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+/*
+** 2010 July 12
+**
+** 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 an implementation of the "dbstat" virtual table.
+**
+** The dbstat virtual table is used to extract low-level storage
+** information from an SQLite database in order to implement the
+** "sqlite3_analyzer" utility. See the ../tool/spaceanal.tcl script
+** for an example implementation.
+**
+** Additional information is available on the "dbstat.html" page of the
+** official SQLite documentation.
+*/
+
+#include "sqliteInt.h" /* Requires access to internal data structures */
+#if (defined(SQLITE_ENABLE_DBSTAT_VTAB) || defined(SQLITE_TEST)) \
+ && !defined(SQLITE_OMIT_VIRTUALTABLE)
+
+/*
+** The pager and btree modules arrange objects in memory so that there are
+** always approximately 200 bytes of addressable memory following each page
+** buffer. This way small buffer overreads caused by corrupt database pages
+** do not cause undefined behaviour. This module pads each page buffer
+** by the following number of bytes for the same purpose.
+*/
+#define DBSTAT_PAGE_PADDING_BYTES 256
+
+/*
+** Page paths:
+**
+** The value of the 'path' column describes the path taken from the
+** root-node of the b-tree structure to each page. The value of the
+** root-node path is '/'.
+**
+** The value of the path for the left-most child page of the root of
+** a b-tree is '/000/'. (Btrees store content ordered from left to right
+** so the pages to the left have smaller keys than the pages to the right.)
+** The next to left-most child of the root page is
+** '/001', and so on, each sibling page identified by a 3-digit hex
+** value. The children of the 451st left-most sibling have paths such
+** as '/1c2/000/, '/1c2/001/' etc.
+**
+** Overflow pages are specified by appending a '+' character and a
+** six-digit hexadecimal value to the path to the cell they are linked
+** from. For example, the three overflow pages in a chain linked from
+** the left-most cell of the 450th child of the root page are identified
+** by the paths:
+**
+** '/1c2/000+000000' // First page in overflow chain
+** '/1c2/000+000001' // Second page in overflow chain
+** '/1c2/000+000002' // Third page in overflow chain
+**
+** If the paths are sorted using the BINARY collation sequence, then
+** the overflow pages associated with a cell will appear earlier in the
+** sort-order than its child page:
+**
+** '/1c2/000/' // Left-most child of 451st child of root
+*/
+static const char zDbstatSchema[] =
+ "CREATE TABLE x("
+ " name TEXT," /* 0 Name of table or index */
+ " path TEXT," /* 1 Path to page from root (NULL for agg) */
+ " pageno INTEGER," /* 2 Page number (page count for aggregates) */
+ " pagetype TEXT," /* 3 'internal', 'leaf', 'overflow', or NULL */
+ " ncell INTEGER," /* 4 Cells on page (0 for overflow) */
+ " payload INTEGER," /* 5 Bytes of payload on this page */
+ " unused INTEGER," /* 6 Bytes of unused space on this page */
+ " mx_payload INTEGER," /* 7 Largest payload size of all cells */
+ " pgoffset INTEGER," /* 8 Offset of page in file (NULL for agg) */
+ " pgsize INTEGER," /* 9 Size of the page (sum for aggregate) */
+ " schema TEXT HIDDEN," /* 10 Database schema being analyzed */
+ " aggregate BOOLEAN HIDDEN" /* 11 aggregate info for each table */
+ ")"
+;
+
+/* Forward reference to data structured used in this module */
+typedef struct StatTable StatTable;
+typedef struct StatCursor StatCursor;
+typedef struct StatPage StatPage;
+typedef struct StatCell StatCell;
+
+/* Size information for a single cell within a btree page */
+struct StatCell {
+ int nLocal; /* Bytes of local payload */
+ u32 iChildPg; /* Child node (or 0 if this is a leaf) */
+ int nOvfl; /* Entries in aOvfl[] */
+ u32 *aOvfl; /* Array of overflow page numbers */
