崔華基於oracle的SQL優化讀書筆記（一）如何得到真實的執行計劃
---恢復內容開始---
得到目標SQL的執行計劃，大致有以下四種方式：
1.explain plan 命令
2.DBMS_XPLAN包
3.SQLPLUS中的autotrace開關
4.10046事件
除了第四種，其他三種方法都有可能是不準的。判斷一個sq計劃任務任務是否準確，就要看目標SQL是否真正被執行。
第一種方法在目標SQL含有綁定變量時不準
第二種方法包裏含有四種方式，記住以下三種：
select * from table(dbms_xplan.display_cursor(null,null,‘advanced‘));
select * from table(dbms_xplan.display_cursor(‘sql_id/hash_value‘,child_cursor_number,‘advanced‘));
select * from table(dbms_xplan.display_awr(‘sql_id‘)); --用於已經被age out 出shared pool的情況
第三種方法，SET AUTOTRACE ON 和 SET AUTOTRACE TRACERONLY執行後可看到實際執行情況（計劃可能不準，因為SET ATUOTRACE命令都是來源於調用explain plan命令）
對於SET AUTOTRACE TRACE TRACEONLY EXPLAIN時，DML語句將會被執行。
此外printsql存儲過程也可用於查看實際的執行計劃，使用topas等命令查看sql的PID
輸入命令exec printsql（1212576，‘SPID‘);
可得到sql、真實的執行計劃以及殺死這個session的語句。具體語句見文末。
最後就是通過AWR（適合10g及其以上版本）報告了，通過命令@’$ORACLE_HOME/rdbms/admin/awrsqrpt.sql‘;
依次輸入 text、1（天數，指最近一天）、起始快照時間、終止快照時間、目標sqlID
printsql內容，文件名為PRINTSQL.prc_
create or replace procedure PRINTSQL
(i_n_id in number,
i_vc_idtype in varchar2) is
/*
功能： 打印對應spid或sid所對應的sql以及其執行計劃
作者： 老熊，dbsnake
創建日期：2010-11-12
輸入參數：
i_n_id: 輸入的spid或sid
i_vc_idtype : 輸入的ID的類型，‘SPID‘表示輸入的是spid，‘SID‘表示輸入的是sid.
輸出參數：
無
輸入輸出參數：
無
調用到的存儲過程：
無
*/
o_vc_return_flag varchar2(4000);
type typsqltext is table of varchar2(1000) index by binary_integer;
typsqltexts typsqltext;
vc_paddr varchar2(4000);
n_hashvalue number;
n_childnumber number;
rec_session v$session%rowtype;
rec_sessionwait v$session_wait%rowtype;
rec_sql v$sql%rowtype;
/*select hash_value,child_number,plan_hash_value,executions,buffer_gets,buffer_gets/decode(executions,0,1,executions) gets_per_exec,
rows_processed,rows_processed/decode(executions,0,1,executions) rows_per_exec,
disk_reads,disk_reads/decode(executions,0,1,executions) reads_per_exec,
cpu_time/1000000 cpu_time,cpu_time/decode(executions,0,1,executions)/1000000 cpu_per_exec,
ELAPSED_TIME/1000000 ELAPSED_TIME,ELAPSED_TIME/decode(executions,0,1,executions)/1000000 ela_per_exec
from v$sql where hash_value=&1
and rownum<=100;*/
type type_hash_value is table of v$sql.HASH_VALUE%type index by binary_integer;
hash_values type_hash_value;
type type_child_number is table of v$sql.CHILD_NUMBER%type index by binary_integer;
child_numbers type_child_number;
type type_plan_hash_value is table of v$sql.PLAN_HASH_VALUE%type index by binary_integer;
plan_hash_values type_plan_hash_value;
type type_execution is table of v$sql.EXECUTIONS%type index by binary_integer;
executions type_execution;
type type_buffer_get is table of v$sql.BUFFER_GETS%type index by binary_integer;
buffer_gets type_buffer_get;
type type_gets_per_exec is table of v$sql.BUFFER_GETS%type index by binary_integer;
gets_per_execs type_gets_per_exec;
type type_rows_processed is table of v$sql.ROWS_PROCESSED%type index by binary_integer;
rows_processeds type_rows_processed;
type type_rows_per_exec is table of v$sql.ROWS_PROCESSED%type index by binary_integer;
rows_per_execs type_rows_per_exec;
type type_disk_read is table of v$sql.DISK_READS%type index by binary_integer;
disk_reads type_disk_read;
type type_reads_per_exec is table of v$sql.DISK_READS%type index by binary_integer;
reads_per_execs type_reads_per_exec;
type type_cpu_time is table of v$sql.CPU_TIME%type index by binary_integer;
cpu_times type_cpu_time;
type type_cpu_per_exec is table of v$sql.CPU_TIME%type index by binary_integer;
cpu_per_execs type_cpu_per_exec;
type type_ELAPSED_TIME is table of v$sql.ELAPSED_TIME%type index by binary_integer;
ELAPSED_TIMEs type_ELAPSED_TIME;
type type_ela_per_exec is table of v$sql.ELAPSED_TIME%type index by binary_integer;
ela_per_execs type_ela_per_exec;
-- cursor c_display_cursor(in_address varchar2, in_hash_value number, in_child_number number) is
s_display_cursor varchar2(32767) := ‘
