Embedded engine hangs or crashes on queries that work against classic server
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                 Key: CORE-4221
                 URL: http://tracker.firebirdsql.org/browse/CORE-4221
             Project: Firebird Core
          Issue Type: Bug
         Environment: Firebird 2.5.2 Security Update 1 build 26540 64-bit on 
Windows 7 64-bit.
            Reporter: Gareth Marshall


I am using Firebird 2.5.2 Security Update 1 build 26540, 64-bit on Windows 7 
64-bit. I am testing using application developed with Delphi XE2 Update 4 
Hotfix 1 and IBObjects 5.2.0 Build 6. I am running my tests on Windows 7 SP1 
64-bit. The same database file is used for all tests. 

The database is using the UTF8 character set, and a page size of 8192 bytes. 
The connections are done using the UTF8 character set. The database contains 
just a single table with the following schema:

CREATE TABLE TEST ( NAME varchar(50) );

The table contains no data.

I generate a query that includes a number of tests ORed to each other. Each 
test just checks to see if the NAME field is equal to the string form of a 
number one larger that the one before, producing n terms in the WHERE clause.

For example, if n is 5, the following query is used:

SELECT * FROM Test T WHERE
T.Name = '1' 
OR T.Name = '2' 
OR T.Name = '3' 
OR T.Name = '4' 
OR T.Name = '5'

When run against classic server, I can have at most 3173 terms in the WHERE 
clause before the query string itself reaches a length of 65530 characters and 
then returns an error. This is pretty much expected behaviour.

When run using the embedded engine, I can successfully have 1052 terms in the 
WHERE clause. In my tests, 1053, 1054, and 1056 terms in the WHERE clause cause 
Firebird to hang when attempting to prepare the query (1052 terms would prepare 
in less than a second; after 30 seconds I killed the test for these values). 
Testing with 1088 or more terms causes the test application to crash with a 
stack overflow in the fbembed.dll. 1052 terms has a query string of length 
20989 characters, while 1053 terms has a query string of length 21010.

I have not tested any other configurations.

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