Flexible options for BASE_BACKUP.

Previously, BASE_BACKUP used an entirely hard-coded syntax, but that's
hard to extend. Instead, adopt the same kind of syntax we've used for
SQL commands such as VACUUM, ANALYZE, COPY, and EXPLAIN, where it's
not necessary for all of the option names to be parser keywords.

In the new syntax, most of the options now take an optional Boolean
argument. To match our practice in other in places, the options which
the old syntax called NOWAIT and NOVERIFY_CHECKSUMS options are in the
new syntax called WAIT and VERIFY_CHECKUMS, and the default value is
false. In the new syntax, the FAST option has been replaced by a
CHECKSUM option whose value may be 'fast' or 'spread'.

This commit does not remove support for the old syntax. It just adds
the new one as an additional option, and makes pg_basebackup prefer
the new syntax when the server is new enough to support it.

Patch by me, reviewed and tested by Fabien Coelho, Sergei Kornilov,
Fujii Masao, and Tushar Ahuja.

Discussion: http://postgr.es/m/CA+TgmobAczXDRO_Gr2euo_TxgzaH1JxbNxvFx=HYvBinefNH8Q@mail.gmail.com
Discussion: http://postgr.es/m/CA+TgmoZGwR=ZVWFeecncubEyPdwghnvfkkdBe9BLccLSiqdf9Q@mail.gmail.com
This commit is contained in:
Robert Haas 2021-10-05 11:50:21 -04:00
parent 68601985e6
commit 0ba281cb4b
6 changed files with 276 additions and 83 deletions

