mariadb/include/row0ext.h
marko 31e200da0b branches/zip: Add clarifying comments that the clustered index record must
be protected from being deleted while any externally stored columns are
being fetched.

row_ext_create(),
row_upd_index_replace_new_col_vals(),
row_upd_index_replace_new_col_vals_index_pos(),
row_sel_sec_rec_is_for_blob(),
row_sel_sec_rec_is_for_clust_rec(): Note that the clustered
index record must be covered by a lock or a page latch.

row_upd_sec_index_entry(), row_upd_clust_rec_by_insert(),
row_undo_mod_upd_exist_sec(): Note that these functions probably
do not obtain an appropriate lock on the clustered index record
before fetching any externally stored columns.
2008-01-11 12:19:59 +00:00

82 lines
2.7 KiB
C

/******************************************************
Caching of externally stored column prefixes
(c) 2006 Innobase Oy
Created September 2006 Marko Makela
*******************************************************/
#ifndef row0ext_h
#define row0ext_h
#include "univ.i"
#include "row0types.h"
#include "data0types.h"
#include "mem0mem.h"
/************************************************************************
Creates a cache of column prefixes of externally stored columns. */
row_ext_t*
row_ext_create(
/*===========*/
/* out,own: column prefix cache */
ulint n_ext, /* in: number of externally stored columns */
const ulint* ext, /* in: col_no's of externally stored columns
in the InnoDB table object, as reported by
dict_col_get_no(); NOT relative to the records
in the clustered index */
const dtuple_t* tuple, /* in: data tuple containing the field
references of the externally stored
columns; must be indexed by col_no;
the clustered index record must be
covered by a lock or a page latch
to prevent deletion (rollback or purge). */
ulint zip_size,/* compressed page size in bytes, or 0 */
mem_heap_t* heap); /* in: heap where created */
/************************************************************************
Looks up a column prefix of an externally stored column. */
UNIV_INLINE
const byte*
row_ext_lookup_ith(
/*===============*/
/* out: column prefix, or NULL if
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
const row_ext_t* ext, /* in/out: column prefix cache */
ulint i, /* in: index of ext->ext[] */
ulint* len); /* out: length of prefix, in bytes,
at most REC_MAX_INDEX_COL_LEN */
/************************************************************************
Looks up a column prefix of an externally stored column. */
UNIV_INLINE
const byte*
row_ext_lookup(
/*===========*/
/* out: column prefix, or NULL if
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
const row_ext_t* ext, /* in: column prefix cache */
ulint col, /* in: column number in the InnoDB
table object, as reported by
dict_col_get_no(); NOT relative to the
records in the clustered index */
ulint* len); /* out: length of prefix, in bytes,
at most REC_MAX_INDEX_COL_LEN */
/* Prefixes of externally stored columns */
struct row_ext_struct{
ulint n_ext; /* number of externally stored columns */
const ulint* ext; /* col_no's of externally stored columns */
byte* buf; /* backing store of the column prefix cache */
ulint len[1]; /* prefix lengths; 0 if not cached */
};
#ifndef UNIV_NONINL
#include "row0ext.ic"
#endif
#endif