diff options
author | Hans-Christoph Steiner <hans@eds.org> | 2012-03-30 20:42:12 -0400 |
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committer | Hans-Christoph Steiner <hans@eds.org> | 2012-03-30 20:42:12 -0400 |
commit | 7bb481fda9ecb134804b49c2ce77ca28f7eea583 (patch) | |
tree | 31b520b9914d3e2453968abe375f2c102772c3dc /src/analyze.c |
Imported Upstream version 2.0.3
Diffstat (limited to 'src/analyze.c')
-rw-r--r-- | src/analyze.c | 1120 |
1 files changed, 1120 insertions, 0 deletions
diff --git a/src/analyze.c b/src/analyze.c new file mode 100644 index 0000000..b6a987a --- /dev/null +++ b/src/analyze.c @@ -0,0 +1,1120 @@ +/* +** 2005 July 8 +** +** 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. +** +************************************************************************* +** This file contains code associated with the ANALYZE command. +** +** The ANALYZE command gather statistics about the content of tables +** and indices. These statistics are made available to the query planner +** to help it make better decisions about how to perform queries. +** +** The following system tables are or have been supported: +** +** CREATE TABLE sqlite_stat1(tbl, idx, stat); +** CREATE TABLE sqlite_stat2(tbl, idx, sampleno, sample); +** CREATE TABLE sqlite_stat3(tbl, idx, nEq, nLt, nDLt, sample); +** +** Additional tables might be added in future releases of SQLite. +** The sqlite_stat2 table is not created or used unless the SQLite version +** is between 3.6.18 and 3.7.8, inclusive, and unless SQLite is compiled +** with SQLITE_ENABLE_STAT2. The sqlite_stat2 table is deprecated. +** The sqlite_stat2 table is superceded by sqlite_stat3, which is only +** created and used by SQLite versions 3.7.9 and later and with +** SQLITE_ENABLE_STAT3 defined. The fucntionality of sqlite_stat3 +** is a superset of sqlite_stat2. +** +** Format of sqlite_stat1: +** +** There is normally one row per index, with the index identified by the +** name in the idx column. The tbl column is the name of the table to +** which the index belongs. In each such row, the stat column will be +** a string consisting of a list of integers. The first integer in this +** list is the number of rows in the index and in the table. The second +** integer is the average number of rows in the index that have the same +** value in the first column of the index. The third integer is the average +** number of rows in the index that have the same value for the first two +** columns. The N-th integer (for N>1) is the average number of rows in +** the index which have the same value for the first N-1 columns. For +** a K-column index, there will be K+1 integers in the stat column. If +** the index is unique, then the last integer will be 1. +** +** The list of integers in the stat column can optionally be followed +** by the keyword "unordered". The "unordered" keyword, if it is present, +** must be separated from the last integer by a single space. If the +** "unordered" keyword is present, then the query planner assumes that +** the index is unordered and will not use the index for a range query. +** +** If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat +** column contains a single integer which is the (estimated) number of +** rows in the table identified by sqlite_stat1.tbl. +** +** Format of sqlite_stat2: +** +** The sqlite_stat2 is only created and is only used if SQLite is compiled +** with SQLITE_ENABLE_STAT2 and if the SQLite version number is between +** 3.6.18 and 3.7.8. The "stat2" table contains additional information +** about the distribution of keys within an index. The index is identified by +** the "idx" column and the "tbl" column is the name of the table to which +** the index belongs. There are usually 10 rows in the sqlite_stat2 +** table for each index. +** +** The sqlite_stat2 entries for an index that have sampleno between 0 and 9 +** inclusive are samples of the left-most key value in the index taken at +** evenly spaced points along the index. Let the number of samples be S +** (10 in the standard build) and let C be the number of rows in the index. +** Then the sampled rows are given by: +** +** rownumber = (i*C*2 + C)/(S*2) +** +** For i between 0 and S-1. Conceptually, the index space is divided into +** S uniform buckets and the samples are the middle row from each bucket. +** +** The format for sqlite_stat2 is recorded here for legacy reference. This +** version of SQLite does not support sqlite_stat2. It neither reads nor +** writes the sqlite_stat2 table. This version of SQLite only supports +** sqlite_stat3. +** +** Format for sqlite_stat3: +** +** The sqlite_stat3 is an enhancement to sqlite_stat2. A new name is +** used to avoid compatibility