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sync up, see ChangeLog for details

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This commit is contained in:
brianb
2004-02-06 02:34:20 +00:00
parent ede5601bf2
commit a74094c667
15 changed files with 539 additions and 200 deletions
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112
src/libmdb/index.c
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@@ -262,6 +262,10 @@ mdb_index_test_sargs(MdbHandle *mdb, MdbIndex *idx, int offset, int len)
MdbSargNode node;
int c_offset = 0, c_len;
//fprintf(stderr,"mdb_index_test_sargs called on ");
//for (i=0;i<len;i++)
//fprintf(stderr,"%02x ",mdb->pg_buf[offset+i]);
//fprintf(stderr,"\n");
for (i=0;i<idx->num_keys;i++) {
c_offset++; /* the per column null indicator/flags */
col=g_ptr_array_index(table->columns,idx->key_col_num[i]-1);
@@ -326,14 +330,18 @@ mdb_index_find_next_on_page(MdbHandle *mdb, MdbIndexPage *ipg)
return ipg->len;
}
void mdb_index_page_init(MdbIndexPage *ipg)
void mdb_index_page_reset(MdbIndexPage *ipg)
{
memset(ipg, 0, sizeof(MdbIndexPage));
ipg->offset = 0xf8; /* start byte of the index entries */
ipg->mask_pos = 0x16;
ipg->mask_bit=0;
ipg->len = 0;
}
void mdb_index_page_init(MdbIndexPage *ipg)
{
memset(ipg, 0, sizeof(MdbIndexPage));
mdb_index_page_reset(ipg);
}
/*
* find the next leaf page if any given a chain. Assumes any exhausted leaf
* pages at the end of the chain have been peeled off before the call.
@@ -361,8 +369,10 @@ mdb_find_next_leaf(MdbHandle *mdb, MdbIndex *idx, MdbIndexChain *chain)
do {
ipg->len = 0;
//printf("finding next on pg %lu\n", ipg->pg);
if (!mdb_index_find_next_on_page(mdb, ipg))
if (!mdb_index_find_next_on_page(mdb, ipg)) {
//printf("find_next_on_page returned 0\n");
return 0;
}
pg = mdb_pg_get_int24_msb(mdb, ipg->offset + ipg->len - 3);
//printf("Looking at pg %lu at %lu %d\n", pg, ipg->offset, ipg->len);
ipg->offset += ipg->len;
@@ -373,7 +383,7 @@ mdb_find_next_leaf(MdbHandle *mdb, MdbIndex *idx, MdbIndexChain *chain)
*/
newipg = mdb_chain_add_page(mdb, chain, pg);
newipg = mdb_find_next_leaf(mdb, idx, chain);
//printf("returning pg %lu\n",newipg->pg);
printf("returning pg %lu\n",newipg->pg);
return newipg;
} while (!passed);
/* no more pages */
@@ -396,6 +406,10 @@ mdb_chain_add_page(MdbHandle *mdb, MdbIndexChain *chain, guint32 pg)
return ipg;
}
/*
* returns the bottom page of the IndexChain, if IndexChain is empty it
* initializes it by reading idx->first_pg (the root page)
*/
MdbIndexPage *
mdb_index_read_bottom_pg(MdbHandle *mdb, MdbIndex *idx, MdbIndexChain *chain)
{
@@ -451,8 +465,65 @@ mdb_index_find_next(MdbHandle *mdb, MdbIndex *idx, MdbIndexChain *chain, guint32
*/
if (!mdb_index_find_next_on_page(mdb, ipg)) {
//printf("page %lu finished\n",ipg->pg);
if (chain->cur_depth==1) {
//printf("cur_depth == 1 we're out\n");
return 0;
}
/*
* unwind the stack until we find something or reach
* the top.
