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Add statement_timestamp(), clock_timestamp(), and

Browse Source 
transaction_timestamp() (just like now()).

Also update statement_timeout() to mention it is statement arrival time
that is measured.

Catalog version updated.
This commit is contained in:
Bruce Momjian 2006-04-25 00:25:22 +00:00
parent f04080d73b
commit e6004f0151
9 changed files with 180 additions and 64 deletions
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5
doc/src/sgml/config.sgml
View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.55 2006/04/23 03:39:48 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.56 2006/04/25 00:25:15 momjian Exp $ -->
<chapter Id="runtime-config">
<title>Server Configuration</title>
@ -3279,7 +3279,8 @@ SELECT * FROM parent WHERE key = 2400;
<listitem>
<para>
Abort any statement that takes over the specified number of
milliseconds. If <varname>log_min_error_statement</> is set to
milliseconds, starting from the time the command arrives at the server
from the client. If <varname>log_min_error_statement</> is set to
<literal>ERROR</> or lower, the statement that timed out will also be
logged. A value of zero (the default) turns off the
limitation.

97
doc/src/sgml/func.sgml
View File

@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.314 2006/04/23 03:39:50 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.315 2006/04/25 00:25:15 momjian Exp $ -->
<chapter id="functions">
<title>Functions and Operators</title>
@ -5302,6 +5302,15 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
<indexterm>
<primary>now</primary>
</indexterm>
<indexterm>
<primary>transaction_timestamp</primary>
</indexterm>
<indexterm>
<primary>statement_timestamp</primary>
</indexterm>
<indexterm>
<primary>clock_timestamp</primary>
</indexterm>
<indexterm>
<primary>timeofday</primary>
</indexterm>
@ -5358,7 +5367,7 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
<row>
<entry><literal><function>current_timestamp</function></literal></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Date and time; see <xref linkend="functions-datetime-current">
<entry>Date and time of start of current transaction; see <xref linkend="functions-datetime-current">
</entry>
<entry></entry>
<entry></entry>
@ -5474,8 +5483,36 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
<row>
<entry><literal><function>now</function>()</literal></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Current date and time (equivalent to
<function>current_timestamp</function>); see <xref linkend="functions-datetime-current">
<entry>Date and time of start of current transaction (equivalent to
<function>CURRENT_TIMESTAMP</function>); see <xref linkend="functions-datetime-current">
</entry>
<entry></entry>
<entry></entry>
</row>
<row>
<entry><literal><function>transaction_timestamp</function>()</literal></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Date and time of start of current transaction (equivalent to
<function>CURRENT_TIMESTAMP</function>); see <xref linkend="functions-datetime-current">
</entry>
<entry></entry>
<entry></entry>
</row>
<row>
<entry><literal><function>statement_timestamp</function>()</literal></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Date and time of start of current statement; see <xref linkend="functions-datetime-current">
</entry>
<entry></entry>
<entry></entry>
</row>
<row>
<entry><literal><function>clock_timestamp</function>()</literal></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Current date and time (changes during statement execution); see <xref linkend="functions-datetime-current">
</entry>
<entry></entry>
<entry></entry>
@ -5484,7 +5521,8 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
<row>
<entry><literal><function>timeofday</function>()</literal></entry>
<entry><type>text</type></entry>
<entry>Current date and time; see <xref linkend="functions-datetime-current">
<entry>Current date and time (like <function>clock_timestamp</>), but as a Unix-style <type>text</> value;
see <xref linkend="functions-datetime-current">
</entry>
<entry></entry>
<entry></entry>
@ -6072,7 +6110,7 @@ SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'MST';
</sect2>
<sect2 id="functions-datetime-current">
<title>Current Date/Time</title>
<title>Date/Time of Transaction Start</title>
<indexterm>
<primary>date</primary>
@ -6085,8 +6123,8 @@ SELECT TIMESTAMP WITH TIME ZONE '2001-02-16 20:38:40-05' AT TIME ZONE 'MST';
</indexterm>
<para>
The following functions are available to obtain the current date and/or
time:
The following functions are available to obtain the date and/or
time of the start of the current transaction:
<synopsis>
CURRENT_DATE
CURRENT_TIME
@ -6138,12 +6176,6 @@ SELECT LOCALTIMESTAMP;
</screen>
</para>
<para>
The function <function>now()</function> is the traditional
<productname>PostgreSQL</productname> equivalent to
<function>CURRENT_TIMESTAMP</function>.
</para>
<para>
It is important to know that
<function>CURRENT_TIMESTAMP</function> and related functions return
@ -6152,26 +6184,31 @@ SELECT LOCALTIMESTAMP;
the intent is to allow a single transaction to have a consistent
notion of the <quote>current</quote> time, so that multiple
modifications within the same transaction bear the same
time stamp.
time stamp. Consider using <function>statement_timestamp</> or
<function>clock_timestamp</> if you need something that changes
more frequently.
</para>
<note>
<para>
Other database systems may advance these values more
frequently.
</para>
</note>
<para>
<function>CURRENT_TIMESTAMP</> might not be the
transaction start time on other database systems.
For this reason, and for completeness,
<function>transaction_timestamp</> is provided.
The function <function>now()</function> is the traditional
<productname>PostgreSQL</productname> equivalent to
the SQL-standard <function>CURRENT_TIMESTAMP</function>.
</para>
<para>
There is also the function <function>timeofday()</function> which
returns the wall-clock time and advances during transactions. For
historical reasons <function>timeofday()</function> returns a
<type>text</type> string rather than a <type>timestamp</type>
value:
<screen>
SELECT timeofday();
<lineannotation>Result: </lineannotation><computeroutput>Sat Feb 17 19:07:32.000126 2001 EST</computeroutput>
</screen>
<function>STATEMENT_TIMESTAMP</> is the time the statement
arrived at the server from the client. It is not the time
the command started execution. If multiple commands were
sent as a single query string to the server, each command
has the same <function>STATEMENT_TIMESTAMP</> because they
all arrived at the same time. Also, commands executed
by server-side functions have a <function>STATEMENT_TIMESTAMP</>
based on the time the client sent the query that triggered
the function, not the time the function was executed.
</para>
<para>