+ int nLastOvfl; /* Bytes of payload on final overflow page */
+ int iOvfl; /* Iterates through aOvfl[] */
+};
+
+/* Size information for a single btree page */
+struct StatPage {
+ u32 iPgno; /* Page number */
+ u8 *aPg; /* Page buffer from sqlite3_malloc() */
+ int iCell; /* Current cell */
+ char *zPath; /* Path to this page */
+
+ /* Variables populated by statDecodePage(): */
+ u8 flags; /* Copy of flags byte */
+ int nCell; /* Number of cells on page */
+ int nUnused; /* Number of unused bytes on page */
+ StatCell *aCell; /* Array of parsed cells */
+ u32 iRightChildPg; /* Right-child page number (or 0) */
+ int nMxPayload; /* Largest payload of any cell on the page */
+};
+
+/* The cursor for scanning the dbstat virtual table */
+struct StatCursor {
+ sqlite3_vtab_cursor base; /* base class. MUST BE FIRST! */
+ sqlite3_stmt *pStmt; /* Iterates through set of root pages */
+ u8 isEof; /* After pStmt has returned SQLITE_DONE */
+ u8 isAgg; /* Aggregate results for each table */
+ int iDb; /* Schema used for this query */
+
+ StatPage aPage[32]; /* Pages in path to current page */
+ int iPage; /* Current entry in aPage[] */
+
+ /* Values to return. */
+ u32 iPageno; /* Value of 'pageno' column */
+ char *zName; /* Value of 'name' column */
+ char *zPath; /* Value of 'path' column */
+ char *zPagetype; /* Value of 'pagetype' column */
+ int nPage; /* Number of pages in current btree */
+ int nCell; /* Value of 'ncell' column */
+ int nMxPayload; /* Value of 'mx_payload' column */
+ i64 nUnused; /* Value of 'unused' column */
+ i64 nPayload; /* Value of 'payload' column */
+ i64 iOffset; /* Value of 'pgOffset' column */
+ i64 szPage; /* Value of 'pgSize' column */
+};
+
+/* An instance of the DBSTAT virtual table */
+struct StatTable {
+ sqlite3_vtab base; /* base class. MUST BE FIRST! */
+ sqlite3 *db; /* Database connection that owns this vtab */
+ int iDb; /* Index of database to analyze */
+};
+
+#ifndef get2byte
+# define get2byte(x) ((x)[0]<<8 | (x)[1])
+#endif
+
+/*
+** Connect to or create a new DBSTAT virtual table.
+*/
+static int statConnect(
+ sqlite3 *db,
+ void *pAux,
+ int argc, const char *const*argv,
+ sqlite3_vtab **ppVtab,
+ char **pzErr
+){
+ StatTable *pTab = 0;
+ int rc = SQLITE_OK;
+ int iDb;
+ (void)pAux;
+
+ if( argc>=4 ){
+ Token nm;
+ sqlite3TokenInit(&nm, (char*)argv[3]);
+ iDb = sqlite3FindDb(db, &nm);
+ if( iDb<0 ){
+ *pzErr = sqlite3_mprintf("no such database: %s", argv[3]);
+ return SQLITE_ERROR;
+ }
+ }else{
+ iDb = 0;
+ }
+ sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
+ rc = sqlite3_declare_vtab(db, zDbstatSchema);
+ if( rc==SQLITE_OK ){
+ pTab = (StatTable *)sqlite3_malloc64(sizeof(StatTable));
+ if( pTab==0 ) rc = SQLITE_NOMEM_BKPT;
+ }
+
+ assert( rc==SQLITE_OK || pTab==0 );
+ if( rc==SQLITE_OK ){
+ memset(pTab, 0, sizeof(StatTable));
+ pTab->db = db;
+ pTab->iDb = iDb;
+ }
+
+ *ppVtab = (sqlite3_vtab*)pTab;
+ return rc;
+}
+
+/*
+** Disconnect from or destroy the DBSTAT virtual table.
+*/
+static int statDisconnect(sqlite3_vtab *pVtab){
+ sqlite3_free(pVtab);
+ return SQLITE_OK;
+}
+
+/*
+** Compute the best query strategy and return the result in idxNum.
+**
+** idxNum-Bit Meaning
+** ---------- ----------------------------------------------
+** 0x01 There is a schema=? term in the WHERE clause
+** 0x02 There is a name=? term in the WHERE clause
+** 0x04 There is an aggregate=? term in the WHERE clause
+** 0x08 Output should be ordered by name and path
+*/
+static int statBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+ int i;
+ int iSchema = -1;
+ int iName = -1;
+ int iAgg = -1;
+ (void)tab;
+
+ /* Look for a valid schema=? constraint. If found, change the idxNum to
+ ** 1 and request the value of that constraint be sent to xFilter. And
+ ** lower the cost estimate to encourage the constrained version to be
+ ** used.
