3464047 - Statement cache corruption messages with ASE crash due to SSQLCACHE_SPIN - SAP ASE

• ASE error log reports messages indicating that statement cache is corrupt
• Types of messages reported are
  
  
  • Informational messages that do not (immediately) affect ASE processes or server:
    
    (ssql__choose_victim) SAP_ASE INFO: SSQL_DESC at 0x0x7f9275d347f0 with ssql_keep as 1 was on freelink. Freelink next is 0x0x7f923cc4f0b8, prev is 0x0x7f93af7498b8
    (ssql_release) SAP_ASE INFO: SSQL_DESC at 0x0x7f9275d347f0 was added to freelink already. Freelink next is 0x0x7f932f3500b8, prev is 0x0x7f93ddcaa5b8
    
    
    
  • These may be followed by signal 11 sequence that causes ASE to crash due to spid holding spinlock SSQLCACHE_SPIN
  • The stacks contain code functions pointing to statement cache, starting with sqt_ or ssql_
  • Examples are shown below, other patterns can be possible:
    
    Current process (0x79d027b) infected with signal 11 (SIGSEGV)
    Address 0x0x000000000108c490 (sqt_releases_ssql+0x1b3) ...
    
    Spinlocks held by  kpid 127730299
    Spinlock SSQLCACHE_SPIN[i] at address 0x00007f8fb1394480 owned by 127730299
    
    or
    
    Current process (0x72bf03f6) infected with signal 11 (SIGSEGV)
    Address 0x0x0000000001576182 (ubfshrink+0x13f) ...
    ...
    Spinlock SSQLCACHE_SPIN[i] at address 0x00007f7492b08480 owned by 1925121014
    
    with stack containing 
    
    ubfshrink
    ssql_save_SQL
    sqt_put_in_stmtcache

SAP Adaptive Server Enterprise (ASE) 16.0 SP03 & SP04 

KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , BC-DB-SYB , Business Suite on Adaptive Server Enterprise , Problem