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branches/zip: In purge, avoid dereferencing unset BLOB pointers of freshly 

inserted, uncommitted clustered index records when determining if a
secondary index record that contains a column prefix of an externally
stored column is referencing the clustered index record.

field_ref_zero[]: A BLOB pointer full of zero, for use in comparisons.

btr_copy_externally_stored_field_prefix(): Assert that the BLOB pointer is set.

row_ext_lookup_ith(), row_ext_lookup(), row_ext_lookup_low(): Document
that field_ref_zero is returned when the BLOB cannot be fetched.

row_ext_lookup_low(): Return field_ref_zero and *len = 0 when the
BLOB pointer is unset.

row_build_index_entry(): Return NULL when a needed BLOB pointer cannot
be dereferenced (row_ext_lookup returns field_ref_zero).  Check the
return value for NULL in callers.

row_vers_impl_x_locked_off_kernel(): Avoid comparisons when
row_build_index_entry() returns NULL.

row_vers_old_has_index_entry(): Ignore records for which
row_build_index_entry() returns NULL.  The entry should never be NULL
in rollback, but it may be NULL in purge.

row_merge_buf_add(): Assert that row_ext_lookup() does not return
field_ref_zero.  The table will be locked during index creation.
pull/374/head
marko 18 years ago
parent
110781a39e
commit
06299dddd4
13 changed files with 95 additions and 20 deletions
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  1. 7
      btr/btr0cur.c
  2. 5
      include/btr0cur.h
  3. 8
      include/row0ext.h
  4. 12
      include/row0ext.ic
  5. 5
      include/row0row.h
  6. 13
      row/row0ext.c
  7. 2
      row/row0merge.c
  8. 4
      row/row0purge.c
  9. 8
      row/row0row.c
  10. 2
      row/row0uins.c
  11. 6
      row/row0umod.c
  12. 2
      row/row0upd.c
  13. 41
      row/row0vers.c

7
btr/btr0cur.c
View File

@ -68,6 +68,11 @@ this many index pages */
/*--------------------------------------*/
#define BTR_BLOB_HDR_SIZE 8
/* A BLOB field reference full of zero, for use in assertions and tests.
Initially, BLOB field references are set to zero, in
dtuple_convert_big_rec(). */
const byte field_ref_zero[BTR_EXTERN_FIELD_REF_SIZE];
/***********************************************************************
Marks all extern fields in a record as owned by the record. This function
should be called if the delete mark of a record is removed: a not delete
@ -4528,6 +4533,8 @@ btr_copy_externally_stored_field_prefix(
memcpy(buf, data, local_len);
data += local_len;
ut_a(memcmp(data, field_ref_zero, BTR_EXTERN_FIELD_REF_SIZE));
space_id = mach_read_from_4(data + BTR_EXTERN_SPACE_ID);
page_no = mach_read_from_4(data + BTR_EXTERN_PAGE_NO);

5
include/btr0cur.h
View File

@ -712,6 +712,11 @@ extern ulint btr_cur_n_sea;
extern ulint btr_cur_n_non_sea_old;
extern ulint btr_cur_n_sea_old;
/* A BLOB field reference full of zero, for use in assertions and tests.
Initially, BLOB field references are set to zero, in
dtuple_convert_big_rec(). */
extern const byte field_ref_zero[BTR_EXTERN_FIELD_REF_SIZE];
#ifndef UNIV_NONINL
#include "btr0cur.ic"
#endif

8
include/row0ext.h
View File

@ -35,7 +35,9 @@ byte*
row_ext_lookup_ith(
/*===============*/
/* out: column prefix, or NULL if
the column is not stored externally */
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
row_ext_t* ext, /* in/out: column prefix cache */
ulint i, /* in: ith element of ext */
const byte* field, /* in: locally stored part of the column */
@ -49,7 +51,9 @@ byte*
row_ext_lookup(
/*===========*/
/* out: column prefix, or NULL if
the column is not stored externally */
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
row_ext_t* ext, /* in/out: column prefix cache */
ulint col, /* in: column number in the InnoDB
table object, as reported by