select case when access_predicates is not null or filter_predicates is not null then ‘‘*‘‘ else ‘‘ ‘‘ end || substr(to_char(id, ‘‘999‘‘), -3) as p_id,
lpad(‘‘ ‘‘, depth) || operation || ‘‘ ‘‘ || options as operation,
object_name as name,
starts,
cardinality as e_rows,
outrows as a_rows,
to_char(to_number(substr(e_time_interval, 2, 9)) * 24 + to_number(substr(e_time_interval, 12, 2)), ‘‘FM900‘‘) || substr(e_time_interval, 14, 9) as a_time,
crgets + cugets as buffers,
case reads when 0 then null else reads end as reads,
case writes when 0 then null else writes end as writes,
case other_tag
when ‘‘PARALLEL_TO_SERIAL‘‘ then ‘‘P->S‘‘
when ‘‘PARALLEL_COMBINED_WITH_PARENT‘‘ then ‘‘PCWP‘‘
when ‘‘PARALLEL_COMBINED_WITH_CHILD‘‘ then ‘‘PCWC‘‘
when ‘‘SERIAL_TO_PARALLEL‘‘ then ‘‘S->P‘‘
when ‘‘PARALLEL_TO_PARALLEL‘‘ then ‘‘P->P‘‘
when ‘‘PARALLEL_FROM_SERIAL‘‘ then ‘‘P<-S‘‘
else other_tag end as in_out,
partition_start,
partition_stop,
distribution,
mem_opt,
mem_one,
last_mem_used || case last_mem_usage when ‘‘OPTIMAL‘‘ then ‘‘ (0)‘‘ when ‘‘ONE PASS‘‘ then ‘‘ (1)‘‘ when ‘‘MULTI-PASS‘‘ then ‘‘ (M)‘‘ end,
case last_degree when 0 then null when 1 then null else last_degree end as last_degree,
--opt_cnt,
--one_cnt,
--multi_cnt,
--max_tmp,
last_tmp,
access_predicates,
filter_predicates,
dynamic_sampling_flag,
id
from (
SELECT /*+ opt_param(‘‘parallel_execution_enabled‘‘, ‘‘false‘‘) */
id, position, depth , operation, options, object_name, cardinality, bytes, temp_space, cost, io_cost,
cpu_cost, partition_start, partition_stop, object_node, other_tag, distribution, null, access_predicates, filter_predicates,
null, null, null, starts, outrows, crgets, cugets, reads, writes, etime, e_time_interval, mem_opt, mem_one, last_mem_used, last_degree, last_mem_usage,
opt_cnt, one_cnt, multi_cnt, max_tmp, last_tmp, dynamic_sampling_flag from (
select /*+ no_merge */
id, depth, position, operation, options,
cost, cardinality, bytes, object_node,
object_name, other_tag, partition_start,
partition_stop, distribution, temp_space, io_cost,
cpu_cost, filter_predicates, access_predicates, other,
last_starts starts,
last_output_rows outrows,
last_cr_buffer_gets crgets,
last_cu_buffer_gets cugets,
last_disk_reads reads,
last_disk_writes writes,
last_elapsed_time etime,
to_char(numtodsinterval(round(last_elapsed_time/10000)*10000/1000000, ‘‘SECOND‘‘)) as e_time_interval,
estimated_optimal_size mem_opt,
estimated_onepass_size mem_one,
last_memory_used last_mem_used,
last_degree,
last_execution last_mem_usage,
optimal_executions opt_cnt,
onepass_executions one_cnt,
multipasses_executions multi_cnt,
max_tempseg_size max_tmp,
last_tempseg_size last_tmp,
case 0 /*instr(other_xml, ‘‘dynamic_sampling‘‘)*/ when 0 then NULL else ‘‘YES‘‘ end as dynamic_sampling_flag
from V$SQL_PLAN_STATISTICS_ALL vp
--where address = hextoraw(:in_address)
where hash_value = :in_hash_value
and child_number = :in_child_number)
)
order by id‘;
s_display_cursor2 varchar2(32767) := ‘
select case when access_predicates is not null or filter_predicates is not null then ‘‘*‘‘ else ‘‘ ‘‘ end || substr(to_char(id, ‘‘999‘‘), -3) as p_id,
lpad(‘‘ ‘‘, depth) || operation || ‘‘ ‘‘ || options as operation,
object_name as name,
cardinality as e_rows,
bytes,
temp_space,
cost,
cpu_cost,
object_node,
case other_tag
when ‘‘PARALLEL_TO_SERIAL‘‘ then ‘‘P->S‘‘
when ‘‘PARALLEL_COMBINED_WITH_PARENT‘‘ then ‘‘PCWP‘‘
when ‘‘PARALLEL_COMBINED_WITH_CHILD‘‘ then ‘‘PCWC‘‘
when ‘‘SERIAL_TO_PARALLEL‘‘ then ‘‘S->P‘‘
when ‘‘PARALLEL_TO_PARALLEL‘‘ then ‘‘P->P‘‘
when ‘‘PARALLEL_FROM_SERIAL‘‘ then ‘‘P<-S‘‘
else other_tag end as in_out,
partition_start,
partition_stop,
distribution,
access_predicates,
filter_predicates,
dynamic_sampling_flag,
id
from (