problems. +** +** The format of the sqlite_stat3 table is similar to the format of +** the sqlite_stat2 table. There are multiple entries for each index. +** The idx column names the index and the tbl column is the table of the +** index. If the idx and tbl columns are the same, then the sample is +** of the INTEGER PRIMARY KEY. The sample column is a value taken from +** the left-most column of the index. The nEq column is the approximate +** number of entires in the index whose left-most column exactly matches +** the sample. nLt is the approximate number of entires whose left-most +** column is less than the sample. The nDLt column is the approximate +** number of distinct left-most entries in the index that are less than +** the sample. +** +** Future versions of SQLite might change to store a string containing +** multiple integers values in the nDLt column of sqlite_stat3. The first +** integer will be the number of prior index entires that are distinct in +** the left-most column. The second integer will be the number of prior index +** entries that are distinct in the first two columns. The third integer +** will be the number of prior index entries that are distinct in the first +** three columns. And so forth. With that extension, the nDLt field is +** similar in function to the sqlite_stat1.stat field. +** +** There can be an arbitrary number of sqlite_stat3 entries per index. +** The ANALYZE command will typically generate sqlite_stat3 tables +** that contain between 10 and 40 samples which are distributed across +** the key space, though not uniformly, and which include samples with +** largest possible nEq values. +*/ +#ifndef SQLITE_OMIT_ANALYZE +#include "sqliteInt.h" + +/* +** This routine generates code that opens the sqlite_stat1 table for +** writing with cursor iStatCur. If the library was built with the +** SQLITE_ENABLE_STAT3 macro defined, then the sqlite_stat3 table is +** opened for writing using cursor (iStatCur+1) +** +** If the sqlite_stat1 tables does not previously exist, it is created. +** Similarly, if the sqlite_stat3 table does not exist and the library +** is compiled with SQLITE_ENABLE_STAT3 defined, it is created. +** +** Argument zWhere may be a pointer to a buffer containing a table name, +** or it may be a NULL pointer. If it is not NULL, then all entries in +** the sqlite_stat1 and (if applicable) sqlite_stat3 tables associated +** with the named table are deleted. If zWhere==0, then code is generated +** to delete all stat table entries. +*/ +static void openStatTable( + Parse *pParse, /* Parsing context */ + int iDb, /* The database we are looking in */ + int iStatCur, /* Open the sqlite_stat1 table on this cursor */ + const char *zWhere, /* Delete entries for this table or index */ + const char *zWhereType /* Either "tbl" or "idx" */ +){ + static const struct { + const char *zName; + const char *zCols; + } aTable[] = { + { "sqlite_stat1", "tbl,idx,stat" }, +#ifdef SQLITE_ENABLE_STAT3 + { "sqlite_stat3", "tbl,idx,neq,nlt,ndlt,sample" }, +#endif + }; + + int aRoot[] = {0, 0}; + u8 aCreateTbl[] = {0, 0}; + + int i; + sqlite3 *db = pParse->db; + Db *pDb; + Vdbe *v = sqlite3GetVdbe(pParse); + if( v==0 ) return; + assert( sqlite3BtreeHoldsAllMutexes(db) ); + assert( sqlite3VdbeDb(v)==db ); + pDb = &db->aDb[iDb]; + + /* Create new statistic tables if they do not exist, or clear them + ** if they do already exist. + */ + for(i=0; i<ArraySize(aTable); i++){ + const char *zTab = aTable[i].zName; + Table *pStat; + if( (pStat = sqlite3FindTable(db, zTab, pDb->zName))==0 ){ + /* The sqlite_stat[12] table does not exist. Create it. Note that a + ** side-effect of the CREATE TABLE statement is to leave the rootpage + ** of the new table in register pParse->regRoot. This is important + ** because the OpenWrite opcode below will be needing it. */ + sqlite3NestedParse(pParse, + "CREATE TABLE %Q.%s(%s)", pDb->zName, zTab, aTable[i].zCols + ); + aRoot[i] = pParse->regRoot; + aCreateTbl[i] = 1; + }else{ + /* The table already exists. If zWhere is not NULL, delete all entries + ** associated with the table zWhere. If zWhere is NULL, delete the + ** entire contents of the table. */ + aRoot[i] = pStat->tnum; + sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab); + if( zWhere ){ + sqlite3NestedParse(pParse, + "DELETE FROM %Q.