System Architecture 2-13
What Happens During Shared-Memory Initialization
Duringshared-memory initialization, disk structures and disk layout are not
affected. Essential address information (such as the locations of the logical
and physical logs) is read from disk. These addresses are used to update
pointers in shared memory.
Step 5: Wake Parent Process
After thetbinit daemon updates all pointers, it wakes the parent tbinit
process and writes a “shared-memory initialization complete” message in
theOnLine message log (specified as MSGPATHin the configuration file). The
prompt returns to the user at this point, and any error messages that might
havepassed from the daemon to the parent process are displayed. The parent
process goes away at this point. Its role is ended.
Steps 6 and 7: Initiate Fast Recovery and First Checkpoint
Shared memory is initialized. Thetbinit daemon initiates fast recovery.
(Refer topage 4-39 for further information about fast recovery.)
Afterfast recovery executes, tbinit initiates a checkpoint. (Refer to page 2-70
for further information about checkpoints.) As part of the checkpoint
procedure (page2-72), tbinit checks the database tblspace index to verify
that all database names are unique. (Refer topage 2-107 for further infor-
mation about the database tblspace.)
Afterthe checkpoint completes, the daemon writes a “checkpoint complete”
message in the OnLine message log.
OnLine is in quiescent mode.
Step 8: Drop Temporary Tables (Optional)
The tbinit daemon begins a search through all dbspaces for temporary
tblspaces. (If you executedtbinit with the -p option, tbinit skips this step.)
Thesetemporary tblspaces would have been left by user processes that died
prematurely and were unable to perform proper cleanup. Any temporary
tblspaces are deleted and the disk space is reclaimed.