The environment was:

• 2 Node Oracle Clusterware 11.1.0.7 Cluster on Linux x86_64 using latest Recommended Patches as of October 19th. (pre PSU 11.1.0.7.1)
• Clusterware installed as unix user crs
• ASM installed as unix user oracle

The ASM instances could be started with SQL*Plus without any problems, but if the ASM instances were started by means of clusterware using srvctl (either from root, crs or oracle) the  ASM instances would crash at diskgroup mount with:

ORA-07445: exception encountered: core dump  [sskgds_find_rtn_hdr()+1171]
[SIGBUS] [ADDR:0x2AACD701342C] [PC:0x25799DF]
[Non-existent physical address] []

Oracle Support identified this behaviour as Bug 6952915, for which there are patches for Linux x86, x86_64 and Solaris Sparc64.

• first PSU, which is available for Grid Control 10.2.0.5
• seperate PSU Patches for Clusterware (CRS)
• Patch Set Updates are now released for ALL non-Windows platform whereas previous PSUs were released for special platforms (e.g. Linux Itanium) on request only.

More info can be found in Metalink Note 854428.1.

Unfortunately, the customer decided to bounce the instance, so that there is no possibility for intensive diagnosis. However, ASH report shows that a dozen sessions either waited on Wait event “cursor: pin S” or were active (ON CPU) without any SQL_ID. An AWR Report showed:

Top 5 Timed Events                                         Avg %Total
~~~~~~~~~~~~~~~~~~                                        wait   Call
Event                                 Waits    Time (s)   (ms)   Time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
cursor: pin S                   140,036,615      24,833      0 ######      Other
CPU time                                             19          72.9
log file sync                         8,767           8      1   30.2     Commit
log file parallel write               9,039           8      1   29.9 System I/O
control file parallel write           1,269           5      4   20.2 System I/O

Oracle Support confirmed that this is Bug 6904068 High CPU usage when there are “cursor: pin S” waits. We have filed a backport request for it, as there is no patch for our platform available yet.

The new Patch Set Updates (PSU) will contain cumulative patches, which contain recommended bugfixes. They will be provided on a the same quarterly basis as the Critical Patch Update (CPU), therefore release months will be January, April, July and October. The Patch Set Update will be described in the release version. E.g. 10.2.0.4.1 will be the first Patch Set Update (PSU), 10.2.0.4.2 the second PSU etc.

As described in the release information, the 10.2.0.4.1 PSU Patch (Patch 8576156) contains all the recommended patch bundles up to July 2009 (Generic, CRS, RAC, Services, DataGuard) as well as the Critical Patch Update July 2009. Moreover 5 additional critical bugfixes are included. OPatch version 10.2.0.4.7 is required for installation of PSU 10.2.0.4.1 and the PSU is rolling installable on RAC environments without downtime.

Later PSU patches can be installed on either the base release or on top of any previous PSU. For example, PSU 10.2.0.4.3 can be installed on top of Base 10.2.0.4.0, PSU 10.2.0.4.1, PSU 10.2.4.0.2.

As already mentioned, the customer has the option to install security patches only by installing the quarterly Critical Patch Update or to install security plus non-security bugfixes by installint the Patch Set Update (PSU). As the PSU 10.2.0.4.1 already contains Critical Patch Update July 2009, the documentation states that future security patches are recommended to be installed not by CPU Patches but through PSU Patches.

Further information can be found in these MetaLink Notes:

854428.1 – Intro to Patch Set Updates (PSU)
850471.1 – Oracle Announces First Patch Set Update For Oracle Database Release 10.2
8576156.8 – Bug 8576156 10.2.0.4.1 Patch Set Update (PSU)
854473.1 – Known Issues with this Patch Set Update 10.2.0.4.1

select p2raw from v$session where event = ‘cursor: pin S wait on X’

The first 2 or 4 bytes from p2raw have to be converted to dec and point to the blocking Session ID. (SID)

The bug occurs if you add/remove redo log groups on a cluster database, which has some of it´s instances shut down.

More information about this Bug, which is tracked with Bug ID 6786022 can be found on MetaLink. There is a patch for 10.2.0.4 and Linux x86-64 available.

• 8k Blocksize

SQL> DROP TABLE t1_8k purge;
 
SQL> CREATE TABLESPACE DEMO8K datafile SIZE 128M blocksize 8192;
 
TABLESPACE created.
 
Elapsed: 00:00:07.35
 
SQL> CREATE TABLE mdecker.t1_8k
(n1 NUMBER,
 n2 NUMBER)
 TABLESPACE DEMO8K;
 
TABLE created.