%s WHERE %s=%Q", pDb->zName, zTab, zWhereType, zWhere + ); + }else{ + /* The sqlite_stat[12] table already exists. Delete all rows. */ + sqlite3VdbeAddOp2(v, OP_Clear, aRoot[i], iDb); + } + } + } + + /* Open the sqlite_stat[13] tables for writing. */ + for(i=0; i<ArraySize(aTable); i++){ + sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb); + sqlite3VdbeChangeP4(v, -1, (char *)3, P4_INT32); + sqlite3VdbeChangeP5(v, aCreateTbl[i]); + } +} + +/* +** Recommended number of samples for sqlite_stat3 +*/ +#ifndef SQLITE_STAT3_SAMPLES +# define SQLITE_STAT3_SAMPLES 24 +#endif + +/* +** Three SQL functions - stat3_init(), stat3_push(), and stat3_pop() - +** share an instance of the following structure to hold their state +** information. +*/ +typedef struct Stat3Accum Stat3Accum; +struct Stat3Accum { + tRowcnt nRow; /* Number of rows in the entire table */ + tRowcnt nPSample; /* How often to do a periodic sample */ + int iMin; /* Index of entry with minimum nEq and hash */ + int mxSample; /* Maximum number of samples to accumulate */ + int nSample; /* Current number of samples */ + u32 iPrn; /* Pseudo-random number used for sampling */ + struct Stat3Sample { + i64 iRowid; /* Rowid in main table of the key */ + tRowcnt nEq; /* sqlite_stat3.nEq */ + tRowcnt nLt; /* sqlite_stat3.nLt */ + tRowcnt nDLt; /* sqlite_stat3.nDLt */ + u8 isPSample; /* True if a periodic sample */ + u32 iHash; /* Tiebreaker hash */ + } *a; /* An array of samples */ +}; + +#ifdef SQLITE_ENABLE_STAT3 +/* +** Implementation of the stat3_init(C,S) SQL function. The two parameters +** are the number of rows in the table or index (C) and the number of samples +** to accumulate (S). +** +** This routine allocates the Stat3Accum object. +** +** The return value is the Stat3Accum object (P). +*/ +static void stat3Init( + sqlite3_context *context, + int argc, + sqlite3_value **argv +){ + Stat3Accum *p; + tRowcnt nRow; + int mxSample; + int n; + + UNUSED_PARAMETER(argc); + nRow = (tRowcnt)sqlite3_value_int64(argv[0]); + mxSample = sqlite3_value_int(argv[1]); + n = sizeof(*p) + sizeof(p->a[0])*mxSample; + p = sqlite3_malloc( n ); + if( p==0 ){ + sqlite3_result_error_nomem(context); + return; + } + memset(p, 0, n); + p->a = (struct Stat3Sample*)&p[1]; + p->nRow = nRow; + p->mxSample = mxSample; + p->nPSample = p->nRow/(mxSample/3+1) + 1; + sqlite3_randomness(sizeof(p->iPrn), &p->iPrn); + sqlite3_result_blob(context, p, sizeof(p), sqlite3_free); +} +static const FuncDef stat3InitFuncdef = { + 2, /* nArg */ + SQLITE_UTF8, /* iPrefEnc */ + 0, /* flags */ + 0, /* pUserData */ + 0, /* pNext */ + stat3Init, /* xFunc */ + 0, /* xStep */ + 0, /* xFinalize */ + "stat3_init", /* zName */ + 0, /* pHash */ + 0 /* pDestructor */ +}; + + +/* +** Implementation of the stat3_push(nEq,nLt,nDLt,rowid,P) SQL function. The +** arguments describe a single key instance. This routine makes the +** decision about whether or not to retain this key for the sqlite_stat3 +** table. +** +** The return value is NULL. +*/ +static void stat3Push( + sqlite3_context *context, + int argc, + sqlite3_value **argv +){ + Stat3Accum *p = (Stat3Accum*)sqlite3_value_blob(argv[4]); + tRowcnt nEq = sqlite3_value_int64(argv[0]); + tRowcnt nLt = sqlite3_value_int64(argv[1]); + tRowcnt nDLt = sqlite3_value_int64(argv[2]); + i64 rowid = sqlite3_value_int64(argv[3]); + u8 isPSample = 0; + u8 doInsert = 0; + int iMin = p->iMin; + struct Stat3Sample *pSample; + int i; + u32 h; + + UNUSED_PARAMETER(context); + UNUSED_PARAMETER(argc); + if( nEq==0 ) return; + h = p->iPrn = p->iPrn*1103515245 + 12345; + if( (nLt/p->nPSample)!=((nEq+nLt)/p->nPSample) ){ + doInsert = isPSample = 1; + }else if( p->nSample<p->mxSample ){ + doInsert = 1; + }else{ + if( nEq>p->a[iMin].nEq || (nEq==p->a[iMin].nEq && h>p->a[iMin].iHash) ){ + doInsert = 1; + } + } + if( !doInsert ) return; + if( p->nSample==p->mxSample ){ + assert( p->nSample - iMin - 1 >= 0 ); + memmove(&p->a[iMin], &p->a[iMin+1], sizeof(p->a[0])*(p->nSample-iMin-1)); + pSample = &p->a[p->nSample-1]; + }else{ + pSample = &p->a[p->nSample++]; + } + pSample->iRowid = rowid; + pSample->nEq = nEq; + pSample->nLt = nLt; + pSample->nDLt = nDLt; + pSample->iHash = h; + pSample->isPSample = isPSample; + + /* Find the new minimum */ + if( p->nSample==p->mxSample ){ + pSample = p->a; + i = 0; + while( pSample->isPSample ){ + i++; + pSample++; + assert( i<p->nSample ); + } + nEq = pSample->nEq; + h = pSample->iHash; + iMin = i; + for(i++, pSample++; i<p->nSample; i++, pSample++){ + if( pSample->isPSample ) continue; + if( pSample->nEq<nEq + || (pSample->nEq==nEq && pSample->iHash<h) + ){ + iMin = i; + nEq = pSample->nEq; + h = pSample->iHash; + } + } + p->iMin = iMin; + } +} +static const FuncDef stat3PushFuncdef = { + 5, /* nArg */ + SQLITE_UTF8, /* iPrefEnc */ + 0, /* flags */ + 0, /* pUserData */ + 0, /* pNext */ + stat3Push, /* xFunc */ + 0, /* xStep */ + 0, /* xFinalize */ + "stat3_push", /* zName */ + 0, /* pHash */ + 0 /* pDestructor */ +}; + +/* +** Implementation of the stat3_get(P,N,...) SQL function. This routine is +** used to query the results. Content is returned for the Nth sqlite_stat3 +** row where N is between 0 and S-1 and S is the number of samples. The +** value returned depends on the number of arguments. +** +** argc==2 result: rowid +** argc==3 result: nEq +** argc==4 result: nLt +** argc==5 result: nDLt +*/ +static void stat3Get( + sqlite3_context *context, + int argc, + sqlite3_value **argv +){ + int n = sqlite3_value_int(argv[1]); + Stat3Accum *p = (Stat3Accum*)sqlite3_value_blob(argv[0]); + + assert( p!