25
src/backend/access/transam/xact.c
View File

@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.219 2006/03/29 21:17:37 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.220 2006/04/25 00:25:17 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -172,6 +172,7 @@ static CommandId currentCommandId;
* keep it inside the TransactionState stack.
*/
static TimestampTz xactStartTimestamp;
static TimestampTz stmtStartTimestamp;
/*
* GID to be used for preparing the current transaction. This is also
@ -427,6 +428,24 @@ GetCurrentTransactionStartTimestamp(void)
return xactStartTimestamp;
}
/*
* GetCurrentStatementStartTimestamp
*/
TimestampTz
GetCurrentStatementStartTimestamp(void)
{
return stmtStartTimestamp;
}
/*
* SetCurrentStatementStartTimestamp
*/
void
SetCurrentStatementStartTimestamp(void)
{
stmtStartTimestamp = GetCurrentTimestamp();
}
/*
* GetCurrentTransactionNestLevel
*
@ -1367,9 +1386,9 @@ StartTransaction(void)
XactLockTableInsert(s->transactionId);
/*
* set now()
* now() and statement_timestamp() should be the same time
*/
xactStartTimestamp = GetCurrentTimestamp();
xactStartTimestamp = stmtStartTimestamp;
/*
* initialize current transaction state fields

83
src/backend/tcop/postgres.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.485 2006/04/22 01:26:00 tgl Exp $
* $PostgreSQL: pgsql/src/backend/tcop/postgres.c,v 1.486 2006/04/25 00:25:18 momjian Exp $
*
* NOTES
* this is the "main" module of the postgres backend and
@ -118,6 +118,12 @@ static volatile sig_atomic_t got_SIGHUP = false;
*/
static bool xact_started = false;
/*
* Flag to keep track of whether we have done statement initialization.
* For extended query protocol this has to be remembered across messages.
*/
static bool command_initialized = false;
/*
* Flag to indicate that we are doing the outer loop's read-from-client,
* as opposed to any random read from client that might happen within
@ -164,6 +170,8 @@ static int ReadCommand(StringInfo inBuf);
static bool log_after_parse(List *raw_parsetree_list,
const char *query_string, char **prepare_string);
static List *pg_rewrite_queries(List *querytree_list);
static void initialize_command(void);
static void finalize_command(void);
static void start_xact_command(void);
static void finish_xact_command(void);
static bool IsTransactionExitStmt(Node *parsetree);
@ -858,7 +866,7 @@ exec_simple_query(const char *query_string)
* one of those, else bad things will happen in xact.c. (Note that this
* will normally change current memory context.)
*/
start_xact_command();
initialize_command();
/*
* Zap any pre-existing unnamed statement. (While not strictly necessary,
@ -1067,7 +1075,7 @@ exec_simple_query(const char *query_string)
/*
* Close down transaction statement, if one is open.
*/
finish_xact_command();
finalize_command();
/*
* If there were no parsetrees, return EmptyQueryResponse message.
@ -1170,7 +1178,7 @@ exec_parse_message(const char *query_string, /* string to execute */
* that this will normally change current memory context.) Nothing happens
* if we are already in one.
*/
start_xact_command();
initialize_command();
/*
* Switch to appropriate context for constructing parsetrees.
@ -1393,7 +1401,7 @@ exec_bind_message(StringInfo input_message)
* this will normally change current memory context.) Nothing happens if
* we are already in one.
*/
start_xact_command();
initialize_command();
/* Switch back to message context */
