greenplumn memtuple 源码
greenplumn memtuple 代码
文件路径：/src/backend/access/common/memtuple.c
/*-------------------------------------------------------------------------
*
* memtuple.c
*
* Portions Copyright (c) 2006-2008, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
*
* IDENTIFICATION
* src/backend/access/common/memtuple.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/memtup.h"
#include "access/tupmacs.h"
#include "access/transam.h"
#include "access/tuptoaster.h"
#include "catalog/pg_type.h"
#include "utils/expandeddatum.h"
#include "cdb/cdbvars.h"
#define MAX_ATTR_COUNT_STATIC_ALLOC 20
/* Memory tuple format:
* 4 byte _mt_len,
* highest bit always 1. (if 0, means it is a heaptuple).
* bit 2-29th is memtuple length, in bytes. It is always 8
* bytes aligned.
* bit 30 is unused.
* bit 31 is set if the memtuple is longer than 64K.
* bit 32 is if has null.
*
* Followed by optional null bitmaps.
*
* Align to bind.column_align, either 4 or 8.
*
* Non-Null attribute:
* Fixed len Attributes.
* The attributes are not in logical order. First we put 8 bytes
* aligned native or native_ptr types. The 4 bytes aligned natives
* then 2 bytes aligned and varlena, then 1 bytes aligned natives.
* Varlena occupy 2bytes in the fixed len area.
*
* Varlena attributes.
*
* The end is again padded to 8 bytes aligned.
*
* Null attributes only occupy one bit in the nullbit map. The non null
* attributes is located from the binding offset/len. If there is null attr,
* we use the null_saves in the binding to figure out how many columns that is
* physically precedes the attribute is null and how much space we have saved,
* then we use off minus saved bytes to find the attribute.
*/
static int
compute_null_bitmap_extra_size(TupleDesc tupdesc, int col_align)
{
int nbytes = (tupdesc->natts + 7) >> 3;
int avail_bytes = (col_align == 4) ? 0 : 4;
Assert(col_align == 4 || col_align == 8);
if (nbytes <= avail_bytes)
return 0;
return TYPEALIGN(col_align, (nbytes - avail_bytes));
}
void destroy_memtuple_binding(MemTupleBinding *pbind)
{
Assert(pbind);
if(pbind->bind.null_saves)
pfree(pbind->bind.null_saves);
if(pbind->bind.null_saves_aligned)
pfree(pbind->bind.null_saves_aligned);
if(pbind->bind.bindings)
pfree(pbind->bind.bindings);
if(pbind->large_bind.null_saves)
pfree(pbind->large_bind.null_saves);
if(pbind->large_bind.null_saves_aligned)
pfree(pbind->large_bind.null_saves_aligned);
if(pbind->large_bind.bindings)
pfree(pbind->large_bind.bindings);
pfree(pbind);
}
/*
* Manage the space saved by not storing nulls.
* Attr are rearranged in the order of 8 bytes aligned, then 4,
* then 2, then 1. A bit in the null bitmap is set for each
* null attribute. For all possible combinations of 4 null bit,
* we index into a short[16] array to get how many space is saved
* by the nulls.
*/
/* Compute how much space to store the null save entries.
* The null save entries are stored in the binding, not per tuple.
*/
static uint32
compute_null_save_entries(int i)
{
return ((i+7)/8) * 32;
}
/* Add null save space into the entries */
static void
add_null_save(short *null_save, int i, short sz)
{
short* first = null_save + ((i/4) * 16);
unsigned int bit = 1 << (i%4);
for(i=0; i<16; ++i)
{
if( (i & bit) != 0)
first[i] += sz;
}
}
/*
* Sets the binding length according to the following binding's alignment.
* Adds the aligned length into the array holding the space saved from null attributes.
* Returns true if the binding length is aligned to the following binding's alignment.
