"Posting" is the process of recording the current daily prices (seen in the quotepage) into the daily database as the current daily bar. Posting Time is specified in the Session Preferences and is generally setup to occur a minute or two after the session closes. This process is not really needed in the end-of-day case. If you're just downloading your daily data after the session closes, you really have no need to "post". You can turn off this posting by going to Setup > Preferences > Sessions, selecting the session of interest, unchecking the "Post Time" checkbox, and then clicking the Apply button.
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During trading hours, the daily historical data stored in the Investor/RT database typically is up to date only to the previous trading day close. When Investor/RT is used real-time, current open, high, low, close, and volume is kept up-to-date in memory for display in quotepages and charts. During trading hours, daily charts that have a "to present" view period will show the daily bars from the historical data base PLUS one "in progress" bar, the bar being formed in real-time. Each trading session setup in Investor/RT has a session start, stop, and posting time. The posting time is typically equal to or just a few minutes after the session ending time. At the designated posting time, the memory resident OHLCV data is "posted" (recorded) into the daily historical data, adding one daily bar. Posting can be performed manually using the Record Closing Prices command in the Control Menu under Data Management. This will "post" all trading sessions. Alternatively, posting can be performed on a session by session basis by going to Setup > Preferences > Sessions and then picking the session you wish to "post" from the list and click the Post Now button.
End-of-Day Investor/RT users typically do not need the posting feature at all, in which case, you can turn off the automatic posting feature for each session in Setup: Preferences: Sessions. If you typically perform a "historical download", downloading 1 or more days of daily historical data each day, this data is placed directly into the Investor/RT daily database, no posting required. Investor/RT end-of-day users with Dial/Data can obtain closing quotes in bulk using the Bulk Download feature in the Download Data window. These dated bulk download files contain OHLVC data for a particular date. The data is placed directly into the Investor/RT daily database, no posting required. If you use Dial/Data to fetch "Current Quotes" or if you have an external source of current quotation data that you use with Investor/RT's "Current Quotes/Other Data" Import feature, the imported data does NOT go immediately into the database. Just like real-time data, such imported data is placed into memory for display in quotepages and charts, but is not added to the daily database until a "posting" operation is performed. Thus, you can avoid the need to "post" by performing a historical download or a historical import. Keep in mind that historical data importing requires that the date be specified in each "line" of the imported data file along with the closing prices and volume data for that date. If you have current quotation data with no date present in the file, you can import the data as "Current Quotes" and then perform a post history to record the data in the daily database. The posting process uses the current date to record the daily bar, except on weekends when the previous trading day's date (Friday's date except when Friday was a holiday) is used for posting.