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Remove timetravel extension. 

The extension depended on old types which are about to be removed. As
the code additionally was pretty crufty and didn't provide much in the
way of functionality, removing the extension seems to be the best way
forward.  It's fairly trivial to write functionality in plpgsql that
more than covers what timetravel did.

Author: Andres Freund
Discussion:
    https://postgr.es/m/20171213080506.cwjkpcz3bkk6yz2u@alap3.anarazel.de
    https://postgr.es/m/25615.1513115237@sss.pgh.pa.us
This commit is contained in:
Andres Freund 2018-09-28 15:13:42 -07:00
parent 86896be60e
commit 2d10defa77
8 changed files with 4 additions and 764 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
contrib/spi/Makefile
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@ -1,14 +1,13 @@
# contrib/spi/Makefile
MODULES = autoinc insert_username moddatetime refint timetravel
MODULES = autoinc insert_username moddatetime refint
EXTENSION = autoinc insert_username moddatetime refint timetravel
EXTENSION = autoinc insert_username moddatetime refint
DATA = autoinc--1.0.sql autoinc--unpackaged--1.0.sql \
insert_username--1.0.sql insert_username--unpackaged--1.0.sql \
moddatetime--1.0.sql moddatetime--unpackaged--1.0.sql \
refint--1.0.sql refint--unpackaged--1.0.sql \
timetravel--1.0.sql timetravel--unpackaged--1.0.sql
refint--1.0.sql refint--unpackaged--1.0.sql
PGFILEDESC = "spi - examples of using SPI and triggers"
DOCS = $(addsuffix .example, $(MODULES))

19
contrib/spi/timetravel--1.0.sql
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@ -1,19 +0,0 @@
/* contrib/spi/timetravel--1.0.sql */
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
\echo Use "CREATE EXTENSION timetravel" to load this file. \quit
CREATE FUNCTION timetravel()
RETURNS trigger
AS 'MODULE_PATHNAME'
LANGUAGE C;
CREATE FUNCTION set_timetravel(name, int4)
RETURNS int4
AS 'MODULE_PATHNAME'
LANGUAGE C RETURNS NULL ON NULL INPUT;
CREATE FUNCTION get_timetravel(name)
RETURNS int4
AS 'MODULE_PATHNAME'
LANGUAGE C RETURNS NULL ON NULL INPUT;

8
contrib/spi/timetravel--unpackaged--1.0.sql
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@ -1,8 +0,0 @@
/* contrib/spi/timetravel--unpackaged--1.0.sql */
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
\echo Use "CREATE EXTENSION timetravel FROM unpackaged" to load this file. \quit
ALTER EXTENSION timetravel ADD function timetravel();
ALTER EXTENSION timetravel ADD function set_timetravel(name,integer);
ALTER EXTENSION timetravel ADD function get_timetravel(name);