*/
static bool
add_null_save_aligned(MemTupleAttrBinding *bind, short *null_save_aligned, int i, char next_attr_align)
{
Assert(bind);
Assert(bind->len > 0);
Assert(null_save_aligned);
Assert(i >= 0);
bind->len_aligned = att_align_nominal(bind->len, next_attr_align);
add_null_save(null_save_aligned, i, bind->len_aligned);
return (bind->len == bind->len_aligned);
}
/* Compute how much bytes are saved by one byte in the null bit map */
static inline short compute_null_save_b(short *null_saves, unsigned char b)
{
unsigned int blow = (b & 0xF);
unsigned int bhigh = (b >> 4);
return null_saves[blow] + null_saves[16+bhigh];
}
/* compute the null saved bytes by the whole null bit map, by the attribute
* physically precedes the one.
*/
static inline int compute_null_save(short *null_saves, unsigned char *nullbitmaps, int nbyte, unsigned char nbit)
{
int ret = 0;
int curr_byte = 0;
while(curr_byte < nbyte)
{
ret += compute_null_save_b(null_saves, nullbitmaps[curr_byte]);
null_saves += 32;
++curr_byte;
}
ret += compute_null_save_b(null_saves, (nullbitmaps[nbyte] & (nbit-1)));
return ret;
}
#undef MEMTUPLE_INLINE_CHARTYPE
/* Determine if an attr should be treated as offset_len in memtuple */
static bool
att_bind_as_varoffset(Form_pg_attribute attr)
{
#ifdef MEMTUPLE_INLINE_CHARTYPE
return (attr->attlen < 0 /* Varlen type */
&& (
attr->atttypid != BPCHAROID /* Any varlen type except char(N) */
|| attr->atttypmod <= 4 /* char(0)? ever happend? */
|| attr->atttypmod >= 127 /* char(N) that cannot be shorted */
)
);
#else
/*
* XXX
* As optimization, one want to make some char(X) type inline, which
* will save 2 bytes. However, postgres tupdesc is totally messed up
* the lenght of a (var)char(N) type (in typmod). It just get randomly
* set to the right thing or -1. It is really stupid, but it just
* took too much effort to fix everywhere.
*
* It is a shame. Disable this for now.
*/
return attr->attlen < 0;
#endif
}
/* Create columns binding, depends on islarge, using 2 or 4 bytes for offset_len */
static void create_col_bind(MemTupleBindingCols *colbind, bool islarge, TupleDesc tupdesc, int col_align)
{
int i = 0;
int physical_col = 0;
int pass = 0;
uint32 cur_offset = (col_align == 8) ? 8 : 4;
uint32 null_save_entries = compute_null_save_entries(tupdesc->natts);
/* alloc null save entries. Zero it */
colbind->null_saves = (short *) palloc0(sizeof(short) * null_save_entries);
colbind->null_saves_aligned = (short *) palloc0(sizeof(short) * null_save_entries);
colbind->has_null_saves_alignment_mismatch = false;
colbind->has_dropped_attr_alignment_mismatch = false;
/* alloc bindings, no need to zero because we will fill them out */
colbind->bindings = (MemTupleAttrBinding *) palloc(sizeof(MemTupleAttrBinding) * tupdesc->natts);
/*
* The length of each binding is determined according to the alignment
* of the physically following binding. Use this pointer to keep track
* of the previously processed binding.
*/
MemTupleAttrBinding *previous_bind = NULL;
/*
* First pass, do 8 bytes aligned, native type.
* Sencond pass, do 4 bytes aligned, native type.
* Third pass, do 2 bytes aligned, native type.
* Finall, do 1 bytes aligned native type.
*
* depends on islarge, varlena types are either handled in the
* second pass (is large, varoffset using 4 bytes), or in the
* third pass (not large, varoffset using 2 bytes).
