./databases/mysql80-server, MySQL 8, a free SQL database (server)

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Branch: CURRENT, Version: 8.0.36nb2, Package name: mysql-server-8.0.36nb2, Maintainer: pkgsrc-users

MySQL is a SQL (Structured Query Language) database server. SQL is the most
popular database language in the world. MySQL is a client-server implementation
that consists of a server daemon `mysqld' and many different client
programs/libraries.

The main goals of MySQL are speed and robustness.

The base upon which MySQL is built is a set of routines that have been used in
a highly demanding production environment for many years. While MySQL is still
in development it already offers a rich and highly useful function set.

The official way to pronounce 'MySQL' is 'My Ess Que Ell' (Not MY-SEQUEL).

This package contains the MySQL server programs and libraries including
embedded server (by PKG_OPTION).

DEINSTALL [+/-]
MESSAGE.sphinx [+/-]

Required to run:
[textproc/icu] [lang/perl5] [devel/zlib] [devel/libevent] [devel/protobuf] [archivers/lz4] [archivers/zstd] [lang/gcc8-libs] [databases/mysql80-client]

Required to build:
[lang/gcc8]

Master sites:


Version history: (Expand)


CVS history: (Expand)


   2024-04-05 16:01:01 by Thomas Klausner | Files touched by this commit (49)
Log message:
*: recursive bump for protobuf 26.1
   2024-02-16 23:01:10 by Adam Ciarcinski | Files touched by this commit (7) | Package updated
Log message:
mysql80: updated to 8.0.36

Changes in MySQL 8.0.36

Audit Log Notes

In some cases, calling audit_log_read( audit_log_read_bookmark() ) led to an Out \ 
of memory error.

Compilation Notes

Microsoft Windows: MySQL did not compile correctly using Visual Studio 2022.

Improved the -DWITH_ZLIB=system check.

For compiling on Linux, changed the no-error=deprecated-declarations flag to \ 
no-deprecated-declarations for the OpenSSL 3 library.

Our thanks to karry zhang for the contribution.

Optimizer Notes

The hashing algorithm employed yielded poor performance when using a HASH field \ 
to check for uniqueness.

Packaging Notes

Important Change: The GnuPG build key (A8D3785C) used to sign MySQL downloadable \ 
packages has been updated. The previous GnuPG build key (3A79BD29) expired on \ 
2023-12-14. For information about verifying the integrity and authenticity of \ 
MySQL downloadable packages using GnuPG signature checking, or to obtain a copy \ 
of our public GnuPG build key, see Signature Checking Using GnuPG.

Due to the GnuPG key update, systems configured to use repo.mysql.com may report \ 
a signature verification error when upgrading to MySQL 8.0.36 and higher or to \ 
MySQL 8.3.0 and higher using apt or yum. Use one of the following methods to \ 
resolve this issue:

Manually reinstall the MySQL APT or YUM repository setup package from \ 
https://dev.mysql.com/downloads/.

Download the MySQL GnuPG public key and add it your system GPG keyring.

Performance Schema Notes

When executing a stored program, the Performance Schema instrumentation caused \ 
some unnecessary overhead.

As of this release, all stored procedure micro instructions (statement/sp/%), \ 
except statement/sp/stmt, are disabled by default.

The performance of the Performance Schema statement instrumentation has been \ 
improved. Specifically, collecting MESSAGE_TEXT data is now more efficient.

Pluggable Authentication

Beginning with this release, the behavior of the AUTHENTICATION_PAM_LOG \ 
environment variable used in debugging the PAM authentication plugin is changed \ 
as follows:

Setting AUTHENTICATION_PAM_LOG to an arbitrary value (except as noted in the \ 
next item) no longer includes passwords in its diagnostic messages.

To include passwords in the diagnostic messages, set \ 
AUTHENTICATION_PAM_LOG=PAM_LOG_WITH_SECRET_INFO.

For more information, see PAM Authentication Debugging.

Functionality Added or Changed

Important Change: For platforms on which OpenSSL libraries are bundled, the \ 
linked OpenSSL library for MySQL Server has been updated to version 3.0.12. \ 
Issues fixed in OpenSSL version 3.0.12 are described at \ 
https://www.openssl.org/news/cl30.txt.

Bugs Fixed

InnoDB: The hash function used by the adaptive hash index (AHI) was improved to \ 
increase performance.

