Pervasive PSQL Summit v10

Upgrade from v9 to PSQL Summit v10

LawrenceNtim — Mon, 23 Aug 2010 21:03:36 GMT

Hi Support,

I just upgraded from Pervasive version 9 of to Pervasive PSQL Summit v10. I am getting the error message below when trying to activate the License Key:

Error 11316:Unexpected Activation error. Please contact support.

I have confirmed that there is internet connection because I was able to connect to www.google.com

Why is this happening and what will be the next step?

Thanks, Lawrence

EPvDbAdminEngineError, local acces, workgroup, Win7

sweinrich — Fri, 20 Aug 2010 09:42:34 GMT

Hello,

the PvSession.GetAliasNames return an error EPvDbAdminEngineError "Cannot open DbNames.cfg file" on a Win7 Workgroup Engine 10.30 when access from the local machine. When I acces with the same program from a remote machine no error accurs. The same installation on a WXP-machine works fine in both modes.

Thank for the help.

Stefan

Database table creation

KevinM2009 — Wed, 11 Aug 2010 15:23:07 GMT

I am experiencing problems with dropping/recreating a table. The current version of the table has a record length of 1514. When I drop the table and then create it using the "Create SQL" from the "SQL View" tab, the record length is now showing as 1628. Also, the offsets from the X$Field table are not correct, they dont start at 0 and the lengths added to the offset do not add up to the next offset's position.

Pervasive.SQL V10.10 Workgroup License 1 Standalone User 10 Pack

Dmitry12 — Tue, 10 Aug 2010 14:01:36 GMT

Could not prompt. Given license Pervasive. SQL V10.10 Workgroup License 1 Standalone User 10 Pack can unite 10 workstations using by one database?

Remove quotes in Stored Procedure Column Names

agon04 — Sun, 08 Aug 2010 02:51:45 GMT

Hi All,

1) In Pervasive V10 Control Center I open DEMODATA and "Execute in Text" the following statement:

select First_Name"First Name" from Person

Below is the Optput:

<<<<<<<<<<<<<<<<<<<<<<<<
First Name
===============
James
Kanagae
Haniza
.....

2) Then I write the following "Stored Procedure":

CREATE PROCEDURE "firstName" () RETURNS("First Name" CHAR(20));
BEGIN select First_Name from Person; END;

3) Now I "Execute in Text" the following statement:

execute firstName

Below is the Optput:

<<<<<<<<<<<<<<<<<<<<<<<<
"First Name"
====================
James
Kanagae
Haniza
..............

How do I get rid of quotes in the Column Name ?

Regards,

Alex.

System Error: 301.36.0

jorgep — Tue, 03 Aug 2010 01:47:25 GMT

Hi,

What's the meaning of this error or warning in pvsw.log?

I have a case where an application processing a bunch of records from a table on a daily basis is not able to read all the day's records on some days.

This is easy to verify because there's a field called "posted" that's being set to true after each record has been processed otherwise the record remains unposted or unprocessed. If I may add, the processing is being run on the server machine at the end of working hours hence no other program reads or writes on the table in question. Also, because the processing is done on the server where the tables reside, no network traffic is involved.

I always thought it's the application skipping or ignoring some records purposedly for some reason but just by doing a rerun, the missed-out records are read and processed properly the second time around. This has been going on for some time and unexpectedly.

Recently, I discovered that during those occurrences where records were skipped, pvsw.log records System Error: 301.36.0 on the table involved.

What's this error about? How to fix it? The version I have is 10.10.125.000 and it runs on Windows 2003 Server R2.

Thanks.

Data Corruption PSQL10 Windows SBS 2008

j50agl — Mon, 26 Jul 2010 14:40:42 GMT

PSQL Engine 10.21 - Transactional only.

Has been working with absolutely no problems on a Window 2003 Server (4 GB RAM - No MS Exchange or other big application) for over 12 months.

We recently re-installed on a Windows 2008 Small Business (12 GB RAM - Exchange but little else). Things seemed to be fine for just over a week then received Error 2 (File I/O errors) in one file then another. Rebuilt these and all went quiet for just under two weeks then started to get more Error 2s in various files.

Have moved the production database back to original hardware (but with disk subsystem replaced) to get customer up and runnning and all seems well again. So problem would appear to be with SBS 2008 and or machine configuration.