*/
for(pass =0; pass < 4; ++pass)
{
for(i=0; i<tupdesc->natts; ++i)
{
Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
MemTupleAttrBinding *bind = &colbind->bindings[i];
if(pass == 0 && attr->attlen > 0 && attr->attalign == 'd')
{
bind->offset = att_align_nominal(cur_offset, attr->attalign);
bind->len = attr->attlen;
add_null_save(colbind->null_saves, physical_col, attr->attlen);
if (physical_col)
{
/* Set the aligned length of the previous binding according to current alignment. */
if (add_null_save_aligned(previous_bind, colbind->null_saves_aligned, physical_col - 1, 'd'))
{
colbind->has_null_saves_alignment_mismatch = true;
if (attr->attisdropped)
{
colbind->has_dropped_attr_alignment_mismatch = true;
}
}
}
bind->flag = attr->attbyval ? MTB_ByVal_Native : MTB_ByVal_Ptr;
bind->null_byte = physical_col >> 3;
bind->null_mask = 1 << (physical_col-(bind->null_byte << 3));
physical_col += 1;
cur_offset = bind->offset + bind->len;
previous_bind = bind;
}
else if (pass == 1 &&( (attr->attlen > 0 && attr->attalign == 'i')
|| ( islarge && att_bind_as_varoffset(attr))
)
)
{
bind->offset = att_align_nominal(cur_offset, 'i');
bind->len = attr->attlen > 0 ? attr->attlen : 4;
add_null_save(colbind->null_saves, physical_col, bind->len);
if (physical_col)
{
/* Set the aligned length of the previous binding according to current alignment. */
if (add_null_save_aligned(previous_bind, colbind->null_saves_aligned, physical_col - 1, 'i'))
{
colbind->has_null_saves_alignment_mismatch = true;
if (attr->attisdropped)
{
colbind->has_dropped_attr_alignment_mismatch = true;
}
}
}
if(attr->attlen > 0)
bind->flag = attr->attbyval ? MTB_ByVal_Native : MTB_ByVal_Ptr;
else if(attr->attlen == -1)
bind->flag = MTB_ByRef;
else
{
Assert(attr->attlen == -2);
bind->flag = MTB_ByRef_CStr;
}
bind->null_byte = physical_col >> 3;
bind->null_mask = 1 << (physical_col-(bind->null_byte << 3));
physical_col += 1;
cur_offset = bind->offset + bind->len;
previous_bind = bind;
}
else if (pass == 2 && ( (attr->attlen > 0 && attr->attalign == 's')
|| ( !islarge && att_bind_as_varoffset(attr))
)
)
{
bind->offset = att_align_nominal(cur_offset, 's');
bind->len = attr->attlen > 0 ? attr->attlen : 2;
add_null_save(colbind->null_saves, physical_col, bind->len);
if (physical_col)
{
/* Set the aligned length of the previous binding according to current alignment. */
if (add_null_save_aligned(previous_bind, colbind->null_saves_aligned, physical_col - 1, 's'))
{
colbind->has_null_saves_alignment_mismatch = true;
if (attr->attisdropped)
{
colbind->has_dropped_attr_alignment_mismatch = true;
}
}
}
if(attr->attlen > 0)
bind->flag = attr->attbyval ? MTB_ByVal_Native : MTB_ByVal_Ptr;
else if(attr->attlen == -1)
bind->flag = MTB_ByRef;
else
{
Assert(attr->attlen == -2);
bind->flag = MTB_ByRef_CStr;
}
bind->null_byte = physical_col >> 3;
bind->null_mask = 1 << (physical_col-(bind->null_byte << 3));
physical_col += 1;
cur_offset = bind->offset + bind->len;
previous_bind = bind;
}
else if (pass == 3 && (
(attr->attlen > 0 && attr->attalign == 'c')
|| (attr->attlen < 0 && !att_bind_as_varoffset(attr))
)
)
{
bind->offset = att_align_nominal(cur_offset, 'c');
#ifdef MEMTUPLE_INLINE_CHARTYPE
/* Inline CHAR(N) disabled. See att_bind_as_varoffset */
bind->len = attr->attlen > 0 ? attr->attlen : (attr->atttypmod - 3);
#else
bind->len = attr->attlen;
#endif
add_null_save(colbind->null_saves, physical_col, 1);
if (physical_col)
{
/* Set the aligned length of the previous binding according to current alignment. */
if (add_null_save_aligned(previous_bind, colbind->null_saves_aligned, physical_col - 1, 'c'))
{
colbind->has_null_saves_alignment_mismatch = true;
if (attr->attisdropped)
{
colbind->has_dropped_attr_alignment_mismatch = true;
}
}
}
if(attr->attlen > 0 && attr->attbyval)
bind->flag = MTB_ByVal_Native;
else
bind->flag = MTB_ByVal_Ptr;
bind->null_byte = physical_col >> 3;
bind->null_mask = 1 << (physical_col-(bind->null_byte << 3));
physical_col += 1;
cur_offset = bind->offset + bind->len;
previous_bind = bind;
}
}
}
if (physical_col)
{
/* No extra alignment required for the last binding */
add_null_save_aligned(previous_bind, colbind->null_saves_aligned, physical_col - 1, 'c');
}
if (!colbind->has_null_saves_alignment_mismatch)
{
pfree(colbind->null_saves);
colbind->null_saves = NULL;
}
#ifdef USE_DEBUG_ASSERT
for(i=0; i<tupdesc->natts; ++i)
{
MemTupleAttrBinding *bind = &colbind->bindings[i];
Assert(bind->offset[i] != 0);
}
#endif
if(tupdesc->natts != 0)
colbind->var_start = cur_offset;
else
colbind->var_start = 8;
Assert(tupdesc->natts == physical_col);
}
/* Create a memtuple binding from the tupdesc. Note we store
* a ref to the tupdesc in the binding, so we assumed the life
* span of the tupdesc is no shorter than the binding.
