# 4825 Corrupted Indexes Can Cause an AV During SELECT Queries

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A table with index issues is hard to dupe so i have been testing some other things to make sure our software handles various errors OK.

I ran into a DBSRVR throwing an access violation when querying a table with known index issue.

Table verify reports "Indexes do not match record data and are invalid"

Table is "bad" but when i run a simple query i get DBSRVR reporting an AV

DBISAM Engine Error # 11279 An unknown error ('Access violation at address 0000000000987D2F in module 'DBSRVR.EXE'. Read of address FFFFFFFFFFFFFE20') occurred with the connection to the database server at '127.0.0.1', please check the server log. Module:TSSCDM. Method:OpenDbQuery. Detail:select * from SMSG_ARCHIVE_MESSAGE_PARTICIPANT where HASYNC_MODIFIED >= '2020-12-08 11:03:58.551 PM' ORDER by HASYNC_MODIFIED

DBSRVR log showed this

12/14/2020 10:38:58 AM [ERROR] Engine error [Access violation at address 0000000000987D2F in module 'dbsrvr.exe'. Read of address FFFFFFFFFFFFFE20] Additional info [select * from SMSG_ARCHIVE_MESSAGE_PARTICIPANT where HASYNC_MODIFIED >= '2020-12-08 11:03:58.551 PM' ORDER by HASYNC_MODI [Client Version: 4.49 User Name: admin Address: 127.0.0.1 Encrypted: No Request: REQUEST_EXECUTESTMT Thread: 1268 Session: 2]