InnoDB: If change buffer entries are present during startup, a disabled \ 
innodb_validate_tablespace_paths option will no longer be enforced and instead \ 
the MySQL server will proceed to validate all tablespaces. Otherwise, secondary \ 
indexes could end up corrupted.

InnoDB: During concurrent DDL and DML operations, DDL could fail if the online \ 
log grew too large. Buffer handling was improved to prevent this issue.

Replication: An issue with calculating the current number of bytes used for \ 
Log_event events in Performance Schema memory instrumentation made it appear as \ 
though the sql/replica_sql thread on the replica grew endlessly and never \ 
decreased in size.

Replication: Stopping replication while replicating CREATE TABLE AS SELECT \ 
caused the server to exit.

Group Replication: A forced START GROUP_REPLICATION while a replication channel \ 
was in an error state could lead to an unplanned server exit.

For building Enterprise Linux 8 RPMs, the build scripts now point to a newer \ 
strip command (under /opt/rh/gcc-toolset-12), and they now check that the \ 
corresponding dwz tool is available.

In some cases, calling a loadable function installed by an improperly \ 
initialized plugin caused an unplanned shutdown.

Found and fixed an assertion failure at handler::ha_index_end() in handler.cc.

When the MYSQL_FIREWALL plugin was configured to use a custom schema, but failed \ 
to initialize properly during the server startup, subsequent errors and failures \ 
could occur.

Some nested queries with GROUP BY were not handled correctly.

References: This issue is a regression of:

In limited cases, passing data to the MD5() encryption function could halt the \ 
server.

Some subselects from views were not always handled correctly.

While performing an operation such as the bulk renaming of many tables, \ 
simultaneously executing a data definition statement similar to CREATE TABLE ... \ 
SELECT could stop the server unexpectedly.

UPDATE HISTOGRAM did not behave as expected in all cases.

UPDATE HISTOGRAM did not behave as expected in all cases.

EXPLAIN ANALYZE did not always produce the expected result.

An error occurred during subquery resolution.

References: This issue is a regression of:

Refreshing of used table information is now postponed to the start of the next \ 
execution, just after tables have been opened, and we know that all table \ 
objects are in a proper state.

Some HAVING queries did not produce expected results.

Some recursive CTEs did not function as expected.

Some queries using OVER (PARTITION ...) were not always executed successfully.

Some subqueries with ROLLUP were not always handled correctly.

Removed the CPACK_COMPONENT_GROUP_INFO_DISPLAY_NAME configuration option from \ 
the Windows installation MSI interface. Now the INFO_BIN and INFO_SRC files are \ 
always installed.

Some queries using windowing functions were not always handled correctly.

In debug builds, a case-altered column name could cause the server to exit.

MySQL Server installation packages contained two copies of the INFO_SRC file.

A SELECT statement within a prepared statement unexpectedly returned different \ 
results on successive executions.

References: This issue is a regression of:

Some SELECT DISTINCT queries were not always handled correctly.

Removed an assertion failure in sql/field.cc.

Sme queries having the form SELECT AVG(...) OVER (PARTITION BY ...) were not \ 
always handled correctly.

Upgrading MySQL using an official MySQL Yum or SUSE repository always enables \ 
the MySQL service. Now it enables the service only after installing, and \ 
preserves (and does not edit) the existing value while upgrading.

For a query with a derived condition pushdown where a column in the condition \ 
needs to be replaced, a matching item could not found, even when known to be \ 
present, when the replacement item was wrapped in a ROLLUP while the matching \ 
item was not.

References: This issue is a regression of:

Performing an arithmetic operation on the result over a window function in a \ 
stored procedure gave the correct result the first time the procedure was \ 
executed, but returned an incorrect result on all subsequent invocations.

References: See also:

MySQL did not build correctly using the musl version of libc.

Our thanks to Sam James for the contribution.

