Limited entries in tx_realurl_urldata (max. 500.000) ? Older entries deleted ?

[ulrichbayern]

I have a web project (Typo3 7.6.23 and realurl 2.3.0) with more than 1.5 million urls.
I still wanted to bring in all my urls into the tx_realurl_urldata e.g. by a linkchecker. Everything is fine, but i never get more than 500.000 entries into this table. I can see the growing of the uid-autoincrement and the urls are created correctly with cHash, but older entries are suddenly deleted.
This can be proofed because the Min_value of uid is always getting bigger if new urls come in, so this means older (correct urls) are simply deleted. A SQL-query with Count shows always a number between 480.000 and 498.000, although the value of the uid shows, that about 270.000 entries were made before. So there is a mismatch !
This means for me, that older urls which shows always the right content, suddenly showed wrong content, because the (still existing) url was not more in the tx_realurl_urldata.

Is this a heavy bug or is this a mistake of my own, maybe a false configuration somewhere ?

Greetings, Uli.

[ulrichbayern]

Is maybe "tx_realurl | updateLevel" in "sys_registry" the reason for this behaviour ?

[ulrichbayern]

Update:

i read the article [http://www.schmutt.de/127/innodb-wird-zu-gros/] and tried it out because i thought that InnoDB is the problem:
i changed all tables from InnoDB to MyISAM, but after maybe 1000 records, the same behaviour: the oldest records are further deleted, if new ones come into the table.

[ulrichbayern]

Solved:
file "DatabaseCache.php" in "typo3conf/ext/realurl/Classes/Cache" was responsible for that. Sorry, i haven't seen that earlier.