553
contrib/spi/timetravel.c
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@ -1,553 +0,0 @@
/*
* contrib/spi/timetravel.c
*
*
* timetravel.c -- function to get time travel feature
* using general triggers.
*
* Modified by BÖJTHE Zoltán, Hungary, mailto:urdesobt@axelero.hu
*/
#include "postgres.h"
#include <ctype.h>
#include "access/htup_details.h"
#include "catalog/pg_type.h"
#include "commands/trigger.h"
#include "executor/spi.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/nabstime.h"
#include "utils/rel.h"
PG_MODULE_MAGIC;
/* AbsoluteTime currabstime(void); */
typedef struct
{
char *ident;
SPIPlanPtr splan;
} EPlan;
static EPlan *Plans = NULL; /* for UPDATE/DELETE */
static int nPlans = 0;
typedef struct _TTOffList
{
struct _TTOffList *next;
char name[FLEXIBLE_ARRAY_MEMBER];
} TTOffList;
static TTOffList *TTOff = NULL;
static int findTTStatus(char *name);
static EPlan *find_plan(char *ident, EPlan **eplan, int *nplans);
/*
* timetravel () --
* 1. IF an update affects tuple with stop_date eq INFINITY
* then form (and return) new tuple with start_date eq current date
* and stop_date eq INFINITY [ and update_user eq current user ]
* and all other column values as in new tuple, and insert tuple
* with old data and stop_date eq current date
* ELSE - skip updating of tuple.
* 2. IF a delete affects tuple with stop_date eq INFINITY
* then insert the same tuple with stop_date eq current date
* [ and delete_user eq current user ]
* ELSE - skip deletion of tuple.
* 3. On INSERT, if start_date is NULL then current date will be
* inserted, if stop_date is NULL then INFINITY will be inserted.
* [ and insert_user eq current user, update_user and delete_user
* eq NULL ]
*
* In CREATE TRIGGER you are to specify start_date and stop_date column
* names:
* EXECUTE PROCEDURE
* timetravel ('date_on', 'date_off' [,'insert_user', 'update_user', 'delete_user' ] ).
*/
#define MaxAttrNum 5
#define MinAttrNum 2
#define a_time_on 0
#define a_time_off 1
#define a_ins_user 2
#define a_upd_user 3
#define a_del_user 4
PG_FUNCTION_INFO_V1(timetravel);
Datum /* have to return HeapTuple to Executor */
timetravel(PG_FUNCTION_ARGS)
{
TriggerData *trigdata = (TriggerData *) fcinfo->context;
Trigger *trigger; /* to get trigger name */
int argc;
char **args; /* arguments */
int attnum[MaxAttrNum]; /* fnumbers of start/stop columns */
Datum oldtimeon,
oldtimeoff;
Datum newtimeon,
newtimeoff,
newuser,
nulltext;
Datum *cvals; /* column values */
char *cnulls; /* column nulls */
char *relname; /* triggered relation name */
Relation rel; /* triggered relation */
HeapTuple trigtuple;
HeapTuple newtuple = NULL;
HeapTuple rettuple;
TupleDesc tupdesc; /* tuple description */
int natts; /* # of attributes */
EPlan *plan; /* prepared plan */
char ident[2 * NAMEDATALEN];
bool isnull; /* to know is some column NULL or not */
bool isinsert = false;
int ret;
int i;
/*
* Some checks first...
*/
/* Called by trigger manager ? */
if (!CALLED_AS_TRIGGER(fcinfo))
elog(ERROR, "timetravel: not fired by trigger manager");
/* Should be called for ROW trigger */
if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
elog(ERROR, "timetravel: must be fired for row");
/* Should be called BEFORE */
if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event))
elog(ERROR, "timetravel: must be fired before event");
/* INSERT ? */
if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
isinsert = true;
if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
newtuple = trigdata->tg_newtuple;
trigtuple = trigdata->tg_trigtuple;
rel = trigdata->tg_relation;
relname = SPI_getrelname(rel);
/* check if TT is OFF for this relation */
if (0 == findTTStatus(relname))
{
/* OFF - nothing to do */
pfree(relname);
return PointerGetDatum((newtuple != NULL) ? newtuple : trigtuple);
}
trigger = trigdata->tg_trigger;
argc = trigger->tgnargs;
if (argc != MinAttrNum && argc != MaxAttrNum)
elog(ERROR, "timetravel (%s): invalid (!= %d or %d) number of arguments %d",
relname, MinAttrNum, MaxAttrNum, trigger->tgnargs);
args = trigger->tgargs;
tupdesc = rel->rd_att;
natts = tupdesc->natts;
for (i = 0; i < MinAttrNum; i++)
{
attnum[i] = SPI_fnumber(tupdesc, args[i]);
if (attnum[i] <= 0)
elog(ERROR, "timetravel (%s): there is no attribute %s", relname, args[i]);
if (SPI_gettypeid(tupdesc, attnum[i]) != ABSTIMEOID)