=0 ); + if( p->nSample<=n ) return; + switch( argc ){ + case 2: sqlite3_result_int64(context, p->a[n].iRowid); break; + case 3: sqlite3_result_int64(context, p->a[n].nEq); break; + case 4: sqlite3_result_int64(context, p->a[n].nLt); break; + default: sqlite3_result_int64(context, p->a[n].nDLt); break; + } +} +static const FuncDef stat3GetFuncdef = { + -1, /* nArg */ + SQLITE_UTF8, /* iPrefEnc */ + 0, /* flags */ + 0, /* pUserData */ + 0, /* pNext */ + stat3Get, /* xFunc */ + 0, /* xStep */ + 0, /* xFinalize */ + "stat3_get", /* zName */ + 0, /* pHash */ + 0 /* pDestructor */ +}; +#endif /* SQLITE_ENABLE_STAT3 */ + + + + +/* +** Generate code to do an analysis of all indices associated with +** a single table. +*/ +static void analyzeOneTable( + Parse *pParse, /* Parser context */ + Table *pTab, /* Table whose indices are to be analyzed */ + Index *pOnlyIdx, /* If not NULL, only analyze this one index */ + int iStatCur, /* Index of VdbeCursor that writes the sqlite_stat1 table */ + int iMem /* Available memory locations begin here */ +){ + sqlite3 *db = pParse->db; /* Database handle */ + Index *pIdx; /* An index to being analyzed */ + int iIdxCur; /* Cursor open on index being analyzed */ + Vdbe *v; /* The virtual machine being built up */ + int i; /* Loop counter */ + int topOfLoop; /* The top of the loop */ + int endOfLoop; /* The end of the loop */ + int jZeroRows = -1; /* Jump from here if number of rows is zero */ + int iDb; /* Index of database containing pTab */ + int regTabname = iMem++; /* Register containing table name */ + int regIdxname = iMem++; /* Register containing index name */ + int regStat1 = iMem++; /* The stat column of sqlite_stat1 */ +#ifdef SQLITE_ENABLE_STAT3 + int regNumEq = regStat1; /* Number of instances. Same as regStat1 */ + int regNumLt = iMem++; /* Number of keys less than regSample */ + int regNumDLt = iMem++; /* Number of distinct keys less than regSample */ + int regSample = iMem++; /* The next sample value */ + int regRowid = regSample; /* Rowid of a sample */ + int regAccum = iMem++; /* Register to hold Stat3Accum object */ + int regLoop = iMem++; /* Loop counter */ + int regCount = iMem++; /* Number of rows in the table or index */ + int regTemp1 = iMem++; /* Intermediate register */ + int regTemp2 = iMem++; /* Intermediate register */ + int once = 1; /* One-time initialization */ + int shortJump = 0; /* Instruction address */ + int iTabCur = pParse->nTab++; /* Table cursor */ +#endif + int regCol = iMem++; /* Content of a column in analyzed table */ + int regRec = iMem++; /* Register holding completed record */ + int regTemp = iMem++; /* Temporary use register */ + int regNewRowid = iMem++; /* Rowid for the inserted record */ + + + v = sqlite3GetVdbe(pParse); + if( v==0 || NEVER(pTab==0) ){ + return; + } + if( pTab->tnum==0 ){ + /* Do not gather statistics on views or virtual tables */ + return; + } + if( memcmp(pTab->zName, "sqlite_", 7)==0 ){ + /* Do not gather statistics on system tables */ + return; + } + assert( sqlite3BtreeHoldsAllMutexes(db) ); + iDb = sqlite3SchemaToIndex(db, pTab->pSchema); + assert( iDb>=0 ); + assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); +#ifndef SQLITE_OMIT_AUTHORIZATION + if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0, + db->aDb[iDb].zName ) ){ + return; + } +#endif + + /* Establish a read-lock on the table at the shared-cache level. */ + sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName); + + iIdxCur = pParse->nTab++; + sqlite3VdbeAddOp4(v, OP_String8, 0, regTabname, 0, pTab->zName, 0); + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ + int nCol; + KeyInfo *pKey; + int addrIfNot = 0; /* address of OP_IfNot */ + int *aChngAddr; /* Array of jump instruction addresses */ + + if( pOnlyIdx && pOnlyIdx!