View File

@ -2517,7 +2517,7 @@ The commands accepted in replication mode are:
</varlistentry>
<varlistentry id="protocol-replication-base-backup" xreflabel="BASE_BACKUP">
<term><literal>BASE_BACKUP</literal> [ <literal>LABEL</literal> <replaceable>'label'</replaceable> ] [ <literal>PROGRESS</literal> ] [ <literal>FAST</literal> ] [ <literal>WAL</literal> ] [ <literal>NOWAIT</literal> ] [ <literal>MAX_RATE</literal> <replaceable>rate</replaceable> ] [ <literal>TABLESPACE_MAP</literal> ] [ <literal>NOVERIFY_CHECKSUMS</literal> ] [ <literal>MANIFEST</literal> <replaceable>manifest_option</replaceable> ] [ <literal>MANIFEST_CHECKSUMS</literal> <replaceable>checksum_algorithm</replaceable> ]
<term><literal>BASE_BACKUP</literal> [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ]
<indexterm><primary>BASE_BACKUP</primary></indexterm>
</term>
<listitem>
@ -2540,52 +2540,55 @@ The commands accepted in replication mode are:
</varlistentry>
<varlistentry>
<term><literal>PROGRESS</literal></term>
<term><literal>PROGRESS [ <replaceable class="parameter">boolean</replaceable> ]</literal></term>
<listitem>
<para>
Request information required to generate a progress report. This will
send back an approximate size in the header of each tablespace, which
can be used to calculate how far along the stream is done. This is
calculated by enumerating all the file sizes once before the transfer
is even started, and might as such have a negative impact on the
performance. In particular, it might take longer before the first data
If set to true, request information required to generate a progress
report. This will send back an approximate size in the header of each
tablespace, which can be used to calculate how far along the stream
is done. This is calculated by enumerating all the file sizes once
before the transfer is even started, and might as such have a
negative impact on the performance. In particular, it might take
longer before the first data
is streamed. Since the database files can change during the backup,
the size is only approximate and might both grow and shrink between
the time of approximation and the sending of the actual files.
The default is false.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>FAST</literal></term>
<term><literal>CHECKPOINT { 'fast' | 'spread' }</literal></term>
<listitem>
<para>
Request a fast checkpoint.
Sets the type of checkpoint to be performed at the beginning of the
base backup. The default is <literal>spread</literal>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>WAL</literal></term>
<term><literal>WAL [ <replaceable class="parameter">boolean</replaceable> ]</literal></term>
<listitem>
<para>
Include the necessary WAL segments in the backup. This will include
all the files between start and stop backup in the
If set to true, include the necessary WAL segments in the backup.
This will include all the files between start and stop backup in the
<filename>pg_wal</filename> directory of the base directory tar
file.
file. The default is false.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>NOWAIT</literal></term>
<term><literal>WAIT [ <replaceable class="parameter">boolean</replaceable> ]</literal></term>
<listitem>
<para>
By default, the backup will wait until the last required WAL
If set to true, the backup will wait until the last required WAL
segment has been archived, or emit a warning if log archiving is
not enabled. Specifying <literal>NOWAIT</literal> disables both
the waiting and the warning, leaving the client responsible for
ensuring the required log is available.
not enabled. If false, the backup will neither wait nor warn,
leaving the client responsible for ensuring the required log is
available. The default is true.
</para>
</listitem>
</varlistentry>
@ -2605,25 +2608,25 @@ The commands accepted in replication mode are:
</varlistentry>
<varlistentry>
<term><literal>TABLESPACE_MAP</literal></term>
<term><literal>TABLESPACE_MAP [ <replaceable class="parameter">boolean</replaceable> ]</literal></term>
<listitem>
<para>
Include information about symbolic links present in the directory
<filename>pg_tblspc</filename> in a file named
If true, include information about symbolic links present in the
directory <filename>pg_tblspc</filename> in a file named
<filename>tablespace_map</filename>. The tablespace map file includes
each symbolic link name as it exists in the directory
<filename>pg_tblspc/</filename> and the full path of that symbolic link.
The default is false.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>NOVERIFY_CHECKSUMS</literal></term>
<term><literal>VERIFY_CHECKSUMS [ <replaceable class="parameter">boolean</replaceable> ]</literal></term>
<listitem>
<para>
By default, checksums are verified during a base backup if they are
enabled. Specifying <literal>NOVERIFY_CHECKSUMS</literal> disables
this verification.
If true, checksums are verified during a base backup if they are
enabled. If false, this is skipped. The default is true.
</para>
</listitem>
</varlistentry>
@ -2708,6 +2711,7 @@ The commands accepted in replication mode are:
</varlistentry>
</variablelist>
</para>
<para>
After the second regular result set, one or more CopyOutResponse results
will be sent, one for the main data directory and one for each additional tablespace other
@ -2788,6 +2792,17 @@ The commands accepted in replication mode are:
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>BASE_BACKUP</literal> [ <literal>LABEL</literal> <replaceable>'label'</replaceable> ] [ <literal>PROGRESS</literal> ] [ <literal>FAST</literal> ] [ <literal>WAL</literal> ] [ <literal>NOWAIT</literal> ] [ <literal>MAX_RATE</literal> <replaceable>rate</replaceable> ] [ <literal>TABLESPACE_MAP</literal> ] [ <literal>NOVERIFY_CHECKSUMS</literal> ] [ <literal>MANIFEST</literal> <replaceable>manifest_option</replaceable> ] [ <literal>MANIFEST_CHECKSUMS</literal> <replaceable>checksum_algorithm</replaceable> ]
</term>
<listitem>
<para>
For compatibility with older releases, this alternative syntax for
the <literal>BASE_BACKUP</literal> command is still supported.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>

