Overview
Comment: | Try to optimize LIKE and GLOB operators when RHS contains no wildcard. Ticket [e090183531fc274747] |
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Downloads: | Tarball | ZIP archive | SQL archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: | 613a87d62fd1f8526d53136efae5adae91824bcf |
User & Date: | drh 2010-07-22 12:33:57 |
Context
2010-07-22
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15:44 | Add test/threadtest3.c, containing multi-thread tests implemented in C. check-in: aad88cf5 user: dan tags: trunk | |
12:33 | Try to optimize LIKE and GLOB operators when RHS contains no wildcard. Ticket [e090183531fc274747] check-in: 613a87d6 user: drh tags: trunk | |
11:40 | Tweaks to the virtual table documentation contained in comments of sqlite3.h. No changes to actual code. check-in: f5866d47 user: drh tags: trunk | |
Changes
Changes to src/where.c.
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z = pRight->u.zToken; } if( z ){ cnt = 0; while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){ cnt++; } if( cnt!=0 && c!=0 && 255!=(u8)z[cnt-1] ){ Expr *pPrefix; *pisComplete = z[cnt]==wc[0] && z[cnt+1]==0; pPrefix = sqlite3Expr(db, TK_STRING, z); if( pPrefix ) pPrefix->u.zToken[cnt] = 0; *ppPrefix = pPrefix; if( op==TK_VARIABLE ){ Vdbe *v = pParse->pVdbe; sqlite3VdbeSetVarmask(v, pRight->iColumn); if( *pisComplete && pRight->u.zToken[1] ){ |
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z = pRight->u.zToken;
}
if( z ){
cnt = 0;
while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){
cnt++;
}
if( cnt!=0 && 255!=(u8)z[cnt-1] ){
Expr *pPrefix;
*pisComplete = c==wc[0] && z[cnt+1]==0;
pPrefix = sqlite3Expr(db, TK_STRING, z);
if( pPrefix ) pPrefix->u.zToken[cnt] = 0;
*ppPrefix = pPrefix;
if( op==TK_VARIABLE ){
Vdbe *v = pParse->pVdbe;
sqlite3VdbeSetVarmask(v, pRight->iColumn);
if( *pisComplete && pRight->u.zToken[1] ){
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Changes to test/analyze3.test.
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set like "a%" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {101 0 100} do_test analyze3-2.5 { set like "%a" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {999 999 100} #------------------------------------------------------------------------- # This block of tests checks that statements are correctly marked as # expired when the values bound to any parameters that may affect the # query plan are modified. # |
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set like "a%" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {101 0 100} do_test analyze3-2.5 { set like "%a" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {999 999 100} do_test analyze3-2.6 { set like "a" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {101 0 0} do_test analyze3-2.7 { set like "ab" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {11 0 0} do_test analyze3-2.8 { set like "abc" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {2 0 1} do_test analyze3-2.9 { set like "a_c" sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like } } {101 0 10} #------------------------------------------------------------------------- # This block of tests checks that statements are correctly marked as # expired when the values bound to any parameters that may affect the # query plan are modified. # |
Changes to test/like.test.
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queryplan {
SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
}
} {abc abcd nosort {} i1}
do_test like-3.4 {
set sqlite_like_count
} 0
# Partial optimization when the pattern does not end in '%'
#
do_test like-3.5 {
set sqlite_like_count 0
queryplan {
SELECT x FROM t1 WHERE x LIKE 'a_c' ORDER BY 1;
................................................................................
PRAGMA case_sensitive_like=off;
SELECT x FROM t1 WHERE x GLOB 'a[bc]d' ORDER BY 1;
}
} {abd acd nosort {} i1}
do_test like-3.24 {
set sqlite_like_count
} 6
# No optimization if the LHS of the LIKE is not a column name or
# if the RHS is not a string.
#
do_test like-4.1 {
execsql {PRAGMA case_sensitive_like=on}
set sqlite_like_count 0
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queryplan { SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1; } } {abc abcd nosort {} i1} do_test like-3.4 { set sqlite_like_count } 0 # The LIKE optimization still works when the RHS is a string with no # wildcard. Ticket [e090183531fc2747] # do_test like-3.4.2 { queryplan { SELECT x FROM t1 WHERE x LIKE 'a' ORDER BY 1; } } {a nosort {} i1} do_test like-3.4.3 { queryplan { SELECT x FROM t1 WHERE x LIKE 'ab' ORDER BY 1; } } {ab nosort {} i1} do_test like-3.4.4 { queryplan { SELECT x FROM t1 WHERE x LIKE 'abcd' ORDER BY 1; } } {abcd nosort {} i1} do_test like-3.4.5 { queryplan { SELECT x FROM t1 WHERE x LIKE 'abcde' ORDER BY 1; } } {nosort {} i1} # Partial optimization when the pattern does not end in '%' # do_test like-3.5 { set sqlite_like_count 0 queryplan { SELECT x FROM t1 WHERE x LIKE 'a_c' ORDER BY 1; ................................................................................ PRAGMA case_sensitive_like=off; SELECT x FROM t1 WHERE x GLOB 'a[bc]d' ORDER BY 1; } } {abd acd nosort {} i1} do_test like-3.24 { set sqlite_like_count } 6 # GLOB optimization when there is no wildcard. Ticket [e090183531fc2747] # do_test like-3.25 { queryplan { SELECT x FROM t1 WHERE x GLOB 'a' ORDER BY 1; } } {a nosort {} i1} do_test like-3.26 { queryplan { SELECT x FROM t1 WHERE x GLOB 'abcd' ORDER BY 1; } } {abcd nosort {} i1} do_test like-3.27 { queryplan { SELECT x FROM t1 WHERE x GLOB 'abcde' ORDER BY 1; } } {nosort {} i1} # No optimization if the LHS of the LIKE is not a column name or # if the RHS is not a string. # do_test like-4.1 { execsql {PRAGMA case_sensitive_like=on} set sqlite_like_count 0 |