+ */
+ for(i=0; i<pIdxInfo->nConstraint; i++){
+ if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
+ if( pIdxInfo->aConstraint[i].usable==0 ){
+ /* Force DBSTAT table should always be the right-most table in a join */
+ return SQLITE_CONSTRAINT;
+ }
+ switch( pIdxInfo->aConstraint[i].iColumn ){
+ case 0: { /* name */
+ iName = i;
+ break;
+ }
+ case 10: { /* schema */
+ iSchema = i;
+ break;
+ }
+ case 11: { /* aggregate */
+ iAgg = i;
+ break;
+ }
+ }
+ }
+ i = 0;
+ if( iSchema>=0 ){
+ pIdxInfo->aConstraintUsage[iSchema].argvIndex = ++i;
+ pIdxInfo->aConstraintUsage[iSchema].omit = 1;
+ pIdxInfo->idxNum |= 0x01;
+ }
+ if( iName>=0 ){
+ pIdxInfo->aConstraintUsage[iName].argvIndex = ++i;
+ pIdxInfo->idxNum |= 0x02;
+ }
+ if( iAgg>=0 ){
+ pIdxInfo->aConstraintUsage[iAgg].argvIndex = ++i;
+ pIdxInfo->idxNum |= 0x04;
+ }
+ pIdxInfo->estimatedCost = 1.0;
+
+ /* Records are always returned in ascending order of (name, path).
+ ** If this will satisfy the client, set the orderByConsumed flag so that
+ ** SQLite does not do an external sort.
+ */
+ if( ( pIdxInfo->nOrderBy==1
+ && pIdxInfo->aOrderBy[0].iColumn==0
+ && pIdxInfo->aOrderBy[0].desc==0
+ ) ||
+ ( pIdxInfo->nOrderBy==2
+ && pIdxInfo->aOrderBy[0].iColumn==0
+ && pIdxInfo->aOrderBy[0].desc==0
+ && pIdxInfo->aOrderBy[1].iColumn==1
+ && pIdxInfo->aOrderBy[1].desc==0
+ )
+ ){
+ pIdxInfo->orderByConsumed = 1;
+ pIdxInfo->idxNum |= 0x08;
+ }
+
+ return SQLITE_OK;
+}
+
+/*
+** Open a new DBSTAT cursor.
+*/
+static int statOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+ StatTable *pTab = (StatTable *)pVTab;
+ StatCursor *pCsr;
+
+ pCsr = (StatCursor *)sqlite3_malloc64(sizeof(StatCursor));
+ if( pCsr==0 ){
+ return SQLITE_NOMEM_BKPT;
+ }else{
+ memset(pCsr, 0, sizeof(StatCursor));
+ pCsr->base.pVtab = pVTab;
+ pCsr->iDb = pTab->iDb;
+ }
+
+ *ppCursor = (sqlite3_vtab_cursor *)pCsr;
+ return SQLITE_OK;
+}
+
+static void statClearCells(StatPage *p){
+ int i;
+ if( p->aCell ){
+ for(i=0; i<p->nCell; i++){
+ sqlite3_free(p->aCell[i].aOvfl);
+ }
+ sqlite3_free(p->aCell);
+ }
+ p->nCell = 0;
+ p->aCell = 0;
+}
+
+static void statClearPage(StatPage *p){
+ u8 *aPg = p->aPg;
+ statClearCells(p);
+ sqlite3_free(p->zPath);
+ memset(p, 0, sizeof(StatPage));
+ p->aPg = aPg;
+}
+
+static void statResetCsr(StatCursor *pCsr){
+ int i;
+ /* In some circumstances, specifically if an OOM has occurred, the call
+ ** to sqlite3_reset() may cause the pager to be reset (emptied). It is
+ ** important that statClearPage() is called to free any page refs before
+ ** this happens. dbsqlfuzz 9ed3e4e3816219d3509d711636c38542bf3f40b1. */
+ for(i=0; i<ArraySize(pCsr->aPage); i++){
+ statClearPage(&pCsr->aPage[i]);
+ sqlite3_free(pCsr->aPage[i].aPg);
+ pCsr->aPage[i].aPg = 0;
+ }
+ sqlite3_reset(pCsr->pStmt);
+ pCsr->iPage = 0;
+ sqlite3_free(pCsr->zPath);
+ pCsr->zPath = 0;
+ pCsr->isEof = 0;
+}
+
+/* Resize the space-used counters inside of the cursor */
+static void statResetCounts(StatCursor *pCsr){
+ pCsr->nCell = 0;
+ pCsr->nMxPayload = 0;
+ pCsr->nUnused = 0;
+ pCsr->nPayload = 0;
+ pCsr->szPage = 0;
+ pCsr->nPage = 0;
+}
+
+/*
+** Close a DBSTAT cursor.
