Hellgren, Johan wrote > > Hello list, > > We are currently developing a large e-commerce site using SAPDB > 7.4.3.27. We do expect to see a large number of inserts into the > database, and are therefore considering how to assign key values for the > inserted rows. Using a sequence is what we presently consider doing, as > it has served us well in past, smaller implementations. >
The implicit used primary key, called syskey CHAR (8) BYTE, which can be selected when specifying SYSKEY in the select-list afterwards does not serve your needs? > I see in the documentation that sequences can be created with maximum > values up to 38 digits, but I have been unable to find any mention of > any issues associated with using a single sequence for very high > transaction volumes. I'd thus like to ask the list if there are any > recommendations for the maximum number of transactions (nextval selects) > per second (or other volume-based metric) a single sequence can support > without having locking or other performance issues. Why do you want to do NEXTVAL-selects? Do you use the NEXTVAL-value in more than one row? If not, then use <sequence_name>.NEXTVAL in the insert itself to shorten the way and avoid superfluous communication between application/client and server. On the other hand: when using sequences very heavily, it is a good idea to use the CACHE-option when creating the sequence. http://dev.mysql.com/doc/maxdb/en/6d/117c29d14811d2a97400a0c9449261/fram eset.htm The cache will be good for performance, but will cause the loss of some numbers in case of shutdown of the server. > Also, are there any > changes in sequence performance in MaxDB 7.5 (and 7.6) compared to SAPDB > 7.4? > No Elke SAP Labs Berlin > Thanks in advance for your insight! > /Johan Hellgren > > -- > MaxDB Discussion Mailing List > For list archives: http://lists.mysql.com/maxdb > To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MaxDB Discussion Mailing List For list archives: http://lists.mysql.com/maxdb To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
