@ -56,6 +56,33 @@ ResourceOwnerForgetTupleDesc(ResourceOwner owner, TupleDesc tupdesc)
ResourceOwnerForget ( owner , PointerGetDatum ( tupdesc ) , & tupdesc_resowner_desc ) ;
}
/*
* populate_compact_attribute
* Fill in the corresponding CompactAttribute element from the
* Form_pg_attribute for the given attribute number . This must be called
* whenever a change is made to a Form_pg_attribute in the TupleDesc .
*/
void
populate_compact_attribute ( TupleDesc tupdesc , int attnum )
{
Form_pg_attribute src = TupleDescAttr ( tupdesc , attnum ) ;
CompactAttribute * dst = & tupdesc - > compact_attrs [ attnum ] ;
memset ( dst , 0 , sizeof ( CompactAttribute ) ) ;
dst - > attcacheoff = - 1 ;
dst - > attlen = src - > attlen ;
dst - > attbyval = src - > attbyval ;
dst - > attispackable = ( src - > attstorage ! = TYPSTORAGE_PLAIN ) ;
dst - > atthasmissing = src - > atthasmissing ;
dst - > attisdropped = src - > attisdropped ;
dst - > attgenerated = ( src - > attgenerated ! = ' \0 ' ) ;
dst - > attnotnull = src - > attnotnull ;
dst - > attalign = src - > attalign ;
}
/*
* CreateTemplateTupleDesc
* This function allocates an empty tuple descriptor structure .
@ -74,18 +101,20 @@ CreateTemplateTupleDesc(int natts)
Assert ( natts > = 0 ) ;
/*
* Allocate enough memory for the tuple descriptor , including th e
* attribute rows .
* Allocate enough memory for the tuple descriptor , the CompactAttribut e
* array and also an array of FormData_pg_attribute .
*
* Note : the attribute array stride is sizeof ( FormData_pg_attribute ) ,
* since we declare the array elements as FormData_pg_attribute for
* notational convenience . However , we only guarantee that the first
* ATTRIBUTE_FIXED_PART_SIZE bytes of each entry are valid ; most code that
* copies tupdesc entries around copies just that much . In principle that
* could be less due to trailing padding , although with the current
* definition of pg_attribute there probably isn ' t any padding .
* Note : the FormData_pg_attribute array stride is
* sizeof ( FormData_pg_attribute ) , since we declare the array elements as
* FormData_pg_attribute for notational convenience . However , we only
* guarantee that the first ATTRIBUTE_FIXED_PART_SIZE bytes of each entry
* are valid ; most code that copies tupdesc entries around copies just
* that much . In principle that could be less due to trailing padding ,
* although with the current definition of pg_attribute there probably
* isn ' t any padding .
*/
desc = ( TupleDesc ) palloc ( offsetof ( struct TupleDescData , attrs ) +
desc = ( TupleDesc ) palloc ( offsetof ( struct TupleDescData , compact_attrs ) +
natts * sizeof ( CompactAttribute ) +
natts * sizeof ( FormData_pg_attribute ) ) ;
/*
@ -117,8 +146,10 @@ CreateTupleDesc(int natts, Form_pg_attribute *attrs)
desc = CreateTemplateTupleDesc ( natts ) ;
for ( i = 0 ; i < natts ; + + i )
{
memcpy ( TupleDescAttr ( desc , i ) , attrs [ i ] , ATTRIBUTE_FIXED_PART_SIZE ) ;
populate_compact_attribute ( desc , i ) ;
}
return desc ;
}
@ -155,6 +186,54 @@ CreateTupleDescCopy(TupleDesc tupdesc)
att - > atthasmissing = false ;
att - > attidentity = ' \0 ' ;
att - > attgenerated = ' \0 ' ;
populate_compact_attribute ( desc , i ) ;
}
/* We can copy the tuple type identification, too */
desc - > tdtypeid = tupdesc - > tdtypeid ;
desc - > tdtypmod = tupdesc - > tdtypmod ;
return desc ;
}
/*
* CreateTupleDescTruncatedCopy
* This function creates a new TupleDesc with only the first ' natts '
* attributes from an existing TupleDesc
*
* ! ! ! Constraints and defaults are not copied ! ! !
