Experimental est_count pragma.

FossilOrigin-Name: 340822afbe0c6b47fdd789c56acd9e1058a434cb

diff --git a/manifest b/manifest
index 335c3844f347cc47baea348ce918ab51d4245f69..615523ae78ea65271d2ffa149065da920cb9d473 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sthe\sability\sfor\sthe\sPRAGMA\sstatement\sto\saccept\smultiple\sarguments.\nCurrently\sall\sarguments\sother\sthan\sthe\sfirst\sare\signored.
-D 2016-10-20T18:20:10.293
+C Experimental\sest_count\spragma.
+D 2016-10-20T22:02:43.512
 F Makefile.in 6fd48ffcf7c2deea7499062d1f3747f986c19678
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 5151cc64c4c05f3455f4f692ad11410a810d937f
@@ -329,8 +329,8 @@ F src/auth.c 930b376a9c56998557367e6f7f8aaeac82a2a792
 F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b
 F src/bitvec.c 3ee4c8b2c94ed3a7377256e18199e6ff5cf33f63
 F src/btmutex.c bc87dd3b062cc26edfe79918de2200ccb8d41e73
-F src/btree.c 4d035fb52b0ef9658d43dfe604413185dff7a5d1
-F src/btree.h d05b2fcc290991a8a3d9ea1816ddd55a4359dcde
+F src/btree.c c58b8a52ad8a74d48835a0471fadec0851d113fb
+F src/btree.h 012576c1d0000e96ccc785c6fe22b4be8211f0d9
 F src/btreeInt.h c18b7d2a3494695133e4e60ee36061d37f45d9a5
 F src/build.c e22e66fb34e1e50bb7869a510923bfe58db3071a
 F src/callback.c 2e76147783386374bf01b227f752c81ec872d730
@@ -379,8 +379,8 @@ F src/parse.y 07f68096c97093793ed04d69db8bb75e55c3e00e
 F src/pcache.c 5ff2a08f76a9c1b22f43eb063b7068fb085465ac
 F src/pcache.h 2cedcd8407eb23017d92790b112186886e179490
 F src/pcache1.c e3967219b2a92b9edcb9324a4ba75009090d3953
-F src/pragma.c 3ad504c61bcddacc231662f83ac41aceea639ff2
-F src/pragma.h 64c78a648751b9f4f297276c4eb7507b14b4628c
+F src/pragma.c baf707463944a0788df1503e9920c36edca1fe8f
+F src/pragma.h 30d6559672c6755be452ea5fdf2e9bf32acc69a3
 F src/prepare.c b1140c3d0cf59bc85ace00ce363153041b424b7a
 F src/printf.c a5f0ca08ddede803c241266abb46356ec748ded1
 F src/random.c ba2679f80ec82c4190062d756f22d0c358180696
@@ -453,7 +453,7 @@ F src/update.c 8179e699dbd45b92934fd02d3d8e3732e8da8802
 F src/utf.c 699001c79f28e48e9bcdf8a463da029ea660540c
 F src/util.c 3e2da6101888d073e79ecc6af5e0a2f70fa1e498
 F src/vacuum.c 913970b9d86dd6c2b8063ef1af421880f1464ec3
-F src/vdbe.c c93ae647b3b302234f3593fd686577216aa22543
+F src/vdbe.c c07f9a771c82619be14cc5368b19623ed8f3a30d
 F src/vdbe.h c044be7050ac6bf596eecc6ab159f5dbc020a3b7
 F src/vdbeInt.h 0a18713d0a2fec6807d076bd333d9bf3e57530cd
 F src/vdbeapi.c 8272f9342c39ab8d7eb4b9decc6caa7bc75b7d83
@@ -1464,7 +1464,7 @@ F tool/mkmsvcmin.tcl 2f12f7fa8858bbe61cf81820a2da96c79ed1ca8d
 F tool/mkopcodec.tcl d1b6362bd3aa80d5520d4d6f3765badf01f6c43c
 F tool/mkopcodeh.tcl a01d2c1d8a6205b03fc635adf3735b4c523befd3
 F tool/mkopts.tcl 66ac10d240cc6e86abd37dc908d50382f84ff46e
-F tool/mkpragmatab.tcl f0d5bb266d1d388cf86fce5ba01a891e95d72d41
+F tool/mkpragmatab.tcl bf6417cc44d42c1d024ac7036b59b9a8d4476470
 F tool/mkspeedsql.tcl a1a334d288f7adfe6e996f2e712becf076745c97
 F tool/mksqlite3c-noext.tcl fef88397668ae83166735c41af99d79f56afaabb
 F tool/mksqlite3c.tcl 06b2e6a0f21cc0a5d70fbbd136b3e0a96470645e
@@ -1526,10 +1526,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 56474ebca3fdddb8f3c5156f06dc42dc0a65256c
-R 7df9a33a3d365e65a71615f92b26cc61
-T *branch * multi-arg-pragma
-T *sym-multi-arg-pragma *
-T -sym-trunk *
+P fd81d8a4300c36d02f07371b722124ccf619654c
+R 43cd10c5c43a5cc4c174b3be405d48f3
+T *branch * est_count_pragma
+T *sym-est_count_pragma *
+T -sym-multi-arg-pragma *
 U drh
-Z 4afce9abc23c76c5686e4f8a5162325b
+Z 5a2d49857d0ed608295dc142049c4e6c

