** ^(If the sqlite3_vtab_distinct() interface returns 2, that means ** that the query planner does not need the rows returned in any particular -** order, as long as rows with the same values in all "aOrderBy" columns +** order, as long as rows with the same values in all "colUsed" columns ** are adjacent.)^ ^(Furthermore, only a single row for each particular -** combination of values in the columns identified by the "aOrderBy" field +** combination of values in the columns identified by the "colUsed" field ** needs to be returned.)^ ^It is always ok for two or more rows with the same -** values in all "aOrderBy" columns to be returned, as long as all such rows +** values in all "colUsed" columns to be returned, as long as all such rows ** are adjacent. ^The virtual table may, if it chooses, omit extra rows -** that have the same value for all columns identified by "aOrderBy". +** that have the same value for all columns identified by "colUsed". ** ^However omitting the extra rows is optional. ** This mode is used for a DISTINCT query. **
** ^(If the sqlite3_vtab_distinct() interface returns 3, that means -** that the query planner needs only distinct rows but it does need the -** rows to be sorted.)^ ^The virtual table implementation is free to omit -** rows that are identical in all aOrderBy columns, if it wants to, but +** that the query planner needs only rows that are distinct over the +** set of columns defined by "colUsed" but it does need the +** rows to be sorted according to the order defined by "aOrderBy".)^ +** ^The virtual table implementation is free to omit +** rows that are identical in all "colUsed" columns, if it wants to, but ** it is not required to omit any rows. This mode is used for queries ** that have both DISTINCT and ORDER BY clauses. ** diff --git a/src/sqliteInt.h b/src/sqliteInt.h index aa8bfc4b7b..d98a4f7f06 100644 --- a/src/sqliteInt.h +++ b/src/sqliteInt.h @@ -3312,6 +3312,7 @@ struct SrcItem { unsigned isOn :1; /* u3.pOn was once valid and non-NULL */ unsigned isSynthUsing :1; /* u3.pUsing is synthesized from NATURAL */ unsigned isNestedFrom :1; /* pSelect is a SF_NestedFrom subquery */ + unsigned rowidUsed :1; /* The ROWID of this table is referenced */ } fg; int iCursor; /* The VDBE cursor number used to access this table */ union { diff --git a/src/treeview.c b/src/treeview.c index d3346b4686..fa9eac6142 100644 --- a/src/treeview.c +++ b/src/treeview.c @@ -194,8 +194,10 @@ void sqlite3TreeViewSrcList(TreeView *pView, const SrcList *pSrc){ x.printfFlags |= SQLITE_PRINTF_INTERNAL; sqlite3_str_appendf(&x, "{%d:*} %!S", pItem->iCursor, pItem); if( pItem->pTab ){ - sqlite3_str_appendf(&x, " tab=%Q nCol=%d ptr=%p used=%llx", - pItem->pTab->zName, pItem->pTab->nCol, pItem->pTab, pItem->colUsed); + sqlite3_str_appendf(&x, " tab=%Q nCol=%d ptr=%p used=%llx%s", + pItem->pTab->zName, pItem->pTab->nCol, pItem->pTab, + pItem->colUsed, + pItem->fg.rowidUsed ? "+rowid" : ""); } if( (pItem->fg.jointype & (JT_LEFT|JT_RIGHT))==(JT_LEFT|JT_RIGHT) ){ sqlite3_str_appendf(&x, " FULL-OUTER-JOIN"); diff --git a/src/where.c b/src/where.c index 13a362dcca..fac0f6c5eb 100644 --- a/src/where.c +++ b/src/where.c @@ -1416,7 +1416,7 @@ static sqlite3_index_info *allocateIndexInfo( } if( i==n ){ nOrderBy = n; - if( (pWInfo->wctrlFlags & WHERE_DISTINCTBY) ){ + if( (pWInfo->wctrlFlags & WHERE_DISTINCTBY) && !pSrc->fg.rowidUsed ){ eDistinct = 2 + ((pWInfo->wctrlFlags & WHERE_SORTBYGROUP)!=0); }else if( pWInfo->wctrlFlags & WHERE_GROUPBY ){ eDistinct = 1; From df903fe0565e3793888bbd8f8a329245eec4d9ea Mon Sep 17 00:00:00 2001 From: drh <> Date: Mon, 20 May 2024 16:00:27 +0000 Subject: [PATCH 2/2] Improvements to the sqlite3_vtab_distinct() documentation. FossilOrigin-Name: 6ee041d34f292b94701919f51bbb9e12bcb9e0c4f45e4c0b83f30ff328070637 --- manifest | 15 ++++++--------- manifest.uuid | 2 +- src/sqlite.h.in | 49 ++++++++++++++++++++++++++++++++++--------------- 3 files changed, 41 insertions(+), 25 deletions(-) diff --git a/manifest b/manifest index 401fc0177e..ce10a0198d 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Fix\sthe\sdefinition\sof\ssqlite3_vtab_distinct()\ssuch\sthat\sreturn\scodes\s2\sand\n3\smean\sthat\sall\srows\smust\sbe\sdistinct\sover\s"colUsed"\swhich\sis\sa\ssuperset\sof\n"aOrderBy".