greenplumn tupconvert 源码
greenplumn tupconvert 代码
文件路径：/src/backend/access/common/tupconvert.c
/*-------------------------------------------------------------------------
*
* tupconvert.c
* Tuple conversion support.
*
* These functions provide conversion between rowtypes that are logically
* equivalent but might have columns in a different order or different sets of
* dropped columns.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/access/common/tupconvert.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "access/tupconvert.h"
#include "executor/tuptable.h"
#include "utils/builtins.h"
/*
* The conversion setup routines have the following common API:
*
* The setup routine checks whether the given source and destination tuple
* descriptors are logically compatible. If not, it throws an error.
* If so, it returns NULL if they are physically compatible (ie, no conversion
* is needed), else a TupleConversionMap that can be used by execute_attr_map_tuple
* to perform the conversion.
*
* The TupleConversionMap, if needed, is palloc'd in the caller's memory
* context. Also, the given tuple descriptors are referenced by the map,
* so they must survive as long as the map is needed.
*
* The caller must supply a suitable primary error message to be used if
* a compatibility error is thrown. Recommended coding practice is to use
* gettext_noop() on this string, so that it is translatable but won't
* actually be translated unless the error gets thrown.
*
*
* Implementation notes:
*
* The key component of a TupleConversionMap is an attrMap[] array with
* one entry per output column. This entry contains the 1-based index of
* the corresponding input column, or zero to force a NULL value (for
* a dropped output column). The TupleConversionMap also contains workspace
* arrays.
*/
/*
* Set up for tuple conversion, matching input and output columns by
* position. (Dropped columns are ignored in both input and output.)
*
* Note: the errdetail messages speak of indesc as the "returned" rowtype,
* outdesc as the "expected" rowtype. This is okay for current uses but
* might need generalization in future.
*/
TupleConversionMap *
convert_tuples_by_position(TupleDesc indesc,
TupleDesc outdesc,
const char *msg)
{
TupleConversionMap *map;
AttrNumber *attrMap;
int nincols;
int noutcols;
int n;
int i;
int j;
bool same;
/* Verify compatibility and prepare attribute-number map */
n = outdesc->natts;
attrMap = (AttrNumber *) palloc0(n * sizeof(AttrNumber));
j = 0; /* j is next physical input attribute */
nincols = noutcols = 0; /* these count non-dropped attributes */
same = true;
for (i = 0; i < n; i++)
{
Form_pg_attribute att = TupleDescAttr(outdesc, i);
Oid atttypid;
int32 atttypmod;
if (att->attisdropped)
continue; /* attrMap[i] is already 0 */
noutcols++;
atttypid = att->atttypid;
atttypmod = att->atttypmod;
for (; j < indesc->natts; j++)
{
att = TupleDescAttr(indesc, j);
if (att->attisdropped)
continue;
nincols++;
/* Found matching column, check type */
if (atttypid != att->atttypid ||
(atttypmod != att->atttypmod && atttypmod >= 0))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg_internal("%s", _(msg)),
errdetail("Returned type %s does not match expected type %s in column %d.",
format_type_with_typemod(att->atttypid,
att->atttypmod),
format_type_with_typemod(atttypid,
atttypmod),
noutcols)));
attrMap[i] = (AttrNumber) (j + 1);
j++;
break;
}
if (attrMap[i] == 0)
same = false; /* we'll complain below */
}
/* Check for unused input columns */
for (; j < indesc->natts; j++)
{
if (TupleDescAttr(indesc, j)->attisdropped)
continue;
nincols++;
same = false; /* we'll complain below */
}
/* Report column count mismatch using the non-dropped-column counts */
if (!same)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg_internal("%s", _(msg)),
errdetail("Number of returned columns (%d) does not match "
"expected column count (%d).",
nincols, noutcols)));
/*
* Check to see if the map is one-to-one, in which case we need not do a
* tuple conversion.
*/
if (indesc->natts == outdesc->natts)
{
for (i = 0; i < n; i++)
{
Form_pg_attribute inatt;
Form_pg_attribute outatt;
if (attrMap[i] == (i + 1))
continue;
/*
* If it's a dropped column and the corresponding input column is
* also dropped, we needn't convert. However, attlen and attalign
* must agree.
