Sorry, but google does not let me use a gmail account for some reason.
But I'm interested in the slides, I'll email you from my business
account.

And indeed it is used as a queue.
Maybe you can explain the following snapshot from the dynamic SQL:
It's a snapshot taken with a 120 seconds interval (after reset):

Number of executions               = 13
Number of compilations             = 0
Worst preparation time (ms)        = 4
Best preparation time (ms)         = 1
Internal rows deleted              = 0
Internal rows inserted             = 0
Rows read                          = 0
Internal rows updated              = 0
Rows written                       = 0
Statement sorts                    = 0
Statement sort overflows           = 0
Total sort time                    = 0
Buffer pool data logical reads     = 0
Buffer pool data physical reads    = 0
Buffer pool temporary data logical reads   = 0
Buffer pool temporary data physical reads  = 0
Buffer pool index logical reads    = 192060
Buffer pool index physical reads   = 192041
Buffer pool temporary index logical reads  = 0
Buffer pool temporary index physical reads = 0
Total execution time (sec.ms)      = 58.367505
Total user cpu time (sec.ms)       = 5.380000
Total system cpu time (sec.ms)     = 9.150000
Statement text                     = (SELECT MIN(EVENT_SEQ) + ? FROM
FMC.HS_AUDIT_TRAIL)

The table looks likes this and has > 20 miljoen rows.

------------------------------------------------
-- DDL Statements for table "FMC     "."HS_AUDIT_TRAIL"
------------------------------------------------

CREATE TABLE "FMC     "."HS_AUDIT_TRAIL"  (
                 "EVENT_SEQ" DECIMAL(16,0) NOT NULL WITH DEFAULT 0 ,
                 "CREATED" TIMESTAMP ,
                 "EVENT" INTEGER ,
                 "TEMPL_VALID_FROM" TIMESTAMP ,
                 "PROCESS_NAME" VARCHAR(63) ,
                 "PROCESS_ID" VARCHAR(64) ,
                 "TOP_LVL_PROC_NAME" VARCHAR(63) ,
                 "TOP_LVL_PROC_ID" VARCHAR(64) ,
                 "PARENT_PROC_NAME" VARCHAR(63) ,
                 "PARENT_PROC_ID" VARCHAR(64) ,
                 "PROC_TEMPL_NAME" VARCHAR(32) ,
                 "BLOCK_NAMES" VARCHAR(254) ,
                 "USER_NAME" VARCHAR(32) ,
                 "SECOND_USER_NAME" VARCHAR(32) ,
                 "ACTIVITY_NAME" VARCHAR(32) ,
                 "ACTIVITY_TYPE" INTEGER ,
                 "ACTIVITY_STATE" INTEGER ,
                 "COMMAND_PARAMETERS" VARCHAR(1024) ,
                 "PROGRAM_NAME" VARCHAR(32) ,
                 "ACTIVITY_RC" INTEGER ,
                 "ASSOCIATED_OBJECT" VARCHAR(64) ,
                 "OBJECT_DESCRIPTION" VARCHAR(254) ,
                 "SECOND_ACT_NAME" VARCHAR(32) ,
                 "EXTERNAL_CONTEXT" VARCHAR(254) )
                IN "HFX" ;
ALTER TABLE "FMC     "."HS_AUDIT_TRAIL" VOLATILE CARDINALITY;

-- DDL Statements for indexes on Table "FMC     "."HS_AUDIT_TRAIL"

CREATE INDEX "FMC     "."HS_AT_SEQ_INDEX" ON "FMC
"."HS_AUDIT_TRAIL"
               ("EVENT_SEQ" ASC);

There are no trigger on the table.
After doing a full reorg from the index only the snapshot looked like
this:

Number of executions               = 55
Number of compilations             = 0
Worst preparation time (ms)        = 12
Best preparation time (ms)         = 0
Internal rows deleted              = 0
Internal rows inserted             = 0
Rows read                          = 0
Internal rows updated              = 0
Rows written                       = 0
Statement sorts                    = 0
Statement sort overflows           = 0
Total sort time                    = 0
Buffer pool data logical reads     = 0
Buffer pool data physical reads    = 0
Buffer pool temporary data logical reads   = 0
Buffer pool temporary data physical reads  = 0
Buffer pool index logical reads    = 9130
Buffer pool index physical reads   = 0
Buffer pool temporary index logical reads  = 0
Buffer pool temporary index physical reads = 0
Total execution time (sec.ms)      = 0.120709
Total user cpu time (sec.ms)       = 0.000000
Total system cpu time (sec.ms)     = 0.000000
Statement text                     = (SELECT MIN(EVENT_SEQ) + ? FROM
FMC.HS_AUDIT_TRAIL)

Even after the reorg each query takes an average of 166 i/o's. Must be
a big index tree.
Don't know how I can find out exactly how big the tree is in size and
levels.