Any ideas where to start looking?

MIN function is not working for selecting from columns defined as IDENTITY

goker1 — Fri, 23 Jul 2010 15:56:39 GMT

We have just noticed this strange behavior during our 8.7 -> 10.x conversion. If you have a table with column defined as IDENTITY, and you do a "SELECT MIN (column_name) from table_name" on that column, it does not return anything in 10.x, but works fine in 8.7. MAX function for that table works fine on both version of the database engine.

Have anybody else ever seen/noticed this?

PervasiveOLEDB provider is not registered on the local machine on Windows 2008 x64

rashidhsiddiqui — Wed, 21 Jul 2010 13:41:11 GMT

I am facing a problem for couple of days. I am using Windows Service for .Net 2.0. The service is using Pervasive v.10 to get the data from third party application database Sage Timberline Office Service Management.

I was initially perfectly able to connect to Pervsive database using OLEDB provider on X86 operating system. But when the code compiled and Pervasive SQL connection call is made, then error thrown on opening connection "PervasiveOLEDB provider is not registered on the local machine".

After quite an effort, i finally used Pervasive.Data.SqlClient.PsqlConnection and Pervasive.Data.SqlClient.dll version(3.0; which was supplied alongwith Pervasive v.10 installation) to able to open connection.

My question is this, whether Pervasive SQL v.10 supports OLEDB connections? If yes, then how?

Please any one if know the answer then reply me as soon as possible.
Thanx in advance.

Using Btrieve with C#

rohini.kurkal — Tue, 20 Jul 2010 16:01:24 GMT

Is there any sample code for reading and writing the .DAT files (PSQl v10) using Btrieve in C#?
Can I use Btrieve API with C# and how?
Where are the code examples for C#?

Thanks.

Pervasive 10, PHP and ODBC

Brasse — Tue, 13 Jul 2010 15:50:18 GMT

Hello, im experimenting with ODBC at the moment, and ive run in to a problem. Currently our business software lives in a Pervasive database, and unfortunately som column names contains swedish letters. For example: D2021_Företag So when i try this SQL: 'SELECT TOP 5 D2021_Företag FROM PUFIRMA' i get this error: Warning: odbc_exec() [function.odbc-exec]: SQL error: [Pervasive][ODBC Client Interface][LNA][Pervasive][ODBC Engine Interface]Invalid column name: 'D2021_Företag'., SQL state S0022 in SQLExecDirect in C:\xampp\htdocs\company.php on line 81 Im using PHP Version 5.3.1 Apache/2.2.14 (Win32) Windows 2003 How can i solve this?

Query causes PSQL 10.30.017 engine to crash

bbergin — Tue, 13 Jul 2010 04:16:42 GMT

The query below causes Pervasive SQL 10.30.017 to crash. We've already discovered that using DISTINCT in cross-database queries cause the database engine to crash. In this instance, it looks like using CASE statements in a cross-database query causes the engine to crash as well.

SELECT c.name, m.last_name, m.first_name, m.addr1, m.city, m.state, m.zip,
m.hire_date, m.ss_alpha, m.sex, m.birth_date,
Case m.eeo_class
when 1 then 'Officials and Managers'
when 11 then 'Executive'
when 12 then 'Manager'
when 2 then 'Professionals'
when 3 then 'Technician'
when 4 then 'Sales'
when 5 then 'Administrative Support'
when 6 then 'Craft Workers'
when 7 then 'Operatives'
when 8 then 'Laborers'
when 9 then 'Service Workers'
end as EEO_Class,
m.hourly, m.freq,
CASE m.empl_status
when 1 then 'Regular FT'
when 2 then 'Regular PT With Benefits'
when 3 then 'Regular PT Without Benefits'
when 4 then 'Temp FT'
when 5 then 'Temp PT'
when 6 then 'Leave of Absense'
when 7 then 'On Call'
END AS FT_Status,
m.base_rate as Base_Rate, m.gross_yr
FROM APEX132010.PR_MAST m inner join
APEX132010.CL_MAST C ON M.LOC_NO = C.LOC_NO
WHERE c.loc_no in (2919,3071,3373,3375,3467,2918,2983,2920,3393,3374,3401,3320,3092,2956)
and active_stat = 'A'
UNION
SELECT c.name,m.last_name, m.first_name, m.addr1, m.city,m.state,m.zip,
m.hire_date, m.ss_alpha, m.sex, m.birth_date,
Case m.eeo_class
when 1 then 'Officials and Managers'
when 11 then 'Executive'
when 12 then 'Manager'
when 2 then 'Professionals'
when 3 then 'Technician'
when 4 then 'Sales'
when 5 then 'Administrative Support'
when 6 then 'Craft Workers'
when 7 then 'Operatives'
when 8 then 'Laborers'
when 9 then 'Service Workers'
end as EEO_Class,
m.hourly, m.freq,
CASE m.empl_status
when 1 then 'Regular FT'
when 2 then 'Regular PT With Benefits'
when 3 then 'Regular PT Without Benefits'
when 4 then 'Temp FT'
when 5 then 'Temp PT'
when 6 then 'Leave of Absense'
when 7 then 'On Call'
END AS FT_Status,
m.base_rate as Base_Rate, m.gross_yr
FROM APEX152010.PR_MAST m inner join
APEX152010.CL_MAST C ON M.LOC_NO = C.LOC_NO
WHERE c.loc_no = 2014
AND active_stat = 'A'
ORDER BY c.name, m.last_name, m.first_name;

