--- /dev/null
+/*
+** 2026-04-13
+**
+** 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.
+**
+******************************************************************************
+**
+** Partial reimplement of the sqlite3_analyzer utility program as
+** loadable SQL function.
+*/
+#include "sqlite3ext.h"
+SQLITE_EXTENSION_INIT1
+#include <assert.h>
+#include <string.h>
+
+/*
+** State information for the analysis
+*/
+typedef struct Analysis Analysis;
+struct Analysis {
+ sqlite3 *db; /* Database connection */
+ sqlite3_context *context; /* SQL function context */
+ sqlite3_str *pOut; /* Write output here */
+ char *zSU; /* Name of the temp.space_used table */
+ const char *zSchema; /* Schema to be analyzed */
+};
+
+/*
+** Free all memory associated with the Analysis objecct
+*/
+static void analysisFree(Analysis *p){
+ if( p->zSU ){
+ char *zSql = sqlite3_mprintf("DROP TABLE temp.%s;", p->zSU);
+ if( zSql ){
+ sqlite3_exec(p->db, zSql, 0, 0, 0);
+ sqlite3_free(zSql);
+ }
+ }
+ sqlite3_str_free(p->pOut);
+ sqlite3_free(p->zSU);
+}
+
+/*
+** Report an OOM
+*/
+static void analysisOom(Analysis *p){
+ sqlite3_result_error_nomem(p->context);
+ analysisFree(p);
+}
+
+/*
+** Prepare and return an SQL statement.
+*/
+static sqlite3_stmt *analysisVPrep(Analysis *p, const char *zFmt, va_list ap){
+ char *zSql;
+ int rc;
+ sqlite3_stmt *pStmt = 0;
+ zSql = sqlite3_vmprintf(zFmt, ap);
+ if( zSql==0 ){ analysisOom(p); return 0; }
+ rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
+ sqlite3_free(zSql);
+ if( rc ){
+ sqlite3_result_error(p->context, "SQL error", -1);
+ sqlite3_finalize(pStmt);
+ analysisFree(p);
+ return 0;
+ }
+ return pStmt;
+}
+static sqlite3_stmt *analysisPrepare(Analysis *p, const char *zFormat, ...){
+ va_list ap;
+ sqlite3_stmt *pStmt = 0;
+ va_start(ap, zFormat);
+ pStmt = analysisVPrep(p,zFormat,ap);
+ va_end(ap);
+ return pStmt;
+}
+
+/*
+** Run SQL. Return the number of errors.
+*/
+static int analysisSql(Analysis *p, const char *zFormat, ...){
+ va_list ap;
+ int rc;
+ sqlite3_stmt *pStmt = 0;
+ va_start(ap, zFormat);
+ pStmt = analysisVPrep(p,zFormat,ap);
+ va_end(ap);
+ if( pStmt==0 ) return 1;
+ while( (rc = sqlite3_step(pStmt))==SQLITE_ROW ){}
+ return sqlite3_finalize(pStmt);
+}
+
+/*
+** SQL Function: analyze(SCHEMA)
+**
+** Analyze the database schema named in the argument. Return text
+** containing the analysis.
+*/
+static void analyzeFunc(
+ sqlite3_context *context,
+ int argc,
+ sqlite3_value **argv
+){
+ int rc;
+ sqlite3_stmt *pStmt;
+ int n;
+ Analysis s;
+ sqlite3_uint64 r[2];
+
+ memset(&s, 0, sizeof(s));
+ s.db = sqlite3_context_db_handle(context);
+ s.context = context;
+ s.pOut = sqlite3_str_new(0);
+ if( s.pOut==0 ){ analysisOom(&s); return; }
+ s.zSchema = (const char*)sqlite3_value_text(argv[0]);
+ sqlite3_randomness(sizeof(r), &r);
+ s.zSU = sqlite3_mprintf("analysis%016x%016x", r[0], r[1]);
+ if( s.zSU==0 ){ analysisOom(&s); return; }
+
+ /* The s.zSU table contains the data used for the analysis.