SELECT /*+ opt_param(‘‘parallel_execution_enabled‘‘, ‘‘false‘‘) */
id, position, depth , operation, options, object_name, cardinality, bytes, temp_space, cost, io_cost,
cpu_cost, partition_start, partition_stop, object_node, other_tag, distribution, null, access_predicates, filter_predicates,
null, null, null, starts, outrows, crgets, cugets, reads, writes, etime, e_time_interval, mem_opt, mem_one, last_mem_used, last_degree, last_mem_usage,
opt_cnt, one_cnt, multi_cnt, max_tmp, last_tmp, dynamic_sampling_flag from (
select /*+ no_merge */
id, depth, position, operation, options,
cost, cardinality, bytes, object_node,
object_name, other_tag, partition_start,
partition_stop, distribution, temp_space, io_cost,
cpu_cost, filter_predicates, access_predicates, other,
0 starts,
0 outrows,
0 crgets,
0 cugets,
0 reads,
0 writes,
0 etime,
0 e_time_interval,
0 mem_opt,
0 mem_one,
null last_mem_used,
0 last_degree,
null last_mem_usage,
0 opt_cnt,
0 one_cnt,
0 multi_cnt,
0 max_tmp,
0 last_tmp,
case 0 /*instr(other_xml, ‘‘dynamic_sampling‘‘)*/ when 0 then NULL else ‘‘YES‘‘ end as dynamic_sampling_flag
from V$SQL_PLAN vp
--where address = hextoraw(:in_address)
where hash_value = :in_hash_value
and child_number = :in_child_number)
)
order by id‘;
type t_list_varchar2 is table of varchar2(4000) index by pls_integer;
type t_column_record is record (
a_data t_list_varchar2,
b_has_data boolean,
s_heading varchar2(255),
b_is_number boolean default false,
s_alignment varchar2(20),
n_max_size pls_integer);
type t_column_list is table of t_column_record index by pls_integer;
a_column_list t_column_list;
n_row_size pls_integer;
s_row varchar2(4000);
a_access_pred t_list_varchar2;
a_filter_pred t_list_varchar2;
s_plan_hash varchar2(255);
a_dyn_sampl t_list_varchar2;
a_id_list t_list_varchar2;
s_output varchar2(32767);
s_sql_address varchar2(255);
s_hash_value varchar2(255);
s_child_num varchar2(255);
b_has_stat boolean := TRUE;
max_line_size constant pls_integer := 255;
c_display_cursor sys_refcursor;
n_cnt pls_integer;
function has_collection_only_nulls(in_coll in t_list_varchar2)
return boolean is
b_return boolean := true;
begin
if in_coll.count > 0 then
for i in in_coll.first..in_coll.last loop
if in_coll(i) is not null then
b_return := false;
exit;
end if;
end loop;
end if;
return b_return;
end has_collection_only_nulls;
function get_max_size(in_coll in t_list_varchar2)
return pls_integer is
n_return pls_integer := 0;
begin
if in_coll.count > 0 then
for i in in_coll.first..in_coll.last loop
if in_coll(i) is not null then
n_return := greatest(n_return, length(in_coll(i)));
end if;
end loop;
end if;
return n_return;
end get_max_size;
function display_cursor_format_number(in_data in varchar2)
return varchar2 is
s_return varchar2(20);
s_trail varchar2(32767);
s_data varchar2(32767);
n_number number;
n_delim_pos number;
e_num_val_error exception;
pragma exception_init(e_num_val_error, -6502);
begin
n_delim_pos := instr(in_data, ‘ ‘);
if n_delim_pos > 0 then
s_trail := substr(in_data, n_delim_pos);
s_data := substr(in_data, 1, n_delim_pos - 1);
else
s_data := in_data;
end if;
n_number := to_number(s_data);
s_return :=
case
when n_number >= 100000000000000000000 then to_char(n_number/1000000000000000000, ‘FM99999‘) || ‘E‘
when n_number >= 100000000000000000 then to_char(n_number/1000000000000000, ‘FM99999‘) || ‘P‘
when n_number >= 100000000000000 then to_char(n_number/1000000000000, ‘FM99999‘) || ‘T‘
when n_number >= 100000000000 then to_char(n_number/1000000000, ‘FM99999‘) || ‘G‘
when n_number >= 100000000 then to_char(n_number/1000000, ‘FM99999‘) || ‘M‘
when n_number >= 100000 then to_char(n_number/1000, ‘FM99999‘) || ‘K‘
else to_char(n_number, ‘FM99999‘)
end;
return s_return || s_trail;
exception
when e_num_val_error then
