summaryrefslogtreecommitdiff
path: root/tool/showdb.c
diff options
context:
space:
mode:
Diffstat (limited to 'tool/showdb.c')
-rw-r--r--tool/showdb.c224
1 files changed, 224 insertions, 0 deletions
diff --git a/tool/showdb.c b/tool/showdb.c
index 057abd3..d378d05 100644
--- a/tool/showdb.c
+++ b/tool/showdb.c
@@ -9,6 +9,7 @@
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
+#include "sqlite3.h"
static int pagesize = 1024; /* Size of a database page */
@@ -451,6 +452,224 @@ static void decode_trunk_page(
}
/*
+** A short text comment on the use of each page.
+*/
+static char **zPageUse;
+
+/*
+** Add a comment on the use of a page.
+*/
+static void page_usage_msg(int pgno, const char *zFormat, ...){
+ va_list ap;
+ char *zMsg;
+
+ va_start(ap, zFormat);
+ zMsg = sqlite3_vmprintf(zFormat, ap);
+ va_end(ap);
+ if( pgno<=0 || pgno>mxPage ){
+ printf("ERROR: page %d out of bounds. Range=1..%d. Msg: %s\n",
+ pgno, mxPage, zMsg);
+ sqlite3_free(zMsg);
+ return;
+ }
+ if( zPageUse[pgno]!=0 ){
+ printf("ERROR: page %d used multiple times:\n", pgno);
+ printf("ERROR: previous: %s\n", zPageUse[pgno]);
+ printf("ERROR: current: %s\n", zPageUse[pgno]);
+ sqlite3_free(zPageUse[pgno]);
+ }
+ zPageUse[pgno] = zMsg;
+}
+
+/*
+** Find overflow pages of a cell and describe their usage.
+*/
+static void page_usage_cell(
+ unsigned char cType, /* Page type */
+ unsigned char *a, /* Cell content */
+ int pgno, /* page containing the cell */
+ int cellno /* Index of the cell on the page */
+){
+ int i;
+ int nDesc = 0;
+ int n = 0;
+ i64 nPayload;
+ i64 rowid;
+ int nLocal;
+ i = 0;
+ if( cType<=5 ){
+ a += 4;
+ n += 4;
+ }
+ if( cType!=5 ){
+ i = decodeVarint(a, &nPayload);
+ a += i;
+ n += i;
+ nLocal = localPayload(nPayload, cType);
+ }else{
+ nPayload = nLocal = 0;
+ }
+ if( cType==5 || cType==13 ){
+ i = decodeVarint(a, &rowid);
+ a += i;
+ n += i;
+ }
+ if( nLocal<nPayload ){
+ int ovfl = decodeInt32(a+nLocal);
+ int cnt = 0;
+ while( ovfl && (cnt++)<mxPage ){
+ page_usage_msg(ovfl, "overflow %d from cell %d of page %d",
+ cnt, cellno, pgno);
+ a = getContent((ovfl-1)*pagesize, 4);
+ ovfl = decodeInt32(a);
+ free(a);
+ }
+ }
+}
+
+
+/*
+** Describe the usages of a b-tree page
+*/
+static void page_usage_btree(
+ int pgno, /* Page to describe */
+ int parent, /* Parent of this page. 0 for root pages */
+ int idx, /* Which child of the parent */
+ const char *zName /* Name of the table */
+){
+ unsigned char *a;
+ const char *zType = "corrupt node";
+ int nCell;
+ int i;
+ int hdr = pgno==1 ? 100 : 0;
+
+ if( pgno<=0 || pgno>mxPage ) return;
+ a = getContent((pgno-1)*pagesize, pagesize);
+ switch( a[hdr] ){
+ case 2: zType = "interior node of index"; break;
+ case 5: zType = "interior node of table"; break;
+ case 10: zType = "leaf of index"; break;
+ case 13: zType = "leaf of table"; break;
+ }
+ if( parent ){
+ page_usage_msg(pgno, "%s [%s], child %d of page %d",
+ zType, zName, idx, parent);
+ }else{
+ page_usage_msg(pgno, "root %s [%s]", zType, zName);
+ }
+ nCell = a[hdr+3]*256 + a[hdr+4];
+ if( a[hdr]==2 || a[hdr]==5 ){
+ int cellstart = hdr+12;
+ unsigned int child;
+ for(i=0; i<nCell; i++){
+ int ofst;
+
+ ofst = cellstart + i*2;
+ ofst = a[ofst]*256 + a[ofst+1];
+ child = decodeInt32(a+ofst);
