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Code and docs review for pg_column_size() patch.

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This commit is contained in:
Tom Lane
2005-08-02 16:11:57 +00:00
parent f023fc6689
commit 0001e98d54
4 changed files with 130 additions and 108 deletions
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76
src/backend/access/heap/tuptoaster.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.50 2005/07/06 19:02:52 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.51 2005/08/02 16:11:57 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -268,6 +268,38 @@ toast_raw_datum_size(Datum value)
return result;
}
/* ----------
* toast_datum_size
*
* Return the physical storage size (possibly compressed) of a varlena datum
* ----------
*/
Size
toast_datum_size(Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Size result;
if (VARATT_IS_EXTERNAL(attr))
{
/*
* Attribute is stored externally - return the extsize whether
* compressed or not. We do not count the size of the toast
* pointer ... should we?
*/
result = attr->va_content.va_external.va_extsize;
}
else
{
/*
* Attribute is stored inline either compressed or not, just
* calculate the size of the datum in either case.
*/
result = VARSIZE(attr);
}
return result;
}
/* ----------
* toast_delete -
@@ -1436,45 +1468,3 @@ toast_fetch_datum_slice(varattrib *attr, int32 sliceoffset, int32 length)
return result;
}
/* ----------
* toast_datum_size
*
* Show the (possibly compressed) size of a datum
* ----------
*/
Size
toast_datum_size(Datum value)
{
varattrib *attr = (varattrib *) DatumGetPointer(value);
Size result;
if (VARATT_IS_EXTERNAL(attr))
{
/*
* Attribute is stored externally - If it is compressed too,
* then we need to get the external datum and calculate its size,
* otherwise we just use the external rawsize.
*/
if (VARATT_IS_COMPRESSED(attr))
{
varattrib *attrext = toast_fetch_datum(attr);
result = VARSIZE(attrext);
pfree(attrext);
}
else
result = attr->va_content.va_external.va_rawsize;
}
else
{
/*
* Attribute is stored inline either compressed or not, just
* calculate the size of the datum in either case.
*/
result = VARSIZE(attr);
}
return result;
}

49
src/backend/utils/adt/varlena.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.130 2005/07/29 03:17:55 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.131 2005/08/02 16:11:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2574,38 +2574,49 @@ md5_bytea(PG_FUNCTION_ARGS)
}
/*
* Return the length of a datum, possibly compressed
* Return the size of a datum, possibly compressed
*
* Works on any data type
*/
Datum
pg_column_size(PG_FUNCTION_ARGS)
{
Datum value = PG_GETARG_DATUM(0);
int result;
Datum value = PG_GETARG_DATUM(0);
int32 result;
int typlen;
/* fn_extra stores the fixed column length, or -1 for varlena. */
if (fcinfo->flinfo->fn_extra == NULL) /* first call? */
/* On first call, get the input type's typlen, and save at *fn_extra */
if (fcinfo->flinfo->fn_extra == NULL)
{
/* On the first call lookup the datatype of the supplied argument */
Oid argtypeid = get_fn_expr_argtype(fcinfo->flinfo, 0);
int typlen = get_typlen(argtypeid);
/* Lookup the datatype of the supplied argument */
Oid argtypeid = get_fn_expr_argtype(fcinfo->flinfo, 0);
if (typlen == 0)
{
/* Oid not in pg_type, should never happen. */
typlen = get_typlen(argtypeid);
if (typlen == 0) /* should not happen */
elog(ERROR, "cache lookup failed for type %u", argtypeid);
}
fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
sizeof(int));
*(int *)fcinfo->flinfo->fn_extra = typlen;
*((int *) fcinfo->flinfo->fn_extra) = typlen;
}
else
typlen = *((int *) fcinfo->flinfo->fn_extra);
if (*(int *)fcinfo->flinfo->fn_extra != -1)
PG_RETURN_INT32(*(int *)fcinfo->flinfo->fn_extra);
if (typlen == -1)
{
/* varlena type, possibly toasted */
result = toast_datum_size(value);
}
else if (typlen == -2)
{
/* cstring */
result = strlen(DatumGetCString(value)) + 1;
}
else
{
result = toast_datum_size(value) - VARHDRSZ;
PG_RETURN_INT32(result);
/* ordinary fixed-width type */
result = typlen;
}
PG_RETURN_INT32(result);
}

4
src/include/catalog/pg_proc.h
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.379 2005/07/29 14:47:01 momjian Exp $
* $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.380 2005/08/02 16:11:57 tgl Exp $
*
* NOTES
* The script catalog/genbki.sh reads this file and generates .bki
@@ -3701,7 +3701,7 @@ DATA(insert OID = 2560 ( pg_postmaster_start_time PGNSP PGUID 12 f f t f s 0 11
DESCR("postmaster start time");
/* Column storage size */
DATA(insert OID = 1269 ( pg_column_size PGNSP PGUID 12 f f t f i 1 23 "2276" _null_ _null_ _null_ pg_column_size - _null_ ));
DATA(insert OID = 1269 ( pg_column_size PGNSP PGUID 12 f f t f s 1 23 "2276" _null_ _null_ _null_ pg_column_size - _null_ ));
DESCR("bytes required to store the value, perhaps with compression");
/* new functions for Y-direction rtree opclasses */