MemoryContextSwitchTo(MessageContext);
@ -1759,7 +1767,7 @@ exec_execute_message(const char *portal_name, long max_rows)
* Ensure we are in a transaction command (this should normally be the
* case already due to prior BIND).
*/
start_xact_command();
initialize_command();
/*
* If we are in aborted transaction state, the only portals we can
@ -1883,7 +1891,7 @@ exec_describe_statement_message(const char *stmt_name)
* Start up a transaction command. (Note that this will normally change
* current memory context.) Nothing happens if we are already in one.
*/
start_xact_command();
initialize_command();
/* Switch back to message context */
MemoryContextSwitchTo(MessageContext);
@ -1961,7 +1969,7 @@ exec_describe_portal_message(const char *portal_name)
* Start up a transaction command. (Note that this will normally change
* current memory context.) Nothing happens if we are already in one.
*/
start_xact_command();
initialize_command();
/* Switch back to message context */
MemoryContextSwitchTo(MessageContext);
@ -2000,7 +2008,44 @@ exec_describe_portal_message(const char *portal_name)
/*
* Convenience routines for starting/committing a single command.
* Start xact if necessary, and set statement_timestamp() and optionally
* statement_timeout.
*/
static void
initialize_command(void)
{
if (!command_initialized)
{
SetCurrentStatementStartTimestamp();
/* Set statement timeout running, if any */
if (StatementTimeout > 0)
enable_sig_alarm(StatementTimeout, true);
else
cancel_from_timeout = false;
command_initialized = true;
}
start_xact_command();
}
static void
finalize_command(void)
{
if (command_initialized)
{
/* Cancel any active statement timeout before committing */
disable_sig_alarm(true);
command_initialized = false;
}
finish_xact_command();
}
/*
* Check if the newly-arrived query string needs to have an implicit
* transaction started.
*/
static void
start_xact_command(void)
@ -2009,13 +2054,8 @@ start_xact_command(void)
{
ereport(DEBUG3,
(errmsg_internal("StartTransactionCommand")));
StartTransactionCommand();
/* Set statement timeout running, if any */
if (StatementTimeout > 0)
enable_sig_alarm(StatementTimeout, true);
else
cancel_from_timeout = false;
StartTransactionCommand();
xact_started = true;
}
@ -2026,10 +2066,6 @@ finish_xact_command(void)
{
if (xact_started)
{
/* Cancel any active statement timeout before committing */
disable_sig_alarm(true);
/* Now commit the command */
ereport(DEBUG3,
(errmsg_internal("CommitTransactionCommand")));
@ -3137,7 +3173,8 @@ PostgresMain(int argc, char *argv[], const char *username)
/* We don't have a transaction command open anymore */
xact_started = false;
command_initialized = false;
/* Now we can allow interrupts again */
RESUME_INTERRUPTS();
}
@ -3305,7 +3342,7 @@ PostgresMain(int argc, char *argv[], const char *username)
pgstat_report_activity("<FASTPATH> function call");
/* start an xact for this function invocation */
start_xact_command();
initialize_command();
/* switch back to message context */
MemoryContextSwitchTo(MessageContext);
@ -3328,7 +3365,7 @@ PostgresMain(int argc, char *argv[], const char *username)
}
/* commit the function-invocation transaction */
finish_xact_command();
finalize_command();
send_ready_for_query = true;
break;
@ -3416,7 +3453,7 @@ PostgresMain(int argc, char *argv[], const char *username)
case 'S': /* sync */
pq_getmsgend(&input_message);
finish_xact_command();
finalize_command();
send_ready_for_query = true;
break;

