git.postgresql.org Git - postgresql.git/commitdiff

git projects / postgresql.git / commitdiff

author Peter Eisentraut <peter@eisentraut.org>

Mon, 9 Mar 2020 08:22:22 +0000 (09:22 +0100)

committer Peter Eisentraut <peter@eisentraut.org>

Mon, 9 Mar 2020 08:34:55 +0000 (09:34 +0100)

This allows a trigger function to determine for an UPDATE trigger
which columns were actually updated. This allows some optimizations
in generic trigger functions such as lo_manage and
tsvector_update_trigger.

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/flat/11c5f156-67a9-0fb5-8200-2a8018eb2e0c@2ndquadrant.com

contrib/lo/expected/lo.out patch | blob | blame | history

contrib/lo/lo.c patch | blob | blame | history

contrib/lo/sql/lo.sql patch | blob | blame | history

doc/src/sgml/trigger.sgml patch | blob | blame | history

src/backend/commands/trigger.c patch | blob | blame | history

src/backend/utils/adt/tsvector_op.c patch | blob | blame | history

src/include/commands/trigger.h patch | blob | blame | history

diff --git a/contrib/lo/expected/lo.out b/contrib/lo/expected/lo.out

index f7104aee3f08eb1d85dd7bafb1efc0601b74188b..c63e4b1c704fb4f20380339d6abb5597d9da12af 100644 (file)

--- a/contrib/lo/expected/lo.out

+++ b/contrib/lo/expected/lo.out

@@ -36,6 +36,14 @@ SELECT lo_get(43214);

(1 row)

+-- test updating of unrelated column

+UPDATE image SET title = 'beautiful picture' WHERE title = 'beautiful image';

+SELECT lo_get(43214);

+ lo_get

+--------

+ \x

+(1 row)

DELETE FROM image;

SELECT lo_get(43214);

ERROR: large object 43214 does not exist

diff --git a/contrib/lo/lo.c b/contrib/lo/lo.c

index 4585923ee2b5aa257905a29ab9102dd50ec6daa1..b9847081db6c6cfc29a15ad641bcf3b630e6b7db 100644 (file)

--- a/contrib/lo/lo.c

+++ b/contrib/lo/lo.c

@@ -74,7 +74,8 @@ lo_manage(PG_FUNCTION_ARGS)

* Here, if the value of the monitored attribute changes, then the large

* object associated with the original value is unlinked.

- if (newtuple != NULL)

+ if (newtuple != NULL &&

+ bms_is_member(attnum - FirstLowInvalidHeapAttributeNumber, trigdata->tg_updatedcols))

{

char *orig = SPI_getvalue(trigtuple, tupdesc, attnum);

char *newv = SPI_getvalue(newtuple, tupdesc, attnum);

diff --git a/contrib/lo/sql/lo.sql b/contrib/lo/sql/lo.sql

index 34ba6f00ec0b91ab9725e4437e05fc92bf94dbb6..770395092450802cd867bdec4febe70c0119e9ef 100644 (file)

--- a/contrib/lo/sql/lo.sql

+++ b/contrib/lo/sql/lo.sql

@@ -18,6 +18,11 @@ UPDATE image SET raster = 43214 WHERE title = 'beautiful image';

SELECT lo_get(43213);

SELECT lo_get(43214);

+-- test updating of unrelated column

+UPDATE image SET title = 'beautiful picture' WHERE title = 'beautiful image';

+SELECT lo_get(43214);

DELETE FROM image;

SELECT lo_get(43214);

diff --git a/doc/src/sgml/trigger.sgml b/doc/src/sgml/trigger.sgml

index 6f323a903b535c844079cf42495b205a4c825fda..7d9ad4763aa05c74c35f0fb85290b68b48f7f0cd 100644 (file)

--- a/doc/src/sgml/trigger.sgml

+++ b/doc/src/sgml/trigger.sgml

@@ -517,6 +517,7 @@ typedef struct TriggerData

TupleTableSlot *tg_newslot;

Tuplestorestate *tg_oldtable;

Tuplestorestate *tg_newtable;

+ const Bitmapset *tg_updatedcols;

} TriggerData;

</programlisting>

@@ -759,6 +760,30 @@ typedef struct Trigger

</listitem>

</varlistentry>

+ <varlistentry>

+ <term><structfield>tg_updatedcols</structfield></term>

+ <listitem>

+ <para>

+ For <literal>UPDATE</literal> triggers, a bitmap set indicating the

+ columns that were updated by the triggering command. Generic trigger

+ functions can use this to optimize actions by not having to deal with

+ columns that were not changed.

+ </para>

+ <para>

+ As an example, to determine whether a column with attribute number

+ <varname>attnum</varname> (1-based) is a member of this bitmap set,

+ call <literal>bms_is_member(attnum -

+ FirstLowInvalidHeapAttributeNumber,

+ trigdata->tg_updatedcols))</literal>.

+ </para>

+ <para>

+ For triggers other than <literal>UPDATE</literal> triggers, this will

+ be <symbol>NULL</symbol>.

