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OP_Column optimization: Do not check for an oversize row header unless the

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row header size is larger than the content available on the local page.

FossilOrigin-Name: 8125b74cb46c372b9a319f6270f1c396767accd7
This commit is contained in:
drh
2015-10-16 12:53:47 +00:00
parent c24658b5d7
commit 848a3326f7
3 changed files with 21 additions and 20 deletions
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27
src/vdbe.c
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@@ -2440,19 +2440,6 @@ case OP_Column: {
pC->nHdrParsed = 0;
aOffset[0] = offset;
/* Make sure a corrupt database has not given us an oversize header.
** Do this now to avoid an oversize memory allocation.
**
** Type entries can be between 1 and 5 bytes each. But 4 and 5 byte
** types use so much data space that there can only be 4096 and 32 of
** them, respectively. So the maximum header length results from a
** 3-byte type for each of the maximum of 32768 columns plus three
** extra bytes for the header length itself. 32768*3 + 3 = 98307.
*/
if( offset > 98307 || offset > pC->payloadSize ){
rc = SQLITE_CORRUPT_BKPT;
goto op_column_error;
}
if( avail<offset ){
/* pC->aRow does not have to hold the entire row, but it does at least
@@ -2461,6 +2448,20 @@ case OP_Column: {
** dynamically allocated. */
pC->aRow = 0;
pC->szRow = 0;
/* Make sure a corrupt database has not given us an oversize header.
** Do this now to avoid an oversize memory allocation.
**
** Type entries can be between 1 and 5 bytes each. But 4 and 5 byte
** types use so much data space that there can only be 4096 and 32 of
** them, respectively. So the maximum header length results from a
** 3-byte type for each of the maximum of 32768 columns plus three
** extra bytes for the header length itself. 32768*3 + 3 = 98307.
*/
if( offset > 98307 || offset > pC->payloadSize ){
rc = SQLITE_CORRUPT_BKPT;
goto op_column_error;
}
}
/* The following goto is an optimization. It can be omitted and