In some cases, selecting from a view leaked a small amount of memory.
   2023-11-15 19:14:46 by Thomas Klausner | Files touched by this commit (55)
Log message:
*: bump for protobuf 25
   2023-11-08 14:21:43 by Thomas Klausner | Files touched by this commit (2377)
Log message:
*: recursive bump for icu 74.1
   2023-11-02 13:20:06 by Thomas Klausner | Files touched by this commit (54)
Log message:
*: recursive bump for protobuf
   2023-10-25 00:11:51 by Thomas Klausner | Files touched by this commit (2298)
Log message:
*: bump for openssl 3
   2023-07-18 16:03:59 by Nia Alarie | Files touched by this commit (5)
Log message:
databases: Convert packages to using USE_(CC|CXX)_FEATURES
   2023-05-23 23:01:12 by Adam Ciarcinski | Files touched by this commit (13) | Package updated
Log message:
mysql80: updated to 8.0.33

8.0.33

Functionality Added or Changed

Important Change: For platforms on which OpenSSL libraries are bundled, the \ 
linked OpenSSL library for MySQL Server has been updated to version 1.1.1t. \ 
Issues fixed in OpenSSL version 1.1.1t are described at \ 
https://www.openssl.org/news/cl111.txt.

Replication: As part of ongoing work to change old terminology used in MySQL \ 
products, the terms “master”, “slave”, and “MTS” have been replaced \ 
in error messages relating to MySQL Replication by “source”, “replica”, \ 
and “MTA”, respectively. This includes all error messages listed in \ 
messages_to_clients.txt and messages_to_error_log.txt relating to replication; \ 
the present task does not perform this replacement for messages used in other \ 
contexts.

See the MySQL 8.0 Error Message Reference, for more information.

Replication: mysqlbinlog --start-position now accepts values up to \ 
18446744073709551615, unless the --read-from-remote-server or \ 
--read-from-remote-source option is also used, in which case the maximum is \ 
4294967295.

Binary packages that include curl rather than linking to the system curl library \ 
have been upgraded to use curl 7.88.1.

The use of a generated column with DEFAULT(col_name) to specify the default \ 
value for a named column is not permitted and now emits an error message.

Bugs Fixed

NDB Cluster: Occasional temporary errors which could occur when opening a table \ 
from the NDB dictionary while repeatedly performing concurrent schema operations \ 
were not retried.

NDB Cluster: During iteration, ordered index scans retain a cursor position \ 
within each concurrently scanned ordered index fragment. Ordered index fragments \ 
are modified and balanced as a result of committing DML transactions, which can \ 
require scan cursors to be moved within the tree. When running with query \ 
threads configured (AutomaticThreadConfig set to 1), multiple threads can access \ 
the same index fragment tree structure, and the scans of multiple threads can \ 
have their cursors present in the same structure.

The current issue arose due to an assumption in the logic for moving scan \ 
cursors when committing DML operations that all scan cursors belonged to the LDM \ 
thread owning the index fragment, which did not allow for the possibility that \ 
such fragments might belong to query threads.

InnoDB: Dead code removal.

InnoDB: Error messages related to innodb_doublewrite moved to the error log.

InnoDB: Prevent online DDL operations from accessing out-of-bounds memory.

InnoDB: ALTER TABLE ... AUTO_INCREMENT could be set to less than MAX + 1 and not \ 
forced to MAX + 1.

InnoDB: Innodb_data_pending_fsyncs could show extremely high inaccurate values \ 
because of a variable overflow.

Partitioning: Some IN() queries on partitioned tables were not always handled \ 
correctly.

Partitioning: Queries using the INDEX_MERGE optimizer hint was not handled \ 
correctly in all cases.

Replication: XA transactions whose XIDs contained null bytes could not be recovered.

Replication: When binlog_order_commits was set equal to 1, for any two \ 
transactions and for any sub-step of the commit phase, the transaction that was \ 
written to the binary log first did not always execute the sub-step first, as \ 
expected.

Replication: The binary log recovery process did not report all possible error \ 
states.

Replication: Following CHANGE REPLICATION SOURCE TO \ 
SOURCE_CONNECTION_AUTO_FAILOVER=1, failover generated a number of misleading \ 
warnings in the log that implied there were problems when in fact conditions \ 
were those expected for such a failover. These log messages have been updated \ 
accordingly.

Replication: When a transaction failed, as a side effect, extraneous error \ 
messages relating the replication data repositories were written to the log. Now \ 
in such cases, we suppress such error messages, which are not directly related \ 
to the issue of the failed transaction or its cause.

Replication: Setting binlog_order_commits to OFF could lead to a missed GTID in \ 
the next binary log file's Previous_gtids event.

Our thanks to Yewei Xu and the Tencent team for the contribution.