=pIdx ) continue; + VdbeNoopComment((v, "Begin analysis of %s", pIdx->zName)); + nCol = pIdx->nColumn; + aChngAddr = sqlite3DbMallocRaw(db, sizeof(int)*nCol); + if( aChngAddr==0 ) continue; + pKey = sqlite3IndexKeyinfo(pParse, pIdx); + if( iMem+1+(nCol*2)>pParse->nMem ){ + pParse->nMem = iMem+1+(nCol*2); + } + + /* Open a cursor to the index to be analyzed. */ + assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) ); + sqlite3VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb, + (char *)pKey, P4_KEYINFO_HANDOFF); + VdbeComment((v, "%s", pIdx->zName)); + + /* Populate the register containing the index name. */ + sqlite3VdbeAddOp4(v, OP_String8, 0, regIdxname, 0, pIdx->zName, 0); + +#ifdef SQLITE_ENABLE_STAT3 + if( once ){ + once = 0; + sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead); + } + sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regCount); + sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_STAT3_SAMPLES, regTemp1); + sqlite3VdbeAddOp2(v, OP_Integer, 0, regNumEq); + sqlite3VdbeAddOp2(v, OP_Integer, 0, regNumLt); + sqlite3VdbeAddOp2(v, OP_Integer, -1, regNumDLt); + sqlite3VdbeAddOp4(v, OP_Function, 1, regCount, regAccum, + (char*)&stat3InitFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 2); +#endif /* SQLITE_ENABLE_STAT3 */ + + /* The block of memory cells initialized here is used as follows. + ** + ** iMem: + ** The total number of rows in the table. + ** + ** iMem+1 .. iMem+nCol: + ** Number of distinct entries in index considering the + ** left-most N columns only, where N is between 1 and nCol, + ** inclusive. + ** + ** iMem+nCol+1 .. Mem+2*nCol: + ** Previous value of indexed columns, from left to right. + ** + ** Cells iMem through iMem+nCol are initialized to 0. The others are + ** initialized to contain an SQL NULL. + */ + for(i=0; i<=nCol; i++){ + sqlite3VdbeAddOp2(v, OP_Integer, 0, iMem+i); + } + for(i=0; i<nCol; i++){ + sqlite3VdbeAddOp2(v, OP_Null, 0, iMem+nCol+i+1); + } + + /* Start the analysis loop. This loop runs through all the entries in + ** the index b-tree. */ + endOfLoop = sqlite3VdbeMakeLabel(v); + sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop); + topOfLoop = sqlite3VdbeCurrentAddr(v); + sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1); /* Increment row counter */ + + for(i=0; i<nCol; i++){ + CollSeq *pColl; + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regCol); + if( i==0 ){ + /* Always record the very first row */ + addrIfNot = sqlite3VdbeAddOp1(v, OP_IfNot, iMem+1); + } + assert( pIdx->azColl!=0 ); + assert( pIdx->azColl[i]!=0 ); + pColl = sqlite3LocateCollSeq(pParse, pIdx->azColl[i]); + aChngAddr[i] = sqlite3VdbeAddOp4(v, OP_Ne, regCol, 0, iMem+nCol+i+1, + (char*)pColl, P4_COLLSEQ); + sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); + VdbeComment((v, "jump if column %d changed", i)); +#ifdef SQLITE_ENABLE_STAT3 + if( i==0 ){ + sqlite3VdbeAddOp2(v, OP_AddImm, regNumEq, 1); + VdbeComment((v, "incr repeat count")); + } +#endif + } + sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop); + for(i=0; i<nCol; i++){ + sqlite3VdbeJumpHere(v, aChngAddr[i]); /* Set jump dest for the OP_Ne */ + if( i==0 ){ + sqlite3VdbeJumpHere(v, addrIfNot); /* Jump dest for OP_IfNot */ +#ifdef SQLITE_ENABLE_STAT3 + sqlite3VdbeAddOp4(v, OP_Function, 1, regNumEq, regTemp2, + (char*)&stat3PushFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 5); + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, pIdx->nColumn, regRowid); + sqlite3VdbeAddOp3(v, OP_Add, regNumEq, regNumLt, regNumLt); + sqlite3VdbeAddOp2(v, OP_AddImm, regNumDLt, 1); + sqlite3VdbeAddOp2(v, OP_Integer, 1, regNumEq); +#endif + } + sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1); + sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1); + } + sqlite3DbFree(db, aChngAddr); + + /* Always jump here after updating the iMem+1...iMem+1+nCol counters */ + sqlite3VdbeResolveLabel(v, endOfLoop); + + sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, topOfLoop); + sqlite3VdbeAddOp1(v, OP_Close, iIdxCur); +#ifdef SQLITE_ENABLE_STAT3 + sqlite3VdbeAddOp4(v, OP_Function, 1, regNumEq, regTemp2, + (char*)&stat3PushFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 5); + sqlite3VdbeAddOp2(v, OP_Integer, -1, regLoop); + shortJump = + sqlite3VdbeAddOp2(v, OP_AddImm, regLoop, 1); + sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regTemp1, + (char*)&stat3GetFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 2); + sqlite3VdbeAddOp1(v, OP_IsNull, regTemp1); + sqlite3VdbeAddOp3(v, OP_NotExists, iTabCur, shortJump, regTemp1); + sqlite3VdbeAddOp3(v, OP_Column, iTabCur, pIdx->aiColumn[0], regSample); + sqlite3ColumnDefault(v, pTab, pIdx->aiColumn[0], regSample); + sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regNumEq, + (char*)&stat3GetFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 3); + sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regNumLt, + (char*)&stat3GetFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 4); + sqlite3VdbeAddOp4(v, OP_Function, 1, regAccum, regNumDLt, + (char*)&stat3GetFuncdef, P4_FUNCDEF); + sqlite3VdbeChangeP5(v, 5); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 6, regRec, "bbbbbb", 0); + sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regNewRowid); + sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regRec, regNewRowid); + sqlite3VdbeAddOp2(v, OP_Goto, 