Re: gc buffer busy and rac testing
Date: Fri, 09 Jan 2009 15:29:40 +0100
Jonathan Lewis pisze:
> Not what I'd hope to see in the simplest case - unless the "simple query"
> is a select for update. Mladen's comments about the overheads of
> generating read-consistent blocks may be relevant though if the query
> is very busy reading blocks which are subject to lots of rapid update
> on the remote node.
PRODUCT_NAME, PRODUCT_DESCRIPTION, CATEGORY_ID, WEIGHT_CLASS, WARRANTY_PERIOD, SUPPLIER_ID, PRODUCT_STATUS, LIST_PRICE, MIN_PRICE, CATALOG_URL, QUANTITY_ON_HAND FROM PRODUCTS, INVENTORIES WHERE PRODUCTS.CATEGORY_ID = :B1 AND INVENTORIES.PRODUCT_ID = PRODUCTS.PRODUCT_IDORDER BY INVENTORIES.WAREHOUSE_ID
> Is the number of waits in the "segments by GC buffer busy waits" similar
> to the number of "gc buffer busy waits" - and do you get any further
> clues from the segment waits by "Current Blocks received", and "CR
> blocks received".
Yes, it's similar.
Here are more detailed stats:
(Gc buffer busy delta)
OBJECT STAT SOE.INVENTORIES [TABLE] 1923481 SOE.ORDER_PK [INDEX] 100771 SOE.ORDER_ITEMS_UK [INDEX] 75944 SOE.ORDER_ITEMS_PK [INDEX] 72561 SOE.ORDERS [TABLE] 47162 SOE.ORD_STATUS_IX [INDEX] 35295 SOE.ITEM_ORDER_IX [INDEX] 12457 SOE.CUSTOMERS_PK [INDEX] 10428
OBJECT STAT SOE.INVENTORIES [TABLE] 426794 SOE.ORD_CUSTOMER_IX [INDEX] 41028 SOE.ORD_STATUS_IX [INDEX] 32213 SOE.ITEM_ORDER_IX [INDEX] 22916 SOE.ORDERS [TABLE] 20142 SOE.ORDER_PK [INDEX] 17339 SOE.ORDER_ITEMS [TABLE] 13218 SOE.CUSTOMERS_PK [INDEX] 960 SOE.CUSTOMERS [TABLE] 379 SOE.ORDER_ITEMS_PK [INDEX] 293
OBJECT STAT SOE.INVENTORIES [TABLE] 125316 SOE.ORD_STATUS_IX [INDEX] 57368 SOE.CUST_EMAIL_IX [INDEX] 47218 SOE.CUST_UPPER_NAME_IX [INDEX] 46755 SOE.ORD_ORDER_DATE_IX [INDEX] 43553 SOE.ORD_CUSTOMER_IX [INDEX] 43294 SOE.ORDERS [TABLE] 32213 SOE.ITEM_ORDER_IX [INDEX] 31624 SOE.ITEM_PRODUCT_IX [INDEX] 27386
> It's also worth checking the 'Global cache transfer stats' looking at
> 'busy' column, as this will give you some clues about whether the
> problem blocks were data blocks, undo blocks, or "other".
Avg global enqueue get time (ms): 7.1 Avg global cache cr block receive time (ms): 7.3 Avg global cache current block receive time (ms): 10.5 Avg global cache cr block build time (ms): 0.0 Avg global cache cr block send time (ms): 0.0 Global cache log flushes for cr blocks served %: 19.0 Avg global cache cr block flush time (ms): 11.9 Avg global cache current block pin time (ms): 2.1 Avg global cache current block send time (ms): 0.0 Global cache log flushes for current blocks served %: 5.2 Avg global cache current block flush time (ms): 22.0
Buffer Wait Statistics
Class Waits Total Wait Time (s) Avg Time (ms) data block 609,973 27,470 45 undo block 102,528 1,478 14 undo header 58,156 450 8 file header block 54 2 31 1st level bmb 14 0 19 2nd level bmb 14 0 9 segment header 3 0 3Received on Fri Jan 09 2009 - 08:29:40 CST