 
-Specifies the number of seconds between sending keepalives on an otherwise idle connection. A value of 0 uses the system default. This parameter is supported only on systems that support the TCP_KEEPINTVL symbol, and on Windows; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero. Note: On Windows, a value of 0 will set this parameter to 1 second, since Windows does not provide a way to read the system default value.
+Specifies the number of seconds between sending keepalives on an otherwise idle connection. A value of 0 uses the system default. This parameter is supported only on systems that support TCP_KEEPINTVL or an equivalent socket option, and on Windows; on other systems, it must be zero. In sessions connected via a Unix-domain socket, this parameter is ignored and always reads as zero. Note: On Windows, a value of 0 will set this parameter to 1 second, since Windows does not provide a way to read the system default value.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: integer
+context: superuser
+boot_val: -1
+unit: kB
+enumvals: None
+
+Specifies the maximum amount of disk space that a session can use for temporary files, such as sort and hash temporary files, or the storage file for a held cursor. A transaction attempting to exceed this limit will be cancelled. The value is specified in kilobytes, and -1 (the default) means no limit. Only superusers can change this setting. This setting constrains the total space used at any instant by all temporary files used by a given PostgreSQL session. It should be noted that disk space used for explicit temporary tables, as opposed to temporary files used behind-the-scenes in query execution, does not count against this limit.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Specifies the number of bytes reserved to track the currently executing command for each active session, for the pg_stat_activity.current_query field. The default value is 1024. This parameter can only be set at server start.
+Specifies the number of bytes reserved to track the currently executing command for each active session, for the pg_stat_activity.query field. The default value is 1024. This parameter can only be set at server start.

--- 9.1
+++ 9.2
@@ -0,0 +1,7 @@
+vartype: bool
+context: superuser
+boot_val: off
+unit: None
+enumvals: None
+
+Enables timing of database I/O calls. This parameter is off by default, because it will repeatedly query the operating system for the current time, which may cause significant overhead on some platforms. You can use the pg_test_timing tool to measure the overhead of timing on your system. I/O timing information is displayed in pg_stat_database, in the output of EXPLAIN when the BUFFERS option is used, and by pg_stat_statements. Only superusers can change this setting.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Specifies the number of transactions by which VACUUM and HOT updates will defer cleanup of dead row versions. The default is zero transactions, meaning that dead row versions can be removed as soon as possible, that is, as soon as they are no longer visible to any open transaction. You may wish to set this to a non-zero value on a primary server that is supporting hot standby servers, as described in Section 25.5. This allows more time for queries on the standby to complete without incurring conflicts due to early cleanup of rows. However, since the value is measured in terms of number of write transactions occurring on the primary server, it is difficult to predict just how much additional grace time will be made available to standby queries. This parameter can only be set in the postgresql.conf file or on the server command line. You should also consider setting hot_standby_feedback as an alternative to using this parameter.
+Specifies the number of transactions by which VACUUM and HOT updates will defer cleanup of dead row versions. The default is zero transactions, meaning that dead row versions can be removed as soon as possible, that is, as soon as they are no longer visible to any open transaction. You may wish to set this to a non-zero value on a primary server that is supporting hot standby servers, as described in Section 25.5. This allows more time for queries on the standby to complete without incurring conflicts due to early cleanup of rows. However, since the value is measured in terms of number of write transactions occurring on the primary server, it is difficult to predict just how much additional grace time will be made available to standby queries. This parameter can only be set in the postgresql.conf file or on the server command line. You should also consider setting hot_standby_feedback on standby server(s) as an alternative to using this parameter.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Specifies the cutoff age (in transactions) that VACUUM should use to decide whether to replace transaction IDs with FrozenXID while scanning a table. The default is 50 million transactions. Although users can set this value anywhere from zero to one billion, VACUUM will silently limit the effective value to half the value of autovacuum_freeze_max_age, so that there is not an unreasonably short time between forced autovacuums. For more information see Section 23.1.4.
+Specifies the cutoff age (in transactions) that VACUUM should use to decide whether to replace transaction IDs with FrozenXID while scanning a table. The default is 50 million transactions. Although users can set this value anywhere from zero to one billion, VACUUM will silently limit the effective value to half the value of autovacuum_freeze_max_age, so that there is not an unreasonably short time between forced autovacuums. For more information see Section 23.1.5.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-VACUUM performs a whole-table scan if the table's pg_class.relfrozenxid field has reached the age specified by this setting. The default is 150 million transactions. Although users can set this value anywhere from zero to one billion, VACUUM will silently limit the effective value to 95% of autovacuum_freeze_max_age, so that a periodical manual VACUUM has a chance to run before an anti-wraparound autovacuum is launched for the table. For more information see Section 23.1.4.
+VACUUM performs a whole-table scan if the table's pg_class.relfrozenxid field has reached the age specified by this setting. The default is 150 million transactions. Although users can set this value anywhere from zero to one billion, VACUUM will silently limit the effective value to 95% of autovacuum_freeze_max_age, so that a periodical manual VACUUM has a chance to run before an anti-wraparound autovacuum is launched for the table. For more information see Section 23.1.5.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: 
 enumvals: None
 