Replication: Corrected the SQL statements suggested in the error message text \ 
for ER_RPL_REPLICA_ERROR_RUNNING_QUERY.

Our thanks to Dan McCombs for the contribution.

Replication: A hash scan builds a hash of changes, scans the target table or \ 
index, and applies any matching change for the current entry. In the build \ 
phase, it uses only the before image, and skips any after image. Problems arose \ 
in some cases because generated columns were computed for the (skipped) after \ 
image, leading to replication errors. This is fixed by not computing generated \ 
columns any longer for seek-only calls such as hash scans.

Our thanks to dc huang for the contribution.

Replication: In certain rare cases, it was possible to set gtid_mode=OFF for one \ 
session while another session, after WAIT_FOR_EXECUTED_GTID_SET() was issued by \ 
a user in this second session, was still waiting for the next GTID set from the \ 
first session. This could result in the second session waiting indefinitely for \ 
the function to return.

Group Replication: Accessing the Performance Schema \ 
replication_group_communication_information and replication_group_member_stats \ 
tables in parallel sometimes caused subsequent group replication operations to \ 
hang.

Group Replication: In certain cases, the group replication secondary node \ 
unexpectedly shut down while purging the relay log.

Group Replication: When shutting down the Group Replication plugin, the order in \ 
which the associated events were reported the error log sometimes led to \ 
confusion. To remove any doubts, we now make sure that Plugin group_replication \ 
reported: 'Plugin 'group_replication' has been stopped. is in fact the last log \ 
message relating to the shutdown, written only when all other events associated \ 
with shutting down the plugin have been logged.

Microsoft Windows: The authentication_fido_client plugin stopped responding \ 
during the authentication process if it was unable to find a FIDO device on the \ 
Windows client host.

In certain cases, CONVERT(utf8mb3_column USING UTF16) was rejected with the \ 
error Cannot convert string '\x--...' from binary to utf16.

When joining two tables on a string column, and the column from one of the \ 
tables has an additional predicate comparing it with a temporal literal, \ 
constant propagation in some cases incorrectly caused the join condition to be \ 
modified such that it used temporal rather than string semantics when comparing \ 
the strings. This caused incorrect results to be returned from the join.

Error messages returned after calling the mysql_reset_connection() C API \ 
function in a prepared statement did not identify the function name properly.

Fixed a regression in a previous fix for an issue with windowing functions.

Our thanks to Dmitry Lenev for the contribution.

When replacing subqueries in transforms, the internal flag showing whether a \ 
given query block contains any subqueries (PROP_SUBQUERY) was not updated \ 
afterwards.

A client setting the character set to an impermissible client character set \ 
(ucs2, utf16, utf16le, or utf32) could cause unexpected behavior when the client \ 
used an authentication plugin.

EXPLAIN ANALYZE displayed 0 when the average number of rows was less than 1. To \ 
fix this, we now format numbers in the output of EXPLAIN ANALYZE and EXPLAIN \ 
FORMAT=TREE such that numbers in the range 0.001-999999.5 are printed as decimal \ 
numbers, and numbers outside this range are printed using engineering notation \ 
(for example: 1.23e+9, 934e-6). In addition, trailing zeroes are no longer \ 
printed, and numbers less than 1e-12 are printed as 0.

This helps ensure consistent precision regardless of the number's value and \ 
improve readability, while producing minimal rounding errors.

The NTILE() function did not work correctly in all cases.

Some joins on views did not perform correctly.

Transforming a correlated scalar subquery to a derived table led to a wrong \ 
result for InnoDB tables when the subquery included duplicate predicates. An \ 
example of a query which could be affected by this issue is shown here:

SELECT * FROM t1
WHERE (
  SELECT t2.a FROM t2
  WHERE t2.a = t1.a AND t2.a = t1.a
    ) > 0;

Fixed an assert in sql/item_strfunc.cc that could potentially lead to issues \ 
with the SPACE() function.

Using ROW_COUNT() as the length argument to LPAD() or RPAD() did not perform as \ 
expected.

A query with a window function having an expression with a CASE function in its \ 
ORDER BY clause could lead to a server exit.

The fix for a previous issue introduced an assertion in debug builds when \ 
optimizing a HAVING clause.

