When implementing a multi-way compound SELECT using merge, try to balance

the merge tree.

FossilOrigin-Name: bb8522fe0dc54282ec13672eba9b44ee08f9cb55c1663f1699a61bf96ec1fd04
This commit is contained in:
drh 2021-12-30 00:37:11 +00:00
parent 092ba22cca
commit 38cebe07bb
6 changed files with 180 additions and 23 deletions

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@ -1,5 +1,5 @@
C Minor\schanges\sto\sshell1.test\stest\sresults\sto\saccount\sfor\sthe\snew\sfeature\nof\sthe\sshell\sthat\spoints\sto\sthe\sspecific\spart\sof\sthe\sinput\sline\swhere\sthe\nerror\soccurs.
D 2021-12-29T13:32:36.797
C When\simplementing\sa\smulti-way\scompound\sSELECT\susing\smerge,\stry\sto\sbalance\nthe\smerge\stree.
D 2021-12-30T00:37:11.863
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@ -550,17 +550,17 @@ F src/printf.c 975f1f5417f2526365b6e6d7f22332e3e11806dad844701d92846292b654ba9a
F src/random.c 097dc8b31b8fba5a9aca1697aeb9fd82078ec91be734c16bffda620ced7ab83c
F src/resolve.c 359bc0e445d427583d2ab6110433a5dc777f64a0ecdf8d24826d8b475233ead9
F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
F src/select.c a7a3d9f54eb24821ec5f67f2e5589b68a5d42d46fc5849d7376886777d93a85a
F src/select.c bc130367361e68d3705e0756f913bb8433bccfb0187e0756455308c558b5699a
F src/shell.c.in 41b0e1f3a0c2443cb0a8d25e5d40529c911c574b5fe5a91dc54e19f90947a359
F src/sqlite.h.in a5e0d6bd47e67aabf1475986d36bdcc7bfa9e06566790ebf8e3aa7fa551c9f99
F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
F src/sqlite3ext.h 01eb85e4f2759a5ee79c183f4b2877889d4ffdc49d27ae74529c9579e3c8c0ef
F src/sqliteInt.h 418dd1a178abcc40b86b39cee972083822b17e84888fe56ed7a3b00b473d8bb5
F src/sqliteInt.h 850b013088c4cce47763ce795712135081d47bd21a105bfa62dd431dc66f93b7
F src/sqliteLimit.h d7323ffea5208c6af2734574bae933ca8ed2ab728083caa117c9738581a31657
F src/status.c 4b8bc2a6905163a38b739854a35b826c737333fab5b1f8e03fa7eb9a4799c4c1
F src/table.c 0f141b58a16de7e2fbe81c308379e7279f4c6b50eb08efeec5892794a0ba30d1
F src/tclsqlite.c 48f291e1a7e672a7204884d4c164a8ed3a522ff087c361ada2991f5d54e987f6
F src/test1.c a02b46f382baadfdfb1a541caf55a26aae44619ad0cff4f6d27eeca84594636a
F src/test1.c f13fe747afc7d9af189ce0cdaaf641252c5803db2a32bd3525eec2905c7b4f37
F src/test2.c 3efb99ab7f1fc8d154933e02ae1378bac9637da5
F src/test3.c 61798bb0d38b915067a8c8e03f5a534b431181f802659a6616f9b4ff7d872644
F src/test4.c 7c4420e01c577b5c4add2cb03119743b1a357543d347773b9e717195ea967159
@ -1206,6 +1206,7 @@ F test/memjournal.test 70f3a00c7f84ee2978ad14e831231caa1e7f23915a2c54b4f775a021d
F test/memleak.test 10b9c6c57e19fc68c32941495e9ba1c50123f6e2
F test/memsubsys1.test 9e7555a22173b8f1c96c281ce289b338fcba2abe8b157f8798ca195bbf1d347e
F test/memsubsys2.test 3e4a8d0c05fd3e5fa92017c64666730a520c7e08
F test/merge1.test c5abf7d4eca25b3d5ee96927efff18efc3cee5a8af54b8415cbddd6d4471fd70
F test/minmax.test fe638b55d77d2375531a8f549b338eafcd9adfbd2f72df37ed77d9b26ca0a71a
F test/minmax2.test cf9311babb6f0518d04e42fd6a42c619531c4309a9dd790a2c4e9b3bc595e0de
F test/minmax3.test cc1e8b010136db0d01a6f2a29ba5a9f321034354
@ -1934,8 +1935,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
P 4711fb69547f4f17653ab116030c32fdcc2c836410349d1d025866ffc15704da
R 5c3dff46ade5dadb3b517884aaa3c5ff
P d4870c08893ea9984b1fa1c3a7d04893ad5ed4a2130e9287d169a306cc8ef0a4
R 92d42c20b7697c4ca818b90b713774b8
U drh
Z 1ae7e3c1e437bcf89c5150a79373950f
Z 36a1d0b63e6b59c361f9d34272782b8a
# Remove this line to create a well-formed Fossil manifest.