12
include/row0ext.ic
View File

@ -14,7 +14,9 @@ Looks up and caches a column prefix of an externally stored column. */
byte*
row_ext_lookup_low(
/*===============*/
/* out: column prefix */
/* out: column prefix, or
pointer to field_ref_zero
if the BLOB pointer is unset */
row_ext_t* ext, /* in/out: column prefix cache */
ulint i, /* in: index of ext->ext[] */
const byte* field, /* in: locally stored part of the column */
@ -60,7 +62,9 @@ byte*
row_ext_lookup_ith(
/*===============*/
/* out: column prefix, or NULL if
the column is not stored externally */
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
row_ext_t* ext, /* in/out: column prefix cache */
ulint i, /* in: index of ext->ext[] */
const byte* field, /* in: locally stored part of the column */
@ -91,7 +95,9 @@ byte*
row_ext_lookup(
/*===========*/
/* out: column prefix, or NULL if
the column is not stored externally */
the column is not stored externally,
or pointer to field_ref_zero
if the BLOB pointer is unset */
row_ext_t* ext, /* in/out: column prefix cache */
ulint col, /* in: column number in the InnoDB
table object, as reported by

5
include/row0row.h
View File

@ -59,7 +59,10 @@ dtuple_t*
row_build_index_entry(
/*==================*/
/* out: index entry which should be
inserted or purged */
inserted or purged, or NULL if the
externally stored columns in the
clustered index record are unavailable
and ext != NULL */
const dtuple_t* row, /* in: row which should be
inserted or purged */
row_ext_t* ext, /* in: externally stored column prefixes,

13
row/row0ext.c
View File

@ -20,7 +20,9 @@ Looks up and caches a column prefix of an externally stored column. */
byte*
row_ext_lookup_low(
/*===============*/
/* out: column prefix */
/* out: column prefix, or
pointer to field_ref_zero
if the BLOB pointer is unset */
row_ext_t* ext, /* in/out: column prefix cache */
ulint i, /* in: index of ext->ext[] */
const byte* field, /* in: locally stored part of the column */
@ -31,6 +33,15 @@ row_ext_lookup_low(
byte* buf = ext->buf + i * REC_MAX_INDEX_COL_LEN;
ut_ad(i < ext->n_ext);
ut_a(f_len >= BTR_EXTERN_FIELD_REF_SIZE);
if (UNIV_UNLIKELY(!memcmp(field_ref_zero,
field + f_len - BTR_EXTERN_FIELD_REF_SIZE,
BTR_EXTERN_FIELD_REF_SIZE))) {
/* The BLOB pointer is not set: we cannot fetch it */
*len = 0;
return((byte*) field_ref_zero);
}
*len = ext->len[i] = btr_copy_externally_stored_field_prefix(
buf,

2
row/row0merge.c
View File

@ -281,6 +281,7 @@ row_merge_buf_add(
byte* buf = row_ext_lookup(ext, col_no,
field_data, len, &len);
if (UNIV_LIKELY_NULL(buf)) {
ut_a(buf != field_ref_zero);
if (i < dict_index_get_n_unique(index)) {
dfield_set_data(field, buf, len);
} else {
@ -292,6 +293,7 @@ row_merge_buf_add(
byte* buf = row_ext_lookup(ext, col_no,
field_data, len, &len);
if (UNIV_LIKELY_NULL(buf)) {
ut_a(buf != field_ref_zero);
dfield_set_data(field, buf, len);
}
}

4
row/row0purge.c
View File

@ -340,7 +340,7 @@ row_purge_del_mark(
entry = row_build_index_entry(node->row,
node->ext,
index, heap);
ut_a(entry);
row_purge_remove_sec_if_poss(node, index, entry);
node->index = dict_table_get_next_index(node->index);
@ -387,7 +387,7 @@ row_purge_upd_exist_or_extern(
/* Build the older version of the index entry */
entry = row_build_index_entry(node->row, node->ext,
index, heap);
ut_a(entry);
row_purge_remove_sec_if_poss(node, index, entry);
}

8
row/row0row.c
View File

@ -67,7 +67,10 @@ dtuple_t*
row_build_index_entry(
/*==================*/
/* out: index entry which should be
inserted or purged */
inserted or purged, or NULL if the
externally stored columns in the
clustered index record are unavailable
and ext != NULL */
const dtuple_t* row, /* in: row which should be
inserted or purged */
row_ext_t* ext, /* in: externally stored column prefixes,
@ -122,6 +125,9 @@ row_build_index_entry(
dfield_get_data(dfield),
len, &len);
if (UNIV_LIKELY_NULL(buf)) {
if (UNIV_UNLIKELY(buf == field_ref_zero)) {
return(NULL);
}
dfield_set_data(dfield, buf, len);
}
}