+ ** The table name contains 128-bits of randomness to avoid
+ ** collisions with preexisting tables in temp.
+ */
+ rc = analysisSql(&s,
+ "CREATE TABLE temp.%s(\n"
+ " name text, -- A table or index\n"
+ " tblname text, -- Table that owns name\n"
+ " is_index boolean, -- TRUE if it is an index\n"
+ " is_without_rowid boolean, -- TRUE if WITHOUT ROWID table\n"
+ " nentry int, -- Number of entries in the BTree\n"
+ " leaf_entries int, -- Number of leaf entries\n"
+ " depth int, -- Depth of the b-tree\n"
+ " payload int, -- Total data stored in this table/index\n"
+ " ovfl_payload int, -- Total data stored on overflow pages\n"
+ " ovfl_cnt int, -- Number of entries that use overflow\n"
+ " mx_payload int, -- Maximum payload size\n"
+ " int_pages int, -- Interior pages used\n"
+ " leaf_pages int, -- Leaf pages used\n"
+ " ovfl_pages int, -- Overflow pages used\n"
+ " int_unused int, -- Unused bytes on interior pages\n"
+ " leaf_unused int, -- Unused bytes on primary pages\n"
+ " ovfl_unused int -- Unused bytes on overflow pages\n"
+ ");",
+ s.zSU
+ );
+ if( rc ) return;
+
+ /* Populate the s.zSU table
+ */
+ rc = analysisSql(&s,
+ "WITH\n"
+ " allidx(idxname) AS (\n"
+ " SELECT name FROM main.sqlite_schema WHERE type='index'\n"
+ " ),\n"
+ " allobj(allname,tblname,isidx,isworowid) AS (\n"
+ " SELECT 'sqlite_schema',\n"
+ " 'sqlite_schema',\n"
+ " 0,\n"
+ " 0\n"
+ " UNION ALL\n"
+ " SELECT name,\n"
+ " tbl_name,\n"
+ " type='index',\n"
+ " EXISTS(SELECT 1\n"
+ " FROM pragma_index_list(sqlite_schema.name,%Q)\n"
+ " WHERE pragma_index_list.origin='pk'\n"
+ " AND pragma_index_list.name NOT IN allidx)\n"
+ " FROM \"%w\".sqlite_schema\n"
+ " )\n"
+ "INSERT INTO temp.%s\n"
+ " SELECT\n"
+ " allname,\n"
+ " tblname,\n"
+ " isidx,\n"
+ " isworowid,\n"
+ " sum(ncell),\n"
+ " sum((pagetype='leaf')*ncell),\n"
+ " max((length(if(path GLOB '*+*','',path))+3)/4),\n"
+ " sum(payload),\n"
+ " sum((pagetype='overflow')*payload),\n"
+ " sum(path GLOB '*+000000'),\n"
+ " max(mx_payload),\n"
+ " sum(pagetype='internal'),\n"
+ " sum(pagetype='leaf'),\n"
+ " sum(pagetype='overflow'),\n"
+ " sum((pagetype='internal')*unused),\n"
+ " sum((pagetype='leaf')*unused),\n"
+ " sum((pagetype='overflow')*unused)\n"
+ " FROM allobj CROSS JOIN dbstat(%Q) \n"
+ " WHERE dbstat.name=allobj.allname\n"
+ " GROUP BY allname;\n",
+ s.zSchema, /* pragma_index_list(...,%Q) */
+ s.zSchema, /* %w.sqlite_schema */
+ s.zSU, /* INTO temp.%s */
+ s.zSchema /* JOIN dbstat(%Q) */
+ );
+ if( rc ) return;
+
+ /* TBD: Generate report text here */
+
+ /* Append SQL statements that will recreate the raw data used for
+ ** the analysis.
