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Generated columns

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This is an SQL-standard feature that allows creating columns that are
computed from expressions rather than assigned, similar to a view or
materialized view but on a column basis.

This implements one kind of generated column: stored (computed on
write).  Another kind, virtual (computed on read), is planned for the
future, and some room is left for it.

Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com
This commit is contained in:
Peter Eisentraut
2019-03-30 08:13:09 +01:00
parent 6b8b5364dd
commit fc22b6623b
84 changed files with 3067 additions and 157 deletions
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40
src/pl/plperl/plperl.c
View File

@ -266,7 +266,7 @@ static plperl_proc_desc *compile_plperl_function(Oid fn_oid,
bool is_trigger,
bool is_event_trigger);
static SV *plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc);
static SV *plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generated);
static SV *plperl_hash_from_datum(Datum attr);
static SV *plperl_ref_from_pg_array(Datum arg, Oid typid);
static SV *split_array(plperl_array_info *info, int first, int last, int nest);
@ -1644,13 +1644,19 @@ plperl_trigger_build_args(FunctionCallInfo fcinfo)
hv_store_string(hv, "name", cstr2sv(tdata->tg_trigger->tgname));
hv_store_string(hv, "relid", cstr2sv(relid));
/*
* Note: In BEFORE trigger, stored generated columns are not computed yet,
* so don't make them accessible in NEW row.
*/
if (TRIGGER_FIRED_BY_INSERT(tdata->tg_event))
{
event = "INSERT";
if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
hv_store_string(hv, "new",
plperl_hash_from_tuple(tdata->tg_trigtuple,
tupdesc));
tupdesc,
!TRIGGER_FIRED_BEFORE(tdata->tg_event)));
}
else if (TRIGGER_FIRED_BY_DELETE(tdata->tg_event))
{
@ -1658,7 +1664,8 @@ plperl_trigger_build_args(FunctionCallInfo fcinfo)
if (TRIGGER_FIRED_FOR_ROW(tdata->tg_event))
hv_store_string(hv, "old",
plperl_hash_from_tuple(tdata->tg_trigtuple,
tupdesc));
tupdesc,
true));
}
else if (TRIGGER_FIRED_BY_UPDATE(tdata->tg_event))
{
@ -1667,10 +1674,12 @@ plperl_trigger_build_args(FunctionCallInfo fcinfo)
{
hv_store_string(hv, "old",
plperl_hash_from_tuple(tdata->tg_trigtuple,
tupdesc));
tupdesc,
true));
hv_store_string(hv, "new",
plperl_hash_from_tuple(tdata->tg_newtuple,
tupdesc));
tupdesc,
!TRIGGER_FIRED_BEFORE(tdata->tg_event)));
}
}
else if (TRIGGER_FIRED_BY_TRUNCATE(tdata->tg_event))
@ -1791,6 +1800,11 @@ plperl_modify_tuple(HV *hvTD, TriggerData *tdata, HeapTuple otup)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot set system attribute \"%s\"",
key)));
if (attr->attgenerated)
ereport(ERROR,
(errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
errmsg("cannot set generated column \"%s\"",
key)));
modvalues[attn - 1] = plperl_sv_to_datum(val,
attr->atttypid,
@ -3012,7 +3026,7 @@ plperl_hash_from_datum(Datum attr)
tmptup.t_len = HeapTupleHeaderGetDatumLength(td);
tmptup.t_data = td;
sv = plperl_hash_from_tuple(&tmptup, tupdesc);
sv = plperl_hash_from_tuple(&tmptup, tupdesc, true);
ReleaseTupleDesc(tupdesc);
return sv;
@ -3020,7 +3034,7 @@ plperl_hash_from_datum(Datum attr)
/* Build a hash from all attributes of a given tuple. */
static SV *
plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc)
plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc, bool include_generated)
{
dTHX;
HV *hv;
@ -3044,6 +3058,13 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc)
if (att->attisdropped)
continue;
if (att->attgenerated)
{
/* don't include unless requested */
if (!include_generated)
continue;
}
attname = NameStr(att->attname);
attr = heap_getattr(tuple, i + 1, tupdesc, &isnull);
@ -3198,7 +3219,7 @@ plperl_spi_execute_fetch_result(SPITupleTable *tuptable, uint64 processed,
av_extend(rows, processed);
for (i = 0; i < processed; i++)
{
row = plperl_hash_from_tuple(tuptable->vals[i], tuptable->tupdesc);
row = plperl_hash_from_tuple(tuptable->vals[i], tuptable->tupdesc, true);
av_push(rows, row);
}
hv_store_string(result, "rows",
@ -3484,7 +3505,8 @@ plperl_spi_fetchrow(char *cursor)
else
{
row = plperl_hash_from_tuple(SPI_tuptable->vals[0],
SPI_tuptable->tupdesc);
SPI_tuptable->tupdesc,
true);
}
SPI_freetuptable(SPI_tuptable);
}