\s\sAlso,\sdisallow\sreturn\scodes\s2\sand\s3\sif\sthe\srowid\sof\sthe\svirtual\ntable\sis\saccessed. -D 2024-05-18T20:00:08.988 +C Improvements\sto\sthe\ssqlite3_vtab_distinct()\sdocumentation. +D 2024-05-20T16:00:27.117 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724 @@ -756,7 +756,7 @@ F src/resolve.c 22f1fa3423b377c02ae78d451cfeb1c2d96dcf0389c0642cbdcd19d3bfd7ae01 F src/rowset.c 8432130e6c344b3401a8874c3cb49fefe6873fec593294de077afea2dce5ec97 F src/select.c 1a841c38974d45cf15a7611398479182b61ad4c187423c380741d8b1688fe607 F src/shell.c.in 8f2406e4e8d726452e48058d117f52e86b789f47435157b0418fb06c631349b6 -F src/sqlite.h.in 6d645f9c2da3b64ea44944024df0c733bba186ee200d849a72a25bf8ae9beac4 +F src/sqlite.h.in c71d9ef76a6d32dc7ff2d373f2e57ce09056af26c1457bcadae5358b7628c7c3 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8 F src/sqlite3ext.h 3f046c04ea3595d6bfda99b781926b17e672fd6d27da2ba6d8d8fc39981dcb54 F src/sqliteInt.h 6a9fa3902c9faca2b57060e822f2afadfbf96d64c4ede81e201f0e0c42d7e4aa @@ -2191,11 +2191,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0 -P 1a073f9acfb691eebf4a8cc78a72ff47ebbb6aba4acede6755fa3faefae48f2b -R be7ef6a3dcb331720f0112bf3c3e9c8c -T *branch * vtab-distinct-fix -T *sym-vtab-distinct-fix * -T -sym-trunk * +P 922731ce98c0ce7837784ff7966049e59fa73da2aa04abf3506503b6fc4aa048 +R 65c04e4dfc1793594341c544753e5e70 U drh -Z 3a71e5f761d3443220a5a5a181b974f3 +Z 4b4899e535e10a58b98edaa878f294f3 # Remove this line to create a well-formed Fossil manifest. diff --git a/manifest.uuid b/manifest.uuid index 6968f2e6b3..1200d1128c 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -922731ce98c0ce7837784ff7966049e59fa73da2aa04abf3506503b6fc4aa048 \ No newline at end of file +6ee041d34f292b94701919f51bbb9e12bcb9e0c4f45e4c0b83f30ff328070637 \ No newline at end of file diff --git a/src/sqlite.h.in b/src/sqlite.h.in index 459af929b1..549b52a153 100644 --- a/src/sqlite.h.in +++ b/src/sqlite.h.in @@ -9942,26 +9942,45 @@ const char *sqlite3_vtab_collation(sqlite3_index_info*,int); **
** ^(If the sqlite3_vtab_distinct() interface returns 2, that means ** that the query planner does not need the rows returned in any particular -** order, as long as rows with the same values in all "colUsed" columns -** are adjacent.)^ ^(Furthermore, only a single row for each particular -** combination of values in the columns identified by the "colUsed" field -** needs to be returned.)^ ^It is always ok for two or more rows with the same -** values in all "colUsed" columns to be returned, as long as all such rows -** are adjacent. ^The virtual table may, if it chooses, omit extra rows -** that have the same value for all columns identified by "colUsed". -** ^However omitting the extra rows is optional. +** order, as long as rows with the same values in all columns identified +** by "aOrderBy" are adjacent.)^ ^(Furthermore, when two or more rows +** contain the same values for all columns identified by "colUsed", all but +** one such row may optionally be omitted from the result.)^ +** The virtual table is not required to omit rows that are duplicates +** over the "colUsed" columns, but if the virtual table can do that without +** too much extra effort, it could potentially help the query to run faster. ** This mode is used for a DISTINCT query. **
-** ^(If the sqlite3_vtab_distinct() interface returns 3, that means -** that the query planner needs only rows that are distinct over the -** set of columns defined by "colUsed" but it does need the -** rows to be sorted according to the order defined by "aOrderBy".)^ -** ^The virtual table implementation is free to omit -** rows that are identical in all "colUsed" columns, if it wants to, but -** it is not required to omit any rows. This mode is used for queries +** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the +** virtual table must return rows in the order defined by "aOrderBy" as +** if the sqlite3_vtab_distinct() interface had returned 0. However if +** two or more rows in the result have the same values for all columns +** identified by "colUsed", then all but one such row may optionally be +** omitted.)^ Like when the return value is 2, the virtual table +** is not required to omit rows that are duplicates over the "colUsed" +** columns, but if the virtual table can do that without +** too much extra effort, it could potentially help the query to run faster. +** This mode is used for queries ** that have both DISTINCT and ORDER BY clauses. ** ** +**
The following table summarizes the conditions under which the +** virtual table is allowed to set the "orderByConsumed" flag based on +** the value returned by sqlite3_vtab_distinct(). This table is a +** restatement of the previous four paragraphs: +** +**
| sqlite3_vtab_distinct() return value +** | Rows are returned in aOrderBy order +** | Rows with the same value in all aOrderBy columns are adjacent +** | Duplicates over all colUsed columns may be omitted +** |
| 0 | yes | yes | no +** |
| 1 | no | yes | no +** |
| 2 | no | yes | yes +** |
| 3 | yes | yes | yes +** |