elog(ERROR, "timetravel (%s): attribute %s must be of abstime type",
relname, args[i]);
}
for (; i < argc; i++)
{
attnum[i] = SPI_fnumber(tupdesc, args[i]);
if (attnum[i] <= 0)
elog(ERROR, "timetravel (%s): there is no attribute %s", relname, args[i]);
if (SPI_gettypeid(tupdesc, attnum[i]) != TEXTOID)
elog(ERROR, "timetravel (%s): attribute %s must be of text type",
relname, args[i]);
}
/* create fields containing name */
newuser = CStringGetTextDatum(GetUserNameFromId(GetUserId(), false));
nulltext = (Datum) NULL;
if (isinsert)
{ /* INSERT */
int chnattrs = 0;
int chattrs[MaxAttrNum];
Datum newvals[MaxAttrNum];
bool newnulls[MaxAttrNum];
oldtimeon = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_on], &isnull);
if (isnull)
{
newvals[chnattrs] = GetCurrentAbsoluteTime();
newnulls[chnattrs] = false;
chattrs[chnattrs] = attnum[a_time_on];
chnattrs++;
}
oldtimeoff = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_off], &isnull);
if (isnull)
{
if ((chnattrs == 0 && DatumGetInt32(oldtimeon) >= NOEND_ABSTIME) ||
(chnattrs > 0 && DatumGetInt32(newvals[a_time_on]) >= NOEND_ABSTIME))
elog(ERROR, "timetravel (%s): %s is infinity", relname, args[a_time_on]);
newvals[chnattrs] = NOEND_ABSTIME;
newnulls[chnattrs] = false;
chattrs[chnattrs] = attnum[a_time_off];
chnattrs++;
}
else
{
if ((chnattrs == 0 && DatumGetInt32(oldtimeon) > DatumGetInt32(oldtimeoff)) ||
(chnattrs > 0 && DatumGetInt32(newvals[a_time_on]) > DatumGetInt32(oldtimeoff)))
elog(ERROR, "timetravel (%s): %s gt %s", relname, args[a_time_on], args[a_time_off]);
}
pfree(relname);
if (chnattrs <= 0)
return PointerGetDatum(trigtuple);
if (argc == MaxAttrNum)
{
/* clear update_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = true;
chattrs[chnattrs] = attnum[a_upd_user];
chnattrs++;
/* clear delete_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = true;
chattrs[chnattrs] = attnum[a_del_user];
chnattrs++;
/* set insert_user value */
newvals[chnattrs] = newuser;
newnulls[chnattrs] = false;
chattrs[chnattrs] = attnum[a_ins_user];
chnattrs++;
}
rettuple = heap_modify_tuple_by_cols(trigtuple, tupdesc,
chnattrs, chattrs,
newvals, newnulls);
return PointerGetDatum(rettuple);
/* end of INSERT */
}
/* UPDATE/DELETE: */
oldtimeon = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_on], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_on]);
oldtimeoff = SPI_getbinval(trigtuple, tupdesc, attnum[a_time_off], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_off]);
/*
* If DELETE/UPDATE of tuple with stop_date neq INFINITY then say upper
* Executor to skip operation for this tuple
*/
if (newtuple != NULL)
{ /* UPDATE */
newtimeon = SPI_getbinval(newtuple, tupdesc, attnum[a_time_on], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_on]);
newtimeoff = SPI_getbinval(newtuple, tupdesc, attnum[a_time_off], &isnull);
if (isnull)
elog(ERROR, "timetravel (%s): %s must be NOT NULL", relname, args[a_time_off]);
if (oldtimeon != newtimeon || oldtimeoff != newtimeoff)
elog(ERROR, "timetravel (%s): you cannot change %s and/or %s columns (use set_timetravel)",
relname, args[a_time_on], args[a_time_off]);
}
if (oldtimeoff != NOEND_ABSTIME)
{ /* current record is a deleted/updated record */
pfree(relname);
return PointerGetDatum(NULL);
}
newtimeoff = GetCurrentAbsoluteTime();
/* Connect to SPI manager */
if ((ret = SPI_connect()) < 0)
elog(ERROR, "timetravel (%s): SPI_connect returned %d", relname, ret);
/* Fetch tuple values and nulls */
cvals = (Datum *) palloc(natts * sizeof(Datum));
cnulls = (char *) palloc(natts * sizeof(char));
for (i = 0; i < natts; i++)
{
cvals[i] = SPI_getbinval(trigtuple, tupdesc, i + 1, &isnull);
cnulls[i] = (isnull) ? 'n' : ' ';
}
/* change date column(s) */
cvals[attnum[a_time_off] - 1] = newtimeoff; /* stop_date eq current date */
cnulls[attnum[a_time_off] - 1] = ' ';
if (!newtuple)
{ /* DELETE */
if (argc == MaxAttrNum)
{
cvals[attnum[a_del_user] - 1] = newuser; /* set delete user */
cnulls[attnum[a_del_user] - 1] = ' ';
}
}
/*
* Construct ident string as TriggerName $ TriggeredRelationId and try to
* find prepared execution plan.
*/
snprintf(ident, sizeof(ident), "%s$%u", trigger->tgname, rel->rd_id);
plan = find_plan(ident, &Plans, &nPlans);
/* if there is no plan ... */
if (plan->splan == NULL)
{
SPIPlanPtr pplan;
Oid *ctypes;
char sql[8192];
char separ = ' ';
/* allocate ctypes for preparation */