0, shortJump); + sqlite3VdbeJumpHere(v, shortJump+2); +#endif + + /* Store the results in sqlite_stat1. + ** + ** The result is a single row of the sqlite_stat1 table. The first + ** two columns are the names of the table and index. The third column + ** is a string composed of a list of integer statistics about the + ** index. The first integer in the list is the total number of entries + ** in the index. There is one additional integer in the list for each + ** column of the table. This additional integer is a guess of how many + ** rows of the table the index will select. If D is the count of distinct + ** values and K is the total number of rows, then the integer is computed + ** as: + ** + ** I = (K+D-1)/D + ** + ** If K==0 then no entry is made into the sqlite_stat1 table. + ** If K>0 then it is always the case the D>0 so division by zero + ** is never possible. + */ + sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regStat1); + if( jZeroRows<0 ){ + jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, iMem); + } + for(i=0; i<nCol; i++){ + sqlite3VdbeAddOp4(v, OP_String8, 0, regTemp, 0, " ", 0); + sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regStat1, regStat1); + sqlite3VdbeAddOp3(v, OP_Add, iMem, iMem+i+1, regTemp); + sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1); + sqlite3VdbeAddOp3(v, OP_Divide, iMem+i+1, regTemp, regTemp); + sqlite3VdbeAddOp1(v, OP_ToInt, regTemp); + sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regStat1, regStat1); + } + sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0); + sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid); + sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regNewRowid); + sqlite3VdbeChangeP5(v, OPFLAG_APPEND); + } + + /* If the table has no indices, create a single sqlite_stat1 entry + ** containing NULL as the index name and the row count as the content. + */ + if( pTab->pIndex==0 ){ + sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pTab->tnum, iDb); + VdbeComment((v, "%s", pTab->zName)); + sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat1); + sqlite3VdbeAddOp1(v, OP_Close, iIdxCur); + jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1); + }else{ + sqlite3VdbeJumpHere(v, jZeroRows); + jZeroRows = sqlite3VdbeAddOp0(v, OP_Goto); + } + sqlite3VdbeAddOp2(v, OP_Null, 0, regIdxname); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0); + sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regNewRowid); + sqlite3VdbeAddOp3(v, OP_Insert, iStatCur, regRec, regNewRowid); + sqlite3VdbeChangeP5(v, OPFLAG_APPEND); + if( pParse->nMem<regRec ) pParse->nMem = regRec; + sqlite3VdbeJumpHere(v, jZeroRows); +} + + +/* +** Generate code that will cause the most recent index analysis to +** be loaded into internal hash tables where is can be used. +*/ +static void loadAnalysis(Parse *pParse, int iDb){ + Vdbe *v = sqlite3GetVdbe(pParse); + if( v ){ + sqlite3VdbeAddOp1(v, OP_LoadAnalysis, iDb); + } +} + +/* +** Generate code that will do an analysis of an entire database +*/ +static void analyzeDatabase(Parse *pParse, int iDb){ + sqlite3 *db = pParse->db; + Schema *pSchema = db->aDb[iDb].pSchema; /* Schema of database iDb */ + HashElem *k; + int iStatCur; + int iMem; + + sqlite3BeginWriteOperation(pParse, 0, iDb); + iStatCur = pParse->nTab; + pParse->nTab += 3; + openStatTable(pParse, iDb, iStatCur, 0, 0); + iMem = pParse->nMem+1; + assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); + for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){ + Table *pTab = (Table*)sqliteHashData(k); + analyzeOneTable(pParse, pTab, 0, iStatCur, iMem); + } + loadAnalysis(pParse, iDb); +} + +/* +** Generate code that will do an analysis of a single table in +** a database. If pOnlyIdx is not NULL then it is a single index +** in pTab that should be analyzed. +*/ +static void analyzeTable(Parse *pParse, Table *pTab, Index *pOnlyIdx){ + int iDb; + int iStatCur; + + assert( pTab!=0 ); + assert( sqlite3BtreeHoldsAllMutexes(pParse->db) ); + iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema); + sqlite3BeginWriteOperation(pParse, 0, iDb); + iStatCur = pParse->nTab; + pParse->nTab += 3; + if( pOnlyIdx ){ + openStatTable(pParse, iDb, iStatCur, pOnlyIdx->zName, "idx"); + }else{ + openStatTable(pParse, iDb, iStatCur, pTab->zName, "tbl"); + } + analyzeOneTable(pParse, pTab, pOnlyIdx, iStatCur, pParse->nMem+1); + loadAnalysis(pParse, iDb); +} + +/* +** Generate code for the ANALYZE command. The parser calls this routine +** when it recognizes an ANALYZE command. +** +** ANALYZE -- 1 +** ANALYZE <database> -- 2 +** ANALYZE ?<database>.?