When using mysqld_multi, the system that obscures "--password" usage \ 
as "--password=*****" would also match "--password-history" \ 
and "--password-require-current" definitions as \ 
"--password", but now explicitly checks for "--password=" \ 
instead.

In some cases, calling the mysql_bind_param() C API function could cause the \ 
server to become unresponsive.

The authentication_oci_client plugin was unable to open a valid configuration \ 
file if any of its entries contained an equals sign character separated by \ 
spaces (for example, key_file = /home/user/.oci/oci_api_key.pem). Now, both \ 
'key=value' and 'key = value' entry formats are supported.

Incorrect results were returned when the result of an INTERSECT or EXCEPT \ 
operation was joined with another table. This issue affected these operations in \ 
such cases when used with either DISTINCT or ALL.

When preparing a view query, the operation used the system character set \ 
(instead of the character set stored in data dictionary) and then reported an \ 
invalid character-string error.

Prepared statements that operate on derived tables, including views, could stop \ 
unexpectedly due to problems with the code for reopening tables after an error.

Removed an assertion raised in certain cases by the RANDOM_BYTES() function in \ 
debug builds.

There was an issue in how persisted variables were set on startup, causing \ 
certain variables not to get properly set to their persisted value.

The MAKETIME() function did not perform correctly in all cases.

Some functions with multiple arguments did not produce the expected results.

A table reference in an ORDER BY outside the parenthesized query block in which \ 
the table was used, and which query block had no LIMIT or ORDER BY of its own, \ 
raised an error.

A left join with an impossible condition as part of an ON clause was not \ 
optimized as in MySQL 5.7, so that in MySQL 8.0, the query executed more quickly \ 
without the impossible condition than with it. An example of such a query, \ 
impossible condition included, is SELECT * FROM t1 JOIN t2 ON t1.c1=t2.c1 AND \ 
1=2.

When a user defined function was part of a derived table that was merged into \ 
the outer query block, or was part of a subquery converted to a semi-join, \ 
knowledge of whether this UDF was deterministic (or not) was lost during \ 
processing.

With JSON logging enabled and an event subclass specified in the audit log \ 
filter definition, an empty item ("" : { }) was appended to the end of \ 
the logged event.

Some subqueries did not execute properly.

After the asymmetric_encrypt() component function in a SELECT query encountered \ 
a NULL field to decrypt, it could return NULL values for other non-NULL \ 
encrypted fields.

The server did not always shut down cleanly after uninstalling the audit log plugin.

Certain antijoins were not handled correctly by the server.

When the MySQL 5.7 Optimizer has 2 choices for an index to filter rows, one \ 
primary and one secondary, it picks a range scan on the secondary index because \ 
the range scan uses more key parts. MySQL 8.0 did not use this logic, instead \ 
choosing the primary index to filter rows with WHERE clause filtering. Primary \ 
key use is not suitable in such cases due to the presence of LIMIT, and due to \ 
the nature of data distribution. The secondary index was not considered while \ 
resolving order by due to constant elimination. This resulted in much different \ 
query plans in MySQL 5.7 and MySQL 8.0 for the same query.

We solve this issue in MySQL 8.0 by skipping the constant key parts of the index \ 
during order-by evaluation only if the query is constant-optimized, which can be \ 
done at this time, but not during LIMIT analysis.

The MySQL data dictionary caches failed lookups of se_private_id values (IDs \ 
which are not found), which speeds up execution of code specific to InnoDB, \ 
relying on the fact that InnoDB does not reuse these IDs. This assumption does \ 
not necessarily hold for other storage engines, most notably NDB, where this \ 
problem was resolved previously by not using this cache.

We extend the previous fix made for NDB so that the cache lookup is now employed \ 
only when the table uses the InnoDB storage engine.

Unexpected results were seen in some queries using DENSE_RANK(), possibly with \ 
the addition of WITH ROLLUP.

Fixed an assert raised in sql/sql_tmp_table.cc following work done previously to \ 
reimplement ROLLUP processing.

Some CTEs that did not use any tables were not always handled correctly.

Accessing rows from a window frame of a window function call present only in the \ 
query's ORDER BY list raised an error.

PERCENT_RANK() used with ORDER BY column did not return the correct result.

The --exclude-tables and --include-tables mysqlpump options did not handle views.

Changed the MySQL systemd service unit configuration from \ 
After=network-online.target to Wants=network-online.target to ensure that all \ 
configured network devices are available and have an IP address assigned before \ 
the service is started.