return in_data;
end display_cursor_format_number;
procedure put_line_smart(in_string in varchar2, in_line_prefix in varchar2 default ‘‘, in_line_size in pls_integer default 180) is
n_offset pls_integer;
s_delimiter varchar2(1);
n_size_current_line pls_integer;
n_line_counter pls_integer;
begin
n_offset := 1;
n_size_current_line := in_line_size;
n_line_counter := 1;
while case when n_line_counter > 1 and length(in_line_prefix) > 0
then length(in_string) + length(in_line_prefix)
else length(in_string) end
+ 1 - n_offset > in_line_size loop
-- dbms_output.put_line(‘Debug n_offset: ‘ || n_offset);
if n_line_counter > 1 and length(in_line_prefix) > 0 then
n_size_current_line := greatest(n_size_current_line - length(in_line_prefix), length(in_line_prefix) + 10);
end if;
-- dbms_output.put_line(‘Debug n_size_current_line: ‘ || n_size_current_line);
loop
s_delimiter := substr(in_string, n_offset - 1 + n_size_current_line, 1);
exit when s_delimiter in (‘ ‘, chr(9), chr(10), chr(13)/*, ‘(‘, ‘)‘, ‘[‘, ‘]‘*/) or n_size_current_line < 1;
n_size_current_line := n_size_current_line - 1;
end loop;
if n_size_current_line < 1 then
if n_line_counter > 1 and length(in_line_prefix) > 0 then
n_size_current_line := greatest(n_size_current_line - length(in_line_prefix), length(in_line_prefix) + 10);
else
n_size_current_line := in_line_size;
end if;
end if;
if s_delimiter in (chr(13), chr(10)) then
n_size_current_line := n_size_current_line - 1;
end if;
dbms_output.put_line(case when n_line_counter > 1 then in_line_prefix end || substr(in_string, n_offset, n_size_current_line));
if s_delimiter in (chr(13), chr(10)) then
while substr(in_string, n_offset - 1 + n_size_current_line, 1) in (chr(10), chr(13)) loop
n_size_current_line := n_size_current_line + 1;
end loop;
end if;
n_offset := n_offset + n_size_current_line;
n_size_current_line := in_line_size;
n_line_counter := n_line_counter + 1;
end loop;
dbms_output.put_line(case when n_line_counter > 1 then in_line_prefix end || substr(in_string, n_offset));
end put_line_smart;
begin
dbms_output.put_line(‘--------------------------------------------------------------------------------------‘);
if ( upper(i_vc_idtype) = ‘SPID‘ ) then
select addr into vc_paddr from v$process where spid=to_char(i_n_id);
select * into rec_session from v$session where paddr=vc_paddr;
select * into rec_sessionwait from v$session_wait where sid=rec_session.SID;
select decode(sql_hash_value,0,prev_hash_value,sql_hash_value) into n_hashvalue from v$session where sid=rec_session.SID;
select sql_text bulk collect into typsqltexts from v$sqltext where hash_value=n_hashvalue order by piece;
if ( typsqltexts.count > 0 ) then
for i in typsqltexts.first .. typsqltexts.last loop
---這裏處理掉"dbms_output.put_line"不能處理超過255個字符的限制,並且考慮到了sql語句中可能有中文
loop
exit when typsqltexts(i) is null;
dbms_output.put_line( substrb( typsqltexts(i), 1, 254 ) );
typsqltexts(i) := substrb( typsqltexts(i), 255 );
end loop;
end loop;
else
dbms_output.put_line(‘The sql text has been aged out from the shared pool.‘);
end if;
elsif ( upper(i_vc_idtype) = ‘SID‘ ) then
select * into rec_session from v$session where sid=i_n_id;
select decode(sql_hash_value,0,prev_hash_value,sql_hash_value) into n_hashvalue from v$session where sid=i_n_id;
select sql_text bulk collect into typsqltexts from v$sqltext where hash_value=n_hashvalue order by piece;
if ( typsqltexts.count > 0 ) then
for i in typsqltexts.first .. typsqltexts.last loop
---這裏處理掉"dbms_output.put_line"不能處理超過255個字符的限制,並且考慮到了sql語句中可能有中文
loop
exit when typsqltexts(i) is null;
dbms_output.put_line( substrb( typsqltexts(i), 1, 254 ) );
typsqltexts(i) := substrb( typsqltexts(i), 255 );
end loop;
end loop;
else
dbms_output.put_line(‘The sql text has been aged out from the shared pool.‘);