2
row/row0uins.c
View File

@ -283,7 +283,7 @@ row_undo_ins(
entry = row_build_index_entry(node->row, node->ext,
node->index, node->heap);
ut_a(entry);
err = row_undo_ins_remove_sec(node->index, entry);
if (err != DB_SUCCESS) {

6
row/row0umod.c
View File

@ -515,7 +515,7 @@ row_undo_mod_upd_del_sec(
entry = row_build_index_entry(node->row, node->ext,
index, heap);
ut_a(entry);
err = row_undo_mod_del_mark_or_remove_sec(node, thr, index,
entry);
if (err != DB_SUCCESS) {
@ -555,7 +555,7 @@ row_undo_mod_del_mark_sec(
entry = row_build_index_entry(node->row, node->ext,
index, heap);
ut_a(entry);
err = row_undo_mod_del_unmark_sec_and_undo_update(
BTR_MODIFY_LEAF, thr, index, entry);
if (err == DB_FAIL) {
@ -610,7 +610,7 @@ row_undo_mod_upd_exist_sec(
/* Build the newest version of the index entry */
entry = row_build_index_entry(node->row, node->ext,
index, heap);
ut_a(entry);
/* NOTE that if we updated the fields of a
delete-marked secondary index record so that
alphabetically they stayed the same, e.g.,

2
row/row0upd.c
View File

@ -1380,6 +1380,7 @@ row_upd_sec_index_entry(
/* Build old index entry */
entry = row_build_index_entry(node->row, node->ext, index, heap);
ut_a(entry);
log_free_check();
mtr_start(&mtr);
@ -1559,6 +1560,7 @@ row_upd_clust_rec_by_insert(
node->state = UPD_NODE_INSERT_CLUSTERED;
entry = row_build_index_entry(node->row, node->ext, index, heap);
ut_a(entry);
row_upd_index_replace_new_col_vals(entry, index, node->update,
NULL, heap);

41
row/row0vers.c
View File

@ -167,6 +167,14 @@ row_vers_impl_x_locked_off_kernel(
prev_version, clust_offsets,
&ext, heap);
entry = row_build_index_entry(row, ext, index, heap);
/* entry may be NULL if a record was inserted
in place of a deleted record, and the BLOB
pointers of the new record were not
initialized yet. But in that case,
prev_version should be NULL.
We will play it safe and avoid dereferencing
entry when it is NULL, later in this function. */
}
mutex_enter(&kernel_mutex);
@ -201,7 +209,7 @@ row_vers_impl_x_locked_off_kernel(
/* We check if entry and rec are identified in the alphabetical
ordering */
if (0 == cmp_dtuple_rec(entry, rec, offsets)) {
if (entry && 0 == cmp_dtuple_rec(entry, rec, offsets)) {
/* The delete marks of rec and prev_version should be
equal for rec to be in the state required by
prev_version */
@ -337,13 +345,28 @@ row_vers_old_has_index_entry(
rec, clust_offsets, &ext, heap);
entry = row_build_index_entry(row, ext, index, heap);
/* If entry == NULL, the record contains unset BLOB
pointers. This must be a freshly inserted record. If
this is called from
row_purge_remove_sec_if_poss_low(), the thread will
hold latches on the clustered index and the secondary
index. Because the insert works in three steps:
(1) insert the record to clustered index
(2) store the BLOBs and update BLOB pointers
(3) insert records to secondary indexes
the purge thread can safely ignore freshly inserted
records and delete the secondary index record. The
thread that inserted the new record will be inserting
the secondary index records. */
/* NOTE that we cannot do the comparison as binary
fields because the row is maybe being modified so that
the clustered index record has already been updated
to a different binary value in a char field, but the
the clustered index record has already been updated to
a different binary value in a char field, but the
collation identifies the old and new value anyway! */
if (!dtuple_coll_cmp(ientry, entry)) {
if (entry && !dtuple_coll_cmp(ientry, entry)) {
mem_heap_free(heap);
@ -380,13 +403,19 @@ row_vers_old_has_index_entry(
&ext, heap);
entry = row_build_index_entry(row, ext, index, heap);
/* If entry == NULL, the record contains unset
BLOB pointers. This must be a freshly
inserted record that we can safely ignore.
For the justification, see the comments after
the previous row_build_index_entry() call. */
/* NOTE that we cannot do the comparison as binary
fields because maybe the secondary index record has
already been updated to a different binary value in
a char field, but the collation identifies the old
and new value anyway! */
if (!dtuple_coll_cmp(ientry, entry)) {
if (entry && !dtuple_coll_cmp(ientry, entry)) {
mem_heap_free(heap);

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