+ </para>

+ </listitem>

+ </varlistentry>

</variablelist>

</para>

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c

index 325228c4eb1969b38d1393830505d689a2475723..513427edf146ae5102cafad9e40eb5b6f2132d25 100644 (file)

--- a/src/backend/commands/trigger.c

+++ b/src/backend/commands/trigger.c

@@ -2591,6 +2591,7 @@ ExecBSUpdateTriggers(EState *estate, ResultRelInfo *relinfo)

LocTriggerData.tg_event = TRIGGER_EVENT_UPDATE |

TRIGGER_EVENT_BEFORE;

LocTriggerData.tg_relation = relinfo->ri_RelationDesc;

+ LocTriggerData.tg_updatedcols = updatedCols;

for (i = 0; i < trigdesc->numtriggers; i++)

{

Trigger *trigger = &trigdesc->triggers[i];

@@ -2699,6 +2700,7 @@ ExecBRUpdateTriggers(EState *estate, EPQState *epqstate,

TRIGGER_EVENT_BEFORE;

LocTriggerData.tg_relation = relinfo->ri_RelationDesc;

updatedCols = GetAllUpdatedColumns(relinfo, estate);

+ LocTriggerData.tg_updatedcols = updatedCols;

for (i = 0; i < trigdesc->numtriggers; i++)

{

Trigger *trigger = &trigdesc->triggers[i];

@@ -3255,6 +3257,7 @@ typedef struct AfterTriggerSharedData

Oid ats_relid; /* the relation it's on */

CommandId ats_firing_id; /* ID for firing cycle */

struct AfterTriggersTableData *ats_table; /* transition table access */

+ Bitmapset *ats_modifiedcols; /* modified columns */

} AfterTriggerSharedData;

typedef struct AfterTriggerEventData *AfterTriggerEvent;

@@ -3954,6 +3957,8 @@ AfterTriggerExecute(EState *estate,

LocTriggerData.tg_event =

evtshared->ats_event & (TRIGGER_EVENT_OPMASK | TRIGGER_EVENT_ROW);

LocTriggerData.tg_relation = rel;

+ if (TRIGGER_FOR_UPDATE(LocTriggerData.tg_trigger->tgtype))

+ LocTriggerData.tg_updatedcols = evtshared->ats_modifiedcols;

MemoryContextReset(per_tuple_context);

@@ -5641,6 +5646,7 @@ AfterTriggerSaveEvent(EState *estate, ResultRelInfo *relinfo,

new_shared.ats_table = transition_capture->tcs_private;

else

new_shared.ats_table = NULL;

+ new_shared.ats_modifiedcols = modifiedCols;

afterTriggerAddEvent(&afterTriggers.query_stack[afterTriggers.query_depth].events,

&new_event, &new_shared);

diff --git a/src/backend/utils/adt/tsvector_op.c b/src/backend/utils/adt/tsvector_op.c

index 790355082d97ea0e67f9c04451335f222d00c2c0..108dd998c7a5bd4c853c1e585d96f341d7f26aa2 100644 (file)

--- a/src/backend/utils/adt/tsvector_op.c

+++ b/src/backend/utils/adt/tsvector_op.c

@@ -2416,6 +2416,7 @@ tsvector_update_trigger(PG_FUNCTION_ARGS, bool config_column)

bool isnull;

text *txt;

Oid cfgId;

+ bool update_needed;

/* Check call context */

if (!CALLED_AS_TRIGGER(fcinfo)) /* internal error */

@@ -2428,9 +2429,15 @@ tsvector_update_trigger(PG_FUNCTION_ARGS, bool config_column)

elog(ERROR, "tsvector_update_trigger: must be fired BEFORE event");

if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))

+ {

rettuple = trigdata->tg_trigtuple;

+ update_needed = true;

+ }

else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))

+ {

rettuple = trigdata->tg_newtuple;

+ update_needed = false; /* computed below */

+ }

else

elog(ERROR, "tsvector_update_trigger: must be fired for INSERT or UPDATE");

@@ -2518,6 +2525,9 @@ tsvector_update_trigger(PG_FUNCTION_ARGS, bool config_column)

errmsg("column \"%s\" is not of a character type",

trigger->tgargs[i])));

+ if (bms_is_member(numattr - FirstLowInvalidHeapAttributeNumber, trigdata->tg_updatedcols))

+ update_needed = true;

datum = SPI_getbinval(rettuple, rel->rd_att, numattr, &isnull);

if (isnull)

continue;

@@ -2530,16 +2540,19 @@ tsvector_update_trigger(PG_FUNCTION_ARGS, bool config_column)

pfree(txt);

}

- /* make tsvector value */

- datum = TSVectorGetDatum(make_tsvector(&prs));

- isnull = false;

+ if (update_needed)

+ {

+ /* make tsvector value */

+ datum = TSVectorGetDatum(make_tsvector(&prs));

+ isnull = false;

- /* and insert it into tuple */

- rettuple = heap_modify_tuple_by_cols(rettuple, rel->rd_att,

- 1, &tsvector_attr_num,

- &datum, &isnull);

+ /* and insert it into tuple */

+ rettuple = heap_modify_tuple_by_cols(rettuple, rel->rd_att,

+ 1, &tsvector_attr_num,

+ &datum, &isnull);

- pfree(DatumGetPointer(datum));

+ pfree(DatumGetPointer(datum));

+ }

return PointerGetDatum(rettuple);

}

diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h

index 5d691926433e8aab2b33a3e56606da89950fd00b..a40ddf5db52cab4771a3dfdd94703d11ca1e532b 100644 (file)

--- a/src/include/commands/trigger.h

+++ b/src/include/commands/trigger.h

@@ -39,6 +39,7 @@ typedef struct TriggerData

TupleTableSlot *tg_newslot;

Tuplestorestate *tg_oldtable;

Tuplestorestate *tg_newtable;

+ const Bitmapset *tg_updatedcols;

} TriggerData;

This is the main PostgreSQL git repository.

RSS Atom