mirror of
https://github.com/sqlite/sqlite.git
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234 lines
6.9 KiB
C
234 lines
6.9 KiB
C
/*
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** 2018-12-04
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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**
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** This file implements a utility program used to help determine which
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** indexes in a database schema are used and unused, and how often specific
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** indexes are used.
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*/
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#include "sqlite3.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <string.h>
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static void usage(const char *argv0){
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printf("Usage: %s [OPTIONS] DATABASE LOG\n\n", argv0);
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printf(
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"DATABASE is an SQLite database against which various statements\n"
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"have been run. The SQL text is stored in LOG. LOG is an SQLite\n"
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"database with this schema:\n"
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"\n"
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" CREATE TABLE sqllog(sql TEXT);\n"
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"\n"
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"This utility program analyzes statements contained in LOG and prints\n"
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"a report showing how many times each index in DATABASE is used by the\n"
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"statements in LOG.\n"
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"\n"
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"DATABASE only needs to contain the schema used by the statements in\n"
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"LOG. The content can be removed from DATABASE.\n"
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);
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printf(
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"\nOPTIONS:\n\n"
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" --progress N Show a progress message after every N input rows\n"
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" -q Omit error message when parsing log entries\n"
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" --using NAME Print SQL statements that use index NAME\n"
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);
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printf("\nAnalysis will be done by SQLite version %s dated %.20s\n"
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"checkin number %.40s. Different versions\n"
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"of SQLite might use different indexes.\n",
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sqlite3_libversion(), sqlite3_sourceid(), sqlite3_sourceid()+21);
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exit(1);
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}
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int main(int argc, char **argv){
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sqlite3 *db = 0; /* The main database */
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sqlite3_stmt *pStmt = 0; /* a query */
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char *zSql;
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int nErr = 0;
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int rc;
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int bQuiet = 0;
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int i, j;
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const char *zUsing = 0;
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sqlite3_stmt *pIncrCnt = 0;
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int nRow = 0;
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int iProgress = 0;
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for(i=j=1; i<argc; i++){
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const char *z = argv[i];
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if( z[0]=='-' ){
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z++;
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if( z[0]=='-' ) z++;
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if( strcmp(z,"progress")==0 ){
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if( i+1<argc ){
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iProgress = strtol(argv[++i],0,0);
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continue;
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}
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printf("The --progress option requires an argument\n");
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exit(0);
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}
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if( strcmp(z,"q")==0 ){
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bQuiet = 1;
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continue;
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}
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if( strcmp(z,"using")==0 ){
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if( i+1<argc ){
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zUsing = argv[++i];
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continue;
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}
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printf("The --using option requires an argument\n");
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exit(0);
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}
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if( strcmp(z, "help")==0 || strcmp(z, "?")==0 ){
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usage(argv[0]);
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}
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printf("Unknown command-line option: \"%s\"\n", argv[i]);
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exit(0);
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}else{
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if( j<i ) argv[j++] = argv[i];
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}
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}
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argc = j;
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if( argc!=3 ) usage(argv[0]);
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rc = sqlite3_open_v2(argv[1], &db, SQLITE_OPEN_READONLY, 0);
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if( rc ){
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printf("Cannot open \"%s\" for reading: %s\n", argv[1], sqlite3_errmsg(db));
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goto errorOut;
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}
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rc = sqlite3_prepare_v2(db, "SELECT * FROM sqlite_schema", -1, &pStmt, 0);
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if( rc ){
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printf("Cannot read the schema from \"%s\" - %s\n", argv[1],
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sqlite3_errmsg(db));
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goto errorOut;
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}
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sqlite3_finalize(pStmt);
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pStmt = 0;
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rc = sqlite3_exec(db,
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"CREATE TABLE temp.idxu(\n"
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" tbl TEXT COLLATE nocase,\n"
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" idx TEXT COLLATE nocase,\n"
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" cnt INT,\n"
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" PRIMARY KEY(idx)\n"
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") WITHOUT ROWID;", 0, 0, 0);
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if( rc ){
