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branches/zip: Identify records in the modification log by heap_no.

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page_zip_compress(), page_zip_decompress(), page_zip_write_rec():
Note that the end marker of the modification log is 1 byte.

page_zip_find_heap_no(): Remove.

page_zip_apply_log(): Remove parameter "page".  Instead of a 2-byte offset
to the record, decode the heap number using a variable-length code.

page_zip_write_rec(): Check the range of heap_no with debug assertions.
Encode the heap number instead of an offset to the start of the record.
This commit is contained in:
marko 2006-03-01 13:39:56 +00:00
parent c86de5b837
commit d1c2a0f5c1
1 changed files with 43 additions and 81 deletions
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124
page/page0zip.c
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@ -496,8 +496,8 @@ page_zip_compress(
c_stream.next_out = buf;
/* Subtract the space reserved for uncompressed data. */
/* Page header, end marker of modification log */
c_stream.avail_out = buf_end - buf - PAGE_ZIP_DIR_SLOT_SIZE;
/* Page header and the end marker of the modification log */
c_stream.avail_out = buf_end - buf - 1;
/* Dense page directory and uncompressed columns, if any */
if (page_is_leaf(page)) {
trx_id_col = dict_index_get_sys_col_pos(index, DATA_TRX_ID);
@ -644,7 +644,7 @@ page_zip_compress(
ut_ad(externs == c_stream.next_out
+ c_stream.avail_out
+ PAGE_ZIP_DIR_SLOT_SIZE/* mod log */);
+ 1/* end of modification log */);
/* Copy the BLOB pointer */
memcpy(externs, c_stream.next_in,
@ -736,9 +736,10 @@ zlib_error:
ut_ad(buf + c_stream.total_out == c_stream.next_out);
ut_ad((ulint) (storage - c_stream.next_out) >= c_stream.avail_out);
/* Zero out the area reserved for the modification log */
memset(c_stream.next_out, 0, c_stream.avail_out
+ PAGE_ZIP_DIR_SLOT_SIZE);
/* Zero out the area reserved for the modification log.
Space for the end marker of the modification log is not
included in avail_out. */
memset(c_stream.next_out, 0, c_stream.avail_out + 1/* end marker */);
page_zip->m_end = page_zip->m_start = PAGE_DATA + c_stream.total_out;
page_zip->n_blobs = n_blobs;
@ -1070,55 +1071,6 @@ page_zip_set_extra_bytes(
return(TRUE);
}
/**************************************************************************
Find the heap number of a record by binary search in the sorted
dense page directory. */
static
ulint
page_zip_find_heap_no(
/*==================*/
/* out: the heap number of the smallest record
in recs[] that is >= start; 0 if not found */
const byte* start, /* in: start address of the record */
rec_t** recs, /* in: dense page directory,
sorted by address (indexed by heap_no - 2) */
ulint n_dense)/* in: number of entries in recs[] */
{
ulint low = 0;
ulint high = n_dense;
ulint mid;
for (;;) {
mid = (low + high) / 2;
/* 'start' should be at least REC_N_NEW_EXTRA_BYTES
smaller than the matching entry in recs[] */
ut_ad(start != recs[mid]);
if (UNIV_UNLIKELY(low == high)) {
if (UNIV_UNLIKELY(start > recs[high])) {
return(0);
}
break;
}
if (start > recs[mid]) {
/* Too high */
high = mid;
} else {
/* Either this is too low, or we found a match. */
low = mid + 1;
if (start > recs[low]) {
/* The adjacent record does not match.
This is the closest match. */
break;
}
}
}
return(mid + 2);
}
/**************************************************************************
Apply the modification log to an uncompressed page. */
static
@ -1129,7 +1081,6 @@ page_zip_apply_log(
or NULL on failure */
const byte* data, /* in: modification log */
ulint size, /* in: maximum length of the log, in bytes */
page_t* page, /* out: uncompressed page */
rec_t** recs, /* in: dense page directory,
sorted by address (indexed by heap_no - 2) */
ulint n_dense,/* in: size of recs[] */
@ -1143,30 +1094,28 @@ page_zip_apply_log(
const byte* const end = data + size;
for (;;) {
ulint start;
ulint val;
rec_t* rec;
ulint len;
ulint hs;
start = mach_read_from_2((byte*) data);
if (UNIV_UNLIKELY(data + 2 >= end)) {
return(NULL);
