On 2/28/07, Jonah H. Harris <[EMAIL PROTECTED]> wrote:
Last time I checked, Teradata used a modified Fletcher checksum as well; I wasn't aware of Adler32.
I added adler32 to Gurjeet Singh's crc testing utility, compiled it with gcc 4.0.0 on a single-core Opteron running FC4, and configured it for 8K block sizes. GCC options were -mtune=opteron and the optimizations stated below: Generic optimization: test parameters:: SF=1, block_size=8, list_size=1000 Generating data... done. Time taken : 93 milliseconds Generating CRC using PG (vanilla) algo... done. Time taken : 117 milliseconds Verifying CRC using PG (vanilla) algo... done. Time taken : 89 milliseconds Generating CRC using SliceBy8 algo... done. Time taken : 44 milliseconds Verifying CRC using SliceBy8 algo... done. Time taken : 44 milliseconds Generating CRC using Adler32 algo... done. Time taken : 52 milliseconds Verifying CRC using Adler32 algo... done. Time taken : 53 milliseconds Using -O2 test parameters:: SF=1, block_size=8, list_size=1000 Generating data... done. Time taken : 85 milliseconds Generating CRC using PG (vanilla) algo... done. Time taken : 31 milliseconds Verifying CRC using PG (vanilla) algo... done. Time taken : 30 milliseconds Generating CRC using SliceBy8 algo... done. Time taken : 30 milliseconds Verifying CRC using SliceBy8 algo... done. Time taken : 30 milliseconds Generating CRC using Adler32 algo... done. Time taken : 14 milliseconds Verifying CRC using Adler32 algo... done. Time taken : 14 milliseconds Using -O3 test parameters:: SF=1, block_size=8, list_size=1000 Generating data... done. Time taken : 87 milliseconds Generating CRC using PG (vanilla) algo... done. Time taken : 31 milliseconds Verifying CRC using PG (vanilla) algo... done. Time taken : 31 milliseconds Generating CRC using SliceBy8 algo... done. Time taken : 30 milliseconds Verifying CRC using SliceBy8 algo... done. Time taken : 30 milliseconds Generating CRC using Adler32 algo... done. Time taken : 14 milliseconds Verifying CRC using Adler32 algo... done. Time taken : 15 milliseconds Interesting... -- Jonah H. Harris, Software Architect | phone: 732.331.1324 EnterpriseDB Corporation | fax: 732.331.1301 33 Wood Ave S, 3rd Floor | [EMAIL PROTECTED] Iselin, New Jersey 08830 | http://www.enterprisedb.com/ ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