end if;
else
dbms_output.put_line(‘invalid input id type parameter!‘);
return;
end if;
dbms_output.put_line(‘--------------------------------------------------------------------------------------‘);
dbms_output.put_line(‘The session id is ‘ || rec_session.SID);
dbms_output.put_line(‘The status is ‘ || rec_session.STATUS);
dbms_output.put_line(‘The sql hash value is ‘ || rec_session.SQL_HASH_VALUE);
--dbms_output.put_line(‘The child cursor number is ‘ || rec_session.SQL_CHILD_NUMBER);
dbms_output.put_line(‘The prev hash value is ‘ || rec_session.PREV_HASH_VALUE);
--dbms_output.put_line(‘The prev child cursor number is ‘ || rec_session.PREV_CHILD_NUMBER);
dbms_output.put_line(‘The osuser is ‘ || rec_session.OSUSER);
dbms_output.put_line(‘The machine is ‘ || rec_session.MACHINE);
dbms_output.put_line(‘The terminal is ‘ || rec_session.TERMINAL);
dbms_output.put_line(‘The program is ‘ || rec_session.PROGRAM);
dbms_output.put_line(‘The event is ‘ || rec_sessionwait.EVENT);
dbms_output.put_line(‘--------------------------------------------------------------------------------------‘);
--demo: alter system kill session ‘417,21188‘ immediate;
dbms_output.put_line(‘alter system kill session ‘‘‘ || rec_session.SID || ‘,‘ || rec_session.SERIAL# || ‘‘‘ immediate;‘);
select hash_value,child_number,plan_hash_value,executions,buffer_gets,buffer_gets/decode(executions,0,1,executions) gets_per_exec,
rows_processed,rows_processed/decode(executions,0,1,executions) rows_per_exec,
disk_reads,disk_reads/decode(executions,0,1,executions) reads_per_exec,
cpu_time/1000000 cpu_time,cpu_time/decode(executions,0,1,executions)/1000000 cpu_per_exec,
ELAPSED_TIME/1000000 ELAPSED_TIME,ELAPSED_TIME/decode(executions,0,1,executions)/1000000 ela_per_exec
bulk collect into hash_values,child_numbers,plan_hash_values,executions,buffer_gets,gets_per_execs,
rows_processeds,rows_per_execs,disk_reads,reads_per_execs,cpu_times,cpu_per_execs,ELAPSED_TIMEs,ela_per_execs
from v$sql where hash_value=n_hashvalue and rownum<=100;
if( hash_values.count > 0 ) then
for i in hash_values.first .. hash_values.last loop
dbms_output.put_line(‘--------------------------------------------------------------------------------------‘);
dbms_output.put_line(‘The hash_value is ‘ || hash_values(i));
dbms_output.put_line(‘The child_number is ‘ || child_numbers(i));
dbms_output.put_line(‘The plan_hash_value is ‘ || plan_hash_values(i));
dbms_output.put_line(‘The execution is ‘ || executions(i));
dbms_output.put_line(‘The buffer_gets is ‘ || buffer_gets(i));
dbms_output.put_line(‘The gets_per_exec is ‘ || gets_per_execs(i));
dbms_output.put_line(‘The rows_processed is ‘ || rows_processeds(i));
dbms_output.put_line(‘The rows_per_exec is ‘ || rows_per_execs(i));
dbms_output.put_line(‘The disk_reads is ‘ || disk_reads(i));
dbms_output.put_line(‘The reads_per_exec is ‘ || reads_per_execs(i));
dbms_output.put_line(‘The cpu_time is ‘ || cpu_times(i));
dbms_output.put_line(‘The cpu_per_exec is ‘ || cpu_per_execs(i));
dbms_output.put_line(‘The ELAPSED_TIME is ‘ || ELAPSED_TIMEs(i));
dbms_output.put_line(‘The ela_per_exec is ‘ || ela_per_execs(i));
dbms_output.put_line(‘--------------------------------------------------------------------------------------‘);
s_hash_value := n_hashvalue;
s_child_num := child_numbers(i);
-- Header information
dbms_output.put_line(chr(13));
put_line_smart(in_string => ‘ HASH_VALUE: ‘ || s_hash_value || ‘ CHILD_NUMBER: ‘ || s_child_num , in_line_size => max_line_size);
put_line_smart(in_string => ‘---------------------------------------------------------------------------------------------------------------------------------------------‘, in_line_size => max_line_size);
begin
execute immediate ‘