ctypes = (Oid *) palloc(natts * sizeof(Oid));
/*
* Construct query: INSERT INTO _relation_ VALUES ($1, ...)
*/
snprintf(sql, sizeof(sql), "INSERT INTO %s VALUES (", relname);
for (i = 1; i <= natts; i++)
{
ctypes[i - 1] = SPI_gettypeid(tupdesc, i);
if (!(TupleDescAttr(tupdesc, i - 1)->attisdropped)) /* skip dropped columns */
{
snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), "%c$%d", separ, i);
separ = ',';
}
}
snprintf(sql + strlen(sql), sizeof(sql) - strlen(sql), ")");
elog(DEBUG4, "timetravel (%s) update: sql: %s", relname, sql);
/* Prepare plan for query */
pplan = SPI_prepare(sql, natts, ctypes);
if (pplan == NULL)
elog(ERROR, "timetravel (%s): SPI_prepare returned %s", relname, SPI_result_code_string(SPI_result));
/*
* Remember that SPI_prepare places plan in current memory context -
* so, we have to save plan in Top memory context for later use.
*/
if (SPI_keepplan(pplan))
elog(ERROR, "timetravel (%s): SPI_keepplan failed", relname);
plan->splan = pplan;
}
/*
* Ok, execute prepared plan.
*/
ret = SPI_execp(plan->splan, cvals, cnulls, 0);
if (ret < 0)
elog(ERROR, "timetravel (%s): SPI_execp returned %d", relname, ret);
/* Tuple to return to upper Executor ... */
if (newtuple)
{ /* UPDATE */
int chnattrs = 0;
int chattrs[MaxAttrNum];
Datum newvals[MaxAttrNum];
char newnulls[MaxAttrNum];
newvals[chnattrs] = newtimeoff;
newnulls[chnattrs] = ' ';
chattrs[chnattrs] = attnum[a_time_on];
chnattrs++;
newvals[chnattrs] = NOEND_ABSTIME;
newnulls[chnattrs] = ' ';
chattrs[chnattrs] = attnum[a_time_off];
chnattrs++;
if (argc == MaxAttrNum)
{
/* set update_user value */
newvals[chnattrs] = newuser;
newnulls[chnattrs] = ' ';
chattrs[chnattrs] = attnum[a_upd_user];
chnattrs++;
/* clear delete_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = 'n';
chattrs[chnattrs] = attnum[a_del_user];
chnattrs++;
/* set insert_user value */
newvals[chnattrs] = nulltext;
newnulls[chnattrs] = 'n';
chattrs[chnattrs] = attnum[a_ins_user];
chnattrs++;
}
/*
* Use SPI_modifytuple() here because we are inside SPI environment
* but rettuple must be allocated in caller's context.
*/
rettuple = SPI_modifytuple(rel, newtuple, chnattrs, chattrs, newvals, newnulls);
}
else
/* DELETE case */
rettuple = trigtuple;
SPI_finish(); /* don't forget say Bye to SPI mgr */
pfree(relname);
return PointerGetDatum(rettuple);
}
/*
* set_timetravel (relname, on) --
* turn timetravel for specified relation ON/OFF
*/
PG_FUNCTION_INFO_V1(set_timetravel);
Datum
set_timetravel(PG_FUNCTION_ARGS)
{
Name relname = PG_GETARG_NAME(0);
int32 on = PG_GETARG_INT32(1);
char *rname;
char *d;
char *s;
int32 ret;
TTOffList *prev,
*pp;
prev = NULL;
for (pp = TTOff; pp; prev = pp, pp = pp->next)
{
if (namestrcmp(relname, pp->name) == 0)
break;
}
if (pp)
{
/* OFF currently */
if (on != 0)
{
/* turn ON */
if (prev)
prev->next = pp->next;
else
TTOff = pp->next;
free(pp);
}
ret = 0;
}
else
{
/* ON currently */
if (on == 0)
{
/* turn OFF */
s = rname = DatumGetCString(DirectFunctionCall1(nameout, NameGetDatum(relname)));
if (s)
{
pp = malloc(offsetof(TTOffList, name) + strlen(rname) + 1);
if (pp)
{
pp->next = NULL;
d = pp->name;
while (*s)
*d++ = tolower((unsigned char) *s++);
*d = '\0';
if (prev)
prev->next = pp;
else
TTOff = pp;
}
pfree(rname);
}
}
ret = 1;
}
PG_RETURN_INT32(ret);
}
/*
* get_timetravel (relname) --
* get timetravel status for specified relation (ON/OFF)
*/
PG_FUNCTION_INFO_V1(get_timetravel);
Datum
get_timetravel(PG_FUNCTION_ARGS)
{
Name relname = PG_GETARG_NAME(0);
TTOffList *pp;
for (pp = TTOff; pp; pp = pp->next)
{
if (namestrcmp(relname, pp->name) == 0)
PG_RETURN_INT32(0);
}
PG_RETURN_INT32(1);
}
static int
findTTStatus(char *name)
{
TTOffList *pp;
for (pp = TTOff; pp; pp = pp->next)
if (pg_strcasecmp(name, pp->name) == 0)
return 0;
return 1;
}
/*
AbsoluteTime
currabstime()
{
return GetCurrentAbsoluteTime();
}
*/
static EPlan *
find_plan(char *ident, EPlan **eplan, int *nplans)
{
EPlan *newp;
int i;
if (*nplans > 0)
{
for (i = 0; i < *nplans; i++)
{
if (strcmp((*eplan)[i].ident, ident) == 0)
break;
}
if (i != *nplans)
return (*eplan + i);
*eplan = (EPlan *) realloc(*eplan, (i + 1) * sizeof(EPlan));
newp = *eplan + i;
}
else
{
newp = *eplan = (EPlan *) malloc(sizeof(EPlan));
(*nplans) = i = 0;
}
newp->ident = strdup(ident);
newp->splan = NULL;
(*nplans)++;
return newp;
}