}
if (UNIV_UNLIKELY(!start)) {
val = *data++;
if (UNIV_UNLIKELY(!val)) {
break;
}
if (UNIV_UNLIKELY(start < PAGE_ZIP_START)) {
if (val & 0x80) {
val = (val & 0x7f) << 7 | *data++;
}
if (UNIV_UNLIKELY(data >= end)) {
return(NULL);
}
if (UNIV_UNLIKELY(val >= n_dense)) {
return(NULL);
}
data += 2;
/* Determine the heap number of the record. */
hs = page_zip_find_heap_no(page + start, recs, n_dense)
<< REC_HEAP_NO_SHIFT;
if (UNIV_UNLIKELY(!hs)) {
return(NULL);
}
/* Determine the heap number and status bits of the record. */
rec = recs[val - 1];
hs = (val + 1) << REC_HEAP_NO_SHIFT;
hs |= heap_status & ((1 << REC_HEAP_NO_SHIFT) - 1);
/* This may either be an old record that is being
@ -1184,8 +1133,6 @@ page_zip_apply_log(
heap_status & REC_STATUS_NODE_PTR,
offsets);
rec = page + start + rec_offs_extra_size(offsets);
mach_write_to_2(rec - REC_NEW_HEAP_NO, hs);
/* Copy the extra bytes (backwards). */
@ -1290,7 +1237,10 @@ page_zip_decompress(
/* The dense directory excludes the infimum and supremum records. */
n_dense = page_dir_get_n_heap(page_zip->data) - 2;
ut_a(n_dense * PAGE_ZIP_DIR_SLOT_SIZE < page_zip->size);
if (UNIV_UNLIKELY(n_dense * PAGE_ZIP_DIR_SLOT_SIZE
>= page_zip->size)) {
return(FALSE);
}
heap = mem_heap_create(n_dense * (3 * sizeof *recs));
recsc = recs = mem_heap_alloc(heap, n_dense * (2 * sizeof *recs));
@ -1328,6 +1278,8 @@ page_zip_decompress(
ut_a(err == Z_OK);
d_stream.next_in = page_zip->data + PAGE_DATA;
/* Subtract the space reserved for
the page header and the end marker of the modification log. */
d_stream.avail_in = page_zip->size - (PAGE_DATA + 1);
d_stream.next_out = page + PAGE_ZIP_START;
@ -1633,7 +1585,7 @@ zlib_done:
const byte* mod_log_ptr;
mod_log_ptr = page_zip_apply_log(
page_zip->data + page_zip->m_start,
d_stream.avail_in, page, recs, n_dense,
d_stream.avail_in, recs, n_dense,
heap_status, index, offsets);
if (UNIV_UNLIKELY(!mod_log_ptr)) {
@ -1765,6 +1717,7 @@ page_zip_write_rec(
page_t* page;
byte* data;
byte* storage;
ulint heap_no;
ut_ad(buf_block_get_page_zip(buf_block_align((byte*)rec)) == page_zip);
ut_ad(page_zip_simple_validate(page_zip));
@ -1783,17 +1736,26 @@ page_zip_write_rec(
- PAGE_DIR - PAGE_DIR_SLOT_SIZE
* page_dir_get_n_slots(page));
heap_no = rec_get_heap_no_new((rec_t*) rec);
ut_ad(heap_no >= 2); /* not infimum or supremum */
ut_ad(heap_no < page_dir_get_n_heap(page));
/* Append to the modification log. */
data = page_zip->data + page_zip->m_end;
ut_ad(!mach_read_from_2(data));
{
/* Identify the record by writing its start address. 0 is
/* Identify the record by writing its heap number - 1. 0 is
reserved to indicate the end of the modification log. */
const byte* start = rec_get_start((rec_t*) rec, offsets);
const byte* b = rec - REC_N_NEW_EXTRA_BYTES;
mach_write_to_2(data, ut_align_offset(start, UNIV_PAGE_SIZE));
if (heap_no - 1 >= 128) {
*data++ = 0x80 | (heap_no - 1) >> 7;
} else {
*data++ = heap_no - 1;
}
/* Write the extra bytes backwards, so that
rec_offs_extra_size() can be easily computed in
page_zip_apply_log() by invoking
@ -1847,7 +1809,7 @@ page_zip_write_rec(
/* Copy roll_ptr and trx_id to the uncompressed area. */
memcpy(storage - (DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN)
* (rec_get_heap_no_new((rec_t*) rec) - 2),
* (heap_no - 2),
start,
DATA_TRX_ID_LEN + DATA_ROLL_PTR_LEN);
ut_a(data < storage
@ -1855,7 +1817,7 @@ page_zip_write_rec(
* (page_dir_get_n_heap(page) - 2)
- page_zip->n_blobs
* BTR_EXTERN_FIELD_REF_SIZE
- 2 /* for the modification log terminator */);
- 1 /* for the modification log terminator */);
} else {
/* This is a node pointer page. */
ulint len;
@ -1871,13 +1833,13 @@ page_zip_write_rec(
/* Copy the node pointer to the uncompressed area. */
memcpy(storage - REC_NODE_PTR_SIZE
* (rec_get_heap_no_new((rec_t*) rec) - 2),
* (heap_no - 2),
rec + len,
REC_NODE_PTR_SIZE);
ut_a(data < storage
- REC_NODE_PTR_SIZE
* (page_dir_get_n_heap(page) - 2)
- 2 /* for the modification log terminator */);
- 1 /* for the modification log terminator */);
}
page_zip->m_end = data - page_zip->data;