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Imported InnoDB plugin with changes.

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storage/innobase/row/row0ext.c
 
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/******************************************************
 
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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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UNIV_INTERN
 
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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
 
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                                columns; must be indexed by col_no;
 
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                                the clustered index record must be
 
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                                covered by a lock or a page latch
 
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                                to prevent deletion (rollback or purge). */
 
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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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}