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Use PG_PAGE_SIZE_DEFAULT constant instead of pageSize variable.

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Page size is passed around a lot but in fact it can only have one value, PG_PAGE_SIZE_DEFAULT, which is checked when pg_control is loaded. There may be an argument for supporting multiple page sizes in the future but for now just use the constant to simplify the code.

There is also a significant performance benefit.  Because pageSize was being used in pageChecksumBlock() the main loop was neither unrolled nor vectorized (-funroll-loops -ftree-vectorize) as it is now with a constant loop boundary.
This commit is contained in:
David Steele
2020-03-05 09:14:27 -05:00
parent 91f321fb86
commit 4ab8943ca8
13 changed files with 48 additions and 65 deletions
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12
src/postgres/pageChecksum.c
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@ -101,11 +101,10 @@ do { \
} while (0)
static uint32_t
pageChecksumBlock(const unsigned char *page, unsigned int pageSize)
pageChecksumBlock(const unsigned char *page)
{
FUNCTION_TEST_BEGIN();
FUNCTION_TEST_PARAM_P(UCHARDATA, page);
FUNCTION_TEST_PARAM(UINT, pageSize);
FUNCTION_TEST_END();
ASSERT(page != NULL);
@ -119,7 +118,7 @@ pageChecksumBlock(const unsigned char *page, unsigned int pageSize)
memcpy(sums, checksumBaseOffsets, sizeof(checksumBaseOffsets));
/* main checksum calculation */
for (i = 0; i < pageSize / sizeof(uint32_t) / N_SUMS; i++)
for (i = 0; i < PG_PAGE_SIZE_DEFAULT / sizeof(uint32_t) / N_SUMS; i++)
for (j = 0; j < N_SUMS; j++)
CHECKSUM_COMP(sums[j], dataArray[i][j]);
@ -142,12 +141,11 @@ The checksum includes the block number (to detect the case where a page is someh
(excluding the checksum itself), and the page data.
***********************************************************************************************************************************/
uint16_t
pgPageChecksum(const unsigned char *page, unsigned int blockNo, unsigned int pageSize)
pgPageChecksum(const unsigned char *page, unsigned int blockNo)
{
FUNCTION_TEST_BEGIN();
FUNCTION_TEST_PARAM_P(UCHARDATA, page);
FUNCTION_TEST_PARAM(UINT, blockNo);
FUNCTION_TEST_PARAM(UINT, pageSize);
FUNCTION_TEST_END();
ASSERT(page != NULL);
@ -158,7 +156,7 @@ pgPageChecksum(const unsigned char *page, unsigned int blockNo, unsigned int pag
uint16_t originalChecksum = pageHeader->pd_checksum;
pageHeader->pd_checksum = 0;
uint32_t checksum = pageChecksumBlock(page, pageSize);
uint32_t checksum = pageChecksumBlock(page);
pageHeader->pd_checksum = originalChecksum;
// Mix in the block number to detect transposed pages
@ -204,5 +202,5 @@ pgPageChecksumTest(
// LSN is after the backup started so checksum is not tested because pages may be torn
(((PageHeader)page)->pd_lsn.xlogid >= ignoreWalId && ((PageHeader)page)->pd_lsn.xrecoff >= ignoreWalOffset) ||
// Checksum is valid if a full page
(pageSize == PG_PAGE_SIZE_DEFAULT && ((PageHeader)page)->pd_checksum == pgPageChecksum(page, blockNo, pageSize)));
(pageSize == PG_PAGE_SIZE_DEFAULT && ((PageHeader)page)->pd_checksum == pgPageChecksum(page, blockNo)));
}