-Specifies the minimum number of past log file segments kept in the pg_xlog directory, in case a standby server needs to fetch them for streaming replication. Each segment is normally 16 megabytes. If a standby server connected to the primary falls behind by more than wal_keep_segments segments, the primary might remove a WAL segment still needed by the standby, in which case the replication connection will be terminated. (However, the standby server can recover by fetching the segment from archive, if WAL archiving is in use.) This sets only the minimum number of segments retained in pg_xlog; the system might need to retain more segments for WAL archival or to recover from a checkpoint. If wal_keep_segments is zero (the default), the system doesn't keep any extra segments for standby purposes, so the number of old WAL segments available to standby servers is a function of the location of the previous checkpoint and status of WAL archiving. This parameter has no effect on restartpoints. This parameter can only be set in the postgresql.conf file or on the server command line.
+Specifies the minimum number of past log file segments kept in the pg_xlog directory, in case a standby server needs to fetch them for streaming replication. Each segment is normally 16 megabytes. If a standby server connected to the sending server falls behind by more than wal_keep_segments segments, the sending server might remove a WAL segment still needed by the standby, in which case the replication connection will be terminated. Downstream connections will also eventually fail as a result. (However, the standby server can recover by fetching the segment from archive, if WAL archiving is in use.) This sets only the minimum number of segments retained in pg_xlog; the system might need to retain more segments for WAL archival or to recover from a checkpoint. If wal_keep_segments is zero (the default), the system doesn't keep any extra segments for standby purposes, so the number of old WAL segments available to standby servers is a function of the location of the previous checkpoint and status of WAL archiving. This parameter can only be set in the postgresql.conf file or on the server command line.

--- 9.1
+++ 9.2
@@ -4,4 +4,4 @@
 unit: s
 enumvals: None
 
-Specifies the minimum frequency for the WAL receiver process on the standby to send information about replication progress to the primary, where it can be seen using the pg_stat_replication view. The standby will report the last transaction log position it has written, the last position it has flushed to disk, and the last position it has applied. This parameter's value is the maximum interval, in seconds, between reports. Updates are sent each time the write or flush positions change, or at least as often as specified by this parameter. Thus, the apply position may lag slightly behind the true position. Setting this parameter to zero disables status updates completely. This parameter can only be set in the postgresql.conf file or on the server command line. The default value is 10 seconds. When replication_timeout is enabled on the primary, wal_receiver_status_interval must be enabled, and its value must be less than the value of replication_timeout.
+Specifies the minimum frequency for the WAL receiver process on the standby to send information about replication progress to the primary or upstream standby, where it can be seen using the pg_stat_replication view. The standby will report the last transaction log position it has written, the last position it has flushed to disk, and the last position it has applied. This parameter's value is the maximum interval, in seconds, between reports. Updates are sent each time the write or flush positions change, or at least as often as specified by this parameter. Thus, the apply position may lag slightly behind the true position. Setting this parameter to zero disables status updates completely. This parameter can only be set in the postgresql.conf file or on the server command line. The default value is 10 seconds. When replication_timeout is enabled on a sending server, wal_receiver_status_interval must be enabled, and its value must be less than the value of replication_timeout.

--- 9.1
+++ 9.2
@@ -1,7 +0,0 @@
-vartype: integer
-context: sighup
-boot_val: 1000
-unit: ms
-enumvals: None
-
-Specifies the delay between activity rounds for WAL sender processes. In each round the WAL sender sends any WAL accumulated since the last round to the standby server. It then sleeps for wal_sender_delay milliseconds, and repeats. The sleep is interrupted by transaction commit, so the effects of a committed transaction are sent to standby servers as soon as the commit happens, regardless of this setting. The default value is one second (1s). Note that on many systems, the effective resolution of sleep delays is 10 milliseconds; setting wal_sender_delay to a value that is not a multiple of 10 might have the same results as setting it to the next higher multiple of 10. This parameter can only be set in the postgresql.conf file or on the server command line.