Peoplesoft PeopleTools Performance Tuning Upgrade

PT 8.51.25 SYS DB Sizing – NCHAR() vs NVARCHAR()

Some quick statistics from a PeopleTools 8.51.25 SYS database on SQL Server:

  • Unicode with CHAR (i.e. NCHAR fields)       – DB size 1166 MB
  • Unicode with VARCHAR (i.e. NVARCHAR fields) – DB size 363 MB

That is almost a 70% reduction. Probably not that surprising given the number of character fields, but what is more interesting is the significant improvement in performance due to the increased number of rows per page for many tables.

An extreme example of this can be seen in PSAUDIT – using NCHAR this is close to 1200 characters wide due to 15 NCHAR(65) KEYn columns. Typically, the vast majority of the KEYn columns are empty since it is relatively rare for audited tables to have more than 5 key fields. Using NVARCHAR I have seen an average row width of 150 characters – meaning that a page holds 6 times as many rows on average.

Note: A value of 4 in the DATABASE_OPTIONS column of PSSTATUS will enable VARCHARs on SQL Server.

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