I don't think this query is malformed in any way. Even if it were, why would the database crash because of it?

Cast as Int not working - returning 1 less.

billegge — Wed, 30 Jun 2010 11:29:51 GMT

Using Engine 10.12

The following SQL statement returns

CastInt = 29839
NoCast = 29840

select
cast(Truncate(298.4058, 2)*100 as int) as CastInt,
Truncate(298.4058, 2)*100 as NoCast

-Bill Egge

File Versions

adam.jackson — Wed, 30 Jun 2010 13:26:11 GMT

Hi,

We have recently migrated to v10. We have been rebuilding our files but because of the time it takes we cannot do them all at once. We are now near the end and would like to determine which tables need rebuilding. Is there a tool that will list all the tables indicating which Pervasive version they are?

TIA

Adam

"Could not retrieve the table information" error in SSIS using Pervasive OLE DB connection

Henry Wilson — Wed, 23 Jun 2010 12:41:04 GMT

I am trying view table names of demodata in SSIS Package Configuration.

I was able to create OLE DB Connection and was able to test connect it successfully.

In the data flow tab, under ‘OLE DB connection manager’,

I was able to select the OLE DB connection I created.

Now when I select “Table or View” under “Data access mode” and try to view tables by clicking the dropdown of “Name of the table or the view”, I get the error:
Could not retrieve the table information for the connection manager 'DEMODATA.DEMODATA'.

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

Any help on how to resolve this will be greatly appreciated.
I am using Pervasive V10.1.
Thanks,

Henry

Mirtheil's reply:

You mention v10.1 in your message but are posting in the v9 forum. What's the exact version of PSQL you are using? Specifically, what's the version of POLEDB.DLL and W3ODBCEI.DLL (or W3ODBCCI.DLL)?
If you are really using 10.1, have you considered updating to the 10.31 patch?

Mirtheil
I do not answer question via email. Please post questions in the forum.

Pervasive Transaction Logs

Erick Paquin — Fri, 25 Jun 2010 15:09:01 GMT

Hi Everyone,

Transaction logging is turned ON by default when installing Pervasive. We have come up with a situation at a customer's site where the transaction log folder keeps growing out of proportion and is taking alot of disk space.

I was under the impression that the logs would clear themselves out when restarting pervasive but It doesn't in this particular case.

Can someone shed a bit of light as to why that would be? Why do the logs don't clear out? Are they crucial or can I just delete them?

Thanks for the help.

Erick P. Montreal

PSQL SERVER 10.30 (x64) does NOT support ADO.NET providers 3.2

jsheil — Mon, 21 Jun 2010 10:25:00 GMT

Hi members,

I have been working on some ETL packages with SSIS and have recently moved to using the PSQL providers for ADO.NET rather than using ODBC, which was giving me terrible problems with the newer windows architecture (windows 7 and windows 2008 server mainly). This switch over was going smoothly for the main part with some small issues rearing their ugly heads. However when i went to install my latest packages onto a clients test server, with the ADO.NET 3.2 provider my extract packages did not work full stop. I had a look at the instance of the server install on the machine, and it was PSQL Server 10 SP3 (x64), which is 10.30.