+*/
+static int statClose(sqlite3_vtab_cursor *pCursor){
+ StatCursor *pCsr = (StatCursor *)pCursor;
+ statResetCsr(pCsr);
+ sqlite3_finalize(pCsr->pStmt);
+ sqlite3_free(pCsr);
+ return SQLITE_OK;
+}
+
+/*
+** For a single cell on a btree page, compute the number of bytes of
+** content (payload) stored on that page. That is to say, compute the
+** number of bytes of content not found on overflow pages.
+*/
+static int getLocalPayload(
+ int nUsable, /* Usable bytes per page */
+ u8 flags, /* Page flags */
+ int nTotal /* Total record (payload) size */
+){
+ int nLocal;
+ int nMinLocal;
+ int nMaxLocal;
+
+ if( flags==0x0D ){ /* Table leaf node */
+ nMinLocal = (nUsable - 12) * 32 / 255 - 23;
+ nMaxLocal = nUsable - 35;
+ }else{ /* Index interior and leaf nodes */
+ nMinLocal = (nUsable - 12) * 32 / 255 - 23;
+ nMaxLocal = (nUsable - 12) * 64 / 255 - 23;
+ }
+
+ nLocal = nMinLocal + (nTotal - nMinLocal) % (nUsable - 4);
+ if( nLocal>nMaxLocal ) nLocal = nMinLocal;
+ return nLocal;
+}
+
+/* Populate the StatPage object with information about the all
+** cells found on the page currently under analysis.
+*/
+static int statDecodePage(Btree *pBt, StatPage *p){
+ int nUnused;
+ int iOff;
+ int nHdr;
+ int isLeaf;
+ int szPage;
+
+ u8 *aData = p->aPg;
+ u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];
+
+ p->flags = aHdr[0];
+ if( p->flags==0x0A || p->flags==0x0D ){
+ isLeaf = 1;
+ nHdr = 8;
+ }else if( p->flags==0x05 || p->flags==0x02 ){
+ isLeaf = 0;
+ nHdr = 12;
+ }else{
+ goto statPageIsCorrupt;
+ }
+ if( p->iPgno==1 ) nHdr += 100;
+ p->nCell = get2byte(&aHdr[3]);
+ p->nMxPayload = 0;
+ szPage = sqlite3BtreeGetPageSize(pBt);
+
+ nUnused = get2byte(&aHdr[5]) - nHdr - 2*p->nCell;
+ nUnused += (int)aHdr[7];
+ iOff = get2byte(&aHdr[1]);
+ while( iOff ){
+ int iNext;
+ if( iOff>=szPage ) goto statPageIsCorrupt;
+ nUnused += get2byte(&aData[iOff+2]);
+ iNext = get2byte(&aData[iOff]);
+ if( iNext<iOff+4 && iNext>0 ) goto statPageIsCorrupt;
+ iOff = iNext;
+ }
+ p->nUnused = nUnused;
+ p->iRightChildPg = isLeaf ? 0 : sqlite3Get4byte(&aHdr[8]);
+
+ if( p->nCell ){
+ int i; /* Used to iterate through cells */
+ int nUsable; /* Usable bytes per page */
+
+ sqlite3BtreeEnter(pBt);
+ nUsable = szPage - sqlite3BtreeGetReserveNoMutex(pBt);
+ sqlite3BtreeLeave(pBt);
+ p->aCell = sqlite3_malloc64((p->nCell+1) * sizeof(StatCell));
+ if( p->aCell==0 ) return SQLITE_NOMEM_BKPT;
+ memset(p->aCell, 0, (p->nCell+1) * sizeof(StatCell));
+
+ for(i=0; i<p->nCell; i++){
+ StatCell *pCell = &p->aCell[i];
+
+ iOff = get2byte(&aData[nHdr+i*2]);
+ if( iOff<nHdr || iOff>=szPage ) goto statPageIsCorrupt;
+ if( !isLeaf ){
+ pCell->iChildPg = sqlite3Get4byte(&aData[iOff]);
+ iOff += 4;
+ }
+ if( p->flags==0x05 ){
+ /* A table interior node. nPayload==0. */
+ }else{
+ u32 nPayload; /* Bytes of payload total (local+overflow) */
+ int nLocal; /* Bytes of payload stored locally */
+ iOff += getVarint32(&aData[iOff], nPayload);
+ if( p->flags==0x0D ){
+ u64 dummy;
+ iOff += sqlite3GetVarint(&aData[iOff], &dummy);