View File

@ -19,6 +19,7 @@
#include "access/xlog_internal.h" /* for pg_start/stop_backup */
#include "catalog/pg_type.h"
#include "common/file_perm.h"
#include "commands/defrem.h"
#include "commands/progress.h"
#include "lib/stringinfo.h"
#include "libpq/libpq.h"
@ -764,7 +765,7 @@ parse_basebackup_options(List *options, basebackup_options *opt)
ListCell *lopt;
bool o_label = false;
bool o_progress = false;
bool o_fast = false;
bool o_checkpoint = false;
bool o_nowait = false;
bool o_wal = false;
bool o_maxrate = false;
@ -787,7 +788,7 @@ parse_basebackup_options(List *options, basebackup_options *opt)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->label = strVal(defel->arg);
opt->label = defGetString(defel);
o_label = true;
}
else if (strcmp(defel->defname, "progress") == 0)
@ -796,25 +797,35 @@ parse_basebackup_options(List *options, basebackup_options *opt)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->progress = true;
opt->progress = defGetBoolean(defel);
o_progress = true;
}
else if (strcmp(defel->defname, "fast") == 0)
else if (strcmp(defel->defname, "checkpoint") == 0)
{
if (o_fast)
char *optval = defGetString(defel);
if (o_checkpoint)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->fastcheckpoint = true;
o_fast = true;
if (pg_strcasecmp(optval, "fast") == 0)
opt->fastcheckpoint = true;
else if (pg_strcasecmp(optval, "spread") == 0)
opt->fastcheckpoint = false;
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unrecognized checkpoint type: \"%s\"",
optval)));
o_checkpoint = true;
}
else if (strcmp(defel->defname, "nowait") == 0)
else if (strcmp(defel->defname, "wait") == 0)
{
if (o_nowait)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->nowait = true;
opt->nowait = !defGetBoolean(defel);
o_nowait = true;
}
else if (strcmp(defel->defname, "wal") == 0)
@ -823,19 +834,19 @@ parse_basebackup_options(List *options, basebackup_options *opt)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->includewal = true;
opt->includewal = defGetBoolean(defel);
o_wal = true;
}
else if (strcmp(defel->defname, "max_rate") == 0)
{
long maxrate;
int64 maxrate;
if (o_maxrate)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
maxrate = intVal(defel->arg);
maxrate = defGetInt64(defel);
if (maxrate < MAX_RATE_LOWER || maxrate > MAX_RATE_UPPER)
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
@ -851,21 +862,21 @@ parse_basebackup_options(List *options, basebackup_options *opt)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->sendtblspcmapfile = true;
opt->sendtblspcmapfile = defGetBoolean(defel);
o_tablespace_map = true;
}
else if (strcmp(defel->defname, "noverify_checksums") == 0)
else if (strcmp(defel->defname, "verify_checksums") == 0)
{
if (o_noverify_checksums)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
noverify_checksums = true;
noverify_checksums = !defGetBoolean(defel);
o_noverify_checksums = true;
}
else if (strcmp(defel->defname, "manifest") == 0)
{
char *optval = strVal(defel->arg);
char *optval = defGetString(defel);
bool manifest_bool;
if (o_manifest)
@ -890,7 +901,7 @@ parse_basebackup_options(List *options, basebackup_options *opt)
}
else if (strcmp(defel->defname, "manifest_checksums") == 0)
{
char *optval = strVal(defel->arg);
char *optval = defGetString(defel);
if (o_manifest_checksums)
ereport(ERROR,
@ -905,8 +916,10 @@ parse_basebackup_options(List *options, basebackup_options *opt)
o_manifest_checksums = true;
}
else
elog(ERROR, "option \"%s\" not recognized",
defel->defname);
ereport(ERROR,
errcode(ERRCODE_SYNTAX_ERROR),
errmsg("option \"%s\" not recognized",
defel->defname));
}
if (opt->label == NULL)
opt->label = "base backup";