*/
TupleDesc
CreateTupleDescTruncatedCopy ( TupleDesc tupdesc , int natts )
{
TupleDesc desc ;
int i ;
Assert ( natts < = tupdesc - > natts ) ;
desc = CreateTemplateTupleDesc ( natts ) ;
/* Flat-copy the attribute array */
memcpy ( TupleDescAttr ( desc , 0 ) ,
TupleDescAttr ( tupdesc , 0 ) ,
desc - > natts * sizeof ( FormData_pg_attribute ) ) ;
/*
* Since we ' re not copying constraints and defaults , clear fields
* associated with them .
*/
for ( i = 0 ; i < desc - > natts ; i + + )
{
Form_pg_attribute att = TupleDescAttr ( desc , i ) ;
att - > attnotnull = false ;
att - > atthasdef = false ;
att - > atthasmissing = false ;
att - > attidentity = ' \0 ' ;
att - > attgenerated = ' \0 ' ;
populate_compact_attribute ( desc , i ) ;
}
/* We can copy the tuple type identification, too */
@ -183,6 +262,9 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
TupleDescAttr ( tupdesc , 0 ) ,
desc - > natts * sizeof ( FormData_pg_attribute ) ) ;
for ( i = 0 ; i < desc - > natts ; i + + )
populate_compact_attribute ( desc , i ) ;
/* Copy the TupleConstr data structure, if any */
if ( constr )
{
@ -207,7 +289,7 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
{
if ( constr - > missing [ i ] . am_present )
{
Form_pg_attribute attr = TupleDescAttr ( tupdesc , i ) ;
CompactAttribute * attr = TupleDescCompact Attr ( tupdesc , i ) ;
cpy - > missing [ i ] . am_value = datumCopy ( constr - > missing [ i ] . am_value ,
attr - > attbyval ,
@ -252,7 +334,7 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
{
int i ;
/* Flat-copy the header and attribute array */
/* Flat-copy the header and attribute arrays */
memcpy ( dst , src , TupleDescSize ( src ) ) ;
/*
@ -268,6 +350,8 @@ TupleDescCopy(TupleDesc dst, TupleDesc src)
att - > atthasmissing = false ;
att - > attidentity = ' \0 ' ;
att - > attgenerated = ' \0 ' ;
populate_compact_attribute ( dst , i ) ;
}
dst - > constr = NULL ;
@ -322,6 +406,8 @@ TupleDescCopyEntry(TupleDesc dst, AttrNumber dstAttno,
dstAtt - > atthasmissing = false ;
dstAtt - > attidentity = ' \0 ' ;
dstAtt - > attgenerated = ' \0 ' ;
populate_compact_attribute ( dst , dstAttno - 1 ) ;
}
/*
@ -521,7 +607,7 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
return false ;
if ( missval1 - > am_present )
{
Form_pg_attribute missatt1 = TupleDescAttr ( tupdesc1 , i ) ;
CompactAttribute * missatt1 = TupleDescCompact Attr ( tupdesc1 , i ) ;
if ( ! datumIsEqual ( missval1 - > am_value , missval2 - > am_value ,
missatt1 - > attbyval , missatt1 - > attlen ) )
@ -714,6 +800,8 @@ TupleDescInitEntry(TupleDesc desc,
att - > attcompression = InvalidCompressionMethod ;
att - > attcollation = typeForm - > typcollation ;
populate_compact_attribute ( desc , attributeNumber - 1 ) ;
ReleaseSysCache ( tuple ) ;
}
@ -821,6 +909,8 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
default :
elog ( ERROR , " unsupported type %u " , oidtypeid ) ;
}
populate_compact_attribute ( desc , attributeNumber - 1 ) ;
}
/*
David Rowley
6 months ago