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Fix for bug#20648 We introduce a new field method for knowing "real size", and we now in archive null unused bits of a row to null before writing.

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sql/field.cc:
  data_length for field needs to be calculated directly.
sql/field.h:
  The new method data_length() returns the "real" length of the field.
sql/ha_archive.cc:
  Before a write_row() archive nulls space beyond the size of the row in varchars to make sure that compression only sees NULL.
This commit is contained in:
unknown
2006-08-14 03:29:17 -07:00
parent 6071b686b1
commit ba8be73946
3 changed files with 33 additions and 0 deletions
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5
sql/field.cc
View File

@@ -6412,6 +6412,11 @@ void Field_varstring::sql_type(String &res) const
}
uint Field_varstring::data_length(const char *from)
{
return length_bytes == 1 ? (uint) (uchar) *ptr : uint2korr(ptr);
}
/*
Functions to create a packed row.
Here the number of length bytes are depending on the given max_length

6
sql/field.h
View File

@@ -144,6 +144,11 @@ public:
table, which is located on disk).
*/
virtual uint32 pack_length_in_rec() const { return pack_length(); }
/*
data_length() return the "real size" of the data in memory.
*/
virtual uint32 data_length(const char *from) { return pack_length(); }
virtual uint32 sort_length() const { return pack_length(); }
virtual void reset(void) { bzero(ptr,pack_length()); }
virtual void reset_fields() {}
@@ -1102,6 +1107,7 @@ public:
int key_cmp(const byte *str, uint length);
uint packed_col_length(const char *to, uint length);
uint max_packed_col_length(uint max_length);
uint data_length(const char *from);
uint size_of() const { return sizeof(*this); }
enum_field_types real_type() const { return MYSQL_TYPE_VARCHAR; }
bool has_charset(void) const

22
sql/ha_archive.cc
View File

@@ -710,6 +710,28 @@ int ha_archive::write_row(byte *buf)
if (init_archive_writer())
DBUG_RETURN(HA_ERR_CRASHED_ON_USAGE);
/*
Varchar structures are constant in size but are not cleaned up request
to request. The following sets all unused space to null to improve
compression.
*/
for (Field **field=table->field ; *field ; field++)
{
DBUG_PRINT("archive",("Pack is %d\n", (*field)->pack_length()));
DBUG_PRINT("archive",("MyPack is %d\n", (*field)->data_length((char*) buf + (*field)->offset())));
if ((*field)->real_type() == MYSQL_TYPE_VARCHAR)
{
uint actual_length= (*field)->data_length((char*) buf + (*field)->offset());
uint offset= (*field)->offset() + actual_length +
(actual_length > 255 ? 2 : 1);
DBUG_PRINT("archive",("Offset is %d -> %d\n", actual_length, offset));
/*
if ((*field)->pack_length() + (*field)->offset() != offset)
bzero(buf + offset, (size_t)((*field)->pack_length() + (actual_length > 255 ? 2 : 1) - (*field)->data_length));
*/
}
}
share->rows_recorded++;
rc= real_write_row(buf, share->archive_write);
pthread_mutex_unlock(&share->mutex);