+ }
+ if( nPayload>(u32)p->nMxPayload ) p->nMxPayload = nPayload;
+ nLocal = getLocalPayload(nUsable, p->flags, nPayload);
+ if( nLocal<0 ) goto statPageIsCorrupt;
+ pCell->nLocal = nLocal;
+ assert( nPayload>=(u32)nLocal );
+ assert( nLocal<=(nUsable-35) );
+ if( nPayload>(u32)nLocal ){
+ int j;
+ int nOvfl = ((nPayload - nLocal) + nUsable-4 - 1) / (nUsable - 4);
+ if( iOff+nLocal+4>nUsable || nPayload>0x7fffffff ){
+ goto statPageIsCorrupt;
+ }
+ pCell->nLastOvfl = (nPayload-nLocal) - (nOvfl-1) * (nUsable-4);
+ pCell->nOvfl = nOvfl;
+ pCell->aOvfl = sqlite3_malloc64(sizeof(u32)*nOvfl);
+ if( pCell->aOvfl==0 ) return SQLITE_NOMEM_BKPT;
+ pCell->aOvfl[0] = sqlite3Get4byte(&aData[iOff+nLocal]);
+ for(j=1; j<nOvfl; j++){
+ int rc;
+ u32 iPrev = pCell->aOvfl[j-1];
+ DbPage *pPg = 0;
+ rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPrev, &pPg, 0);
+ if( rc!=SQLITE_OK ){
+ assert( pPg==0 );
+ return rc;
+ }
+ pCell->aOvfl[j] = sqlite3Get4byte(sqlite3PagerGetData(pPg));
+ sqlite3PagerUnref(pPg);
+ }
+ }
+ }
+ }
+ }
+
+ return SQLITE_OK;
+
+statPageIsCorrupt:
+ p->flags = 0;
+ statClearCells(p);
+ return SQLITE_OK;
+}
+
+/*
+** Populate the pCsr->iOffset and pCsr->szPage member variables. Based on
+** the current value of pCsr->iPageno.
+*/
+static void statSizeAndOffset(StatCursor *pCsr){
+ StatTable *pTab = (StatTable *)((sqlite3_vtab_cursor *)pCsr)->pVtab;
+ Btree *pBt = pTab->db->aDb[pTab->iDb].pBt;
+ Pager *pPager = sqlite3BtreePager(pBt);
+ sqlite3_file *fd;
+ sqlite3_int64 x[2];
+
+ /* If connected to a ZIPVFS backend, find the page size and
+ ** offset from ZIPVFS.
+ */
+ fd = sqlite3PagerFile(pPager);
+ x[0] = pCsr->iPageno;
+ if( sqlite3OsFileControl(fd, 230440, &x)==SQLITE_OK ){
+ pCsr->iOffset = x[0];
+ pCsr->szPage += x[1];
+ }else{
+ /* Not ZIPVFS: The default page size and offset */
+ pCsr->szPage += sqlite3BtreeGetPageSize(pBt);
+ pCsr->iOffset = (i64)pCsr->szPage * (pCsr->iPageno - 1);
+ }
+}
+
+/*
+** Load a copy of the page data for page iPg into the buffer belonging
+** to page object pPg. Allocate the buffer if necessary. Return SQLITE_OK
+** if successful, or an SQLite error code otherwise.
+*/
+static int statGetPage(
+ Btree *pBt, /* Load page from this b-tree */
+ u32 iPg, /* Page number to load */
+ StatPage *pPg /* Load page into this object */
+){
+ int pgsz = sqlite3BtreeGetPageSize(pBt);
+ DbPage *pDbPage = 0;
+ int rc;
+
+ if( pPg->aPg==0 ){
+ pPg->aPg = (u8*)sqlite3_malloc(pgsz + DBSTAT_PAGE_PADDING_BYTES);
+ if( pPg->aPg==0 ){
+ return SQLITE_NOMEM_BKPT;
+ }
+ memset(&pPg->aPg[pgsz], 0, DBSTAT_PAGE_PADDING_BYTES);
+ }
+
+ rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPg, &pDbPage, 0);
+ if( rc==SQLITE_OK ){
+ const u8 *a = sqlite3PagerGetData(pDbPage);
+ memcpy(pPg->aPg, a, pgsz);
+ sqlite3PagerUnref(pDbPage);
+ }
+
+ return rc;
+}
+
+/*
+** Move a DBSTAT cursor to the next entry. Normally, the next
+** entry will be the next page, but in aggregated mode (pCsr->isAgg!=0),
+** the next entry is the next btree.