*/
MemTupleBinding *create_memtuple_binding(TupleDesc tupdesc)
{
MemTupleBinding *pbind = (MemTupleBinding *) palloc(sizeof(MemTupleBinding));
int i;
pbind->tupdesc = tupdesc;
pbind->column_align = 4;
for(i = 0; i < tupdesc->natts; ++i)
{
Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
if (attr->attlen > 0 && attr->attalign == 'd')
pbind->column_align = 8;
}
pbind->null_bitmap_extra_size = compute_null_bitmap_extra_size(tupdesc, pbind->column_align);
create_col_bind(&pbind->bind, false, tupdesc, pbind->column_align);
create_col_bind(&pbind->large_bind, true, tupdesc, pbind->column_align);
return pbind;
}
static uint32
compute_memtuple_size_using_bind(Datum *values,
bool *isnull,
int nullbit_extra,
int first_null_idx,
uint32 *nullsaves,
MemTupleBindingCols *colbind,
TupleDesc tupdesc)
{
uint32 data_length = colbind->var_start;
int i;
*nullsaves = 0;
if (first_null_idx < tupdesc->natts)
{
data_length += nullbit_extra;
for(i = first_null_idx; i < tupdesc->natts; ++i)
{
Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
MemTupleAttrBinding *bind = &colbind->bindings[i];
if (isnull[i] || attr->attisdropped)
{
int len;
Assert(bind->len >= 0);
Assert(bind->len_aligned >= 0);
Assert(bind->len_aligned >= bind->len);
len = bind->len_aligned;
*nullsaves += len;
data_length -= len;
}
}
}
for(i = 0; i < tupdesc->natts; ++i)
{
MemTupleAttrBinding *bind = &colbind->bindings[i];
Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
if (isnull[i] || attr->attisdropped)
continue;
if (bind->flag == MTB_ByVal_Native || bind->flag == MTB_ByVal_Ptr)
continue;
/* Varlen stuff */
/* We plan to convert to short varlena even if it is not currently */
if (bind->flag == MTB_ByRef &&
attr->attstorage != 'p' &&
value_type_could_short(DatumGetPointer(values[i]), attr->atttypid))
{
data_length += VARSIZE_ANY_EXHDR(DatumGetPointer(values[i])) + VARHDRSZ_SHORT;
}
else if (bind->flag == MTB_ByRef &&
VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(values[i])))
{
/*
* we want to flatten the expanded value so that the constructed
* tuple doesn't depend on it
*/
data_length = att_align_nominal(data_length, attr->attalign);
data_length += EOH_get_flat_size(DatumGetEOHP(values[i]));
}
else
{
data_length = att_align_nominal(data_length, attr->attalign);
data_length = att_addlength_datum(data_length, attr->attlen, values[i]);
}
}
return MEMTUP_ALIGN(data_length);
}
/*
* Compute the memtuple size.
*
* Returns the size. *nullsaves is an output parameter. It is set to the
* length that is "saved" by null attributes; it should of no interest to
* the caller, except that if you call memtuple_form_to(), you need to pass
* it along as an argument. Similarly *has_nulls is an output parameter that
* is set to indicate whether any of the attributes were nulls.
