Memo field data loss

[youwannawhat]

We lost our production server for about 5 minutes yesterday. When it came back online, I started getting phone calls from the data entry personnel complaining about lost data. All records entered yesterday had all of the 'Memo' data fields(Comments, Transaction memo field) wiped out. All other data appears intact, and all other memo records before yesterday are still there. Ever heard of anything like this?

 

[Mike Gagnon]

Any chance of having a recent backup?

 

[youwannawhat]

The loss was limited the data entered yesterday, and it only affected the memo fields(comments, translog, etc). So, even the previous night's backup wouldn't help. I was more concerned as to the cause, and whether Foxpro is notorious for data loss in the event of server outages.

 

[GriffMG]

Youwannawhat,

Sorry, but memo fields (and I suppose generals to be pedantic) are the vunerable ones in a power outage.

The tables seem to generally be well 'committed' to the OS, but sometimes VFP will retain the memo info in buffer.

If the app is your own, can you see if you can modify the system so the process forces VFP to let go of the files from time to time?

HTH
Regards

Griff
Keep [Smile]ing

 

[Gandalf23]

The answer is that when you use pack in your code and the system crashes at that time, you CAN loose the data in the memo. We also had it. Not using pack in your code will help.

Greetings.

 

[DSummZZZ]

Vulnerable? That is an understatement. .DBF's are as vulnerable as memo files, as are .CDX's. Power outages, crashes, three-finger boot, all these kill VFP files. .DBF's a lot of times will only lose a small number of uncommitted records, but the bulk f the file is usually salvagable. Index files usually have to be recreated from scratch, and memo files are a hot in the dark. Avoid them whenever possible. Anyway, there are several good threads on "data corruption" in this forum so do a search on that and you can get some tips on prevention and repair.

Dave S.

 

[AChiado]

Hi,

you can use FLUSH command to ensure that modifications you make to all open tables and indexes are saved to disk. Andrea C.P.
Italy

 

[rgbean]

Andrea,
Ah, if that were only so. All FLUSH does is release it to the OS (i.e. it gets it out of the FoxPro buffers), it's still up to the OS, HD drivers and/or controller to physically write it to disk. While your statement was close to being true when running FoxPro DOS on a DOS only system, now when running under Windows and using Novell / NT / 2000 for a file server that use large file caches, and may have caching controllers, you never know when (or even IF) it's written to disk.

Rick

 

[youwannawhat]

Thanks everyone. I also discovered today that the data was probably not 'lost', but rather corrupted, merged, and slammed into the memo fields of about 10 of the 137,000 records in the table, causing 'Fatal Error' messages anytime I queried against the table. I uncovered a copy of a data repair utility. What a lifesaver! Problem solved for now. Thanks again.