select sql_text,
plan_hash_value
from v$sql
where hash_value = to_number(:s_hash_value)
and child_number = to_number(:s_child_num)‘
into s_output, s_plan_hash using s_hash_value, s_child_num;
exception
when NO_DATA_FOUND then
null;
when others then
dbms_output.put_line(‘Error getting SQL text from V$SQL, check privileges‘);
end;
put_line_smart(s_output);
dbms_output.put_line(chr(13));
open c_display_cursor for s_display_cursor using to_number(s_hash_value), to_number(s_child_num);
n_cnt := 1;
fetch c_display_cursor into
a_column_list(1).a_data(n_cnt), -- a_p_id(n_cnt),
a_column_list(2).a_data(n_cnt), -- a_operation(n_cnt),
a_column_list(3).a_data(n_cnt), -- a_name(n_cnt),
a_column_list(4).a_data(n_cnt), -- a_starts(n_cnt),
a_column_list(5).a_data(n_cnt), -- a_e_rows(n_cnt),
a_column_list(6).a_data(n_cnt), -- a_a_rows(n_cnt),
a_column_list(7).a_data(n_cnt), -- a_a_time(n_cnt),
a_column_list(8).a_data(n_cnt), -- a_buffers(n_cnt),
a_column_list(9).a_data(n_cnt), -- a_reads(n_cnt),
a_column_list(10).a_data(n_cnt), -- a_writes(n_cnt),
a_column_list(11).a_data(n_cnt), -- a_in_out(n_cnt),
a_column_list(12).a_data(n_cnt), -- a_partition_start(n_cnt),
a_column_list(13).a_data(n_cnt), -- a_partition_stop(n_cnt),
a_column_list(14).a_data(n_cnt), -- a_distribution(n_cnt),
a_column_list(15).a_data(n_cnt), -- a_last_mem_usage(n_cnt),
a_column_list(16).a_data(n_cnt), -- a_last_degree(n_cnt),
a_column_list(17).a_data(n_cnt), -- a_mem_opt(n_cnt),
a_column_list(18).a_data(n_cnt), -- a_mem_one(n_cnt),
--a_column_list(17).a_data(n_cnt), -- a_opt_cnt(n_cnt),
--a_column_list(18).a_data(n_cnt), -- a_one_cnt(n_cnt),
--a_column_list(19).a_data(n_cnt), -- a_multi_cnt(n_cnt),
--a_column_list(22).a_data(n_cnt), -- a_max_tmp(n_cnt),
a_column_list(19).a_data(n_cnt), -- a_last_tmp(n_cnt),
a_access_pred(n_cnt),
a_filter_pred(n_cnt),
a_dyn_sampl(n_cnt),
a_id_list(n_cnt);
if c_display_cursor%notfound then
close c_display_cursor;
--dbms_output.put_line(‘Debug : Select V$SQL_PLAN‘);
b_has_stat := FALSE;
a_column_list(1).s_heading := ‘Id‘; --a_column_list(1).b_is_number := true;
a_column_list(2).s_heading := ‘Operation‘;
a_column_list(3).s_heading := ‘Name‘;
a_column_list(4).s_heading := ‘Rows‘; a_column_list(4).b_is_number := true;
a_column_list(5).s_heading := ‘Bytes‘; a_column_list(5).b_is_number := true;
a_column_list(6).s_heading := ‘TempSpc‘; a_column_list(6).b_is_number := true;
a_column_list(7).s_heading := ‘Cost‘;a_column_list(7).b_is_number := true;
a_column_list(8).s_heading := ‘Cpu-Cost‘;a_column_list(8).b_is_number := true;
a_column_list(9).s_heading := ‘TQ‘;
a_column_list(10).s_heading := ‘In-Out‘;
a_column_list(11).s_heading := ‘Pstart‘; a_column_list(10).b_is_number := true;
a_column_list(12).s_heading := ‘Pstop‘; a_column_list(11).b_is_number := true;
a_column_list(13).s_heading := ‘PQ Distrib‘;
open c_display_cursor for s_display_cursor2 using to_number(s_hash_value), to_number(s_child_num);
n_cnt := 0;
else
-- The plan statistics
a_column_list(1).s_heading := ‘Id‘; --a_column_list(1).b_is_number := true;
a_column_list(2).s_heading := ‘Operation‘;
a_column_list(3).s_heading := ‘Name‘;
a_column_list(4).s_heading := ‘Starts‘; a_column_list(4).b_is_number := true;
a_column_list(5).s_heading := ‘E-Rows‘; a_column_list(5).b_is_number := true;
a_column_list(6).s_heading := ‘A-Rows‘; a_column_list(6).b_is_number := true;
a_column_list(7).s_heading := ‘A-Time‘;
a_column_list(8).s_heading := ‘Buffers‘; a_column_list(8).b_is_number := true;
a_column_list(9).s_heading := ‘Reads‘; a_column_list(9).b_is_number := true;
a_column_list(10).s_heading := ‘Writes‘; a_column_list(10).b_is_number := true;
a_column_list(11).s_heading := ‘In-Out‘;
a_column_list(12).s_heading := ‘Pstart‘; a_column_list(12).b_is_number := true;