To cut a long story short, i ended up installing PSQL SERVER SUMMIT 10.10 (X86) installed via the installation file "PSQL-Client-10.12.014.000-win.x86.exe" which i downloaded from your site. This in conjunction with the ADO.NET providers 3.2 solved the problem. Worryingly though, when i went to install this client it told me that the newer version of PSQL SERVER that was on the machine actually did everything this earlier installation would do, when clearly this is not the case with something as fundamental as connectivity through ADO.NET

So my questions are :-

i.) is there a plan to upgrade the 3.2 providers to actually work with the server version 10.30 ?

ii.) if so, when is this due to be released

Hope someone else finds this useful

Joe

DISTINCT queries with in-line views cause Pervasive 10 to crash

bbergin — Fri, 18 Jun 2010 15:00:34 GMT

If I run a query through the Pervasive Control Center that has multiple in-line views (virtual tables) and that uses the DISTINCT keyword within those views, Pervasive 10 will crash. If I use GROUP BY rather than DISTINCT, then the database does not crash.

Here's an example:

SELECT v_ee.*, v_sp.Spouse_Coverage, v_ch.Child_Coverage
FROM
(SELECT DISTINCT ' 11-' + CONVERT(pm.loc_no,SQL_CHAR) As cl_id, pm.first_name, pm.last_name,
pm.ss_alpha as ss_no, pm.hire_date, pd.cover_beg, pm.term_date, pd.cover_end, pd.emp_amt as Emp_Coverage
FROM APEX112010.pr_mast pm, APEX112010.pr_cded pc, APEX112010.pr_ded pd
WHERE pm.loc_no = pc.loc_no and pm.emp_no = pc.emp_no
and pd.emp_no = pc.emp_no and pd.loc_no = pc.loc_no and pd.code = pc.code and pd.plan = pc.plan
and (pm.active_stat = 'T' or pd.cover_end is not null) and pc.code = 363
and (pd.plan = '1HRT EE NS' or pd.plan = '2HRT EE S')
and pd.plan NOT IN ('BENEFICIAL', '6HRT BC EE', '7HRT BC SP', '8HRT BC CH')
and (pd.cover_end BETWEEN '2010-01-01' AND '2010-03-31'
or pm.term_date BETWEEN '2010-01-01' AND '2010-03-31')) AS v_ee
LEFT JOIN
(SELECT DISTINCT ' 11-' + CONVERT(pm.loc_no,SQL_CHAR) As cl_id, pm.first_name, pm.last_name,
pm.ss_alpha as ss_no, pm.hire_date, pd.cover_beg, pm.term_date, pd.cover_end, pd.emp_amt as Spouse_Coverage
FROM APEX112010.pr_mast pm, APEX112010.pr_cded pc, APEX112010.pr_ded pd
WHERE pm.loc_no = pc.loc_no and pm.emp_no = pc.emp_no
and pd.emp_no = pc.emp_no and pd.loc_no = pc.loc_no and pd.code = pc.code and pd.plan = pc.plan
and (pm.active_stat = 'T' or pd.cover_end is not null) and pc.code = 363
and (pd.plan = '3HRT SP NS' or pd.plan = '4HRT SP S')
and pd.plan NOT IN ('BENEFICIAL', '6HRT BC EE', '7HRT BC SP', '8HRT BC CH')
and (pd.cover_end BETWEEN '2010-01-01' AND '2010-03-31'
or pm.term_date BETWEEN '2010-01-01' AND '2010-03-31')) as v_sp ON v_ee.cl_id = v_sp.cl_id and v_ee.ss_no = v_sp.ss_no
LEFT JOIN
(SELECT DISTINCT ' 11-' + CONVERT(pm.loc_no,SQL_CHAR) As cl_id, pm.first_name, pm.last_name,
pm.ss_alpha as ss_no, pm.hire_date, pd.cover_beg, pm.term_date, pd.cover_end, pd.emp_amt as Child_Coverage
FROM APEX112010.pr_mast pm, APEX112010.pr_cded pc, APEX112010.pr_ded pd
WHERE pm.loc_no = pc.loc_no and pm.emp_no = pc.emp_no
and pd.emp_no = pc.emp_no and pd.loc_no = pc.loc_no and pd.code = pc.code and pd.plan = pc.plan
and (pm.active_stat = 'T' or pd.cover_end is not null) and pc.code = 363
and pd.plan = '5HRT CHILD'
and pd.plan NOT IN ('BENEFICIAL', '6HRT BC EE', '7HRT BC SP', '8HRT BC CH')
and (pd.cover_end BETWEEN '2010-01-01' AND '2010-03-31'
or pm.term_date BETWEEN '2010-01-01' AND '2010-03-31')) as v_ch ON v_ee.cl_id = v_ch.cl_id and v_ee.ss_no = v_ch.ss_no;