 
Elapsed: 00:00:00.02
 
SQL> INSERT INTO t1_8k
SELECT TRUNC(dbms_random.VALUE(10000000,100000000)) n1,
           TO_NUMBER(NULL) AS n2
    FROM dual
CONNECT BY LEVEL <= 500000
/
 
 
500000 ROWS created.
 
Elapsed: 00:00:06.89
 
SQL> BEGIN dbms_stats.gather_table_stats(
        ownname => 'MDECKER',
        tabname => 'T1_8K',
        estimate_percent => 100);
END;
/
 
PL/SQL PROCEDURE successfully completed.
 
Elapsed: 00:00:02.13
 
SQL> SELECT num_rows,blocks FROM dba_tables WHERE table_name = 'T1_8K';
 
  NUM_ROWS     BLOCKS
---------- ----------
    500000        874
 
Elapsed: 00:00:00.15
SQL> UPDATE t1_8k SET n2 = n1;
 
500000 ROWS updated.
 
Elapsed: 00:01:09.04
SQL> COMMIT;

• 16k Blocksize

SQL> CREATE TABLESPACE DEMO16K datafile SIZE 128M blocksize 16384;
 
TABLESPACE created.
 
Elapsed: 00:00:14.75
 
SQL> CREATE TABLE mdecker.t1_16k
(n1 NUMBER,
 n2 NUMBER)
 TABLESPACE DEMO16K;
 
TABLE created.
 
Elapsed: 00:00:00.03
 
SQL> INSERT INTO t1_16k
SELECT TRUNC(dbms_random.VALUE(10000000,100000000)) n1,
           TO_NUMBER(NULL) AS n2
    FROM dual
CONNECT BY LEVEL <= 500000
/  
 
 
500000 ROWS created.
 
Elapsed: 00:00:05.51
SQL> BEGIN dbms_stats.gather_table_stats(
        ownname => 'MDECKER',
        tabname => 'T1_16K',
        estimate_percent => 100);
END;
/  
 
PL/SQL PROCEDURE successfully completed.
 
Elapsed: 00:00:01.78
SQL> SELECT num_rows,blocks FROM dba_tables WHERE table_name = 'T1_16K';
 
  NUM_ROWS     BLOCKS
---------- ----------
    500000        436
 
Elapsed: 00:00:00.07
 
SQL>  UPDATE t1_16k SET n2 = n1;
 
500000 ROWS updated.
 
Elapsed: 00:20:20.89

As you can see, the update statement for the 8k blocksize table took around 69 seconds whereas the same update for the table in the 16k tablespace took more than 20 minutes. When executing oradebug short_stack, you can see that for the 16k update, the stacktrace is similar for many executions. So, a lot of time is spent in the kernel functions ktspfsrch() and ktspscan_bmb().


SQL> oradebug setospid 23668
Oracle pid: 18, Unix process pid: 23668, image: oracle@ora-vm1.intra (TNS V1-V3)
SQL> oradebug short_stack
.....ktspfsrch()+559<-ktspscan_bmb()+315 .....
SQL> oradebug short_stack
.....ktspfsrch()+559<-ktspscan_bmb()+315 .....
SQL> oradebug short_stack
.....ktspfsrch()+559<-ktspscan_bmb()+315 .....


It is important to understand that the problem is not necessarily related to the blocksize, but to the PCTFREE value. More information about this topic can be found here:

http://structureddata.org/files/jl_test_case.html
http://structureddata.org/2008/09/08/understanding-performance/
http://www.oraclealchemist.com/oracle/hey-guys-does-size-matter/

]]> http://www.ora-solutions.net/web/2009/04/09/assm-problem-with-too-low-pctfree/feed/ 0 http://www.ora-solutions.net/web/2009/03/12/intelligent-aka-adaptive-cursor-sharing-problem/ http://www.ora-solutions.net/web/2009/03/12/intelligent-aka-adaptive-cursor-sharing-problem/#comments Thu, 12 Mar 2009 05:01:40 +0000 Martin http://www.ora-solutions.net/web/?p=586 Today, at the last day of Hotsos Symposium 2009 Ric van Dyke presented on “Intelligent (aka adaptive) Cursor Sharing”, a new feature of Oracle Database 11g. The feature was created to fix the shortcomings of bind peeking on columns with histograms. Tom Kyte presented a few years ago on this topic when he talked about the impact of the wheather on Oracle database performance.

During the very interesting presentation Ric presented with a demo how this feature works but also showed a nasty side effect. He tested it on a million row table with a column “object type”, which was skewed. He bound several different values to the object_type bind variable causing 2 different execution plans to be used for the same sql_id. The problem with it was that he ended up with dozens of child cursors showing V$SQL.IS_SHARABLE => N.

It was not known whether this is a bug or whether the whole concept is flawed. I searched on metalink and found the appropriate document:

Bug 6644714 – High number of child cursors with adaptive cursor sharing
This issue is fixed in

* 11.2 (Future Release)
* 11.1.0.7 (Server Patch Set)
Lots of child cursors may be produced with adaptive cursor sharing enabled,
sometimes with overlapping or same bind value selectivity ranges (in v$sql_cs_selectivity).
