1. TABANALYS does not flush the modified blocks on disk:
2. PROBKUP does flush modified blocks on disk:
3. PROQUIET ENABLE flushes the correspondent bi buffers to disk then ai buffers when the AI is switched, but it does not write dirty data buffers to disk. Modified buffers are flushed pre-PROQUIET and post-PROQUIET, not during PROQUIET
Consider the following demonstration:
$ prodb sports2000 sports2000
$ proserve sports2000 -B 128
$ prowin sports2000
FOR EACH customer EXCLUSIVE-LOCK:
ASSIGN customer.name = "x" + customer.name.
ASSIGN customer.name = SUBSTRING(customer.name, 2).
END.
PROMON > R&D > Status: Buffer Cache:
Status: Buffer Cache
Total buffers: 130
Used buffers: 130
Modified buffers: 5
1. DBANALYS / TABANALYS does not flush modified blocks on disk:
$ proutil sports2000 -C dbanalys
PROMON > R&D > Activity: Buffer Cache :
Database Buffer Pool
Logical reads 6287
Logical writes 0
O/S reads 414
O/S writes 0
PROMON > R&D > Status: Buffer Cache :
2. PROBKUP does flush modified blocks on disk:
$ probkup online sports nul
PROMON > R&D > Activity: Buffer Cache :
Database Buffer Pool
Logical reads 1082
Logical writes 0
O/S reads 933
O/S writes 7
PROMON > R&D > Status: Buffer Cache :
3. PROQUIET does not flush modified buffers to disk
- Modified buffers are flushed pre and post PROQUIET, not during PROQUIET
- PROQUIET ENABLE flushes the correspondent bi buffers to disk then ai buffers when the AI is switched, but it does not write dirty data buffers to disk
Run the above code again.
PROMON > R&D > Activity: Buffer Cache :
Database Buffer Pool
Logical reads 1669
Logical writes 0
O/S reads 102
O/S writes 3
PROMON > R&D > Status: Buffer Cache :
Total buffers: 130
Used buffers: 130
Modified buffers: 120
Marked for ckp: 1
$ proquiet sports2000 enablePROMON > R&D > Status: Buffer Cache :
Total buffers: 130
Used buffers: 130
Modified buffers: 118
Enable the APW during database quiesence, to assure the APW effect is demonstrated:
$ proapw sports2000
PROMON > R&D > Status: Buffer Cache :
$ proquiet sports2000 disable
Watch the "Status: Buffer Cache", wait while APWs flush all dirty blocks before shutting the database down:
Total buffers: 130
Used buffers: 130
Modified buffers: 0 ****