*/
inatt = TupleDescAttr(indesc, i);
outatt = TupleDescAttr(outdesc, i);
if (attrMap[i] == 0 &&
inatt->attisdropped &&
inatt->attlen == outatt->attlen &&
inatt->attalign == outatt->attalign)
continue;
same = false;
break;
}
}
else
same = false;
if (same)
{
/* Runtime conversion is not needed */
pfree(attrMap);
return NULL;
}
/* Prepare the map structure */
map = (TupleConversionMap *) palloc(sizeof(TupleConversionMap));
map->indesc = indesc;
map->outdesc = outdesc;
map->attrMap = attrMap;
/* preallocate workspace for Datum arrays */
map->outvalues = (Datum *) palloc(n * sizeof(Datum));
map->outisnull = (bool *) palloc(n * sizeof(bool));
n = indesc->natts + 1; /* +1 for NULL */
map->invalues = (Datum *) palloc(n * sizeof(Datum));
map->inisnull = (bool *) palloc(n * sizeof(bool));
map->invalues[0] = (Datum) 0; /* set up the NULL entry */
map->inisnull[0] = true;
return map;
}
/*
* Set up for tuple conversion, matching input and output columns by name.
* (Dropped columns are ignored in both input and output.) This is intended
* for use when the rowtypes are related by inheritance, so we expect an exact
* match of both type and typmod. The error messages will be a bit unhelpful
* unless both rowtypes are named composite types.
*/
TupleConversionMap *
convert_tuples_by_name(TupleDesc indesc,
TupleDesc outdesc,
const char *msg)
{
TupleConversionMap *map;
AttrNumber *attrMap;
int n = outdesc->natts;
/* Verify compatibility and prepare attribute-number map */
attrMap = convert_tuples_by_name_map_if_req(indesc, outdesc, msg);
if (attrMap == NULL)
{
/* runtime conversion is not needed */
return NULL;
}
/* Prepare the map structure */
map = (TupleConversionMap *) palloc(sizeof(TupleConversionMap));
map->indesc = indesc;
map->outdesc = outdesc;
map->attrMap = attrMap;
/* preallocate workspace for Datum arrays */
map->outvalues = (Datum *) palloc(n * sizeof(Datum));
map->outisnull = (bool *) palloc(n * sizeof(bool));
n = indesc->natts + 1; /* +1 for NULL */
map->invalues = (Datum *) palloc(n * sizeof(Datum));
map->inisnull = (bool *) palloc(n * sizeof(bool));
map->invalues[0] = (Datum) 0; /* set up the NULL entry */
map->inisnull[0] = true;
return map;
}
/*
* Return a palloc'd bare attribute map for tuple conversion, matching input
* and output columns by name. (Dropped columns are ignored in both input and
* output.) This is normally a subroutine for convert_tuples_by_name, but can
* be used standalone.
*/
AttrNumber *
convert_tuples_by_name_map(TupleDesc indesc,
TupleDesc outdesc,
const char *msg)
{
AttrNumber *attrMap;
int outnatts;
int innatts;
int i;
int nextindesc = -1;
outnatts = outdesc->natts;
innatts = indesc->natts;
attrMap = (AttrNumber *) palloc0(outnatts * sizeof(AttrNumber));
for (i = 0; i < outnatts; i++)
{
Form_pg_attribute outatt = TupleDescAttr(outdesc, i);
char *attname;
Oid atttypid;
int32 atttypmod;
int j;
if (outatt->attisdropped)
continue; /* attrMap[i] is already 0 */
attname = NameStr(outatt->attname);
atttypid = outatt->atttypid;
atttypmod = outatt->atttypmod;
/*
* Now search for an attribute with the same name in the indesc. It
* seems likely that a partitioned table will have the attributes in
* the same order as the partition, so the search below is optimized
* for that case. It is possible that columns are dropped in one of
* the relations, but not the other, so we use the 'nextindesc'
* counter to track the starting point of the search. If the inner
* loop encounters dropped columns then it will have to skip over
* them, but it should leave 'nextindesc' at the correct position for
* the next outer loop.
*/
for (j = 0; j < innatts; j++)
{
Form_pg_attribute inatt;
nextindesc++;
if (nextindesc >= innatts)
nextindesc = 0;
inatt = TupleDescAttr(indesc, nextindesc);
if (inatt->attisdropped)
continue;
if (strcmp(attname, NameStr(inatt->attname)) == 0)
{
/* Found it, check type */
if (atttypid != inatt->atttypid || atttypmod != inatt->atttypmod)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not convert row type"),
errdetail("Attribute \"%s\" of type %s does not match corresponding attribute of type %s.",
attname,
format_type_be(outdesc->tdtypeid),
format_type_be(indesc->tdtypeid))));
attrMap[i] = inatt->attnum;
break;
}
}
if (attrMap[i] == 0)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("could not convert row type"),
errdetail("Attribute \"%s\" of type %s does not exist in type %s.",
attname,
format_type_be(outdesc->tdtypeid),
format_type_be(indesc->tdtypeid))));
}
return attrMap;
}
/*
* Returns mapping created by convert_tuples_by_name_map, or NULL if no
* conversion not required. This is a convenience routine for
* convert_tuples_by_name() and other functions.