This problem shows as LOAD_OPTIMIZER_STATS=’Y’ for many of the cursors in V$SQL_SHARED_CURSOR.

– and –

Bug 7213010 – Adaptive cursor sharing generates lots of child cursors

This issue is fixed in

* 11.2 (Future Release)
* 11.1.0.7 (Server Patch Set)

Lots of child cursors may be produced for a query with bind variables
appearing in at least two simple relational predicates
(eg. col :b).

v$sql_cs_selectivity shows that there are multiple equivalent / overlapping
ranges for a single cursor. The number of ranges gets bigger and bigger
as the query is run more times.

I then tried to verify if the problem indeed is gone in 11.1.0.7 and found out, that it isn´t.

Here is my testcase:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434

SQL> @/tmp/setup.sql Connected. SQL> DROP TABLE tab1 purge;   TABLE dropped.   SQL> CREATE TABLE tab1 (a int, 2 b varchar2(20), 3 padding varchar2(200)) 4 tablespace USERS;   TABLE created.   SQL> SQL> DROP sequence myid;   Sequence dropped.   SQL> CREATE sequence myid cache 1000;   Sequence created.   SQL> SQL> begin 2 FOR i IN 1..100000 3 loop 4 INSERT INTO tab1 VALUES (myid.NEXTVAL, 5 'AAAAAAAAAA', 6 rpad('*',200,'*')); 7 end loop; 8 9 FOR i IN 1..1000 10 loop 11 INSERT INTO tab1 VALUES (myid.NEXTVAL, 12 'BBBBBBBBBB', 13 rpad('*',200,'*')); 14 end loop; 15 16 FOR i IN 1..1000 17 loop 18 INSERT INTO tab1 VALUES (myid.NEXTVAL, 19 'CCCCCCCCCC', 20 rpad('*',200,'*')); 21 end loop; 22 23 FOR i IN 1..100 24 loop 25 INSERT INTO tab1 VALUES (myid.NEXTVAL, 26 'DDDDDDDDDD', 27 rpad('*',200,'*')); 28 end loop; 29 30 FOR i IN 1..10 31 loop 32 INSERT INTO tab1 VALUES (myid.NEXTVAL, 33 'EEEEEEEEEE', 34 rpad('*',200,'*')); 35 end loop; 36 37 INSERT INTO tab1 VALUES (myid.NEXTVAL, 38 'FFFFFFFFFF', 39 rpad('*',200,'*')); 40 41 commit; 42 end; 43 /   PL/SQL procedure successfully completed.   SQL> SQL> CREATE INDEX tab1_idx1 ON tab1 (b);   INDEX created.   SQL> SQL> begin dbms_stats.gather_table_stats(ownname => 'MDECKER', 2 tabname => 'TAB1', 3 method_opt =>'FOR ALL COLUMNS SIZE 254', 4 cascade=> TRUE, 5 estimate_percent => 100, 6 no_invalidate => FALSE); 7 end; 8 /   PL/SQL procedure successfully completed.   SQL> SQL> SET LINES 300 SQL> col table_name format a10 SQL> col owner format a8 SQL> SELECT owner, table_name,num_rows, blocks, round((blocks*8192)/1024/1024) AS MB 2 FROM dba_tables WHERE table_name = 'TAB1' AND owner = 'MDECKER';   OWNER TABLE_NAME NUM_ROWS BLOCKS MB -------- ---------- ---------- ---------- ---------- MDECKER TAB1 102111 3268 26   SQL> SQL> prompt "Press Enter to continue" "Press Enter to continue" SQL> pause   SQL> SQL> /* SQL> OWNER TABLE_NAME NUM_ROWS BLOCKS MB SQL> -------- ---------- ---------- ---------- ---------- SQL> MDECKER TAB1 102111 3268 26 SQL> SQL> */ SQL> SQL> SQL> SQL> SELECT b , count(*) FROM mdecker.tab1 GROUP BY b ORDER BY 1 DESC;   B COUNT(*) -------------------- ---------- FFFFFFFFFF 1 EEEEEEEEEE 10 DDDDDDDDDD 100 CCCCCCCCCC 1000 BBBBBBBBBB 1000 AAAAAAAAAA 100000   6 rows selected.   SQL> SQL> /* SQL> B COUNT(*) SQL> -------------------- ---------- SQL> FFFFFFFFFF 1 SQL> EEEEEEEEEE 10 SQL> DDDDDDDDDD 100 SQL> CCCCCCCCCC 1000 SQL> BBBBBBBBBB 1000 SQL> AAAAAAAAAA 100000 SQL> SQL> 6 rows selected. SQL> SQL> */ SQL> SQL> prompt "Press Enter to continue" "Press Enter to continue" SQL> pause   SQL> SELECT num_buckets, histogram FROM dba_tab_col_statistics WHERE table_name = 'TAB1' AND column_name = 'B';   NUM_BUCKETS HISTOGRAM ----------- --------------- 6 FREQUENCY   SQL> SQL> /* SQL> NUM_BUCKETS HISTOGRAM SQL> ----------- --------------- SQL> 6 FREQUENCY SQL> */ SQL> SQL> SQL> SQL> SQL> SQL> SHOW user USER IS "MDECKER" SQL> @/tmp/sql1.txt SQL> SET LINES 300 SQL> SET echo ON SQL> SET pages 10000 SQL> col bind format a120 SQL> prompt "Press enter to run" "Press enter to run" SQL> pause   SQL> SQL> variable myvar varchar2(20) SQL> exec :myvar := 'AAAAAAAAAA';   PL/SQL procedure successfully completed.   