a_column_list(13).s_heading := ‘Pstop‘; a_column_list(13).b_is_number := true;
a_column_list(14).s_heading := ‘PQ Distrib‘;
a_column_list(15).s_heading := ‘OMem‘; a_column_list(15).b_is_number := true;
a_column_list(16).s_heading := ‘1Mem‘; a_column_list(16).b_is_number := true;
a_column_list(17).s_heading := ‘Used-Mem‘; a_column_list(17).b_is_number := true; --a_column_list(15).s_alignment := ‘RIGHT‘;
a_column_list(18).s_heading := ‘Last-Degree‘; a_column_list(18).b_is_number := true;
--a_column_list(19).s_heading := ‘Opt-Cnt‘; a_column_list(17).b_is_number := true;
--a_column_list(20).s_heading := ‘One-Cnt‘; a_column_list(18).b_is_number := true;
--a_column_list(21).s_heading := ‘Multi-Cnt‘; a_column_list(19).b_is_number := true;
--a_column_list(19).s_heading := ‘Max-Tmp‘; a_column_list(19).b_is_number := true;
a_column_list(19).s_heading := ‘Last-Tmp‘; a_column_list(19).b_is_number := true;
n_cnt := 1;
end if;
loop
exit when c_display_cursor%notfound;
n_cnt := n_cnt + 1;
if b_has_stat then
fetch c_display_cursor into
a_column_list(1).a_data(n_cnt), -- a_p_id(n_cnt),
a_column_list(2).a_data(n_cnt), -- a_operation(n_cnt),
a_column_list(3).a_data(n_cnt), -- a_name(n_cnt),
a_column_list(4).a_data(n_cnt), -- a_starts(n_cnt),
a_column_list(5).a_data(n_cnt), -- a_e_rows(n_cnt),
a_column_list(6).a_data(n_cnt), -- a_a_rows(n_cnt),
a_column_list(7).a_data(n_cnt), -- a_a_time(n_cnt),
a_column_list(8).a_data(n_cnt), -- a_buffers(n_cnt),
a_column_list(9).a_data(n_cnt), -- a_reads(n_cnt),
a_column_list(10).a_data(n_cnt), -- a_writes(n_cnt),
a_column_list(11).a_data(n_cnt), -- a_in_out(n_cnt),
a_column_list(12).a_data(n_cnt), -- a_partition_start(n_cnt),
a_column_list(13).a_data(n_cnt), -- a_partition_stop(n_cnt),
a_column_list(14).a_data(n_cnt), -- a_distribution(n_cnt),
a_column_list(15).a_data(n_cnt), -- a_last_mem_usage(n_cnt),
a_column_list(16).a_data(n_cnt), -- a_last_degree(n_cnt),
a_column_list(17).a_data(n_cnt), -- a_mem_opt(n_cnt),
a_column_list(18).a_data(n_cnt), -- a_mem_one(n_cnt),
a_column_list(19).a_data(n_cnt), -- a_last_tmp(n_cnt),
a_access_pred(n_cnt),
a_filter_pred(n_cnt),
a_dyn_sampl(n_cnt),
a_id_list(n_cnt);
else
fetch c_display_cursor into
a_column_list(1).a_data(n_cnt),
a_column_list(2).a_data(n_cnt),
a_column_list(3).a_data(n_cnt),
a_column_list(4).a_data(n_cnt),
a_column_list(5).a_data(n_cnt),
a_column_list(6).a_data(n_cnt),
a_column_list(7).a_data(n_cnt),
a_column_list(8).a_data(n_cnt),
a_column_list(9).a_data(n_cnt),
a_column_list(10).a_data(n_cnt),
a_column_list(11).a_data(n_cnt),
a_column_list(12).a_data(n_cnt),
a_column_list(13).a_data(n_cnt),
a_access_pred(n_cnt),
a_filter_pred(n_cnt),
a_dyn_sampl(n_cnt),
a_id_list(n_cnt);
end if;
end loop;
close c_display_cursor;
if a_column_list(1).a_data.count > 0 then
dbms_output.put_line(‘Plan hash value: ‘ || s_plan_hash);
dbms_output.put_line(chr(13));
n_row_size := 1;
for i in a_column_list.first..a_column_list.last loop
if a_column_list(i).b_is_number then
if a_column_list(i).a_data.count > 0 then
for j in a_column_list(i).a_data.first..a_column_list(i).a_data.last loop
begin
a_column_list(i).a_data(j) := display_cursor_format_number(a_column_list(i).a_data(j));
exception
when others then
dbms_output.put_line(‘Column:‘ || a_column_list(i).s_heading || ‘ Data: ‘ || a_column_list(i).a_data(j));
raise;
end;
end loop;
end if;
end if;
-- column size is greatest of max size of content + 2 (leading + trailing blanks) and size of column heading
a_column_list(i).n_max_size := greatest(get_max_size(a_column_list(i).a_data) + 2, length(a_column_list(i).s_heading) + 2);
a_column_list(i).b_has_data := not has_collection_only_nulls(a_column_list(i).a_data);
if a_column_list(i).b_has_data then