View File

@ -95,13 +95,13 @@ static SQLCmd *make_sqlcmd(void);
%type <node> base_backup start_replication start_logical_replication
create_replication_slot drop_replication_slot identify_system
timeline_history show sql_cmd
%type <list> base_backup_opt_list
%type <defelt> base_backup_opt
%type <list> base_backup_legacy_opt_list generic_option_list
%type <defelt> base_backup_legacy_opt generic_option
%type <uintval> opt_timeline
%type <list> plugin_options plugin_opt_list
%type <defelt> plugin_opt_elem
%type <node> plugin_opt_arg
%type <str> opt_slot var_name
%type <str> opt_slot var_name ident_or_keyword
%type <boolval> opt_temporary
%type <list> create_slot_opt_list
%type <defelt> create_slot_opt
@ -157,12 +157,24 @@ var_name: IDENT { $$ = $1; }
;
/*
* BASE_BACKUP ( option [ 'value' ] [, ...] )
*
* We also still support the legacy syntax:
*
* BASE_BACKUP [LABEL '<label>'] [PROGRESS] [FAST] [WAL] [NOWAIT]
* [MAX_RATE %d] [TABLESPACE_MAP] [NOVERIFY_CHECKSUMS]
* [MANIFEST %s] [MANIFEST_CHECKSUMS %s]
*
* Future options should be supported only using the new syntax.
*/
base_backup:
K_BASE_BACKUP base_backup_opt_list
K_BASE_BACKUP '(' generic_option_list ')'
{
BaseBackupCmd *cmd = makeNode(BaseBackupCmd);
cmd->options = $3;
$$ = (Node *) cmd;
}
| K_BASE_BACKUP base_backup_legacy_opt_list
{
BaseBackupCmd *cmd = makeNode(BaseBackupCmd);
cmd->options = $2;
@ -170,14 +182,14 @@ base_backup:
}
;
base_backup_opt_list:
base_backup_opt_list base_backup_opt
base_backup_legacy_opt_list:
base_backup_legacy_opt_list base_backup_legacy_opt
{ $$ = lappend($1, $2); }
| /* EMPTY */
{ $$ = NIL; }
;
base_backup_opt:
base_backup_legacy_opt:
K_LABEL SCONST
{
$$ = makeDefElem("label",
@ -190,8 +202,8 @@ base_backup_opt:
}
| K_FAST
{
$$ = makeDefElem("fast",
(Node *)makeInteger(true), -1);
$$ = makeDefElem("checkpoint",
(Node *)makeString("fast"), -1);
}
| K_WAL
{
@ -200,8 +212,8 @@ base_backup_opt:
}
| K_NOWAIT
{
$$ = makeDefElem("nowait",
(Node *)makeInteger(true), -1);
$$ = makeDefElem("wait",
(Node *)makeInteger(false), -1);
}
| K_MAX_RATE UCONST
{
@ -215,8 +227,8 @@ base_backup_opt:
}
| K_NOVERIFY_CHECKSUMS
{
$$ = makeDefElem("noverify_checksums",
(Node *)makeInteger(true), -1);
$$ = makeDefElem("verify_checksums",
(Node *)makeInteger(false), -1);
}
| K_MANIFEST SCONST
{
@ -422,6 +434,65 @@ plugin_opt_arg:
sql_cmd:
IDENT { $$ = (Node *) make_sqlcmd(); }
;
generic_option_list:
generic_option_list ',' generic_option
{ $$ = lappend($1, $3); }
| generic_option
{ $$ = list_make1($1); }
;
generic_option:
ident_or_keyword
{
$$ = makeDefElem($1, NULL, -1);
}
| ident_or_keyword IDENT
{
$$ = makeDefElem($1, (Node *) makeString($2), -1);
}
| ident_or_keyword SCONST
{
$$ = makeDefElem($1, (Node *) makeString($2), -1);
}
| ident_or_keyword UCONST
{
$$ = makeDefElem($1, (Node *) makeInteger($2), -1);
}
;
ident_or_keyword:
IDENT { $$ = $1; }
| K_BASE_BACKUP { $$ = "base_backup"; }
| K_IDENTIFY_SYSTEM { $$ = "identify_system"; }
| K_SHOW { $$ = "show"; }
| K_START_REPLICATION { $$ = "start_replication"; }
| K_CREATE_REPLICATION_SLOT { $$ = "create_replication_slot"; }
| K_DROP_REPLICATION_SLOT { $$ = "drop_replication_slot"; }
| K_TIMELINE_HISTORY { $$ = "timeline_history"; }
| K_LABEL { $$ = "label"; }
| K_PROGRESS { $$ = "progress"; }
| K_FAST { $$ = "fast"; }
| K_WAIT { $$ = "wait"; }
| K_NOWAIT { $$ = "nowait"; }
| K_MAX_RATE { $$ = "max_rate"; }
| K_WAL { $$ = "wal"; }
| K_TABLESPACE_MAP { $$ = "tablespace_map"; }
| K_NOVERIFY_CHECKSUMS { $$ = "noverify_checksums"; }
| K_TIMELINE { $$ = "timeline"; }
| K_PHYSICAL { $$ = "physical"; }
| K_LOGICAL { $$ = "logical"; }
| K_SLOT { $$ = "slot"; }
| K_RESERVE_WAL { $$ = "reserve_wal"; }
| K_TEMPORARY { $$ = "temporary"; }
| K_TWO_PHASE { $$ = "two_phase"; }
| K_EXPORT_SNAPSHOT { $$ = "export_snapshot"; }
| K_NOEXPORT_SNAPSHOT { $$ = "noexport_snapshot"; }
| K_USE_SNAPSHOT { $$ = "use_snapshot"; }
| K_MANIFEST { $$ = "manifest"; }
| K_MANIFEST_CHECKSUMS { $$ = "manifest_checksums"; }
;
%%
static SQLCmd *

