mORMot Open Source

sakura

Member

From: Germany

Registered: 2018-02-21

Posts: 228

Website

TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

Hi,

we have manually created a FTS5 Fulltext-Index, where the following SQL code will crash, when using TSQLRequest:

SELECT GlobalID, Module, Service, DefaultDisplayText FROM ukiFtsMap JOIN (SELECT RowID, Rank FROM ukiFtsIndex WHERE ukiFtsIndex MATCH 'max') ON ID = RowID ORDER BY Rank LIMIT 15 OFFSET 0

When removing the Rank from the SELECT statement, all will execute just fine, however, the important match ranking is lost:

SELECT GlobalID, Module, Service, DefaultDisplayText FROM ukiFtsMap JOIN (SELECT RowID FROM ukiFtsIndex WHERE ukiFtsIndex MATCH 'max') ON ID = RowID LIMIT 15 OFFSET 0

First time, I try to execute this statement in the SynDB Explorer, I get the following error message:

[Window Title]
 SynDB Explorer 1.18.5030 (compiled with Delphi 10.3 Rio 32 bit) - FTS

[Main Instruction]
Error

[Content]
Invalid floating point operation

[Expanded Information]
Exception class: EInvalidOp


[^] Hide details  [OK]

Subsequent request will fail with following error:

[Window Title]
 SynDB Explorer 1.18.5030 (compiled with Delphi 10.3 Rio 32 bit) - FTS

[Main Instruction]
Error

[Content]
Access violation at address 0084C1CC in module 'SynDBExplorer.exe'. Read of address 00000008

[Expanded Information]
Exception class: EAccessViolation


[^] Hide details  [OK]

Please note, that the same SQL will run fine with other SQLite Browsers, so I believe the problem is with the mORMot implementation. However, debugging did not get me very far. :-(

The problem can be recreated with the latest nightly build.

Kind regards,
Daniel

@Arnaud: I can send you a copy of the DB3 file for checking into this.

sakura

Member

From: Germany

Registered: 2018-02-21

Posts: 228

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

I have created a simple sample, that will reproduce the problem.

Start SynDB Explorer with a new, empty SQLITE3 DB.

Execute each of the following statement separately, the last on will reproduce the error:

CREATE VIRTUAL TABLE Idx USING fts5(A, tokenize='unicode61');
INSERT INTO Idx (RowID, A) VALUES (1, 'hello world');
INSERT INTO Idx (RowID, A) VALUES (2, 'hello max');
INSERT INTO Idx (RowID, A) VALUES (3, 'hello frank');
SELECT RowID, A FROM Idx WHERE Idx MATCH 'max';
SELECT RowID, A FROM Idx WHERE Idx MATCH 'max' ORDER BY Rank;

Regards,
Daniel

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,242

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

Did you try to debug a little bit and seek on which source code line the floating point error happens?

sakura

Member

From: Germany

Registered: 2018-02-21

Posts: 228

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

Well, as I said, I did not get very far. From

function TSQLDBStatement.FetchAllToJSON(JSON: TStream; Expanded: boolean;
  RewindToFirst: boolean): PtrInt;

...
    while Step(RewindToFirst) do begin

it goes into

function TSQLDBSQLite3Statement.Step(SeekFirst: boolean): boolean;
...
    result := fStatement.Step=SQLITE_ROW;

to

function TSQLRequest.Step: integer;
...
    result := sqlite3_check(RequestDB,sqlite3.step(Request),'Step');

Which seems to be a function within the SQLite driver. (sqlite3.step(Request))

Then it jumps into

function memset(P: Pointer; B: Integer; count: Integer): pointer; cdecl; { always cdecl }
// a fast full pascal version of the standard C library function
begin
  FillCharFast(P^, count, B);
  result := P;
end;

and upon return into the CPU view... :-(

Regards,
Daniel

Last edited by sakura (2019-02-11 18:25:57)

sakura

Member

From: Germany

Registered: 2018-02-21

Posts: 228

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

At some point, following function gets called (Unit SynSQLite3Static):

function log(const val: extended): extended;
asm
  fld val
  fldln2
  fxch
  fyl2x
  fwait
end;

Upon coming to fwait, the exception is thrown.

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,242

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

Could you try to replace the low-level asm code by the following:

function log(const val: extended): extended;
begin
  result := ln(val);
end;

OR
just comment the fwait ?

My guess is that the SQlite3.obj code doesn't use FPU exceptions, so the linked log() value shouldn't be used either...

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,242

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

Update: I guess I found the root cause.

On my side after https://synopse.info/fossil/info/fe4a3b9b56 FTS+RANK works fine now.

sakura

Member

From: Germany

Registered: 2018-02-21

Posts: 228

Website

Re: TSQLRequest EXC with 'Invalid floating point operation' on FTS5 SELECT

Hello Arnaud,

thx for your service, this fixed it for me too.

Kind regards,
Daniel