<tablename> -- 3 +** +** Form 1 causes all indices in all attached databases to be analyzed. +** Form 2 analyzes all indices the single database named. +** Form 3 analyzes all indices associated with the named table. +*/ +void sqlite3Analyze(Parse *pParse, Token *pName1, Token *pName2){ + sqlite3 *db = pParse->db; + int iDb; + int i; + char *z, *zDb; + Table *pTab; + Index *pIdx; + Token *pTableName; + + /* Read the database schema. If an error occurs, leave an error message + ** and code in pParse and return NULL. */ + assert( sqlite3BtreeHoldsAllMutexes(pParse->db) ); + if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){ + return; + } + + assert( pName2!=0 || pName1==0 ); + if( pName1==0 ){ + /* Form 1: Analyze everything */ + for(i=0; i<db->nDb; i++){ + if( i==1 ) continue; /* Do not analyze the TEMP database */ + analyzeDatabase(pParse, i); + } + }else if( pName2->n==0 ){ + /* Form 2: Analyze the database or table named */ + iDb = sqlite3FindDb(db, pName1); + if( iDb>=0 ){ + analyzeDatabase(pParse, iDb); + }else{ + z = sqlite3NameFromToken(db, pName1); + if( z ){ + if( (pIdx = sqlite3FindIndex(db, z, 0))!=0 ){ + analyzeTable(pParse, pIdx->pTable, pIdx); + }else if( (pTab = sqlite3LocateTable(pParse, 0, z, 0))!=0 ){ + analyzeTable(pParse, pTab, 0); + } + sqlite3DbFree(db, z); + } + } + }else{ + /* Form 3: Analyze the fully qualified table name */ + iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pTableName); + if( iDb>=0 ){ + zDb = db->aDb[iDb].zName; + z = sqlite3NameFromToken(db, pTableName); + if( z ){ + if( (pIdx = sqlite3FindIndex(db, z, zDb))!=0 ){ + analyzeTable(pParse, pIdx->pTable, pIdx); + }else if( (pTab = sqlite3LocateTable(pParse, 0, z, zDb))!=0 ){ + analyzeTable(pParse, pTab, 0); + } + sqlite3DbFree(db, z); + } + } + } +} + +/* +** Used to pass information from the analyzer reader through to the +** callback routine. +*/ +typedef struct analysisInfo analysisInfo; +struct analysisInfo { + sqlite3 *db; + const char *zDatabase; +}; + +/* +** This callback is invoked once for each index when reading the +** sqlite_stat1 table. +** +** argv[0] = name of the table +** argv[1] = name of the index (might be NULL) +** argv[2] = results of analysis - on integer for each column +** +** Entries for which argv[1]==NULL simply record the number of rows in +** the table. +*/ +static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){ + analysisInfo *pInfo = (analysisInfo*)pData; + Index *pIndex; + Table *pTable; + int i, c, n; + tRowcnt v; + const char *z; + + assert( argc==3 ); + UNUSED_PARAMETER2(NotUsed, argc); + + if( argv==0 || argv[0]==0 || argv[2]==0 ){ + return 0; + } + pTable = sqlite3FindTable(pInfo->db, argv[0], pInfo->zDatabase); + if( pTable==0 ){ + return 0; + } + if( argv[1] ){ + pIndex = sqlite3FindIndex(pInfo->db, argv[1], pInfo->zDatabase); + }else{ + pIndex = 0; + } + n = pIndex ? pIndex->nColumn : 0; + z = argv[2]; + for(i=0; *z && i<=n; i++){ + v = 0; + while( (c=z[0])>='0' && c<='9' ){ + v = v*10 + c - '0'; + z++; + } + if( i==0 ) pTable->nRowEst = v; + if( pIndex==0 ) break; + pIndex->aiRowEst[i] = v; + if( *z==' ' ) z++; + if( memcmp(z, "unordered", 10)==0 ){ + pIndex->bUnordered = 1; + break; + } + } + return 0; +} + +/* +** If the Index.aSample variable is not NULL, delete the aSample[] array +** and its contents. +*/ +void sqlite3DeleteIndexSamples(sqlite3 *db, Index *pIdx){ +#ifdef SQLITE_ENABLE_STAT3 + if( pIdx->aSample ){ + int j; + for(j=0; j<pIdx->nSample; j++){ + IndexSample *p = &pIdx->aSample[j]; + if( p->eType==SQLITE_TEXT || p->eType==SQLITE_BLOB ){ + sqlite3DbFree(db, p->u.z); + } + } + sqlite3DbFree(db, pIdx->aSample); + } + if( db && db->pnBytesFreed==0 ){ + pIdx->nSample = 0; + pIdx->aSample = 0; + } +#else + UNUSED_PARAMETER(db); + UNUSED_PARAMETER(pIdx); +#endif +} + +#ifdef SQLITE_ENABLE_STAT3 +/* +** Load content from the sqlite_stat3 table into the Index.aSample[] +** arrays of all indices. +*/ +static int loadStat3(sqlite3 *db, const char *zDb){ + int rc; /* Result codes from subroutines */ + sqlite3_stmt *pStmt = 0; /* An SQL statement being run */ + char *zSql; /* Text of the SQL statement */ + Index *pPrevIdx = 0; /* Previous index in the loop */ + int idx = 0; /* slot in pIdx->aSample[] for next sample */ + int eType; /* Datatype of a sample */ + IndexSample *pSample; /* A slot in pIdx->aSample[] */ + + if( !sqlite3FindTable(db, "sqlite_stat3", zDb) ){ + return SQLITE_OK; + } + + zSql = sqlite3MPrintf(db, + "SELECT idx,count(*) FROM %Q.sqlite_stat3" + " GROUP BY idx", zDb); + if( !zSql ){ + return SQLITE_NOMEM; + } + rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); + sqlite3DbFree(db, zSql); + if( rc ) return rc; + + while( sqlite3_step(pStmt)==SQLITE_ROW ){ + char *zIndex; /* Index name */ + Index *pIdx; /* Pointer to