SQL> SET termout off SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor());   PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------- SQL_ID fhtgpcv2m2j4s, child number 0 ------------------------------------- SELECT /* MD_TESTCASE */ * FROM tab1 WHERE b = :myvar   Plan hash value: 2211052296   -------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | -------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | 889 (100)| | |* 1 | TABLE ACCESS FULL| TAB1 | 100K| 20M| 889 (1)| 00:00:11 | --------------------------------------------------------------------------   Predicate Information (IDENTIFIED BY operation id): ---------------------------------------------------   1 - filter("B"=:MYVAR)     18 rows selected.   SQL> SELECT sql_id, is_obsolete, is_bind_sensitive, is_bind_aware, is_shareable, dbms_sqltune.extract_binds(bind_data) bind, plan_hash_value, child_number FROM 2 v$sql WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ fhtgpcv2m2j4s N Y N Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0   SQL> SQL> prompt "Press enter to run" "Press enter to run" SQL> pause   SQL> exec :myvar := 'BBBBBBBBBB';   PL/SQL procedure successfully completed.   SQL> SET termout off SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor());   PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------- SQL_ID fhtgpcv2m2j4s, child number 0 ------------------------------------- SELECT /* MD_TESTCASE */ * FROM tab1 WHERE b = :myvar   Plan hash value: 2211052296   -------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | -------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | 889 (100)| | |* 1 | TABLE ACCESS FULL| TAB1 | 100K| 20M| 889 (1)| 00:00:11 | --------------------------------------------------------------------------   Predicate Information (IDENTIFIED BY operation id): ---------------------------------------------------   1 - filter("B"=:MYVAR)     18 rows selected.   SQL> SELECT sql_id, is_obsolete, is_bind_sensitive, is_bind_aware, is_shareable, dbms_sqltune.extract_binds(bind_data) bind, plan_hash_value, child_number FROM 2 v$sql WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ fhtgpcv2m2j4s N Y N Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0   SQL> SQL> exec :myvar := 'CCCCCCCCCC';   PL/SQL procedure successfully completed.   SQL> prompt "Press enter to run" "Press enter to run" SQL> pause   SQL> SET termout off SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor());   PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------- SQL_ID fhtgpcv2m2j4s, child number 1 ------------------------------------- SELECT /* MD_TESTCASE */ * FROM tab1 WHERE b = :myvar   Plan hash value: 1918680838   ----------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ----------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | 36 (100)| | | 1 | TABLE ACCESS BY INDEX ROWID| TAB1 | 1000 | 210K| 36 (0)| 00:00:01 | |* 2 | INDEX RANGE SCAN | TAB1_IDX1 | 1000 | | 4 (0)| 00:00:01 | -----------------------------------------------------------------------------------------   Predicate Information (IDENTIFIED BY operation id): ---------------------------------------------------   2 - access("B"=:MYVAR)     19 rows selected.   SQL> SELECT sql_id, is_obsolete, is_bind_sensitive, is_bind_aware, is_shareable, dbms_sqltune.extract_binds(bind_data) bind, plan_hash_value, child_number FROM 2 v$sql WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ fhtgpcv2m2j4s N Y N Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0 fhtgpcv2m2j4s N Y Y Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'CCCCCCCCCC', ANYDATA())) 1918680838 1   SQL> SQL> exec :myvar := 'DDDDDDDDDD';   PL/SQL procedure successfully completed.   SQL> prompt "Press enter to run" "Press enter to run" SQL> pause   SQL> SET termout off SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor());   PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------- SQL_ID fhtgpcv2m2j4s, child number 2 ------------------------------------- SELECT /* MD_TESTCASE */ * FROM tab1 WHERE b = :myvar   Plan hash value: 1918680838   ----------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ----------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | 5 (100)| | | 1 | TABLE ACCESS BY INDEX ROWID| TAB1 | 100 | 21600 | 5 (0)| 00:00:01 | |* 2 | INDEX RANGE SCAN | TAB1_IDX1 | 100 | | 1 (0)| 00:00:01 | -----------------------------------------------------------------------------------------   Predicate Information (IDENTIFIED BY operation id): ---------------------------------------------------   2 - access("B"=:MYVAR)     19 rows selected.   