*/
uint32
compute_memtuple_size(MemTupleBinding *pbind, Datum *values, bool *isnull,
uint32 *nullsaves, bool *has_nulls)
{
int first_null_idx;
uint32 ret_len;
int i;
/*
* Check for nulls. Dropped attributes are also treated as NULLs.
*/
*has_nulls = false;
for (i = 0; i < pbind->tupdesc->natts; ++i)
{
Form_pg_attribute attr = TupleDescAttr(pbind->tupdesc, i);
/* treat dropped attibutes as null */
if (isnull[i] || attr->attisdropped)
{
*has_nulls = true;
break;
}
}
first_null_idx = i;
ret_len = compute_memtuple_size_using_bind(values, isnull,
pbind->null_bitmap_extra_size,
first_null_idx, nullsaves,
&pbind->bind, pbind->tupdesc);
if(ret_len <= MEMTUPLE_LEN_FITSHORT)
return ret_len;
ret_len = compute_memtuple_size_using_bind(values, isnull,
pbind->null_bitmap_extra_size,
first_null_idx, nullsaves,
&pbind->large_bind, pbind->tupdesc);
Assert(ret_len > MEMTUPLE_LEN_FITSHORT);
return ret_len;
}
static inline char* memtuple_get_attr_ptr(char *start, MemTupleAttrBinding *bind, short *null_saves, unsigned char *nullp)
{
int ns = 0;
if(nullp)
ns = compute_null_save(null_saves, nullp, bind->null_byte, bind->null_mask);
return start + bind->offset - ns;
}
static inline char* memtuple_get_attr_data_ptr(char *start, MemTupleAttrBinding *bind, short *null_saves, unsigned char* nullp)
{
if(bind->flag == MTB_ByVal_Native || bind->flag == MTB_ByVal_Ptr)
return memtuple_get_attr_ptr(start, bind, null_saves, nullp);
if(bind->len == 2)
return start + (*(uint16 *) memtuple_get_attr_ptr(start, bind, null_saves, nullp));
Assert(bind->len == 4);
return start + (*(uint32 *) memtuple_get_attr_ptr(start, bind, null_saves, nullp));
}
static inline unsigned char *memtuple_get_nullp(MemTuple mtup, MemTupleBinding *pbind)
{
return mtup->PRIVATE_mt_bits;
}
/*
* Form a memtuple from values and isnull. Returns a palloc'd tuple.
*
* This corresponds to heap_form_tuple() for HeapTuples.
*/
MemTuple
memtuple_form(MemTupleBinding *pbind, Datum *values, bool *isnull)
{
uint32 len;
uint32 null_save_len;
bool has_nulls;
MemTuple result;
len = compute_memtuple_size(pbind, values, isnull, &null_save_len, &has_nulls);
result = palloc(len);
memtuple_form_to(pbind, values, isnull, len, null_save_len, has_nulls,
result);
return result;
}
/*
* Form a memtuple from values and isnull, to a prespecified buffer
*
* You must call compute_memtuple_size() before this, and verify that
* the buffer is large enough. Pass through the 'len', 'null_save_len'
* and 'hasnull' values that compute_memtuple_size() returned.
*
* The tuple is written to 'mtup', which must be large enough to hold
* 'len' bytes.
*/
void
memtuple_form_to(MemTupleBinding *pbind,
Datum *values,
bool *isnull,
uint32 len,
uint32 null_save_len,
bool hasnull,
MemTuple mtup)
{
bool hasext = false;
int i;
unsigned char *nullp = NULL;
char *start;
char *varlen_start;
MemTupleBindingCols *colbind;
colbind = (len <= MEMTUPLE_LEN_FITSHORT) ? &pbind->bind : &pbind->large_bind;
memset(mtup, 0, len);
/* Set mtlen, this set the lead bit, len, and clears hasnull bit
* because the len returned from compute size is always max aligned
*/
Assert(len == MEMTUP_ALIGN(len));
memtuple_set_mtlen(mtup, (len | MEMTUP_LEAD_BIT));
if(len > MEMTUPLE_LEN_FITSHORT)
memtuple_set_islarge(mtup);
if(hasnull)
nullp = memtuple_get_nullp(mtup, pbind);
start = (char *) mtup;
varlen_start = ((char *) mtup) + colbind->var_start - null_save_len;
if(hasnull)
{
memtuple_set_hasnull(mtup);
/* if null bitmap is more than 4 bytes, add needed space */
start += pbind->null_bitmap_extra_size;
varlen_start += pbind->null_bitmap_extra_size;
}
/* It is very important to setup the null bitmap first before we
* really put the values into place. Where is the value in the
* memtuple is determined by space saved from nulls, so the bitmap
* is used in the next loop.