the index object */ + int nSample; /* Number of samples */ + + zIndex = (char *)sqlite3_column_text(pStmt, 0); + if( zIndex==0 ) continue; + nSample = sqlite3_column_int(pStmt, 1); + pIdx = sqlite3FindIndex(db, zIndex, zDb); + if( pIdx==0 ) continue; + assert( pIdx->nSample==0 ); + pIdx->nSample = nSample; + pIdx->aSample = sqlite3MallocZero( nSample*sizeof(IndexSample) ); + pIdx->avgEq = pIdx->aiRowEst[1]; + if( pIdx->aSample==0 ){ + db->mallocFailed = 1; + sqlite3_finalize(pStmt); + return SQLITE_NOMEM; + } + } + rc = sqlite3_finalize(pStmt); + if( rc ) return rc; + + zSql = sqlite3MPrintf(db, + "SELECT idx,neq,nlt,ndlt,sample FROM %Q.sqlite_stat3", zDb); + if( !zSql ){ + return SQLITE_NOMEM; + } + rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); + sqlite3DbFree(db, zSql); + if( rc ) return rc; + + while( sqlite3_step(pStmt)==SQLITE_ROW ){ + char *zIndex; /* Index name */ + Index *pIdx; /* Pointer to the index object */ + int i; /* Loop counter */ + tRowcnt sumEq; /* Sum of the nEq values */ + + zIndex = (char *)sqlite3_column_text(pStmt, 0); + if( zIndex==0 ) continue; + pIdx = sqlite3FindIndex(db, zIndex, zDb); + if( pIdx==0 ) continue; + if( pIdx==pPrevIdx ){ + idx++; + }else{ + pPrevIdx = pIdx; + idx = 0; + } + assert( idx<pIdx->nSample ); + pSample = &pIdx->aSample[idx]; + pSample->nEq = (tRowcnt)sqlite3_column_int64(pStmt, 1); + pSample->nLt = (tRowcnt)sqlite3_column_int64(pStmt, 2); + pSample->nDLt = (tRowcnt)sqlite3_column_int64(pStmt, 3); + if( idx==pIdx->nSample-1 ){ + if( pSample->nDLt>0 ){ + for(i=0, sumEq=0; i<=idx-1; i++) sumEq += pIdx->aSample[i].nEq; + pIdx->avgEq = (pSample->nLt - sumEq)/pSample->nDLt; + } + if( pIdx->avgEq<=0 ) pIdx->avgEq = 1; + } + eType = sqlite3_column_type(pStmt, 4); + pSample->eType = (u8)eType; + switch( eType ){ + case SQLITE_INTEGER: { + pSample->u.i = sqlite3_column_int64(pStmt, 4); + break; + } + case SQLITE_FLOAT: { + pSample->u.r = sqlite3_column_double(pStmt, 4); + break; + } + case SQLITE_NULL: { + break; + } + default: assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); { + const char *z = (const char *)( + (eType==SQLITE_BLOB) ? + sqlite3_column_blob(pStmt, 4): + sqlite3_column_text(pStmt, 4) + ); + int n = z ? sqlite3_column_bytes(pStmt, 4) : 0; + pSample->nByte = n; + if( n < 1){ + pSample->u.z = 0; + }else{ + pSample->u.z = sqlite3Malloc(n); + if( pSample->u.z==0 ){ + db->mallocFailed = 1; + sqlite3_finalize(pStmt); + return SQLITE_NOMEM; + } + memcpy(pSample->u.z, z, n); + } + } + } + } + return sqlite3_finalize(pStmt); +} +#endif /* SQLITE_ENABLE_STAT3 */ + +/* +** Load the content of the sqlite_stat1 and sqlite_stat3 tables. The +** contents of sqlite_stat1 are used to populate the Index.aiRowEst[] +** arrays. The contents of sqlite_stat3 are used to populate the +** Index.aSample[] arrays. +** +** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR +** is returned. In this case, even if SQLITE_ENABLE_STAT3 was defined +** during compilation and the sqlite_stat3 table is present, no data is +** read from it. +** +** If SQLITE_ENABLE_STAT3 was defined during compilation and the +** sqlite_stat3 table is not present in the database, SQLITE_ERROR is +** returned. However, in this case, data is read from the sqlite_stat1 +** table (if it is present) before returning. +** +** If an OOM error occurs, this function always sets db->mallocFailed. +** This means if the caller does not care about other errors, the return +** code may be ignored. +*/ +int sqlite3AnalysisLoad(sqlite3 *db, int iDb){ + analysisInfo sInfo; + HashElem *i; + char *zSql; + int rc; + + assert( iDb>=0 && iDb<db->nDb ); + assert( db->aDb[iDb].pBt!=0 ); + + /* Clear any prior statistics */ + assert( sqlite3SchemaMutexHeld(db, iDb, 0) ); + for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){ + Index *pIdx = sqliteHashData(i); + sqlite3DefaultRowEst(pIdx); +#ifdef SQLITE_ENABLE_STAT3 + sqlite3DeleteIndexSamples(db, pIdx); + pIdx->aSample = 0; +#endif + } + + /* Check to make sure the sqlite_stat1 table exists */ + sInfo.db = db; + sInfo.zDatabase = db->aDb[iDb].zName; + if( sqlite3FindTable(db, "sqlite_stat1", sInfo.zDatabase)==0 ){ + return SQLITE_ERROR; + } + + /* Load new statistics out of the sqlite_stat1 table */ + zSql = sqlite3MPrintf(db, + "SELECT tbl,idx,stat FROM %Q.sqlite_stat1", sInfo.zDatabase); + if( zSql==0 ){ + rc = SQLITE_NOMEM; + }else{ + rc = sqlite3_exec(db, zSql, analysisLoader, &sInfo, 0); + sqlite3DbFree(db, zSql); + } + + + /* Load the statistics from the sqlite_stat3 table. */ +#ifdef SQLITE_ENABLE_STAT3 + if( rc==SQLITE_OK ){ + rc = loadStat3(db, sInfo.zDatabase); + } +#endif + + if( rc==SQLITE_NOMEM ){ + db->mallocFailed = 1; + } + return rc; +} + + +#endif /* SQLITE_OMIT_ANALYZE */ |