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@ -1 +1 @@
d4870c08893ea9984b1fa1c3a7d04893ad5ed4a2130e9287d169a306cc8ef0a4
bb8522fe0dc54282ec13672eba9b44ee08f9cb55c1663f1699a61bf96ec1fd04

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@ -3296,6 +3296,8 @@ static int multiSelectOrderBy(
){
int i, j; /* Loop counters */
Select *pPrior; /* Another SELECT immediately to our left */
Select *pSplit; /* Left-most SELECT in the right-hand group */
int nSelect; /* Number of SELECT statements in the compound */
Vdbe *v; /* Generate code to this VDBE */
SelectDest destA; /* Destination for coroutine A */
SelectDest destB; /* Destination for coroutine B */
@ -3341,8 +3343,7 @@ static int multiSelectOrderBy(
/* Patch up the ORDER BY clause
*/
op = p->op;
pPrior = p->pPrior;
assert( pPrior->pOrderBy==0 );
assert( p->pPrior->pOrderBy==0 );
pOrderBy = p->pOrderBy;
assert( pOrderBy );
nOrderBy = pOrderBy->nExpr;
@ -3392,11 +3393,6 @@ static int multiSelectOrderBy(
pKeyMerge = 0;
}
/* Reattach the ORDER BY clause to the query.
*/
p->pOrderBy = pOrderBy;
pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
/* Allocate a range of temporary registers and the KeyInfo needed
** for the logic that removes duplicate result rows when the
** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
@ -3421,9 +3417,30 @@ static int multiSelectOrderBy(
/* Separate the left and the right query from one another
*/
p->pPrior = 0;
nSelect = 1;
if( (op==TK_ALL || op==TK_UNION)
&& OptimizationEnabled(db, SQLITE_BalancedMerge)
){
for(pSplit=p; pSplit->pPrior!=0 && pSplit->op==op; pSplit=pSplit->pPrior){
nSelect++;
assert( pSplit->pPrior->pNext==pSplit );
}
}
if( nSelect<=3 ){
pSplit = p;
}else{
pSplit = p;
for(i=2; i<nSelect; i+=2){ pSplit = pSplit->pPrior; }
}
pPrior = pSplit->pPrior;
pSplit->pPrior = 0;
pPrior->pNext = 0;
assert( p->pOrderBy == pOrderBy );
assert( pOrderBy!=0 || db->mallocFailed );
pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);
if( p->pPrior==0 ){
sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
}
if( pPrior->pPrior==0 ){
sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
}
@ -3577,12 +3594,11 @@ static int multiSelectOrderBy(
/* Reassembly the compound query so that it will be freed correctly
** by the calling function */
if( p->pPrior ){
sqlite3SelectDelete(db, p->pPrior);
if( pSplit->pPrior ){
sqlite3SelectDelete(db, pSplit->pPrior);
}
p->pPrior = pPrior;
pPrior->pNext = p;
pSplit->pPrior = pPrior;
pPrior->pNext = pSplit;
sqlite3ExprListDelete(db, pPrior->pOrderBy);
pPrior->pOrderBy = 0;

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@ -1764,6 +1764,7 @@ struct sqlite3 {
/* TH3 expects this value ^^^^^^^^^^ to be 0x40000. Coordinate any change */
#define SQLITE_BloomFilter 0x00080000 /* Use a Bloom filter on searches */
#define SQLITE_BloomPulldown 0x00100000 /* Run Bloom filters early */
#define SQLITE_BalancedMerge 0x00200000 /* Balance multi-way merges */
#define SQLITE_AllOpts 0xffffffff /* All optimizations */
/*

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@ -7512,6 +7512,7 @@ static int SQLITE_TCLAPI optimization_control(
{ "stat4", SQLITE_Stat4 },
{ "skip-scan", SQLITE_SkipScan },
{ "push-down", SQLITE_PushDown },
{ "balanced-merge", SQLITE_BalancedMerge },
};
if( objc!=4 ){