* NOTE: We cannot set the bitmap in the next loop (even at very
* beginning of next loop), because physical col order is different
* from logical.
*/
if (hasnull)
{
for(i=0; i<pbind->tupdesc->natts; ++i)
{
Form_pg_attribute attr = TupleDescAttr(pbind->tupdesc, i);
if (isnull[i] || attr->attisdropped)
{
MemTupleAttrBinding *bind = &(colbind->bindings[i]);
Assert(hasnull);
nullp[bind->null_byte] |= bind->null_mask;
}
}
}
/* Null bitmap is set up correctly, we can put in values now */
for(i=0; i<pbind->tupdesc->natts; ++i)
{
Form_pg_attribute attr = TupleDescAttr(pbind->tupdesc, i);
MemTupleAttrBinding *bind = &(colbind->bindings[i]);
uint32 attr_len;
if(isnull[i] || attr->attisdropped)
continue;
Assert(bind->offset != 0);
short *null_saves = colbind->null_saves_aligned;
Assert(null_saves);
/* Not null */
switch(bind->flag)
{
case MTB_ByVal_Native:
store_att_byval(memtuple_get_attr_ptr(start, bind, null_saves, nullp),
values[i],
bind->len
);
break;
case MTB_ByVal_Ptr:
if(attr->atttypid != BPCHAROID)
memcpy(memtuple_get_attr_ptr(start, bind, null_saves, nullp),
DatumGetPointer(values[i]),
bind->len
);
else
{
if(VARATT_IS_SHORT(DatumGetPointer(values[i])))
{
attr_len = VARSIZE_SHORT(DatumGetPointer(values[i]));
Assert(attr_len <= bind->len);
memcpy(memtuple_get_attr_ptr(start, bind, null_saves, nullp),
DatumGetPointer(values[i]),
attr_len
);
}
else
{
char *p = memtuple_get_attr_ptr(start, bind, null_saves, nullp);
Assert(VARATT_CAN_MAKE_SHORT(DatumGetPointer(values[i])));
attr_len = VARSIZE(DatumGetPointer(values[i])) - VARHDRSZ + VARHDRSZ_SHORT;
Assert(attr_len <= bind->len);
*p = VARSIZE_TO_SHORT_D(values[i]);
memcpy(p+1, VARDATA(DatumGetPointer(values[i])), attr_len-1);
}
}
break;
case MTB_ByRef:
if(VARATT_IS_EXTERNAL(DatumGetPointer(values[i])))
{
varlen_start = (char *) att_align_nominal((long) varlen_start, attr->attalign);
if (VARATT_IS_EXTERNAL_EXPANDED(DatumGetPointer(values[i])))
{
ExpandedObjectHeader *eoh = DatumGetEOHP(values[i]);
attr_len = EOH_get_flat_size(eoh);
EOH_flatten_into(eoh, varlen_start, attr_len);
}
else
{
attr_len = VARSIZE_EXTERNAL(DatumGetPointer(values[i]));
Assert((varlen_start - (char *) mtup) + attr_len <= len);
memcpy(varlen_start, DatumGetPointer(values[i]), attr_len);
hasext = true;
}
}
else if(VARATT_IS_SHORT(DatumGetPointer(values[i])))
{
attr_len = VARSIZE_SHORT(DatumGetPointer(values[i]));
Assert((varlen_start - (char *) mtup) + attr_len <= len);
memcpy(varlen_start, DatumGetPointer(values[i]), attr_len);
}
else if(attr->attstorage != 'p' &&
value_type_could_short(DatumGetPointer(values[i]), attr->atttypid))
{
attr_len = VARSIZE(DatumGetPointer(values[i])) - VARHDRSZ + VARHDRSZ_SHORT;
*varlen_start = VARSIZE_TO_SHORT_D(values[i]);
Assert((varlen_start - (char *) mtup) + attr_len <= len);
memcpy(varlen_start+1, VARDATA(DatumGetPointer(values[i])), attr_len-1);
}
else
{
/* Must be 4 byte header aligned varlena */
varlen_start = (char *) att_align_nominal((long) varlen_start, attr->attalign);
attr_len = VARSIZE(DatumGetPointer(values[i]));
Assert((varlen_start - (char *) mtup) + attr_len <= len);
memcpy(varlen_start, DatumGetPointer(values[i]), attr_len);
}