View File

@ -1804,10 +1804,6 @@ BaseBackup(void)
TimeLineID latesttli;
TimeLineID starttli;
char *basebkp;
char escaped_label[MAXPGPATH];
char *maxrate_clause = NULL;
char *manifest_clause = NULL;
char *manifest_checksums_clause = "";
int i;
char xlogstart[64];
char xlogend[64];
@ -1816,8 +1812,11 @@ BaseBackup(void)
int serverVersion,
serverMajor;
int writing_to_stdout;
bool use_new_option_syntax = false;
PQExpBufferData buf;
Assert(conn != NULL);
initPQExpBuffer(&buf);
/*
* Check server version. BASE_BACKUP command was introduced in 9.1, so we
@ -1835,6 +1834,8 @@ BaseBackup(void)
serverver ? serverver : "'unknown'");
exit(1);
}
if (serverMajor >= 1500)
use_new_option_syntax = true;
/*
* If WAL streaming was requested, also check that the server is new
@ -1865,20 +1866,48 @@ BaseBackup(void)
/*
* Start the actual backup
*/
PQescapeStringConn(conn, escaped_label, label, sizeof(escaped_label), &i);
AppendStringCommandOption(&buf, use_new_option_syntax, "LABEL", label);
if (estimatesize)
AppendPlainCommandOption(&buf, use_new_option_syntax, "PROGRESS");
if (includewal == FETCH_WAL)
AppendPlainCommandOption(&buf, use_new_option_syntax, "WAL");
if (fastcheckpoint)
{
if (use_new_option_syntax)
AppendStringCommandOption(&buf, use_new_option_syntax,
"CHECKPOINT", "fast");
else
AppendPlainCommandOption(&buf, use_new_option_syntax, "FAST");
}
if (includewal != NO_WAL)
{
if (use_new_option_syntax)
AppendIntegerCommandOption(&buf, use_new_option_syntax, "WAIT", 0);
else
AppendPlainCommandOption(&buf, use_new_option_syntax, "NOWAIT");
}
if (maxrate > 0)
maxrate_clause = psprintf("MAX_RATE %u", maxrate);
AppendIntegerCommandOption(&buf, use_new_option_syntax, "MAX_RATE",
maxrate);
if (format == 't')
AppendPlainCommandOption(&buf, use_new_option_syntax, "TABLESPACE_MAP");
if (!verify_checksums)
{
if (use_new_option_syntax)
AppendIntegerCommandOption(&buf, use_new_option_syntax,
"VERIFY_CHECKSUMS", 0);
else
AppendPlainCommandOption(&buf, use_new_option_syntax,
"NOVERIFY_CHECKSUMS");
}
if (manifest)
{
if (manifest_force_encode)
manifest_clause = "MANIFEST 'force-encode'";
else
manifest_clause = "MANIFEST 'yes'";
AppendStringCommandOption(&buf, use_new_option_syntax, "MANIFEST",
manifest_force_encode ? "force-encode" : "yes");
if (manifest_checksums != NULL)
manifest_checksums_clause = psprintf("MANIFEST_CHECKSUMS '%s'",
manifest_checksums);
AppendStringCommandOption(&buf, use_new_option_syntax,
"MANIFEST_CHECKSUMS", manifest_checksums);
}
if (verbose)
@ -1893,18 +1922,10 @@ BaseBackup(void)
fprintf(stderr, "\n");
}
basebkp =
psprintf("BASE_BACKUP LABEL '%s' %s %s %s %s %s %s %s %s %s",
escaped_label,
estimatesize ? "PROGRESS" : "",
includewal == FETCH_WAL ? "WAL" : "",
fastcheckpoint ? "FAST" : "",
includewal == NO_WAL ? "" : "NOWAIT",
maxrate_clause ? maxrate_clause : "",
format == 't' ? "TABLESPACE_MAP" : "",
verify_checksums ? "" : "NOVERIFY_CHECKSUMS",
manifest_clause ? manifest_clause : "",
manifest_checksums_clause);
if (use_new_option_syntax && buf.len > 0)
basebkp = psprintf("BASE_BACKUP (%s)", buf.data);
else
basebkp = psprintf("BASE_BACKUP %s", buf.data);
if (PQsendQuery(conn, basebkp) == 0)
{