diff --git a/manifest.uuid b/manifest.uuid
index 4f7a6dca1507743937ee2c53460905e802a68838..641e3013bc8259352e416dc2216565a4fc40bc0a 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-fd81d8a4300c36d02f07371b722124ccf619654c
\ No newline at end of file
+340822afbe0c6b47fdd789c56acd9e1058a434cb
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index 1f7225cd8b73c5f94e633247fc5f4847c592a2b6..696e1be98cf40b048be0934cec2573b2bbbe7259 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -5037,6 +5037,69 @@ int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
   return rc;
 }
 
+/*
+** Move the cursor pCur to a location within its b-tree that is
+** approximately the x/1e9*nRow entry in the table, assuming the
+** table contains nRow entries.  So, in other words, if x==0 move
+** to the first entry and if x=1e9 move to the last entry and if
+** x=5e8 move to the middle entry.  The final landing spot is
+** approximate.
+**
+** Write an estimate of the number of entries in the b-tree into
+** the *pnRowEst variable.
+**
+** This routine works by first moving the cursor to the root of the
+** b-tree, then following pointers down to a leaf, selecting a pointer
+** according to x.
+**
+** The estimated number of entries is found by multiplying the number of
+** entries on the leaf page by the number of pointers at each layer of
+** non-leaf pages.
+**
+** Return SQLITE_OK on success or an error code if problems are encountered.
+*/
+int sqlite3BtreeMovetoProportional(
+  BtCursor *pCur,            /* Cursor to reposition */
+  u32 x,                     /* approximate location to position the cursor */
+  sqlite3_uint64 *pnRowEst   /* Write estimated entry count here */
+){
+  sqlite3_uint64 n = 1;
+  int rc;
+  Pgno chldPg;
+  u32 mx = 1000000000;
+  u32 perChild;
+  u16 rx;
+  MemPage *pPage;
+  rc = moveToRoot(pCur);
+  if( rc ) return rc;
+  pPage = pCur->apPage[0];
+  while( !pPage->leaf ){
+    perChild = (mx+pPage->nCell)/(pPage->nCell+1);
+    rx = x/perChild;
+    x %= perChild;
+    mx = perChild;
+    if( rx>=pPage->nCell ){
+      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
+    }else{
+      chldPg = get4byte(findCell(pPage,rx));
+    }
+    n *= pPage->nCell+1;
+    pCur->aiIdx[pCur->iPage] = rx;
+    rc = moveToChild(pCur, chldPg);
+    if( rc ) return rc;
+    pPage = pCur->apPage[pCur->iPage];
+  }
+  *pnRowEst = n*pPage->nCell;
+  if( pPage->nCell==0 ){
+    rx = 0;
+  }else{
+    perChild = mx/pPage->nCell;
+    rx = x/perChild;
+  }
+  pCur->aiIdx[pCur->iPage] = rx;
+  return SQLITE_OK;
+}
+
 /* Move the cursor so that it points to an entry near the key 
 ** specified by pIdxKey or intKey.   Return a success code.
 **

diff --git a/src/btree.h b/src/btree.h
index 0df98a3a64feaa6c51ebeadbd22abfc2cdf42abc..9d23da4008d3c7a79f2602a4c6a5cb422791f772 100644 (file)
--- a/src/btree.h
+++ b/src/btree.h
@@ -238,6 +238,7 @@ void sqlite3BtreeCursorHint(BtCursor*, int, ...);
 #endif
 
 int sqlite3BtreeCloseCursor(BtCursor*);
+int sqlite3BtreeMovetoProportional(BtCursor*,u32,u64*);
 int sqlite3BtreeMovetoUnpacked(
   BtCursor*,
   UnpackedRecord *pUnKey,

diff --git a/src/pragma.c b/src/pragma.c
index fef044d7d6063fddfeb4dc72949de76f2090dbf7..d88a9a0bf80ec7f50f8e88e09653e3d752f94ba2 100644 (file)
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -1381,6 +1381,49 @@ void sqlite3Pragma(
   }
   break;
 