SQL> SELECT sql_id, is_obsolete, is_bind_sensitive, is_bind_aware, is_shareable, dbms_sqltune.extract_binds(bind_data) bind, plan_hash_value, child_number FROM 2 v$sql WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ fhtgpcv2m2j4s N Y N Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'CCCCCCCCCC', ANYDATA())) 1918680838 1 fhtgpcv2m2j4s N Y Y Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'DDDDDDDDDD', ANYDATA())) 1918680838 2   SQL> SQL> exec :myvar := 'EEEEEEEEEE';   PL/SQL procedure successfully completed.   SQL> prompt "Press enter to run" "Press enter to run" SQL> pause   SQL> SET termout off SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor());   PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------- SQL_ID fhtgpcv2m2j4s, child number 3 ------------------------------------- SELECT /* MD_TESTCASE */ * FROM tab1 WHERE b = :myvar   Plan hash value: 1918680838   ----------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ----------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | 2 (100)| | | 1 | TABLE ACCESS BY INDEX ROWID| TAB1 | 10 | 2160 | 2 (0)| 00:00:01 | |* 2 | INDEX RANGE SCAN | TAB1_IDX1 | 10 | | 1 (0)| 00:00:01 | -----------------------------------------------------------------------------------------   Predicate Information (IDENTIFIED BY operation id): ---------------------------------------------------   2 - access("B"=:MYVAR)     19 rows selected.   SQL> SELECT sql_id, is_obsolete, is_bind_sensitive, is_bind_aware, is_shareable, dbms_sqltune.extract_binds(bind_data) bind, plan_hash_value, child_number FROM 2 v$sql WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ fhtgpcv2m2j4s N Y N Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'CCCCCCCCCC', ANYDATA())) 1918680838 1 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'DDDDDDDDDD', ANYDATA())) 1918680838 2 fhtgpcv2m2j4s N Y Y Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'EEEEEEEEEE', ANYDATA())) 1918680838 3   SQL> SQL> exec :myvar := 'FFFFFFFFFF';   PL/SQL procedure successfully completed.   SQL> prompt "Press enter to run" "Press enter to run" SQL> pause   SQL> SET termout off SQL> SELECT * FROM TABLE(dbms_xplan.display_cursor());   PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------- SQL_ID fhtgpcv2m2j4s, child number 4 ------------------------------------- SELECT /* MD_TESTCASE */ * FROM tab1 WHERE b = :myvar   Plan hash value: 1918680838   ----------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ----------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | | | 2 (100)| | | 1 | TABLE ACCESS BY INDEX ROWID| TAB1 | 1 | 216 | 2 (0)| 00:00:01 | |* 2 | INDEX RANGE SCAN | TAB1_IDX1 | 1 | | 1 (0)| 00:00:01 | -----------------------------------------------------------------------------------------   Predicate Information (IDENTIFIED BY operation id): ---------------------------------------------------   2 - access("B"=:MYVAR)     19 rows selected.   SQL> SELECT sql_id, is_obsolete, is_bind_sensitive, is_bind_aware, is_shareable, dbms_sqltune.extract_binds(bind_data) bind, plan_hash_value, child_number FROM 2 v$sql WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ fhtgpcv2m2j4s N Y N Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'CCCCCCCCCC', ANYDATA())) 1918680838 1 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'DDDDDDDDDD', ANYDATA())) 1918680838 2 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'EEEEEEEEEE', ANYDATA())) 1918680838 3 fhtgpcv2m2j4s N Y Y Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'FFFFFFFFFF', ANYDATA())) 1918680838 4

You can see that after parsing for bind CCCCCCCC, the execution plan changes from full table scan to index range scan. Moreover child cursor 1 is marked “is_bind_aware=Y”. When now bind DDDDDDDD is used, there is a new child (#2) and child 1 is set to is_sharable=N. After using bind EEEEEEEE, child #2 is set to sharable=N and a new child #3 is created. This repeats until there are 5 child cursors, 2 of which are set to is_sharable=Y. When the script is executed multiple times, there is even a sixth child cursor.