View File

@ -603,6 +603,67 @@ DropReplicationSlot(PGconn *conn, const char *slot_name)
return true;
}
/*
* Append a "plain" option - one with no value - to a server command that
* is being constructed.
*
* In the old syntax, all options were parser keywords, so you could just
* write things like SOME_COMMAND OPTION1 OPTION2 'opt2value' OPTION3 42. The
* new syntax uses a comma-separated list surrounded by parentheses, so the
* equivalent is SOME_COMMAND (OPTION1, OPTION2 'optvalue', OPTION3 42).
*/
void
AppendPlainCommandOption(PQExpBuffer buf, bool use_new_option_syntax,
char *option_name)
{
if (buf->len > 0 && buf->data[buf->len - 1] != '(')
{
if (use_new_option_syntax)
appendPQExpBufferStr(buf, ", ");
else
appendPQExpBufferChar(buf, ' ');
}
appendPQExpBuffer(buf, " %s", option_name);
}
/*
* Append an option with an associated string value to a server command that
* is being constructed.
*
* See comments for AppendPlainCommandOption, above.
*/
void
AppendStringCommandOption(PQExpBuffer buf, bool use_new_option_syntax,
char *option_name, char *option_value)
{
AppendPlainCommandOption(buf, use_new_option_syntax, option_name);
if (option_value != NULL)
{
size_t length = strlen(option_value);
char *escaped_value = palloc(1 + 2 * length);
PQescapeStringConn(conn, escaped_value, option_value, length, NULL);
appendPQExpBuffer(buf, " '%s'", escaped_value);
pfree(escaped_value);
}
}
/*
* Append an option with an associated integer value to a server command
* is being constructed.
*
* See comments for AppendPlainCommandOption, above.
*/
void
AppendIntegerCommandOption(PQExpBuffer buf, bool use_new_option_syntax,
char *option_name, int32 option_value)
{
AppendPlainCommandOption(buf, use_new_option_syntax, option_name);
appendPQExpBuffer(buf, " %d", option_value);
}
/*
* Frontend version of GetCurrentTimestamp(), since we are not linked with

View File

@ -15,6 +15,7 @@
#include "access/xlogdefs.h"
#include "datatype/timestamp.h"
#include "libpq-fe.h"
#include "pqexpbuffer.h"
extern const char *progname;
extern char *connection_string;
@ -40,6 +41,17 @@ extern bool RunIdentifySystem(PGconn *conn, char **sysid,
TimeLineID *starttli,
XLogRecPtr *startpos,
char **db_name);
extern void AppendPlainCommandOption(PQExpBuffer buf,
bool use_new_option_syntax,
char *option_value);
extern void AppendStringCommandOption(PQExpBuffer buf,
bool use_new_option_syntax,
char *option_name, char *option_value);
extern void AppendIntegerCommandOption(PQExpBuffer buf,
bool use_new_option_syntax,
char *option_name, int32 option_value);
extern bool RetrieveWalSegSize(PGconn *conn);
extern TimestampTz feGetCurrentTimestamp(void);
extern void feTimestampDifference(TimestampTz start_time, TimestampTz stop_time,