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92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
/******************************************************
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Caching of externally stored column prefixes
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(c) 2006 Innobase Oy
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Created September 2006 Marko Makela
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*******************************************************/
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#include "row0ext.h"
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#ifdef UNIV_NONINL
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#include "row0ext.ic"
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#endif
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#include "btr0cur.h"
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/************************************************************************
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Fills the column prefix cache of an externally stored column. */
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static
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void
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row_ext_cache_fill(
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/*===============*/
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row_ext_t* ext, /* in/out: column prefix cache */
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ulint i, /* in: index of ext->ext[] */
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ulint zip_size,/* compressed page size in bytes, or 0 */
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const dfield_t* dfield) /* in: data field */
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{
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const byte* field = dfield_get_data(dfield);
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ulint f_len = dfield_get_len(dfield);
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byte* buf = ext->buf + i * REC_MAX_INDEX_COL_LEN;
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ut_ad(i < ext->n_ext);
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ut_ad(dfield_is_ext(dfield));
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ut_a(f_len >= BTR_EXTERN_FIELD_REF_SIZE);
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if (UNIV_UNLIKELY(!memcmp(field_ref_zero,
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field + f_len - BTR_EXTERN_FIELD_REF_SIZE,
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BTR_EXTERN_FIELD_REF_SIZE))) {
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/* The BLOB pointer is not set: we cannot fetch it */
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ext->len[i] = 0;
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} else {
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/* Fetch at most REC_MAX_INDEX_COL_LEN of the column.
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The column must be non-empty. */
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ext->len[i] = btr_copy_externally_stored_field_prefix(
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buf, REC_MAX_INDEX_COL_LEN, zip_size, field, f_len);
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ut_a(ext->len[i]);
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}
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}
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/************************************************************************
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Creates a cache of column prefixes of externally stored columns. */
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row_ext_t*
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row_ext_create(
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/*===========*/
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/* out,own: column prefix cache */
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ulint n_ext, /* in: number of externally stored columns */
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const ulint* ext, /* in: col_no's of externally stored columns
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in the InnoDB table object, as reported by
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dict_col_get_no(); NOT relative to the records
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in the clustered index */
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const dtuple_t* tuple, /* in: data tuple containing the field
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references of the externally stored columns;
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must be indexed by col_no */
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ulint zip_size,/* compressed page size in bytes, or 0 */
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mem_heap_t* heap) /* in: heap where created */
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{
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ulint i;
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row_ext_t* ret = mem_heap_alloc(heap, (sizeof *ret)
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+ (n_ext - 1) * sizeof ret->len);
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ut_ad(ut_is_2pow(zip_size));
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ut_ad(zip_size <= UNIV_PAGE_SIZE);
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ret->n_ext = n_ext;
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ret->ext = ext;
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ret->buf = mem_heap_alloc(heap, n_ext * REC_MAX_INDEX_COL_LEN);
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#ifdef UNIV_DEBUG
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memset(ret->buf, 0xaa, n_ext * REC_MAX_INDEX_COL_LEN);
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UNIV_MEM_ALLOC(ret->buf, n_ext * REC_MAX_INDEX_COL_LEN);
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#endif
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/* Fetch the BLOB prefixes */
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for (i = 0; i < n_ext; i++) {
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const dfield_t* dfield;
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dfield = dtuple_get_nth_field(tuple, ext[i]);
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row_ext_cache_fill(ret, i, zip_size, dfield);
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}
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return(ret);
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}
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