1 2 3 4 5 6 7 8

SQL_ID I I I I BIND(NAME, POSITION, DUP_POSITION, DATATYPE, DATATYPE_STRING, CHARACTER_SID, PRECISION, SCALE, MAX_LENGTH, LAST_CAPTURED PLAN_HASH_VALUE CHILD_NUMBER EXECUTIONS ------------- - - - - ------------------------------------------------------------------------------------------------------------------------ --------------- ------------ ---------- fhtgpcv2m2j4s N Y N N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 0 2 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'CCCCCCCCCC', ANYDATA())) 1918680838 1 1 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'DDDDDDDDDD', ANYDATA())) 1918680838 2 1 fhtgpcv2m2j4s N Y Y N SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'EEEEEEEEEE', ANYDATA())) 1918680838 3 1 fhtgpcv2m2j4s N Y Y Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'FFFFFFFFFF', ANYDATA())) 1918680838 4 16 fhtgpcv2m2j4s N Y Y Y SQL_BIND_SET(SQL_BIND(NULL, 1, NULL, 1, 'VARCHAR2(32)', 178, NULL, NULL, 32, '12-MAR-09', 'AAAAAAAAAA', ANYDATA())) 2211052296 5 3

I wondered why the cursors are not sharable and queried v$sql_shared_cursor:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

SQL> SELECT * FROM v$sql_shared_cursor WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID ADDRESS CHILD_AD CHILD_NUMBER U S O O S L F E B P I S T A B D L T R I I R L I O E M U T N F A I T D L D B P C S C P T M B M R O P M F L P L A F L R L H ------------- -------- -------- ------------ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - fhtgpcv2m2j4s 23F4E438 23F4DAB0 0 N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N Y N N N N N N fhtgpcv2m2j4s 23F4E438 23D924D8 1 N N N N N N N N N N N N N N N N N N Y N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N fhtgpcv2m2j4s 23F4E438 23D7E888 2 N N N N N N N N N N N N N N N N N N Y N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N fhtgpcv2m2j4s 23F4E438 23D6B8C8 3 N N N N N N N N N N N N N N N N N N Y N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N fhtgpcv2m2j4s 23F4E438 23D574D8 4 N N N N N N N N N N N N N N N N N N Y N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N fhtgpcv2m2j4s 23F4E438 23B983B0 5 N N N N N N N N N N N N N N N N N N Y N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N   6 rows selected.   SQL> SELECT sql_id, address, child_number, LOAD_OPTIMIZER_STATS, row_level_sec_mismatch FROM v$sql_shared_cursor WHERE sql_id = 'fhtgpcv2m2j4s';   SQL_ID ADDRESS CHILD_NUMBER L R ------------- -------- ------------ - - fhtgpcv2m2j4s 245CE53C 0 Y N fhtgpcv2m2j4s 245CE53C 1 N Y fhtgpcv2m2j4s 245CE53C 2 N Y fhtgpcv2m2j4s 245CE53C 3 N Y fhtgpcv2m2j4s 245CE53C 4 N Y fhtgpcv2m2j4s 245CE53C 5 N Y   SQL> SELECT * FROM v$sql_cs_statistics WHERE sql_id = 'fhtgpcv2m2j4s';   ADDRESS HASH_VALUE SQL_ID CHILD_NUMBER BIND_SET_HASH_VALUE P EXECUTIONS ROWS_PROCESSED BUFFER_GETS CPU_TIME -------- ---------- ------------- ------------ ------------------- - ---------- -------------- ----------- ---------- 245CE53C 3308340376 fhtgpcv2m2j4s 5 3946114705 N 1 0 2 0 245CE53C 3308340376 fhtgpcv2m2j4s 5 2785428864 Y 1 0 2 0 245CE53C 3308340376 fhtgpcv2m2j4s 4 1680726256 Y 1 2 3 0 245CE53C 3308340376 fhtgpcv2m2j4s 3 1438126164 Y 1 20 5 0 245CE53C 3308340376 fhtgpcv2m2j4s 2 451655377 Y 1 200 21 0 245CE53C 3308340376 fhtgpcv2m2j4s 1 4078512309 Y 1 2000 169 0 245CE53C 3308340376 fhtgpcv2m2j4s 0 479772785 Y 1 100000 9823 0   7 rows selected.   SQL> SELECT * FROM v$sql_cs_selectivity WHERE sql_id = 'fhtgpcv2m2j4s';   ADDRESS HASH_VALUE SQL_ID CHILD_NUMBER PREDICATE RANGE_ID LOW HIGH -------- ---------- ------------- ------------ ---------------------------------------- ---------- ---------- ---------- 245CE53C 3308340376 fhtgpcv2m2j4s 5 =MYVAR 0 0.000004 0.010773 245CE53C 3308340376 fhtgpcv2m2j4s 4 =MYVAR 0 0.000009 0.010773 245CE53C 3308340376 fhtgpcv2m2j4s 3 =MYVAR 0 0.000088 0.010773 245CE53C 3308340376 fhtgpcv2m2j4s 2 =MYVAR 0 0.000881 0.010773 245CE53C 3308340376 fhtgpcv2m2j4s 1 =MYVAR 0 0.008814 0.010773

It is not clear, why the cursors are not shared and why this is expressed in the flag “row_level_sec_mismatch”. From these tests we can see that the number of child cursors is still quite high.