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printf("Cannot create the result table - %s\n",
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sqlite3_errmsg(db));
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goto errorOut;
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}
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rc = sqlite3_exec(db,
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"INSERT INTO temp.idxu(tbl,idx,cnt)"
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" SELECT tbl_name, name, 0 FROM sqlite_schema"
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" WHERE type='index' AND sql IS NOT NULL", 0, 0, 0);
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/* Open the LOG database */
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zSql = sqlite3_mprintf("ATTACH %Q AS log", argv[2]);
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rc = sqlite3_exec(db, zSql, 0, 0, 0);
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sqlite3_free(zSql);
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if( rc ){
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printf("Cannot open the LOG database \"%s\" - %s\n",
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argv[2], sqlite3_errmsg(db));
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goto errorOut;
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}
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rc = sqlite3_prepare_v2(db,
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"SELECT sql, rowid FROM log.sqllog"
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" WHERE upper(substr(sql,1,5)) NOT IN ('BEGIN','COMMI','ROLLB','PRAGM')",
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-1, &pStmt, 0);
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if( rc ){
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printf("Cannot read the SQLLOG table in the LOG database \"%s\" - %s\n",
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argv[2], sqlite3_errmsg(db));
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goto errorOut;
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}
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rc = sqlite3_prepare_v2(db,
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"UPDATE temp.idxu SET cnt=cnt+1 WHERE idx=?1",
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-1, &pIncrCnt, 0);
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if( rc ){
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printf("Cannot prepare a statement to increment a counter for "
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"indexes used\n");
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goto errorOut;
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}
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/* Update the counts based on LOG */
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while( sqlite3_step(pStmt)==SQLITE_ROW ){
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const char *zLog = (const char*)sqlite3_column_text(pStmt, 0);
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sqlite3_stmt *pS2;
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if( zLog==0 ) continue;
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zSql = sqlite3_mprintf("EXPLAIN QUERY PLAN %s", zLog);
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rc = sqlite3_prepare_v2(db, zSql, -1, &pS2, 0);
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sqlite3_free(zSql);
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if( rc ){
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if( !bQuiet ){
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printf("Cannot compile LOG entry %d (%s): %s\n",
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sqlite3_column_int(pStmt, 1), zLog, sqlite3_errmsg(db));
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fflush(stdout);
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}
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nErr++;
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}else{
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nRow++;
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if( iProgress>0 && (nRow%iProgress)==0 ){
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printf("%d...\n", nRow);
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fflush(stdout);
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}
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while( sqlite3_step(pS2)==SQLITE_ROW ){
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const char *zExplain = (const char*)sqlite3_column_text(pS2,3);
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const char *z1, *z2;
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int n;
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/* printf("EXPLAIN: %s\n", zExplain); */
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z1 = strstr(zExplain, " USING INDEX ");
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if( z1==0 ) continue;
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z1 += 13;
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for(z2=z1+1; z2[0] && z2[1]!='('; z2++){}
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n = z2 - z1;
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if( zUsing && sqlite3_strnicmp(zUsing, z1, n)==0 ){
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printf("Using %s:\n%s\n", zUsing, zLog);
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fflush(stdout);
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}
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sqlite3_bind_text(pIncrCnt,1,z1,n,SQLITE_STATIC);
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sqlite3_step(pIncrCnt);
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sqlite3_reset(pIncrCnt);
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}
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}
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sqlite3_finalize(pS2);
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}
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sqlite3_finalize(pStmt);
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/* Generate the report */
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rc = sqlite3_prepare_v2(db,
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"SELECT tbl, idx, cnt, "
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" (SELECT group_concat(name,',') FROM pragma_index_info(idx))"
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" FROM temp.idxu, main.sqlite_schema"
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" WHERE temp.idxu.tbl=main.sqlite_schema.tbl_name"
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" AND temp.idxu.idx=main.sqlite_schema.name"
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" ORDER BY cnt DESC, tbl, idx",
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-1, &pStmt, 0);
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if( rc ){
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printf("Cannot query the result table - %s\n",
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sqlite3_errmsg(db));
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goto errorOut;
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}
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while( sqlite3_step(pStmt)==SQLITE_ROW ){
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printf("%10d %s on %s(%s)\n",
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sqlite3_column_int(pStmt, 2),
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sqlite3_column_text(pStmt, 1),
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sqlite3_column_text(pStmt, 0),
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sqlite3_column_text(pStmt, 3));
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}
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sqlite3_finalize(pStmt);
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pStmt = 0;
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errorOut:
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sqlite3_finalize(pIncrCnt);
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sqlite3_finalize(pStmt);
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sqlite3_close(db);
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return nErr;
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}
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