5
contrib/spi/timetravel.control
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@ -1,5 +0,0 @@
# timetravel extension
comment = 'functions for implementing time travel'
default_version = '1.0'
module_pathname = '$libdir/timetravel'
relocatable = true

81
contrib/spi/timetravel.example
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@ -1,81 +0,0 @@
drop table tttest;
create table tttest (
price_id int4,
price_val int4,
price_on abstime,
price_off abstime
);
create unique index tttest_idx on tttest (price_id,price_off);
alter table tttest add column q1 text;
alter table tttest add column q2 int;
alter table tttest drop column q1;
create trigger timetravel
before insert or delete or update on tttest
for each row
execute procedure
timetravel (price_on, price_off);
insert into tttest values (1, 1, null, null);
insert into tttest(price_id, price_val) values (2, 2);
insert into tttest(price_id, price_val,price_off) values (3, 3, 'infinity');
insert into tttest(price_id, price_val,price_off) values (4, 4,
abstime('now'::timestamp - '100 days'::interval));
insert into tttest(price_id, price_val,price_on) values (3, 3, 'infinity'); -- duplicate key
select * from tttest;
delete from tttest where price_id = 2;
select * from tttest;
-- what do we see ?
-- get current prices
select * from tttest where price_off = 'infinity';
-- change price for price_id == 3
update tttest set price_val = 30 where price_id = 3;
select * from tttest;
-- now we want to change price_id from 3 to 5 in ALL tuples
-- but this gets us not what we need
update tttest set price_id = 5 where price_id = 3;
select * from tttest;
-- restore data as before last update:
select set_timetravel('tttest', 0); -- turn TT OFF!
select get_timetravel('tttest'); -- check status
delete from tttest where price_id = 5;
update tttest set price_off = 'infinity' where price_val = 30;
select * from tttest;
-- and try change price_id now!
update tttest set price_id = 5 where price_id = 3;
select * from tttest;
-- isn't it what we need ?
select set_timetravel('tttest', 1); -- turn TT ON!
select get_timetravel('tttest'); -- check status
-- we want to correct some date
update tttest set price_on = 'Jan-01-1990 00:00:01' where price_id = 5 and
price_off <> 'infinity';
-- but this doesn't work
-- try in this way
select set_timetravel('tttest', 0); -- turn TT OFF!
select get_timetravel('tttest'); -- check status
update tttest set price_on = '01-Jan-1990 00:00:01' where price_id = 5 and
price_off <> 'infinity';
select * from tttest;
-- isn't it what we need ?
-- get price for price_id == 5 as it was '10-Jan-1990'
select * from tttest where price_id = 5 and
price_on <= '10-Jan-1990' and price_off > '10-Jan-1990';