+*/
+static int statNext(sqlite3_vtab_cursor *pCursor){
+ int rc;
+ int nPayload;
+ char *z;
+ StatCursor *pCsr = (StatCursor *)pCursor;
+ StatTable *pTab = (StatTable *)pCursor->pVtab;
+ Btree *pBt = pTab->db->aDb[pCsr->iDb].pBt;
+ Pager *pPager = sqlite3BtreePager(pBt);
+
+ sqlite3_free(pCsr->zPath);
+ pCsr->zPath = 0;
+
+statNextRestart:
+ if( pCsr->iPage<0 ){
+ /* Start measuring space on the next btree */
+ statResetCounts(pCsr);
+ rc = sqlite3_step(pCsr->pStmt);
+ if( rc==SQLITE_ROW ){
+ int nPage;
+ u32 iRoot = (u32)sqlite3_column_int64(pCsr->pStmt, 1);
+ sqlite3PagerPagecount(pPager, &nPage);
+ if( nPage==0 ){
+ pCsr->isEof = 1;
+ return sqlite3_reset(pCsr->pStmt);
+ }
+ rc = statGetPage(pBt, iRoot, &pCsr->aPage[0]);
+ pCsr->aPage[0].iPgno = iRoot;
+ pCsr->aPage[0].iCell = 0;
+ if( !pCsr->isAgg ){
+ pCsr->aPage[0].zPath = z = sqlite3_mprintf("/");
+ if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+ }
+ pCsr->iPage = 0;
+ pCsr->nPage = 1;
+ }else{
+ pCsr->isEof = 1;
+ return sqlite3_reset(pCsr->pStmt);
+ }
+ }else{
+ /* Continue analyzing the btree previously started */
+ StatPage *p = &pCsr->aPage[pCsr->iPage];
+ if( !pCsr->isAgg ) statResetCounts(pCsr);
+ while( p->iCell<p->nCell ){
+ StatCell *pCell = &p->aCell[p->iCell];
+ while( pCell->iOvfl<pCell->nOvfl ){
+ int nUsable, iOvfl;
+ sqlite3BtreeEnter(pBt);
+ nUsable = sqlite3BtreeGetPageSize(pBt) -
+ sqlite3BtreeGetReserveNoMutex(pBt);
+ sqlite3BtreeLeave(pBt);
+ pCsr->nPage++;
+ statSizeAndOffset(pCsr);
+ if( pCell->iOvfl<pCell->nOvfl-1 ){
+ pCsr->nPayload += nUsable - 4;
+ }else{
+ pCsr->nPayload += pCell->nLastOvfl;
+ pCsr->nUnused += nUsable - 4 - pCell->nLastOvfl;
+ }
+ iOvfl = pCell->iOvfl;
+ pCell->iOvfl++;
+ if( !pCsr->isAgg ){
+ pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
+ pCsr->iPageno = pCell->aOvfl[iOvfl];
+ pCsr->zPagetype = "overflow";
+ pCsr->zPath = z = sqlite3_mprintf(
+ "%s%.3x+%.6x", p->zPath, p->iCell, iOvfl
+ );
+ return z==0 ? SQLITE_NOMEM_BKPT : SQLITE_OK;
+ }
+ }
+ if( p->iRightChildPg ) break;
+ p->iCell++;
+ }
+
+ if( !p->iRightChildPg || p->iCell>p->nCell ){
+ statClearPage(p);
+ pCsr->iPage--;
+ if( pCsr->isAgg && pCsr->iPage<0 ){
+ /* label-statNext-done: When computing aggregate space usage over
+ ** an entire btree, this is the exit point from this function */
+ return SQLITE_OK;
+ }
+ goto statNextRestart; /* Tail recursion */
+ }
+ pCsr->iPage++;
+ if( pCsr->iPage>=ArraySize(pCsr->aPage) ){
+ statResetCsr(pCsr);
+ return SQLITE_CORRUPT_BKPT;
+ }
+ assert( p==&pCsr->aPage[pCsr->iPage-1] );
+
+ if( p->iCell==p->nCell ){
+ p[1].iPgno = p->iRightChildPg;
+ }else{
+ p[1].iPgno = p->aCell[p->iCell].iChildPg;
+ }
+ rc = statGetPage(pBt, p[1].iPgno, &p[1]);
+ pCsr->nPage++;
+ p[1].iCell = 0;
+ if( !pCsr->isAgg ){
+ p[1].zPath = z = sqlite3_mprintf("%s%.3x/", p->zPath, p->iCell);
+ if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+ }
+ p->iCell++;
+ }
+
+
+ /* Populate the StatCursor fields with the values to be returned
+ ** by the xColumn() and xRowid() methods.