n_row_size := n_row_size + a_column_list(i).n_max_size + 1;
end if;
end loop;
-- Header
put_line_smart(in_string => lpad(‘-‘, n_row_size, ‘-‘), in_line_size => max_line_size);
s_row := ‘‘;
for i in a_column_list.first..a_column_list.last loop
if a_column_list(i).b_has_data then
if a_column_list(i).s_alignment is null then
if a_column_list(i).b_is_number then
s_row := s_row || ‘|‘ || lpad(a_column_list(i).s_heading, a_column_list(i).n_max_size - 1) || ‘ ‘;
else
s_row := s_row || ‘|‘ || ‘ ‘ || rpad(a_column_list(i).s_heading, a_column_list(i).n_max_size - 1);
end if;
else
if a_column_list(i).s_alignment = ‘RIGHT‘ then
s_row := s_row || ‘|‘ || lpad(a_column_list(i).s_heading, a_column_list(i).n_max_size - 1) || ‘ ‘;
else
s_row := s_row || ‘|‘ || ‘ ‘ || rpad(a_column_list(i).s_heading, a_column_list(i).n_max_size - 1);
end if;
end if;
end if;
end loop;
s_row := s_row || ‘|‘;
put_line_smart(in_string => s_row, in_line_size => max_line_size);
-- Data
put_line_smart(in_string => lpad(‘-‘, n_row_size, ‘-‘), in_line_size => max_line_size);
for j in a_column_list(1).a_data.first..a_column_list(1).a_data.last loop
s_row := ‘‘;
for i in a_column_list.first..a_column_list.last loop
if a_column_list(i).b_has_data then
if a_column_list(i).b_is_number then
s_row := s_row || ‘|‘ || lpad(nvl(a_column_list(i).a_data(j), ‘ ‘), a_column_list(i).n_max_size - 1) || ‘ ‘;
else
s_row := s_row || ‘|‘ || ‘ ‘ || rpad(nvl(a_column_list(i).a_data(j), ‘ ‘), a_column_list(i).n_max_size - 1);
end if;
end if;
end loop;
s_row := s_row || ‘|‘;
put_line_smart(in_string => s_row, in_line_size => max_line_size);
end loop;
-- Footer
put_line_smart(in_string => lpad(‘-‘, n_row_size, ‘-‘), in_line_size => max_line_size);
-- Predicate information
dbms_output.put_line(chr(13));
dbms_output.put_line(‘Predicate Information (identified by operation id):‘);
dbms_output.put_line(‘---------------------------------------------------‘);
for j in a_column_list(1).a_data.first..a_column_list(1).a_data.last loop
if a_access_pred(j) is not null or a_filter_pred(j) is not null then
s_output := lpad(to_char(to_number(a_id_list(j)), ‘FM9999‘), 4, ‘ ‘) || ‘ - ‘;
if a_access_pred(j) is not null then
put_line_smart(s_output || ‘access(‘ || a_access_pred(j) || ‘)‘, lpad(‘ ‘, length(s_output), ‘ ‘));
end if;
if a_filter_pred(j) is not null then
if a_access_pred(j) is not null then
put_line_smart(lpad(‘ ‘, length(s_output), ‘ ‘) || ‘filter(‘ || a_filter_pred(j) || ‘)‘, lpad(‘ ‘, length(s_output), ‘ ‘));
else
put_line_smart(s_output || ‘filter(‘ || a_filter_pred(j) || ‘)‘, lpad(‘ ‘, length(s_output), ‘ ‘));
end if;
end if;
end if;
end loop;
--dbms_output.put_line(‘DEBUG:Begin Notes‘);
-- Notes section
if not a_column_list(4).b_has_data or a_dyn_sampl(1) = ‘YES‘ then
dbms_output.put_line(chr(13));
dbms_output.put_line(‘Note‘);
dbms_output.put_line(‘-----‘);
end if;
if a_dyn_sampl(1) = ‘YES‘ then
dbms_output.put_line(‘ - dynamic sampling used for this statement‘);
end if;
if not a_column_list(4).b_has_data then
dbms_output.put_line(‘ - Warning: basic plan statistics not available. These are only collected when:‘);
dbms_output.put_line(‘ * parameter ‘‘statistics_level‘‘ is set to ‘‘ALL‘‘, at session or system level‘);
end if;
else
dbms_output.put_line(‘SQL information could not be found for HASH_VALUE: ‘ || s_hash_value || ‘,CHILD_NUMBER: ‘ || s_child_num);
dbms_output.put_line(‘Please verify value of SQL address, hash_value and child_number;‘);
dbms_output.put_line(‘It could also be that the plan is no longer in cursor cache (check v$sql_plan)‘);
end if;
end loop;
end if;
exception
when others then
o_vc_return_flag := ‘E‘ || ‘_‘ || sqlcode || ‘_‘ || sqlerrm;
dbms_output.put_line(o_vc_return_flag);
return;
end PRINTSQL;
/
---恢復內容結束---
崔華基於oracle的SQL優化讀書筆記（一）如何得到真實的執行計劃