]]> http://www.ora-solutions.net/web/2009/03/12/intelligent-aka-adaptive-cursor-sharing-problem/feed/ 4 http://www.ora-solutions.net/web/2009/01/20/session-waiting-for-enq-ro-fast-object-reuse-dbwr-process-spinning-on-cpu/ http://www.ora-solutions.net/web/2009/01/20/session-waiting-for-enq-ro-fast-object-reuse-dbwr-process-spinning-on-cpu/#comments Tue, 20 Jan 2009 16:07:08 +0000 Martin http://www.ora-solutions.net/web/?p=564 select username, event, sql_id, taddr, last_call_et from v$session where sid = 234; USERNAME EVENT [...]]]> I have encountered the following problem on a 10.2.0.4 database on Linux x86_64 today:
A user session has been waiting for “enq: RO – fast object reuse” for almost 60 minutes while executing a “truncate table” SQL statement.

SQL> select username, event, sql_id, taddr, last_call_et from v$session where sid = 234;

USERNAME EVENT SQL_ID TADDR LAST_CALL_ET
———- —————————– ————- —————- ————
MD enq: RO – fast object reuse ljk299jlkj003 0000000153264570 3542

SQL> select sql_text from v$sqlstats where sql_id = ‘ljk299jlkj003′;

SQL_TEXT
————————————-
truncate table tab1

The Session was blocked by the CKPT process:

SQL> select * from dba_waiters;

WAITING_SESSION HOLDING_SESSION LOCK_TYPE MODE_HELD MODE_REQUESTED LOCK_ID1 LOCK_ID2
————— ————— ————————– —————————————- —————————————- ———- ———-
234 423 RO Row-S (SS) Exclusive 65573 1

SQL> select sid, serial#, sql_id, last_call_et, machine, program, username from v$session where sid = 423;

SID SERIAL# SQL_ID LAST_CALL_ET MACHINE PROGRAM
———- ———- ————- ———— —————- ——————————–
423 1 4133636 ora-vm1.intra oracle@ora-vm1.intra (CKPT)

The checkpoint process was waiting for database writer DBWR process, which was spinning on one cpu:

top

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
10712 oracle 25 0 2201m 1.7g 1.7g R 99.5 21.7 108:18.03 oracle

PID 10712 maps to DBW0:

[oracle@ora-vm1 ]$ ps -ef|grep 10712
oracle 10712 1 0 2008 ? 03:23:05 ora_dbw0_MDDB01

mpstat

Linux 2.6.9-78.ELsmp (ora-vm1.intra) 01/20/2009

02:21:56 PM CPU %user %nice %system %iowait %irq %soft %idle intr/s
02:21:57 PM all 49.75 0.00 0.00 0.00 0.00 0.00 50.25 1055.00
02:21:57 PM 0 0.00 0.00 0.00 0.00 0.00 0.00 100.00 1006.00
02:21:57 PM 1 100.00 0.00 0.00 0.00 0.00 0.00 0.00 49.00

02:21:57 PM CPU %user %nice %system %iowait %irq %soft %idle intr/s
02:21:58 PM all 50.75 0.00 0.00 0.50 0.00 0.00 48.76 1161.00
02:21:58 PM 0 1.00 0.00 0.00 1.00 0.00 0.00 98.00 1087.00
02:21:58 PM 1 100.00 0.00 0.00 0.00 0.00 0.00 0.00 74.00

The stack of dbw0 during the time showed these signatures:

[oracle@ora-vm1 oracle]$ pstack 10712
#0 0×000000000074b7fb in kslfre ()
#1 0×00000000010ccc3b in kcbo_exam_buf ()
#2 0×00000000010d0d62 in kcbo_service_ockpt ()
#3 0×0000000001080cd7 in kcbbdrv ()
#4 0×00000000007ddcc2 in ksbabs ()
#5 0×00000000007e4b32 in ksbrdp ()
#6 0×0000000002efcb50 in opirip ()
#7 0×00000000012da326 in opidrv ()
#8 0×0000000001e62456 in sou2o ()
#9 0×00000000006d2555 in opimai_real ()
#10 0×00000000006d240c in main ()
[oracle@ora-vm1 oracle]$ pstack 10712
#0 0×000000000074b36d in kslfre ()
#1 0×00000000010cc203 in kcbo_write_process ()
#2 0×00000000010ce608 in kcbo_write_q ()
#3 0×0000000001080a6d in kcbbdrv ()
#4 0×00000000007ddcc2 in ksbabs ()
#5 0×00000000007e4b32 in ksbrdp ()
#6 0×0000000002efcb50 in opirip ()
#7 0×00000000012da326 in opidrv ()
#8 0×0000000001e62456 in sou2o ()
#9 0×00000000006d2555 in opimai_real ()
#10 0×00000000006d240c in main ()
[oracle@ora-vm1 oracle]$ pstack 10712
#0 0×00000000010ccb60 in kcbo_exam_buf ()
#1 0×00000000010d0d62 in kcbo_service_ockpt ()
#2 0×0000000001080cd7 in kcbbdrv ()
#3 0×00000000007ddcc2 in ksbabs ()
#4 0×00000000007e4b32 in ksbrdp ()
#5 0×0000000002efcb50 in opirip ()
#6 0×00000000012da326 in opidrv ()
#7 0×0000000001e62456 in sou2o ()
#8 0×00000000006d2555 in opimai_real ()
#9 0×00000000006d240c in main ()
[oracle@ora-vm1 oracle]$ pstack 10712
#0 0×00000000010d0da5 in kcbo_service_ockpt ()
#1 0×0000000001080cd7 in kcbbdrv ()
#2 0×00000000007ddcc2 in ksbabs ()
#3 0×00000000007e4b32 in ksbrdp ()
#4 0×0000000002efcb50 in opirip ()
#5 0×00000000012da326 in opidrv ()
#6 0×0000000001e62456 in sou2o ()
#7 0×00000000006d2555 in opimai_real ()
#8 0×00000000006d240c in main ()

A MetaLink Research for the term “kcbo_service_ockpt” leads to Bug 7376934, which is a duplicate of Bug 7385253 – DBWR IS CONSUMING HIGH CPU.