14
src/backend/utils/adt/timestamp.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.162 2006/03/06 22:49:16 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.163 2006/04/25 00:25:18 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -919,6 +919,18 @@ now(PG_FUNCTION_ARGS)
PG_RETURN_TIMESTAMPTZ(GetCurrentTransactionStartTimestamp());
}
Datum
statement_timestamp(PG_FUNCTION_ARGS)
{
PG_RETURN_TIMESTAMPTZ(GetCurrentStatementStartTimestamp());
}
Datum
clock_timestamp(PG_FUNCTION_ARGS)
{
PG_RETURN_TIMESTAMPTZ(GetCurrentTimestamp());
}
Datum
pgsql_postmaster_start_time(PG_FUNCTION_ARGS)
{

4
src/include/access/xact.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/xact.h,v 1.81 2006/03/24 04:32:13 tgl Exp $
* $PostgreSQL: pgsql/src/include/access/xact.h,v 1.82 2006/04/25 00:25:19 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -141,6 +141,8 @@ extern TransactionId GetCurrentTransactionIdIfAny(void);
extern SubTransactionId GetCurrentSubTransactionId(void);
extern CommandId GetCurrentCommandId(void);
extern TimestampTz GetCurrentTransactionStartTimestamp(void);
extern TimestampTz GetCurrentStatementStartTimestamp(void);
extern void SetCurrentStatementStartTimestamp(void);
extern int GetCurrentTransactionNestLevel(void);
extern bool TransactionIdIsCurrentTransactionId(TransactionId xid);
extern void CommandCounterIncrement(void);

4
src/include/catalog/catversion.h
View File

@ -37,7 +37,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.323 2006/04/22 01:26:01 tgl Exp $
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.324 2006/04/25 00:25:20 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 200604211
#define CATALOG_VERSION_NO 200604241
#endif

8
src/include/catalog/pg_proc.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.405 2006/04/05 22:11:55 tgl Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.406 2006/04/25 00:25:20 momjian Exp $
*
* NOTES
* The script catalog/genbki.sh reads this file and generates .bki
@ -1614,6 +1614,12 @@ DATA(insert OID = 1298 ( timetzdate_pl PGNSP PGUID 14 f f t f i 2 1184 "1266
DESCR("convert time with time zone and date to timestamp with time zone");
DATA(insert OID = 1299 ( now PGNSP PGUID 12 f f t f s 0 1184 "" _null_ _null_ _null_ now - _null_ ));
DESCR("current transaction time");
DATA(insert OID = 2647 ( transaction_timestamp PGNSP PGUID 12 f f t f s 0 1184 "" _null_ _null_ _null_ now - _null_ ));
DESCR("current transaction time");
DATA(insert OID = 2648 ( statement_timestamp PGNSP PGUID 12 f f t f s 0 1184 "" _null_ _null_ _null_ statement_timestamp - _null_ ));
DESCR("current statement time");
DATA(insert OID = 2649 ( clock_timestamp PGNSP PGUID 12 f f t f v 0 1184 "" _null_ _null_ _null_ clock_timestamp - _null_ ));
DESCR("current clock time");
/* OIDS 1300 - 1399 */

4
src/include/utils/timestamp.h
View File

@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.59 2006/03/06 22:49:17 momjian Exp $
* $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.60 2006/04/25 00:25:22 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -284,6 +284,8 @@ extern Datum timestamptz_trunc(PG_FUNCTION_ARGS);
extern Datum timestamptz_part(PG_FUNCTION_ARGS);
extern Datum now(PG_FUNCTION_ARGS);
extern Datum statement_timestamp(PG_FUNCTION_ARGS);
extern Datum clock_timestamp(PG_FUNCTION_ARGS);
extern Datum pgsql_postmaster_start_time(PG_FUNCTION_ARGS);