*/
ipg = 0;
while (chain->cur_depth>1 && ipg==0) {
//printf("chain depth %d\n", chain->cur_depth);
chain->cur_depth--;
ipg = mdb_find_next_leaf(mdb, idx, chain);
if (ipg) mdb_index_find_next_on_page(mdb, ipg);
}
if (chain->cur_depth==1)
return 0;
}
*row = mdb->pg_buf[ipg->offset + ipg->len - 1];
*pg = mdb_pg_get_int24_msb(mdb, ipg->offset + ipg->len - 4);
//printf("row = %d pg = %lu ipg->pg = %lu offset = %lu len = %d\n", *row, *pg, ipg->pg, ipg->offset, ipg->len);
passed = mdb_index_test_sargs(mdb, idx, ipg->offset, ipg->len);
ipg->offset += ipg->len;
} while (!passed);
//fprintf(stdout,"len = %d pos %d\n", ipg->len, ipg->mask_pos);
//buffer_dump(mdb->pg_buf, ipg->offset, ipg->offset+ipg->len-1);
return ipg->len;
}
/*
* XXX - FIX ME
* This function is grossly inefficient. It scans the entire index building
* an IndexChain to a specific row. We should be checking the index pages
* for matches against the indexed fields to find the proper leaf page, but
* getting it working first and then make it fast!
*/
int
mdb_index_find_row(MdbHandle *mdb, MdbIndex *idx, MdbIndexChain *chain, guint32 pg, guint16 row)
{
MdbIndexPage *ipg;
int passed = 0;
guint32 datapg;
guint16 datarow;
ipg = mdb_index_read_bottom_pg(mdb, idx, chain);
do {
ipg->len = 0;
/*
* if no more rows on this leaf, try to find a new leaf
*/
if (!mdb_index_find_next_on_page(mdb, ipg)) {
/* back to top? We're done */
if (chain->cur_depth==1)
return 0;
/*
* unwind the stack until we find something or reach
* the top.
@@ -466,19 +537,20 @@ mdb_index_find_next(MdbHandle *mdb, MdbIndex *idx, MdbIndexChain *chain, guint32
if (chain->cur_depth==1)
return 0;
}
*row = mdb->pg_buf[ipg->offset + ipg->len - 1];
*pg = mdb_pg_get_int24_msb(mdb, ipg->offset + ipg->len - 4);
passed = mdb_index_test_sargs(mdb, idx, ipg->offset, ipg->len);
/* test row and pg */
datarow = mdb->pg_buf[ipg->offset + ipg->len - 1];
datapg = mdb_pg_get_int24_msb(mdb, ipg->offset + ipg->len - 4);
if (datapg == pg && datarow == row) {
passed = 1;
}
ipg->offset += ipg->len;
} while (!passed);
//fprintf(stdout,"len = %d pos %d\n", ipg->len, ipg->mask_pos);
//buffer_dump(mdb->pg_buf, ipg->offset, ipg->offset+ipg->len-1);
return ipg->len;
/* index chain from root to leaf should now be in "chain" */
return 1;
}
void mdb_index_walk(MdbTableDef *table, MdbIndex *idx)
{
MdbHandle *mdb = table->entry->mdb;
@@ -520,6 +592,14 @@ mdb_index_dump(MdbTableDef *table, MdbIndex *idx)
}
mdb_index_walk(table, idx);
}
/*
* compute_cost tries to assign a cost to a given index using the sargs
* available in this query.
*
* Indexes with no matching sargs are assigned 0
* Unique indexes are preferred over non-uniques
* Operator preference is equal, like, isnull, others
*/
int mdb_index_compute_cost(MdbTableDef *table, MdbIndex *idx)
{
int i;
@@ -531,7 +611,7 @@ int mdb_index_compute_cost(MdbTableDef *table, MdbIndex *idx)
if (idx->num_keys > 1) {
for (i=0;i<idx->num_keys;i++) {
col=g_ptr_array_index(table->columns,idx->key_col_num[i]-1);
sarg = g_ptr_array_index (col->sargs, 0);
if (col->sargs) sarg = g_ptr_array_index (col->sargs, 0);
if (!sarg || sarg->op != MDB_EQUAL) not_all_equal++;
}
}
@@ -609,6 +689,12 @@ int mdb_index_compute_cost(MdbTableDef *table, MdbIndex *idx)
}
return 0;
}
/*
* choose_index runs mdb_index_compute_cost for each available index and picks
* the best.
*
* Returns strategy to use (table scan, or index scan)
*/
MdbStrategy
mdb_choose_index(MdbTableDef *table, int *choice)
{