IBM 000-8697 - page 96

2-2 IBM Informix OnLine Database Server Administrator’s Guide
OnLine User Processes.................. 2-22
How User Processes Attach to Shared Memory........ 2-24
Step 1: Obtain SERVERNUM............. 2-24
Step 2: Calculate Shared-Memory Key Value ....... 2-25
Steps 3 and 4: Request Shared-Memory Segment and
Attach to SHMBASE ............. 2-25
Step 5: Attach Additional Segments .......... 2-27
User Processes and Critical Sections............ 2-28
OnLine User Process Status and States ........... 2-29
OnLine Database Server Process ............. 2-30
Orphaned Database Server Processes ........... 2-31
OnLine Daemon Processes ................ 2-33
tbinit Daemon ................... 2-33
tbundo Daemon .................. 2-34
tbpgcl Daemon ................... 2-34
Shared Memory and Process Communication.......... 2-36
Shared Memory and Buffer Locks ............ 2-38
Buffer Share Lock................. 2-38
Buffer Update Lock ................ 2-38
Buffer Exclusive Lock ............... 2-39
Managing Shared-Memory Resources ........... 2-39
Shared-Memory Latches .............. 2-41
OnLine Timestamps ................ 2-44
Hash Tables and the Hashing Technique......... 2-46
Shared-Memory Header................ 2-47
Shared-Memory Internal Tables ............. 2-48
OnLine Buffer Table ................ 2-48
OnLine Chunk Table................ 2-49
OnLine Dbspace Table ............... 2-50
OnLine Latch Table ................ 2-51
OnLine Lock Table ................ 2-51
OnLine Page-Cleaner Table ............. 2-52
OnLine Tblspace Table ............... 2-52
OnLine Transaction Table .............. 2-54
OnLine User Table ................ 2-54
Shared-Memory Buffer Pool .............. 2-55
Regular Buffers ................. 2-56
Big Buffers ................... 2-56
OnLine LRU Queues ................. 2-57