+ */
+ if( rc==SQLITE_OK ){
+ int i;
+ StatPage *p = &pCsr->aPage[pCsr->iPage];
+ pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
+ pCsr->iPageno = p->iPgno;
+
+ rc = statDecodePage(pBt, p);
+ if( rc==SQLITE_OK ){
+ statSizeAndOffset(pCsr);
+
+ switch( p->flags ){
+ case 0x05: /* table internal */
+ case 0x02: /* index internal */
+ pCsr->zPagetype = "internal";
+ break;
+ case 0x0D: /* table leaf */
+ case 0x0A: /* index leaf */
+ pCsr->zPagetype = "leaf";
+ break;
+ default:
+ pCsr->zPagetype = "corrupted";
+ break;
+ }
+ pCsr->nCell += p->nCell;
+ pCsr->nUnused += p->nUnused;
+ if( p->nMxPayload>pCsr->nMxPayload ) pCsr->nMxPayload = p->nMxPayload;
+ if( !pCsr->isAgg ){
+ pCsr->zPath = z = sqlite3_mprintf("%s", p->zPath);
+ if( z==0 ) rc = SQLITE_NOMEM_BKPT;
+ }
+ nPayload = 0;
+ for(i=0; i<p->nCell; i++){
+ nPayload += p->aCell[i].nLocal;
+ }
+ pCsr->nPayload += nPayload;
+
+ /* If computing aggregate space usage by btree, continue with the
+ ** next page. The loop will exit via the return at label-statNext-done
+ */
+ if( pCsr->isAgg ) goto statNextRestart;
+ }
+ }
+
+ return rc;
+}
+
+static int statEof(sqlite3_vtab_cursor *pCursor){
+ StatCursor *pCsr = (StatCursor *)pCursor;
+ return pCsr->isEof;
+}
+
+/* Initialize a cursor according to the query plan idxNum using the
+** arguments in argv[0]. See statBestIndex() for a description of the
+** meaning of the bits in idxNum.
+*/
+static int statFilter(
+ sqlite3_vtab_cursor *pCursor,
+ int idxNum, const char *idxStr,
+ int argc, sqlite3_value **argv
+){
+ StatCursor *pCsr = (StatCursor *)pCursor;
+ StatTable *pTab = (StatTable*)(pCursor->pVtab);
+ sqlite3_str *pSql; /* Query of btrees to analyze */
+ char *zSql; /* String value of pSql */
+ int iArg = 0; /* Count of argv[] parameters used so far */
+ int rc = SQLITE_OK; /* Result of this operation */
+ const char *zName = 0; /* Only provide analysis of this table */
+ (void)argc;
+ (void)idxStr;
+
+ statResetCsr(pCsr);
+ sqlite3_finalize(pCsr->pStmt);
+ pCsr->pStmt = 0;
+ if( idxNum & 0x01 ){
+ /* schema=? constraint is present. Get its value */
+ const char *zDbase = (const char*)sqlite3_value_text(argv[iArg++]);
+ pCsr->iDb = sqlite3FindDbName(pTab->db, zDbase);
+ if( pCsr->iDb<0 ){
+ pCsr->iDb = 0;
+ pCsr->isEof = 1;
+ return SQLITE_OK;
+ }
+ }else{
+ pCsr->iDb = pTab->iDb;
+ }
+ if( idxNum & 0x02 ){
+ /* name=? constraint is present */
+ zName = (const char*)sqlite3_value_text(argv[iArg++]);
+ }
+ if( idxNum & 0x04 ){
+ /* aggregate=? constraint is present */
+ pCsr->isAgg = sqlite3_value_double(argv[iArg++])!=0.0;
+ }else{
+ pCsr->isAgg = 0;
+ }
+ pSql = sqlite3_str_new(pTab->db);
+ sqlite3_str_appendf(pSql,
+ "SELECT * FROM ("
+ "SELECT 'sqlite_schema' AS name,1 AS rootpage,'table' AS type"
+ " UNION ALL "
+ "SELECT name,rootpage,type"
+ " FROM \"%w\".sqlite_schema WHERE rootpage!=0)",
+ pTab->db->aDb[pCsr->iDb].zDbSName);
+ if( zName ){
+ sqlite3_str_appendf(pSql, "WHERE name=%Q", zName);
+ }
+ if( idxNum & 0x08 ){
+ sqlite3_str_appendf(pSql, " ORDER BY name");
