• Oracle - performance - sql - wait events

    CURSOR_SHARING : a picture is worth a 1000 words

    Anyone who has been around Oracle performance over the years knows the grief that hard parsing SQL queries can cause on highly concurrent applications. The number one reason for hard parsing has been applications that don’t use bind variables. Without bind variables queries that would otherwise be shared get recompiled because their text is different and Oracle treats them as different queries. Oracle addressed this issue with a parameter called cursor_sharing. The parameter cursor_sharing has three values exact – the default similar – replace literals with bind variables, if a histogram keep literal in place force – replace literals with…