+  /*
+  **   PRAGMA est_row_cnt(<table-or-index>,<fraction>);
+  **
+  ** Seek in <table-or-index> through the first <fraction> of rows and
+  ** estimate the total number of rows based on the path back up to the
+  ** root.
+  */
+  case PragTyp_EST_COUNT: {
+    Index *pIdx;
+    Table *pTab;
+    Pgno iRoot = 0;
+    const char *zName = 0;
+    int regResult;
+    double r;
+    static const char *azCol[] = { "est" };
+    if( (pIdx = sqlite3FindIndex(db, zRight, zDb))!=0 ){
+      iRoot = pIdx->tnum;
+      zName = pIdx->zName;
+    }else if( (pTab = sqlite3FindTable(db, zRight, zDb))!=0 ){
+      iRoot = pTab->tnum;
+      zName = pTab->zName;
+    }else{
+      break;
+    }
+    sqlite3TableLock(pParse, iDb, iRoot, 0, zName);
+    regResult = ++pParse->nMem;
+    setAllColumnNames(v, 1, azCol);
+    if( pValues->nId>=2 ){
+      const char *z = pValues->a[1].zName;
+      sqlite3AtoF(z, &r, sqlite3Strlen30(z), SQLITE_UTF8);
+    }else{
+      r = 0.5;
+    }
+    if( r<0.0 ) r = 0.0;
+    if( r>1.0 ) r = 1.0;
+    sqlite3CodeVerifySchema(pParse, iDb);
+    pParse->nTab++;
+    sqlite3VdbeAddOp4Int(v, OP_OpenRead, 0, iRoot, iDb, 1);
+    sqlite3VdbeAddOp3(v, OP_EstRowCnt, 0, regResult, (int)(r*1000000000));
+    sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, 1);
+  }
+  break;
+
 #ifndef SQLITE_INTEGRITY_CHECK_ERROR_MAX
 # define SQLITE_INTEGRITY_CHECK_ERROR_MAX 100
 #endif

