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a10ae35328
Essentially, the problem is that safemalloc is excruciatingly slow as it checks all allocated blocks for overrun at each memory management primitive, yielding a almost exponential slowdown for the memory management functions (malloc, realloc, free). The overrun check basically consists of verifying some bytes of a block for certain magic keys, which catches some simple forms of overrun. Another minor problem is violation of aliasing rules and that its own internal list of blocks is prone to corruption. Another issue with safemalloc is rather the maintenance cost as the tool has a significant impact on the server code. Given the magnitude of memory debuggers available nowadays, especially those that are provided with the platform malloc implementation, maintenance of a in-house and largely obsolete memory debugger becomes a burden that is not worth the effort due to its slowness and lack of support for detecting more common forms of heap corruption. Since there are third-party tools that can provide the same functionality at a lower or comparable performance cost, the solution is to simply remove safemalloc. Third-party tools can provide the same functionality at a lower or comparable performance cost. The removal of safemalloc also allows a simplification of the malloc wrappers, removing quite a bit of kludge: redefinition of my_malloc, my_free and the removal of the unused second argument of my_free. Since free() always check whether the supplied pointer is null, redudant checks are also removed. Also, this patch adds unit testing for my_malloc and moves my_realloc implementation into the same file as the other memory allocation primitives.
258 lines
8.2 KiB
C++
258 lines
8.2 KiB
C++
/* Copyright (C) 2005-2006 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "sql_priv.h"
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#include "sql_binlog.h"
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#include "sql_parse.h" // check_global_access
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#include "sql_acl.h" // *_ACL
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#include "rpl_rli.h"
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#include "base64.h"
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#include "slave.h" // apply_event_and_update_pos
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#include "log_event.h" // Format_description_log_event,
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// EVENT_LEN_OFFSET,
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// EVENT_TYPE_OFFSET,
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// FORMAT_DESCRIPTION_LOG_EVENT,
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// START_EVENT_V3,
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// Log_event_type,
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// Log_event
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/**
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Execute a BINLOG statement.
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To execute the BINLOG command properly the server needs to know
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which format the BINLOG command's event is in. Therefore, the first
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BINLOG statement seen must be a base64 encoding of the
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Format_description_log_event, as outputted by mysqlbinlog. This
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Format_description_log_event is cached in
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rli->description_event_for_exec.
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@param thd Pointer to THD object for the client thread executing the
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statement.
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*/
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void mysql_client_binlog_statement(THD* thd)
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{
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DBUG_ENTER("mysql_client_binlog_statement");
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DBUG_PRINT("info",("binlog base64: '%*s'",
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(int) (thd->lex->comment.length < 2048 ?
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thd->lex->comment.length : 2048),
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thd->lex->comment.str));
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if (check_global_access(thd, SUPER_ACL))
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DBUG_VOID_RETURN;
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size_t coded_len= thd->lex->comment.length + 1;
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size_t decoded_len= base64_needed_decoded_length(coded_len);
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DBUG_ASSERT(coded_len > 0);
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/*
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Allocation
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*/
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/*
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If we do not have a Format_description_event, we create a dummy
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one here. In this case, the first event we read must be a
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Format_description_event.
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*/
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my_bool have_fd_event= TRUE;
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int err;
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Relay_log_info *rli;
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rli= thd->rli_fake;
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if (!rli)
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{
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rli= thd->rli_fake= new Relay_log_info(FALSE);
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#ifdef HAVE_purify
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rli->is_fake= TRUE;
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#endif
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have_fd_event= FALSE;
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}
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if (rli && !rli->relay_log.description_event_for_exec)
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{
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rli->relay_log.description_event_for_exec=
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new Format_description_log_event(4);
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have_fd_event= FALSE;
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}
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const char *error= 0;
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char *buf= (char *) my_malloc(decoded_len, MYF(MY_WME));
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Log_event *ev = 0;
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/*
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Out of memory check
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*/
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if (!(rli &&
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rli->relay_log.description_event_for_exec &&
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buf))
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{
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my_error(ER_OUTOFMEMORY, MYF(0), 1); /* needed 1 bytes */
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goto end;
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}
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rli->sql_thd= thd;
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rli->no_storage= TRUE;
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for (char const *strptr= thd->lex->comment.str ;
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strptr < thd->lex->comment.str + thd->lex->comment.length ; )
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{
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char const *endptr= 0;
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int bytes_decoded= base64_decode(strptr, coded_len, buf, &endptr);
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#ifndef HAVE_purify
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/*
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This debug printout should not be used for valgrind builds
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since it will read from unassigned memory.