+ }
+ zSql = sqlite3_str_finish(pSql);
+ if( zSql==0 ){
+ return SQLITE_NOMEM_BKPT;
+ }else{
+ rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
+ sqlite3_free(zSql);
+ }
+
+ if( rc==SQLITE_OK ){
+ pCsr->iPage = -1;
+ rc = statNext(pCursor);
+ }
+ return rc;
+}
+
+static int statColumn(
+ sqlite3_vtab_cursor *pCursor,
+ sqlite3_context *ctx,
+ int i
+){
+ StatCursor *pCsr = (StatCursor *)pCursor;
+ switch( i ){
+ case 0: /* name */
+ sqlite3_result_text(ctx, pCsr->zName, -1, SQLITE_TRANSIENT);
+ break;
+ case 1: /* path */
+ if( !pCsr->isAgg ){
+ sqlite3_result_text(ctx, pCsr->zPath, -1, SQLITE_TRANSIENT);
+ }
+ break;
+ case 2: /* pageno */
+ if( pCsr->isAgg ){
+ sqlite3_result_int64(ctx, pCsr->nPage);
+ }else{
+ sqlite3_result_int64(ctx, pCsr->iPageno);
+ }
+ break;
+ case 3: /* pagetype */
+ if( !pCsr->isAgg ){
+ sqlite3_result_text(ctx, pCsr->zPagetype, -1, SQLITE_STATIC);
+ }
+ break;
+ case 4: /* ncell */
+ sqlite3_result_int64(ctx, pCsr->nCell);
+ break;
+ case 5: /* payload */
+ sqlite3_result_int64(ctx, pCsr->nPayload);
+ break;
+ case 6: /* unused */
+ sqlite3_result_int64(ctx, pCsr->nUnused);
+ break;
+ case 7: /* mx_payload */
+ sqlite3_result_int64(ctx, pCsr->nMxPayload);
+ break;
+ case 8: /* pgoffset */
+ if( !pCsr->isAgg ){
+ sqlite3_result_int64(ctx, pCsr->iOffset);
+ }
+ break;
+ case 9: /* pgsize */
+ sqlite3_result_int64(ctx, pCsr->szPage);
+ break;
+ case 10: { /* schema */
+ sqlite3 *db = sqlite3_context_db_handle(ctx);
+ int iDb = pCsr->iDb;
+ sqlite3_result_text(ctx, db->aDb[iDb].zDbSName, -1, SQLITE_STATIC);
+ break;
+ }
+ default: { /* aggregate */
+ sqlite3_result_int(ctx, pCsr->isAgg);
+ break;
+ }
+ }
+ return SQLITE_OK;
+}
+
+static int statRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+ StatCursor *pCsr = (StatCursor *)pCursor;
+ *pRowid = pCsr->iPageno;
+ return SQLITE_OK;
+}
+
+/*
+** Invoke this routine to register the "dbstat" virtual table module
+*/
+int sqlite3DbstatRegister(sqlite3 *db){
+ static sqlite3_module dbstat_module = {
+ 0, /* iVersion */
+ statConnect, /* xCreate */
+ statConnect, /* xConnect */
+ statBestIndex, /* xBestIndex */
+ statDisconnect, /* xDisconnect */
+ statDisconnect, /* xDestroy */
+ statOpen, /* xOpen - open a cursor */
+ statClose, /* xClose - close a cursor */
+ statFilter, /* xFilter - configure scan constraints */
+ statNext, /* xNext - advance a cursor */
+ statEof, /* xEof - check for end of scan */
+ statColumn, /* xColumn - read data */
+ statRowid, /* xRowid - read data */
+ 0, /* xUpdate */
+ 0, /* xBegin */
+ 0, /* xSync */
+ 0, /* xCommit */
+ 0, /* xRollback */
+ 0, /* xFindMethod */
+ 0, /* xRename */
+ 0, /* xSavepoint */
+ 0, /* xRelease */
+ 0, /* xRollbackTo */
+ 0, /* xShadowName */
+ 0 /* xIntegrity */
+ };
+ return sqlite3_create_module(db, "dbstat", &dbstat_module, 0);
+}
+#elif defined(SQLITE_ENABLE_DBSTAT_VTAB)
+int sqlite3DbstatRegister(sqlite3 *db){ return SQLITE_OK; }
+#endif /* SQLITE_ENABLE_DBSTAT_VTAB */
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-21 15:32:51 +0000