*/
AttrNumber *
convert_tuples_by_name_map_if_req(TupleDesc indesc,
TupleDesc outdesc,
const char *msg)
{
AttrNumber *attrMap;
int n = outdesc->natts;
int i;
bool same;
/* Verify compatibility and prepare attribute-number map */
attrMap = convert_tuples_by_name_map(indesc, outdesc, msg);
/*
* Check to see if the map is one-to-one, in which case we need not do a
* tuple conversion.
*/
if (indesc->natts == outdesc->natts)
{
same = true;
for (i = 0; i < n; i++)
{
Form_pg_attribute inatt;
Form_pg_attribute outatt;
if (attrMap[i] == (i + 1))
continue;
/*
* If it's a dropped column and the corresponding input column is
* also dropped, we needn't convert. However, attlen and attalign
* must agree.
*/
inatt = TupleDescAttr(indesc, i);
outatt = TupleDescAttr(outdesc, i);
if (attrMap[i] == 0 &&
inatt->attisdropped &&
inatt->attlen == outatt->attlen &&
inatt->attalign == outatt->attalign)
continue;
same = false;
break;
}
}
else
same = false;
if (same)
{
/* Runtime conversion is not needed */
pfree(attrMap);
return NULL;
}
else
return attrMap;
}
/*
* Perform conversion of a tuple according to the map.
*/
HeapTuple
execute_attr_map_tuple(HeapTuple tuple, TupleConversionMap *map)
{
AttrNumber *attrMap = map->attrMap;
Datum *invalues = map->invalues;
bool *inisnull = map->inisnull;
Datum *outvalues = map->outvalues;
bool *outisnull = map->outisnull;
int outnatts = map->outdesc->natts;
int i;
/*
* Extract all the values of the old tuple, offsetting the arrays so that
* invalues[0] is left NULL and invalues[1] is the first source attribute;
* this exactly matches the numbering convention in attrMap.
*/
heap_deform_tuple(tuple, map->indesc, invalues + 1, inisnull + 1);
/*
* Transpose into proper fields of the new tuple.
*/
for (i = 0; i < outnatts; i++)
{
int j = attrMap[i];
outvalues[i] = invalues[j];
outisnull[i] = inisnull[j];
}
/*
* Now form the new tuple.
*/
return heap_form_tuple(map->outdesc, outvalues, outisnull);
}
/*
* Perform conversion of a tuple slot according to the map.
*/
TupleTableSlot *
execute_attr_map_slot(AttrNumber *attrMap,
TupleTableSlot *in_slot,
TupleTableSlot *out_slot)
{
Datum *invalues;
bool *inisnull;
Datum *outvalues;
bool *outisnull;
int outnatts;
int i;
/* Sanity checks */
Assert(in_slot->tts_tupleDescriptor != NULL &&
out_slot->tts_tupleDescriptor != NULL);
Assert(in_slot->tts_values != NULL && out_slot->tts_values != NULL);
outnatts = out_slot->tts_tupleDescriptor->natts;
/* Extract all the values of the in slot. */
slot_getallattrs(in_slot);
/* Before doing the mapping, clear any old contents from the out slot */
ExecClearTuple(out_slot);
invalues = in_slot->tts_values;
inisnull = in_slot->tts_isnull;
outvalues = out_slot->tts_values;
outisnull = out_slot->tts_isnull;
/* Transpose into proper fields of the out slot. */
for (i = 0; i < outnatts; i++)
{
int j = attrMap[i] - 1;
/* attrMap[i] == 0 means it's a NULL datum. */
if (j == -1)
{
outvalues[i] = (Datum) 0;
outisnull[i] = true;
}
else
{
outvalues[i] = invalues[j];
outisnull[i] = inisnull[j];
}
}
ExecStoreVirtualTuple(out_slot);
return out_slot;
}
/*
* Free a TupleConversionMap structure.
*/
void
free_conversion_map(TupleConversionMap *map)
{
/* indesc and outdesc are not ours to free */
pfree(map->attrMap);
pfree(map->invalues);
pfree(map->inisnull);
pfree(map->outvalues);
pfree(map->outisnull);
pfree(map);
}
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