PSQL 10 SP3 uninstall

ewdavenport — Sat, 19 Jun 2010 18:22:02 GMT

I have a customer running Windows 7 64 bit Ultimate.

We have not had the same issues on our W7 64 Bit Professional workstation.

Failing everything I asked him to uninstall PSQL. I suspected something was wrong with the original installation since some of the pages in the control center options were blank and displaying only partial lettering. For example the page was blank and the instruction that should read move the mouse... only had mov and nothing else. He said that he uninstalled it and then called to see if he should install as service or an app I said Application.

We ran the test app and it failed as before I told him to send me the computer. The first thing I noticed when I started the computer was that PSQL was running as a service. I stopped the Service and Rebooted the computer and it did not load as a service. I then continued to uninstall the PSQL since I do not trust the installation and I cannot. It displays an error stating the PVSW.LOG is locked and it cannot proceed. Retry does nothing and cancel restores to the orignal.

I delete the ProgramData\Pervasive folder where the logs are stored entirely manually without any complaint and try an uninstall again and same result.

Can someone help me figure out how to uninstall pervasive so I can get a clean reinstall.

Thank You

Eric

Worker Threads High / Go Slow

adam.jackson — Thu, 17 Jun 2010 13:58:11 GMT

Hi,

We occassionally get periods where our app runs slowly for about 10 mins or so. We have had it on v8, v 10.1 and now on v10.3. It is always accompanied by the worker threads count going very high. Sometimes but not always there are 1 or 2 transactions. It is very frustrating as we cannot explain it to the users or ourselves. Nothing else in monitor indicates particularly heavy usage. Any ideas what might be causing it?

TIA

Adam

Transaction problems

daviddap — Tue, 01 Jun 2010 17:21:50 GMT

Hi,

I have a Pervasive DB v.10.30 up to date, that is being used by an asp.net application (through Pervasive.Data.SqlClient driver). The same DataBase is being accessed by a few old applications that use an ODBC connection for updates, deletes and inserts and a Btrieve connection to retrieve data (selects).

The Asp .net application has to do a complex opperation, involving updating some tables directly and some through store procedures and triggers.

I think the code is easy enough to follow:

bool OpOk = false; // Operation was OK

// Create the transaction

if ((trans = context.StartTransaction()) == null)
throw new BusinessException("JobBusiness::saveDeliveryLoad. The transaction couldn't be started",
BusinessException.ExceptionType.business);

try
{

// Modify the DB

      if (StoredProcedures.DeliveryStockStatus(load.LoadNo, 'B', false) >= 0) // Store procedure!!
      {
           if (this.saveDeliveryLoad(load, false)) // Save the entity into the DB's table
           {

                // Store procedures
                OpOk = (StoredProcedures.setFullTicketDate(load.LoadNo, (DateTime)load.DatetimeOut, user, reasons, false) >= 0);
                if (!this.CreateRLMovementsForFullTicket(load.LoadNo, (DateTime)load.DatetimeOut))
                      throw new BusinessException(BusinessResource.Error_UnableCreateRLMov,
                           BusinessException.ExceptionType.business);
            }
        }

// Check the result and commit or rollback

        if (OpOk) trans.Commit(); // Commit and close associated connection
        else trans.Rollback(); // Rollback and close associated connection

        return OpOk;

}
catch (StorageException stEx)
{
    if (trans != null) trans.Rollback();
    throw new BusinessException("DeliveryBusiness::LoadFullTicket. Database exception!!",
        stEx, BusinessException.ExceptionType.database);
}
catch
{
    if (trans != null) trans.Rollback();
    throw;
}
finally {
    if (trans != null) trans.Dispose(); // Free the transacion and close its associated connection if still open
}

The problem I have is that from time to time the setFullTicketDate does not work. This store procedure updates just one table in the DB, that is not accessed by the old applications nor updated by any trigger.