diff --git a/src/pragma.h b/src/pragma.h
index 81779e9d4ab9636f488e2d8c0078530cc164fe48..182addc70f61a202ea2e95fd08f728816bb7da69 100644 (file)
--- a/src/pragma.h
+++ b/src/pragma.h
@@ -16,36 +16,37 @@
 #define PragTyp_DATABASE_LIST                 10
 #define PragTyp_DEFAULT_CACHE_SIZE            11
 #define PragTyp_ENCODING                      12
-#define PragTyp_FOREIGN_KEY_CHECK             13
-#define PragTyp_FOREIGN_KEY_LIST              14
-#define PragTyp_INCREMENTAL_VACUUM            15
-#define PragTyp_INDEX_INFO                    16
-#define PragTyp_INDEX_LIST                    17
-#define PragTyp_INTEGRITY_CHECK               18
-#define PragTyp_JOURNAL_MODE                  19
-#define PragTyp_JOURNAL_SIZE_LIMIT            20
-#define PragTyp_LOCK_PROXY_FILE               21
-#define PragTyp_LOCKING_MODE                  22
-#define PragTyp_PAGE_COUNT                    23
-#define PragTyp_MMAP_SIZE                     24
-#define PragTyp_PAGE_SIZE                     25
-#define PragTyp_SECURE_DELETE                 26
-#define PragTyp_SHRINK_MEMORY                 27
-#define PragTyp_SOFT_HEAP_LIMIT               28
-#define PragTyp_STATS                         29
-#define PragTyp_SYNCHRONOUS                   30
-#define PragTyp_TABLE_INFO                    31
-#define PragTyp_TEMP_STORE                    32
-#define PragTyp_TEMP_STORE_DIRECTORY          33
-#define PragTyp_THREADS                       34
-#define PragTyp_WAL_AUTOCHECKPOINT            35
-#define PragTyp_WAL_CHECKPOINT                36
-#define PragTyp_ACTIVATE_EXTENSIONS           37
-#define PragTyp_HEXKEY                        38
-#define PragTyp_KEY                           39
-#define PragTyp_REKEY                         40
-#define PragTyp_LOCK_STATUS                   41
-#define PragTyp_PARSER_TRACE                  42
+#define PragTyp_EST_COUNT                     13
+#define PragTyp_FOREIGN_KEY_CHECK             14
+#define PragTyp_FOREIGN_KEY_LIST              15
+#define PragTyp_INCREMENTAL_VACUUM            16
+#define PragTyp_INDEX_INFO                    17
+#define PragTyp_INDEX_LIST                    18
+#define PragTyp_INTEGRITY_CHECK               19
+#define PragTyp_JOURNAL_MODE                  20
+#define PragTyp_JOURNAL_SIZE_LIMIT            21
+#define PragTyp_LOCK_PROXY_FILE               22
+#define PragTyp_LOCKING_MODE                  23
+#define PragTyp_PAGE_COUNT                    24
+#define PragTyp_MMAP_SIZE                     25
+#define PragTyp_PAGE_SIZE                     26
+#define PragTyp_SECURE_DELETE                 27
+#define PragTyp_SHRINK_MEMORY                 28
+#define PragTyp_SOFT_HEAP_LIMIT               29
+#define PragTyp_STATS                         30
+#define PragTyp_SYNCHRONOUS                   31
+#define PragTyp_TABLE_INFO                    32
+#define PragTyp_TEMP_STORE                    33
+#define PragTyp_TEMP_STORE_DIRECTORY          34
+#define PragTyp_THREADS                       35
+#define PragTyp_WAL_AUTOCHECKPOINT            36
+#define PragTyp_WAL_CHECKPOINT                37
+#define PragTyp_ACTIVATE_EXTENSIONS           38
+#define PragTyp_HEXKEY                        39
+#define PragTyp_KEY                           40
+#define PragTyp_REKEY                         41
+#define PragTyp_LOCK_STATUS                   42
+#define PragTyp_PARSER_TRACE                  43
 #define PragFlag_NeedSchema           0x01
 #define PragFlag_ReadOnly             0x02
 static const struct sPragmaNames {
@@ -172,6 +173,10 @@ static const struct sPragmaNames {
     /* ePragFlag: */ 0,
     /* iArg:      */ 0 },
 #endif
+  { /* zName:     */ "est_count",
+    /* ePragTyp:  */ PragTyp_EST_COUNT,
+    /* ePragFlag: */ PragFlag_NeedSchema,
+    /* iArg:      */ 0 },
 #if !defined(SQLITE_OMIT_FOREIGN_KEY) && !defined(SQLITE_OMIT_TRIGGER)
   { /* zName:     */ "foreign_key_check",
     /* ePragTyp:  */ PragTyp_FOREIGN_KEY_CHECK,
@@ -461,4 +466,4 @@ static const struct sPragmaNames {
     /* iArg:      */ SQLITE_WriteSchema|SQLITE_RecoveryMode },
 #endif
 };
-/* Number of pragmas: 60 on by default, 73 total. */
+/* Number of pragmas: 61 on by default, 74 total. */

diff --git a/src/vdbe.c b/src/vdbe.c
index 09019f3728f9d0392274a95553e9e972ed230a79..40db24d0e4f4ed38a423d7e6a38397828f0bdfb8 100644 (file)
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -4897,6 +4897,31 @@ case OP_Rewind: {        /* jump */
   break;
 }
 
+/*
+** Opcode: EstRowCnt P1 P2 P3 * * *
+**
+** Estimate the number of entries in btree for cursor P1 do a proportional
+** seek to of P3.  Store the result as a floating point value in P2.
+*/
+case OP_EstRowCnt: {  /* out2 */
+  VdbeCursor *pC;
+  BtCursor *pCrsr;
+  int rc;
+  sqlite3_uint64 n = 0;
+
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC->eCurType==CURTYPE_BTREE );
+  pCrsr = pC->uc.pCursor;
+  assert( pCrsr );
+  rc = sqlite3BtreeMovetoProportional(pCrsr, pOp->p3, &n);
+  if( rc ) goto abort_due_to_error;
+  pOut = out2Prerelease(p, pOp);
+  pOut->flags = MEM_Real;
+  pOut->u.r = n;
+  break;
+}
+
 /* Opcode: Next P1 P2 P3 P4 P5
 **
 ** Advance cursor P1 so that it points to the next key/data pair in its

diff --git a/tool/mkpragmatab.tcl b/tool/mkpragmatab.tcl
index 145a365c54e66ad85850e184cf6fc870e54f2c82..cc2c3e263067127b1074b32e1890be4c238cce32 100644 (file)
--- a/tool/mkpragmatab.tcl
+++ b/tool/mkpragmatab.tcl
@@ -251,6 +251,9 @@ set pragma_def {
   FLAG: NeedSchema
   IF:   !defined(SQLITE_OMIT_INTEGRITY_CHECK)
 
+  NAME: est_count
+  FLAG: NeedSchema
+
   NAME: encoding
   IF:   !defined(SQLITE_OMIT_UTF16)