+ */
+ sqlite3_str_appendf(s.pOut,
+ "BEGIN;\n"
+ "CREATE TABLE space_used(\n"
+ " name text, -- A table or index\n" /* 0 */
+ " tblname text, -- Table that owns name\n" /* 1 */
+ " is_index boolean, -- TRUE if it is an index\n" /* 2 */
+ " is_without_rowid boolean, -- TRUE if WITHOUT ROWID table\n" /* 3 */
+ " nentry int, -- Number of entries in the BTree\n" /* 4 */
+ " leaf_entries int, -- Number of leaf entries\n" /* 5 */
+ " depth int, -- Depth of the b-tree\n" /* 6 */
+ " payload int, -- Total data in this table/index\n" /* 7 */
+ " ovfl_payload int, -- Total data on overflow pages\n" /* 8 */
+ " ovfl_cnt int, -- Entries that use overflow\n" /* 9 */
+ " mx_payload int, -- Maximum payload size\n" /* 10 */
+ " int_pages int, -- Interior pages used\n" /* 11 */
+ " leaf_pages int, -- Leaf pages used\n" /* 12 */
+ " ovfl_pages int, -- Overflow pages used\n" /* 13 */
+ " int_unused int, -- Unused bytes on interior pages\n" /* 14 */
+ " leaf_unused int, -- Unused bytes on primary pages\n" /* 15 */
+ " ovfl_unused int -- Unused bytes on overflow pages\n" /* 16 */
+ ");\n"
+ "INSERT INTO space_used VALUES\n"
+ );
+ pStmt = analysisPrepare(&s,
+ "SELECT quote(name), quote(tblname),\n" /* 0..1 */
+ " is_index, is_without_rowid, nentry, leaf_entries,\n" /* 2..5 */
+ " depth, payload, ovfl_payload, ovfl_cnt, mx_payload,\n" /* 6..10 */
+ " int_pages, leaf_pages, ovfl_pages, int_unused,\n" /* 11..14 */
+ " leaf_unused, ovfl_unused\n" /* 15..16 */
+ " FROM temp.%s;",
+ s.zSU);
+ if( pStmt==0 ) return;
+ n = 0;
+ while( sqlite3_step(pStmt)==SQLITE_ROW ){
+ if( n++ ) sqlite3_str_appendf(s.pOut,",\n");
+ sqlite3_str_appendf(s.pOut,
+ " (%s,%s,%lld,%lld,%lld,%lld,%lld,%lld,%lld,"
+ "%lld,%lld,%lld,%lld,%lld,%lld,%lld,%lld)",
+ sqlite3_column_text(pStmt, 0),
+ sqlite3_column_text(pStmt, 1),
+ sqlite3_column_int64(pStmt, 2),
+ sqlite3_column_int64(pStmt, 3),
+ sqlite3_column_int64(pStmt, 4),
+ sqlite3_column_int64(pStmt, 5),
+ sqlite3_column_int64(pStmt, 6),
+ sqlite3_column_int64(pStmt, 7),
+ sqlite3_column_int64(pStmt, 8),
+ sqlite3_column_int64(pStmt, 9),
+ sqlite3_column_int64(pStmt, 10),
+ sqlite3_column_int64(pStmt, 11),
+ sqlite3_column_int64(pStmt, 12),
+ sqlite3_column_int64(pStmt, 13),
+ sqlite3_column_int64(pStmt, 14),
+ sqlite3_column_int64(pStmt, 15),
+ sqlite3_column_int64(pStmt, 16));
+ }
+ sqlite3_str_appendf(s.pOut,"\nCOMMIT;\n");
+ sqlite3_finalize(pStmt);
+
+ if( sqlite3_str_length(s.pOut) ){
+ sqlite3_result_text(context, sqlite3_str_finish(s.pOut), -1,
+ sqlite3_free);
+ s.pOut = 0;
+ }
+ analysisFree(&s);
+}
+
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_analyze_init(
+ sqlite3 *db,
+ char **pzErrMsg,
+ const sqlite3_api_routines *pApi
+){
+ int rc = SQLITE_OK;
+ SQLITE_EXTENSION_INIT2(pApi);
+ (void)pzErrMsg; /* Unused parameter */
+ rc = sqlite3_create_function(db, "analyze", 1,
+ SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
+ 0, analyzeFunc, 0, 0);
+ return rc;
+}
projects / thirdparty / sqlite.git / commitdiff