The real problem is that the application THINKS it worked (and does not receive any exception or error value from the database). On the other hand, the database server locks some indexes in that table, and keeps trying to actually commit the changes until it crashes. Or at least is what I think is happening, because the only thing I can say is that after a while it crashes (stop responding and forces us to restart the server) and after that the database keeps having occasional locking problems (Btrieve error 84) when I try to insert new records on that table. Furthermore, the original transaction that created the problem is half done (all other tables modified save the one updated by the setFullTicketDate store procedure, that remains unchanged), and trying to manually modify this table will just return a corrupted index error (Betrieve Error 4). This happened 3 or 4 times in the last 5 weeks, forcing us to restart the server and rebuild the indexes on that table every time.

The exact error I get when the table is locked is: Pervasive.Data.SqlClient.Lna.k: [LNA][Pervasive][ODBC Engine Interface][Data Record Manager]The record or page is locked(Btrieve Error 84)

I hope the description is not too long and is clear enough. Does somebody have any idea on what is causing this or some work around?

Thanks!

David.

Memory Use limit on 64 bit v10

adam.jackson — Mon, 14 Jun 2010 12:42:58 GMT

Hi,

Is there a limit as to how much physical memory 64 bit Pervasive v10 SP3 will use on a server. I have v10 engine on a W2008 64 bit server running on VMware with 16GB of RAM. I have opened tables whose size totals in excess of 4GB (about 8GB) but the NTDBSMGR64.exe service never uses more than 4Gb. I have opened them using MS Query to get all rows returned. A couple of the bigger tables could not have all rows returned due the 1M row limit in Excel but even so I am confident that I am still well over 4GB.

Regards

Adam

Hardware Specification v10 64 bit server

adam.jackson — Mon, 07 Jun 2010 14:47:29 GMT

Hi,

I am a newbie to this forum so apologies if my etiquette is not quite right. Please feel free to correct if I am asking the wrong things or in the wrong way.

My question is about suitable specification for a Pervasive v10 database server. Our hardware people are suggesting the following:

Processor: Intel Xeon E5540 x 2 (4 cores-per-processor, 8 in total)Memory: 12GBLocal Disks: 72GB x 2 (configured in a mirror)HBA (SAN Connection): Dual Port x 2 (providing for initial resilience and growth potential)

All data will be SAN stored. The exact configuration and size of these volumes will need to be established, but I would suspect we'd want to look at either a mirrored-stripe or vice-versa.

Is this specification above suitable for the following usage pattern and what would be better mirrored-stripe or striped-mirrored or A N Other?

70 concurrent users with about 80 sessions
mixed btrieve and SQL access (The main app is Btrieve but there are regular queries run for reporting and integration purposes)
database size is 16gb growing at 0.75Gb a year
Largest table in terms of record count is about 2.2M growing at 0.5M a year
Largest table in terms of physical size is 1.2 Gb growing at 0.1 Gb per year
table version is 9.5
Server is 32bit W2003 R2 on VMWare but will be 64bit W2008 on physical box specified above
There are a few temporary tables created and dropped regularly depending on programs used. Each user would have own instance of temp table so multiple instances can exist.

Hope someone can help,

TIA

Adam

Columns Redefines in DDF

omaire — Tue, 01 Jun 2010 09:18:29 GMT

In Version 8, I had DDF with redefinitions of fields.

With version 10, the DDF Builder generates errors "overlap".

Is there a way to keep these redefinitions, or to create?

Thanks.

DDF Builder Version 10.30.017.000

Pervasive V10 WG - License Administrator - Error 7218

freddy1302 — Wed, 02 Jun 2010 08:34:46 GMT

Hi,

We downloaded the trial version of PVSW V10 WG 5 users and installed it on a PC, located in Shangai.

We are located in Belgium and we take over the PC to do our job. So we work remote.

We received the License key (CD-key).

We enter the CD-key and when we activate it, we get Error 7218: An error occurred acquiring the machine configuration.

We are logged in as an administrator, so we surely get admin-rights.

Can anayone tell us what to do to so we can activate the key.

Thanks

Freddy Dewulf