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*/
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DBUG_PRINT("info",
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("bytes_decoded: %d strptr: 0x%lx endptr: 0x%lx ('%c':%d)",
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bytes_decoded, (long) strptr, (long) endptr, *endptr,
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*endptr));
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#endif
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if (bytes_decoded < 0)
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{
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my_error(ER_BASE64_DECODE_ERROR, MYF(0));
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goto end;
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}
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else if (bytes_decoded == 0)
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break; // If no bytes where read, the string contained only whitespace
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DBUG_ASSERT(bytes_decoded > 0);
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DBUG_ASSERT(endptr > strptr);
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coded_len-= endptr - strptr;
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strptr= endptr;
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/*
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Now we have one or more events stored in the buffer. The size of
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the buffer is computed based on how much base64-encoded data
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there were, so there should be ample space for the data (maybe
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even too much, since a statement can consist of a considerable
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number of events).
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TODO: Switch to use a stream-based base64 encoder/decoder in
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order to be able to read exactly what is necessary.
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*/
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DBUG_PRINT("info",("binlog base64 decoded_len: %lu bytes_decoded: %d",
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(ulong) decoded_len, bytes_decoded));
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/*
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Now we start to read events of the buffer, until there are no
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more.
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*/
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for (char *bufptr= buf ; bytes_decoded > 0 ; )
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{
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/*
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Checking that the first event in the buffer is not truncated.
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*/
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ulong event_len= uint4korr(bufptr + EVENT_LEN_OFFSET);
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DBUG_PRINT("info", ("event_len=%lu, bytes_decoded=%d",
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event_len, bytes_decoded));
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if (bytes_decoded < EVENT_LEN_OFFSET || (uint) bytes_decoded < event_len)
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{
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my_error(ER_SYNTAX_ERROR, MYF(0));
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goto end;
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}
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/*
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If we have not seen any Format_description_event, then we must
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see one; it is the only statement that can be read in base64
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without a prior Format_description_event.
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*/
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if (!have_fd_event)
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{
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int type = bufptr[EVENT_TYPE_OFFSET];
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if (type == FORMAT_DESCRIPTION_EVENT || type == START_EVENT_V3)
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have_fd_event= TRUE;
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else
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{
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my_error(ER_NO_FORMAT_DESCRIPTION_EVENT_BEFORE_BINLOG_STATEMENT,
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MYF(0), Log_event::get_type_str((Log_event_type)type));
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goto end;
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}
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}
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ev= Log_event::read_log_event(bufptr, event_len, &error,
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rli->relay_log.description_event_for_exec);
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DBUG_PRINT("info",("binlog base64 err=%s", error));
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if (!ev)
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{
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/*
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This could actually be an out-of-memory, but it is more likely
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causes by a bad statement
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*/
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my_error(ER_SYNTAX_ERROR, MYF(0));
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goto end;
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}
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bytes_decoded -= event_len;
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bufptr += event_len;
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DBUG_PRINT("info",("ev->get_type_code()=%d", ev->get_type_code()));
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#ifndef HAVE_purify
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/*
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This debug printout should not be used for valgrind builds
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since it will read from unassigned memory.
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*/
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DBUG_PRINT("info",("bufptr+EVENT_TYPE_OFFSET: 0x%lx",
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(long) (bufptr+EVENT_TYPE_OFFSET)));
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DBUG_PRINT("info", ("bytes_decoded: %d bufptr: 0x%lx buf[EVENT_LEN_OFFSET]: %lu",
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bytes_decoded, (long) bufptr,
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(ulong) uint4korr(bufptr+EVENT_LEN_OFFSET)));
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#endif
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ev->thd= thd;
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/*
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We go directly to the application phase, since we don't need
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to check if the event shall be skipped or not.
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Neither do we have to update the log positions, since that is
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not used at all: the rli_fake instance is used only for error
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reporting.
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*/
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#if !defined(MYSQL_CLIENT) && defined(HAVE_REPLICATION)
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err= ev->apply_event(rli);
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#else
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err= 0;
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#endif
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/*
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Format_description_log_event should not be deleted because it
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will be used to read info about the relay log's format; it
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will be deleted when the SQL thread does not need it,
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i.e. when this thread terminates.
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*/
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if (ev->get_type_code() != FORMAT_DESCRIPTION_EVENT)
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delete ev;
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ev= 0;
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if (err)
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{
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/*
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TODO: Maybe a better error message since the BINLOG statement
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now contains several events.
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*/
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my_error(ER_UNKNOWN_ERROR, MYF(0), "Error executing BINLOG statement");
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goto end;
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}
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}
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}
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DBUG_PRINT("info",("binlog base64 execution finished successfully"));
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my_ok(thd);
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end:
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rli->slave_close_thread_tables(thd);
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my_free(buf);
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DBUG_VOID_RETURN;
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}
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