MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
This table shows statistical information for transaction payloads written to the binary log and relay log, and can be used to calculate the effects of enabling binary log transaction compression. For information on binary log transaction compression, see Section 7.4.4.5, “Binary Log Transaction Compression”.
The
binary_log_transaction_compression_stats
table is populated only when the server instance has a binary
log, and the system variable
binlog_transaction_compression
is set to ON. The statistics cover all
transactions written to the binary log and relay log from the
time the server was started or the table was truncated.
Compressed transactions are grouped by the compression
algorithm used, and uncompressed transactions are grouped
together with the compression algorithm stated as
NONE, so the compression ratio can be
calculated.
The
binary_log_transaction_compression_stats
table has these columns:
LOG_TYPE
Whether these transactions were written to the binary log or relay log.
COMPRESSION_TYPE
The compression algorithm used to compress the transaction
payloads. NONE means the payloads for
these transactions were not compressed, which is correct
in a number of situations (see
Section 7.4.4.5, “Binary Log Transaction Compression”).
TRANSACTION_COUNTER
The number of transactions written to this log type with this compression type.
COMPRESSED_BYTES
The total number of bytes that were compressed and then written to this log type with this compression type, counted after compression.
UNCOMPRESSED_BYTES
The total number of bytes before compression for this log type and this compression type.
COMPRESSION_PERCENTAGE
The compression ratio for this log type and this compression type, expressed as a percentage.
FIRST_TRANSACTION_ID
The ID of the first transaction that was written to this log type with this compression type.
FIRST_TRANSACTION_COMPRESSED_BYTES
The total number of bytes that were compressed and then written to the log for the first transaction, counted after compression.
FIRST_TRANSACTION_UNCOMPRESSED_BYTES
The total number of bytes before compression for the first transaction.
FIRST_TRANSACTION_TIMESTAMP
The timestamp when the first transaction was written to the log.
LAST_TRANSACTION_ID
The ID of the most recent transaction that was written to this log type with this compression type.
LAST_TRANSACTION_COMPRESSED_BYTES
The total number of bytes that were compressed and then written to the log for the most recent transaction, counted after compression.
LAST_TRANSACTION_UNCOMPRESSED_BYTES
The total number of bytes before compression for the most recent transaction.
LAST_TRANSACTION_TIMESTAMP
The timestamp when the most recent transaction was written to the log.
The
binary_log_transaction_compression_stats
table has no indexes.
TRUNCATE TABLE is permitted for
the
binary_log_transaction_compression_stats
table.