138
test/merge1.test Normal file
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@ -0,0 +1,138 @@
# 2021-12-29
#
# The author disclaims copyright to this source code. In place of
# a legal notice, here is a blessing:
#
# May you do good and not evil.
# May you find forgiveness for yourself and forgive others.
# May you share freely, never taking more than you give.
#
#***********************************************************************
#
# Testing the compound-SELECT merge algorithm to ensure that it works
# when it tries to balance the merge tree.
set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix merge1
load_static_extension db series
optimization_control db all on
do_execsql_test 100 {
WITH data(v) AS (
SELECT value FROM generate_series(1,35,3)
UNION ALL
SELECT value FROM generate_series(10,30,4)
UNION ALL
SELECT value FROM generate_series(20,50,5)
UNION ALL
SELECT value FROM generate_series(30,60,6)
UNION ALL
SELECT value FROM generate_series(1,50,7)
UNION ALL
SELECT value FROM generate_series(10,80,8)
)
SELECT v FROM data ORDER BY v;
} {1 1 4 7 8 10 10 10 13 14 15 16 18 18 19 20 22 22 22 25 25 26 26 28 29 30 30 30 31 34 34 35 36 36 40 42 42 43 45 48 50 50 50 54 58 60 66 74}
do_eqp_test 101 {
WITH data(v) AS (
SELECT value FROM generate_series(1,35,3)
UNION ALL
SELECT value FROM generate_series(10,30,4)
UNION ALL
SELECT value FROM generate_series(20,50,5)
UNION ALL
SELECT value FROM generate_series(30,60,6)
UNION ALL
SELECT value FROM generate_series(1,50,7)
UNION ALL
SELECT value FROM generate_series(10,80,8)
)
SELECT v FROM data ORDER BY v;
} {
QUERY PLAN
`--MERGE (UNION ALL)
|--LEFT
| `--MERGE (UNION ALL)
| |--LEFT
| | `--MERGE (UNION ALL)
| | |--LEFT
| | | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| | `--RIGHT
| | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| `--RIGHT
| `--SCAN generate_series VIRTUAL TABLE INDEX 23:
`--RIGHT
`--MERGE (UNION ALL)
|--LEFT
| `--MERGE (UNION ALL)
| |--LEFT
| | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| `--RIGHT
| `--SCAN generate_series VIRTUAL TABLE INDEX 23:
`--RIGHT
`--SCAN generate_series VIRTUAL TABLE INDEX 23:
}
# Same test with the blanced-merge optimization
# disabled. Should give the exact same answer.
#
optimization_control db balanced-merge off
db cache flush
do_execsql_test 110 {
WITH data(v) AS (
SELECT value FROM generate_series(1,35,3)
UNION ALL
SELECT value FROM generate_series(10,30,4)
UNION ALL
SELECT value FROM generate_series(20,50,5)
UNION ALL
SELECT value FROM generate_series(30,60,6)
UNION ALL
SELECT value FROM generate_series(1,50,7)
UNION ALL
SELECT value FROM generate_series(10,80,8)
)
SELECT v FROM data ORDER BY v;
} {1 1 4 7 8 10 10 10 13 14 15 16 18 18 19 20 22 22 22 25 25 26 26 28 29 30 30 30 31 34 34 35 36 36 40 42 42 43 45 48 50 50 50 54 58 60 66 74}
do_eqp_test 111 {
WITH data(v) AS (
SELECT value FROM generate_series(1,35,3)
UNION ALL
SELECT value FROM generate_series(10,30,4)
UNION ALL
SELECT value FROM generate_series(20,50,5)
UNION ALL
SELECT value FROM generate_series(30,60,6)
UNION ALL
SELECT value FROM generate_series(1,50,7)
UNION ALL
SELECT value FROM generate_series(10,80,8)
)
SELECT v FROM data ORDER BY v;
} {
QUERY PLAN
`--MERGE (UNION ALL)
|--LEFT
| `--MERGE (UNION ALL)
| |--LEFT
| | `--MERGE (UNION ALL)
| | |--LEFT
| | | `--MERGE (UNION ALL)
| | | |--LEFT
| | | | `--MERGE (UNION ALL)
| | | | |--LEFT
| | | | | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| | | | `--RIGHT
| | | | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| | | `--RIGHT
| | | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| | `--RIGHT
| | `--SCAN generate_series VIRTUAL TABLE INDEX 23:
| `--RIGHT
| `--SCAN generate_series VIRTUAL TABLE INDEX 23:
`--RIGHT
`--SCAN generate_series VIRTUAL TABLE INDEX 23:
}