AVG(...) OVER (ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING) did not return \ 
the correct result.

A query of the form SELECT 1 FROM t1 WHERE NOT EXISTS (VALUES ROW(1), ROW(2)) \ 
caused an assert in debug builds when the subquery_to_derived optimizer switch \ 
was enabled.

mysqlimport did not escape reserved word table names when used with the --delete \ 
option.

When cloning a condition to push down to a derived table, characters in strings \ 
representing conditions were converted to utfmb4 correctly only for values less \ 
than 128 (the ASCII subset), and code points outside the ASCII subset were \ 
converted to invalid characters, causing the resulting character strings to \ 
become invalid. For derived tables without UNION, this led to problems when a \ 
column name from the derived table used characters outside the ASCII subset, and \ 
was used in the WHERE condition. For derived tables with UNION, it created \ 
problems when a character outside the ASCII subset was present in a WHERE \ 
condition.

We fix these issues by initializing the string used for representing the \ 
condition in such cases to the connection character set.

Using --single-transaction with mysqldump version 8.0.32 required either the \ 
RELOAD or FLUSH_TABLES privilege. This requirement now applies only when both \ 
gtid_mode=ON (default OFF) and with --set-gtid-purged = ON|AUTO (default AUTO).

Fixed a number of issues present in the internal documentation for the scramble \ 
generator algorithm in sha256_scramble_generator.cc and sha2_password_common.cc.

Our thanks to Niklas Keller for the contribution.

CREATE USER IF NOT EXISTS added a password history entry even when the user \ 
already existed and the password was not updated. This caused a subsequent ALTER \ 
USER statement to be rejected.

Many joins using eq_ref access did not perform as well as in previous versions. \ 
This issue was first reported in MySQL 8.0.29.

A hash outer join sometimes incorrectly matched NULL with a decimal zero or an \ 
empty string that used a non-padding collation, leading to erroneous results.

An object used internally by ALTER INSTANCE RELOAD TLS was not freed until the \ 
number of readers reached 0, under the assumption is that the number of readers \ 
should reach 0 fairly frequently. The read lock held during an SSL handshake is \ 
generally an expensive operation, with network calls, so when roundtrips between \ 
the client and the server took excessively long, the lock was held for a \ 
relatively long amount of time. This meant that, when changing the value of this \ 
object and there were a sufficient number of incoming SSL connections being \ 
made, the number of readers might not reach 0 in a reasonable length of time, \ 
leaving the thread holding the lock using 100% of the CPU until the lock was \ 
released.

We fix this by adding a wait after setting the pointer to this object to a new \ 
value, but before releasing the old object.

Our thanks to Sinisa Milivojevic for the contribution.

If mysqldump or mysqlpump could not convert a field's default value to UTF-8 \ 
(for instance, if the field was of type BINARY and the default value did not \ 
coincide with valid UTF-8), the operation produced results that were not valid \ 
to import. Further, using the --hex-blob option did not resolve the issue. We \ 
now convert the default value to the system character set. If this fails, the \ 
server sends the value as hexadecimal instead to make it more human-readable.

A connection using the C API (libmysqlclient) client library could fail with the \ 
FUTURE crypto policy.

While cloning a temporary table for a common table expression which used shared \ 
materialization, the cloned temp table was not marked as using hash \ 
deduplication, leading to wrong results. We now set the hash field for the \ 
cloned temporary table correctly, and update the hidden field count to take this \ 
into account.

CREATE EVENT and ALTER EVENT assumed that all values passed to them (other than \ 
in a DO clause) resolved as scalars without actually checking the values. This \ 
led to assertions when any such values actually rows.

We now perform an explicit check for the number of columns when resolving such \ 
items, and report an error when one produces a row and not a scalar value.

A view reference whose underlying field is a constant is not marked as constant \ 
when the reference is part of an inner table of an outer join. It was found \ 
that, when pushing a condition down to a derived table, the reference was \ 
stripped off and only the underlying field was cloned, which made it a constant, \ 
and led to wrong results.

To fix this problem, we ensure that we do not push such a condition down to the \ 
derived table by adding a check to see first whether the table used by the \ 
condition matches the derived table or is a constant expression; only when it is \ 
one or the other of these do we actually push the condition down.