Patch 7385253 is available for Linux x86_64, HP-UX, Solaris, AIX.
Reference:
MetaLink Note 762085.1 – Subject: ‘enq: RO – fast object reuse’ contention when gathering schema/table statistics in parallel

]]> http://www.ora-solutions.net/web/2009/01/20/session-waiting-for-enq-ro-fast-object-reuse-dbwr-process-spinning-on-cpu/feed/ 0 http://www.ora-solutions.net/web/2009/01/15/huge-space-consumption-by-oracle_homepatch_storage/ http://www.ora-solutions.net/web/2009/01/15/huge-space-consumption-by-oracle_homepatch_storage/#comments Thu, 15 Jan 2009 16:05:01 +0000 Martin http://www.ora-solutions.net/web/?p=559 If you are keeping your system up to date with Patchsets, Patch Bundles, Merge Label Requests (MLR) or Critical Patch Updates (CPU), you will most likely suffer from a huge .patch_storage Subdirectory in your $ORACLE_HOME.

On one of my databases it looked like this:

Space used by $ORACLE_HOME: 7 GB
Space used by $ORACLE_HOME/.patch_storage: 4.3 GB

Can data in this directory be removed?

MetaLink Note 550522.1 (Subject: How To Avoid Disk Full Issues Because OPatch Backups Take Big Amount Of Disk Space.) has the answer and tells you: it depends. Normally, this data is used in order to be able to rollback a patch. However, if you have installed a patchset (eg. 10.2.0.4), then the patches for the previous patchset (10.2.0.3) which are located in the .patch_storage directory are not needed anymore and can be removed. However, I would not recommend that you delete the directories manually yourself, as this would not be supported. Instead let Oracle do it for you:

Recent versions of opatch (current is 10.2.0.4.5 as of January 2009) have a utility included, which removes patches not needed anymore from the .patch_storage directory. Moreover, the opatch utility creates these .patch_storage backup directories more intelligently which should result in less space wasted.

[oracle@vmhost1 ora10]$./OPatch/opatch util Cleanup
Invoking OPatch 10.2.0.4.5

Oracle Interim Patch Installer version 10.2.0.4.5
Copyright (c) 2008, Oracle Corporation. All rights reserved.

UTIL session

Oracle Home : /oracle/ora10
Central Inventory : /oracle/oraInventory
from : /var/opt/oracle/oraInst.loc
OPatch version : 10.2.0.4.5
OUI version : 10.2.0.4.0
OUI location : /oracle/ora10/oui
Log file location : /oracle/ora10/cfgtoollogs/opatch/opatch2009-01-15_17-00-51PM.log

Patch history file: /oracle/ora10/cfgtoollogs/opatch/opatch_history.txt

Invoking utility “cleanup”
OPatch will clean up ‘restore.sh,make.txt’ files and ‘rac,scratch,backup’ directories.
You will be still able to rollback patches after this cleanup.
Do you want to proceed? [y|n]
y
User Responded with: Y
Size of directory “/oracle/ora10/.patch_storage” before cleanup is 4575330012 bytes.
Size of directory “/oracle/ora10/.patch_storage” after cleanup is 188326505 bytes.

UtilSession: Backup area for restore has been cleaned up. For a complete list of files/directories
deleted, Please refer log file.

OPatch succeeded.

180 MB instead of 4 GB. I like that.

]]> http://www.ora-solutions.net/web/2009/01/15/huge-space-consumption-by-oracle_homepatch_storage/feed/ 2