if(bind->len == 2)
*(uint16 *) memtuple_get_attr_ptr(start, bind, null_saves, nullp) = (uint16) (varlen_start - start);
else
{
Assert(bind->len == 4);
*(uint32 *) memtuple_get_attr_ptr(start, bind, null_saves, nullp) = (uint32) (varlen_start - start);
}
varlen_start += attr_len;
break;
case MTB_ByRef_CStr:
varlen_start = (char *) att_align_nominal((long) varlen_start, attr->attalign);
attr_len = strlen(DatumGetCString(values[i])) + 1;
Assert((varlen_start - (char *) mtup) + attr_len <= len);
memcpy(varlen_start, DatumGetPointer(values[i]), attr_len);
if(bind->len == 2)
*(uint16 *) memtuple_get_attr_ptr(start, bind, null_saves, nullp) = (uint16) (varlen_start - start);
else
{
Assert(bind->len == 4);
*(uint32 *) memtuple_get_attr_ptr(start, bind, null_saves, nullp) = (uint32) (varlen_start - start);
}
varlen_start += attr_len;
break;
default:
Assert(!"Not valid binding type");
break;
}
}
Assert((varlen_start - (char *) mtup) <= len);
if (hasext)
memtuple_set_hasext(mtup);
}
bool memtuple_attisnull(MemTuple mtup, MemTupleBinding *pbind, int attnum)
{
MemTupleBindingCols *colbind = memtuple_get_islarge(mtup) ? &pbind->large_bind : &pbind->bind;
unsigned char *nullp;
MemTupleAttrBinding *attrbind;
Assert(mtup && pbind && pbind->tupdesc);
Assert(attnum > 0);
/*
* This used to be an Assert. However, we follow the logic of
* heap_attisnull() and treat attnums > lastatt as NULL. This
* is currently used in ALTER ADD COLUMN NOT NULL.
*
* Unfortunately this also means that the caller needs to be
* extra careful passing in the correct attnum argument.
*/
if (attnum > (int) pbind->tupdesc->natts)
return true;
/*
* is there a NULL value in any of the attributes?
*/
if(!memtuple_get_hasnull(mtup))
return false;
nullp = memtuple_get_nullp(mtup, pbind);
attrbind = &(colbind->bindings[attnum - 1]);
return (nullp[attrbind->null_byte] & attrbind->null_mask);
}
static Datum memtuple_getattr_by_alignment(MemTuple mtup, MemTupleBinding *pbind, int attnum, bool *isnull, bool use_null_saves_aligned)
{
bool hasnull = memtuple_get_hasnull(mtup);
unsigned char *nullp = hasnull ? memtuple_get_nullp(mtup, pbind) : NULL;
char *start = (char *) mtup + (hasnull ? pbind->null_bitmap_extra_size : 0);
Datum ret;
MemTupleBindingCols *colbind = memtuple_get_islarge(mtup) ? &pbind->large_bind : &pbind->bind;
MemTupleAttrBinding *attrbind;
Assert(mtup && pbind && pbind->tupdesc);
Assert(attnum > 0 && attnum <= pbind->tupdesc->natts);
if(isnull)
*isnull = false;
/* input attnum is 1 based. Make it 0 based */
--attnum;
attrbind = &(colbind->bindings[attnum]);
/* null check */
if(hasnull && (nullp[attrbind->null_byte] & attrbind->null_mask))
{
if(isnull)
*isnull = true;
return 0;
}
short *null_saves = (use_null_saves_aligned ? colbind->null_saves_aligned : colbind->null_saves);
Assert(null_saves);
ret = fetchatt(TupleDescAttr(pbind->tupdesc, attnum), memtuple_get_attr_data_ptr(start, attrbind, null_saves, nullp));
return ret;
}
Datum memtuple_getattr(MemTuple mtup, MemTupleBinding *pbind, int attnum, bool *isnull)
{
return memtuple_getattr_by_alignment(mtup, pbind, attnum, isnull, true /* aligned */);
}
/*
* Return a palloc'd copy of 'mtup'.
