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Overview
| Comment: | On the /hash-collisions page, list the longer collisions with links to /whatid. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
3234cf1efe96ad6d62249f1d7ce02a22 |
| User & Date: | drh 2015-02-11 12:36:46.529 |
Context
|
2015-02-11
| ||
| 13:18 | Fix to the /hash-collisions page: Only consider the SHA1 hashes in the BLOB table, not the random hexadecimal identifiers assigned to tickets and tech-notes. The latter two live in a different namespace. check-in: 327eee1452 user: drh tags: trunk | |
| 12:36 | On the /hash-collisions page, list the longer collisions with links to /whatid. check-in: 3234cf1efe user: drh tags: trunk | |
| 12:03 | On the /hash-collisions page show the true first instance of each collision, not the second. check-in: 4ce3a2bfac user: drh tags: trunk | |
Changes
Changes to src/name.c.
| ︙ | ︙ | |||
1063 1064 1065 1066 1067 1068 1069 |
/*
** WEBPAGE: hash-collisions
**
** Show the number of hash collisions for hash prefixes of various lengths.
*/
void hash_collisions_webpage(void){
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/*
** WEBPAGE: hash-collisions
**
** Show the number of hash collisions for hash prefixes of various lengths.
*/
void hash_collisions_webpage(void){
int i, kk;
int nHash = 0;
Stmt q;
char zPrev[UUID_SIZE+1];
struct {
int cnt;
Blob ex;
char z[UUID_SIZE+1];
} aCollide[UUID_SIZE+1];
login_check_credentials();
if( !g.perm.Read ){ login_needed(); return; }
memset(aCollide, 0, sizeof(aCollide));
for(i=0; i<ArraySize(aCollide); i++) blob_init(&aCollide[i].ex,0,0);
memset(zPrev, 0, sizeof(zPrev));
db_prepare(&q,
"SELECT tkt_uuid FROM ticket\n"
"UNION ALL\n"
"SELECT substr(tagname,7) FROM tag WHERE tagname GLOB 'event-*'\n"
"UNION ALL\n"
"SELECT uuid FROM blob\n"
"ORDER BY 1"
);
while( db_step(&q)==SQLITE_ROW ){
const char *zUuid = db_column_text(&q,0);
int n = db_column_bytes(&q,0);
int i;
nHash++;
for(i=0; zPrev[i] && zPrev[i]==zUuid[i]; i++){}
if( i>0 && i<=UUID_SIZE ){
aCollide[i].cnt++;
if( aCollide[i].z[0]==0 ) memcpy(aCollide[i].z, zPrev, n+1);
if( aCollide[i].cnt<25 ){
blob_appendf(&aCollide[i].ex, " %z%.*s</a>",
href("%R/whatis/%.*s", i, zPrev), i, zPrev);
}
}
memcpy(zPrev, zUuid, n+1);
}
db_finalize(&q);
style_header("Hash Prefix Collisions");
@ <table border=1><thead>
@ <tr><th>Length<th>Instances<th>First Instance</tr>
@ </thead><tbody>
for(i=1; i<=UUID_SIZE; i++){
if( aCollide[i].cnt==0 ) continue;
@ <tr><td>%d(i)<td>%d(aCollide[i].cnt)<td>%h(aCollide[i].z)</tr>
}
@ </tbody></table>
@ <p>Total number of hashes: %d(nHash)</p>
kk = 0;
for(i=UUID_SIZE; i>=0; i--){
if( aCollide[i].cnt==0 ) continue;
if( aCollide[i].cnt>200 ) break;
kk += aCollide[i].cnt;
if( aCollide[i].cnt<25 ){
@ <p>Collisions of length %d(i):
}else{
@ <p>First 25 collisions of length %d(i):
}
@ %s(blob_str(&aCollide[i].ex))</p>
}
style_footer();
}
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