93
doc/src/sgml/contrib-spi.sgml
View File

@ -65,99 +65,6 @@
</para>
</sect2>
<sect2>
<title>timetravel &mdash; Functions for Implementing Time Travel</title>
<para>
Long ago, <productname>PostgreSQL</productname> had a built-in time travel feature
that kept the insert and delete times for each tuple. This can be
emulated using these functions. To use these functions,
you must add to a table two columns of <type>abstime</type> type to store
the date when a tuple was inserted (start_date) and changed/deleted
(stop_date):
<programlisting>
CREATE TABLE mytab (
... ...
start_date abstime,
stop_date abstime
... ...
);
</programlisting>
The columns can be named whatever you like, but in this discussion
we'll call them start_date and stop_date.
</para>
<para>
When a new row is inserted, start_date should normally be set to
current time, and stop_date to <literal>infinity</literal>. The trigger
will automatically substitute these values if the inserted data
contains nulls in these columns. Generally, inserting explicit
non-null data in these columns should only be done when re-loading
dumped data.
</para>
<para>
Tuples with stop_date equal to <literal>infinity</literal> are <quote>valid
now</quote>, and can be modified. Tuples with a finite stop_date cannot
be modified anymore &mdash; the trigger will prevent it. (If you need
to do that, you can turn off time travel as shown below.)
</para>
<para>
For a modifiable row, on update only the stop_date in the tuple being
updated will be changed (to current time) and a new tuple with the modified
data will be inserted. Start_date in this new tuple will be set to current
time and stop_date to <literal>infinity</literal>.
</para>
<para>
A delete does not actually remove the tuple but only sets its stop_date
to current time.
</para>
<para>
To query for tuples <quote>valid now</quote>, include
<literal>stop_date = 'infinity'</literal> in the query's WHERE condition.
(You might wish to incorporate that in a view.) Similarly, you can
query for tuples valid at any past time with suitable conditions on
start_date and stop_date.
</para>
<para>
<function>timetravel()</function> is the general trigger function that supports
this behavior. Create a <literal>BEFORE INSERT OR UPDATE OR DELETE</literal>
trigger using this function on each time-traveled table. Specify two
trigger arguments: the actual
names of the start_date and stop_date columns.
Optionally, you can specify one to three more arguments, which must refer
to columns of type <type>text</type>. The trigger will store the name of
the current user into the first of these columns during INSERT, the
second column during UPDATE, and the third during DELETE.
</para>
<para>
<function>set_timetravel()</function> allows you to turn time-travel on or off for
a table.
<literal>set_timetravel('mytab', 1)</literal> will turn TT ON for table <literal>mytab</literal>.
<literal>set_timetravel('mytab', 0)</literal> will turn TT OFF for table <literal>mytab</literal>.
In both cases the old status is reported. While TT is off, you can modify
the start_date and stop_date columns freely. Note that the on/off status
is local to the current database session &mdash; fresh sessions will
always start out with TT ON for all tables.
</para>
<para>
<function>get_timetravel()</function> returns the TT state for a table without
changing it.
</para>
<para>
There is an example in <filename>timetravel.example</filename>.
</para>
</sect2>
<sect2>
<title>autoinc &mdash; Functions for Autoincrementing Fields</title>

2
src/tools/msvc/Install.pm
View File

@ -605,7 +605,7 @@ sub CopySubdirFiles
# Special case for contrib/spi
$flist =
"autoinc.example insert_username.example moddatetime.example refint.example timetravel.example"
"autoinc.example insert_username.example moddatetime.example refint.example"
if ($module eq 'spi');
foreach my $f (split /\s+/, $flist)
{