*
* This corresponds to heap_copytuple() for HeapTuples.
*/
MemTuple
memtuple_copy(MemTuple mtup)
{
MemTuple dest;
uint32 len = memtuple_get_size(mtup);
dest = (MemTuple) palloc(len);
memcpy((char *) dest, (char *) mtup, len);
return dest;
}
static void memtuple_get_values(MemTuple mtup, MemTupleBinding *pbind, Datum *datum, bool *isnull, bool use_null_saves_aligned)
{
int i;
for(i=0; i<pbind->tupdesc->natts; ++i)
datum[i] = memtuple_getattr_by_alignment(mtup, pbind, i+1, &isnull[i], use_null_saves_aligned);
}
void memtuple_deform(MemTuple mtup, MemTupleBinding *pbind, Datum *datum, bool *isnull)
{
memtuple_get_values(mtup, pbind, datum, isnull, true /* aligned */);
}
/*
* Deform a memtuple with old binding alignment.
*
* We assume that the 'mtup' was created using null_saves, where the
* binding length is not aligned to the following binding's alignment. In
* this case, we create an "upgraded" clone using null_saves_aligned, which
* uses properly aligned binding length.
*/
void
memtuple_deform_misaligned(MemTuple mtup, MemTupleBinding *pbind,
Datum *datum, bool *isnull)
{
memtuple_get_values(mtup, pbind, datum, isnull, false /* aligned */);
}
bool MemTupleHasExternal(MemTuple mtup, MemTupleBinding *pbind)
{
MemTupleBindingCols *colbind = memtuple_get_islarge(mtup) ? &pbind->large_bind : &pbind->bind;
int i;
for(i=0; i<pbind->tupdesc->natts; ++i)
{
MemTupleAttrBinding *attrbind = &(colbind->bindings[i]);
if(attrbind->flag == MTB_ByRef)
{
bool isnull;
Datum d = memtuple_getattr(mtup, pbind, i+1, &isnull);
if(!isnull)
{
if(VARATT_IS_EXTERNAL(DatumGetPointer(d)))
return true;
}
}
}
return false;
}
/*
* Check if a memtuple has null attributes with bindings that can possibly be misaligned.
*
* MPP-7372: This is an issue only for memtuples stored in AO tables before applying
* the fix that enforces the proper alignment of the binding length.
*/
bool memtuple_has_misaligned_attribute(MemTuple mtup, MemTupleBinding *pbind)
{
Assert(mtup);
Assert(pbind);
/* Check if the memtuple has an attribute with mismatching alignment and length */
if (!(pbind->bind.has_null_saves_alignment_mismatch))
{
return false;
}
/*
* Check if the memtuple has a dropped attribute with mismatching alignment and length.
* Dropped attributes are treated as null.
*/
if (pbind->bind.has_dropped_attr_alignment_mismatch)
{
return true;
}
/* Check if the memtuple has no null values */
if (!(memtuple_get_hasnull(mtup)))
{
return false;
}
unsigned char *nullp = memtuple_get_nullp(mtup, pbind);
int attr_idx = 0;
/*
* Check if an attribute with mismatching alignment and length is null.
*/
for (attr_idx = 0; attr_idx < pbind->tupdesc->natts; attr_idx++)
{
MemTupleAttrBinding *bind = &pbind->bind.bindings[attr_idx];
if (bind->len != bind->len_aligned &&
(nullp[bind->null_byte] & bind->null_mask))
{
return true;
}
}
return false;
}
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