+ page_usage_btree(child, pgno, i, zName);
+ }
+ child = decodeInt32(a+cellstart-4);
+ page_usage_btree(child, pgno, i, zName);
+ }
+ if( a[hdr]==2 || a[hdr]==10 || a[hdr]==13 ){
+ int cellstart = hdr + 8 + 4*(a[hdr]<=5);
+ for(i=0; i<nCell; i++){
+ int ofst;
+ ofst = cellstart + i*2;
+ ofst = a[ofst]*256 + a[ofst+1];
+ page_usage_cell(a[hdr], a+ofst, pgno, i);
+ }
+ }
+ free(a);
+}
+
+/*
+** Determine page usage by the freelist
+*/
+static void page_usage_freelist(int pgno){
+ unsigned char *a;
+ int cnt = 0;
+ int i;
+ int n;
+ int iNext;
+ int parent = 1;
+
+ while( pgno>0 && pgno<=mxPage && (cnt++)<mxPage ){
+ page_usage_msg(pgno, "freelist trunk #%d child of %d", cnt, parent);
+ a = getContent((pgno-1)*pagesize, pagesize);
+ iNext = decodeInt32(a);
+ n = decodeInt32(a+4);
+ for(i=0; i<n; i++){
+ int child = decodeInt32(a + (i*4+8));
+ page_usage_msg(child, "freelist leaf, child %d of trunk page %d",
+ i, pgno);
+ }
+ free(a);
+ parent = pgno;
+ pgno = iNext;
+ }
+}
+
+/*
+** Try to figure out how every page in the database file is being used.
+*/
+static void page_usage_report(const char *zDbName){
+ int i;
+ int rc;
+ sqlite3 *db;
+ sqlite3_stmt *pStmt;
+ unsigned char *a;
+
+ /* Avoid the pathological case */
+ if( mxPage<1 ){
+ printf("empty database\n");
+ return;
+ }
+
+ /* Open the database file */
+ rc = sqlite3_open(zDbName, &db);
+ if( rc ){
+ printf("cannot open database: %s\n", sqlite3_errmsg(db));
+ sqlite3_close(db);
+ return;
+ }
+
+ /* Set up global variables zPageUse[] and mxPage to record page
+ ** usages */
+ zPageUse = sqlite3_malloc( sizeof(zPageUse[0])*(mxPage+1) );
+ if( zPageUse==0 ) out_of_memory();
+ memset(zPageUse, 0, sizeof(zPageUse[0])*(mxPage+1));
+
+ /* Discover the usage of each page */
+ a = getContent(0, 100);
+ page_usage_freelist(decodeInt32(a+32));
+ free(a);
+ page_usage_btree(1, 0, 0, "sqlite_master");
+ rc = sqlite3_prepare_v2(db,
+ "SELECT type, name, rootpage FROM SQLITE_MASTER WHERE rootpage",
+ -1, &pStmt, 0);
+ if( rc==SQLITE_OK ){
+ while( sqlite3_step(pStmt)==SQLITE_ROW ){
+ int pgno = sqlite3_column_int(pStmt, 2);
+ page_usage_btree(pgno, 0, 0, sqlite3_column_text(pStmt, 1));
+ }
+ }else{
+ printf("ERROR: cannot query database: %s\n", sqlite3_errmsg(db));
+ }
+ sqlite3_finalize(pStmt);
+ sqlite3_close(db);
+
+ /* Print the report and free memory used */
+ for(i=1; i<=mxPage; i++){
+ printf("%5d: %s\n", i, zPageUse[i] ? zPageUse[i] : "???");
+ sqlite3_free(zPageUse[i]);
+ }
+ sqlite3_free(zPageUse);
+ zPageUse = 0;
+}
+
+/*
** Print a usage comment
*/
static void usage(const char *argv0){
@@ -458,6 +677,7 @@ static void usage(const char *argv0){
fprintf(stderr,
"args:\n"
" dbheader Show database header\n"
+ " pgidx Index of how each page is used\n"
" NNN..MMM Show hex of pages NNN through MMM\n"
" NNN..end Show hex of pages NNN through end of file\n"
" NNNb Decode btree page NNN\n"
@@ -503,6 +723,10 @@ int main(int argc, char **argv){
print_db_header();
continue;
}
+ if( strcmp(argv[i], "pgidx")==0 ){
+ page_usage_report(argv[1]);
+ continue;
+ }
if( !isdigit(argv[i][0]) ){
fprintf(stderr, "%s: unknown option: [%s]\n", argv[0], argv[i]);
continue;
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-20 06:43:54 +0000