Why summarization is an important step in project maintenance.
Whenever you summarize a project, the Summarize function updates a special set of so called Summary Tables in the Primavera P6 database. These Summary Tables provide huge performance benefits for the system because they allow the user to be presented with a list of projects, and some high-level details about them, without loading vast amounts of unnecessary activity and resource detail into the client’s memory. Instead, P6 simply loads a small subset of the project’s high-level data. If it were necessary to load all the detail for all the projects for every user logged into the system, the impact on the system’s performance and that of its supporting network would be notable, to say the least.
Many of the Primavera P6 systems I have worked with over the years contained tens of thousands, if not millions of records that have built up over a period of several years. Without the summary tables, the system would get slower and slower over time as the volume of data required to load a simple project list would overwhelm the system. It would become intolerably slow and impractical to use and the only solution would be to archive off and purge all your completed projects in order to keep the traffic to a minimum.
When to summarize
You should perform a Summarize process whenever you change the project.
This will ensure that the project table is showing the correct values whether or not the project is open. It also has another unexpected benefit: your reports will be correct.
If you don’t summarize after you have made any kind of change, and someone runs a report on your project using the Projects subject area, that report will not reflect your changes. Reports based upon the Projects subject area will only show correct data if you’ve either summarized it, or the person running the report opens your project. If they don’t, it will be out of date.
I’ve seen this happen and it can be quite disconcerting when you arrive in a project meeting and the weekly updates you recently entered into Primavera P6 didn’t show up in the Project Managers weekly status report. You’ve either got to explain why your project is behind schedule or fess up to not summarizing. Either way, it’s a bad day at the office.
Take a look at this example.
In the following image, there are two identical projects called Ares Rocket. One is simply a copy of the other. They are both closed, but only one has been summarized.
Note some of the differences. First, the NOT summarized Ares Rocket project seems to have only 3 activities in it. The summarized project shows 80 activities. How about those dates too; different in both cases and no actual dates are showing for the un-summarized project.
A report run on these projects using the Projects or Project/EPS subject areas would show similar errors and could cause a lot of unnecessary explaining to be done. Click on the following image to take a look at this example of a report based upon the Project/EPS subject area.
Again the data is incorrect considering that these two Ares Rocket projects are identical to each other, ARES II summarized and ARES II-1, not so much.
Bottom line – in Primavera P6, if you’ve changed it, summarize it.
I hope this information helps keep you all out of trouble in next week’s status meeting.
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