# Contrib Modules > Changes to contrib extensions and the modules covered by the source document. --- LLMS index: [llms.txt](/en/llms.txt) ---
GASource pages: PDF 89-95Original PDF on GitHub

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Describes new features related to the Contrib modules. #### 3.5.1 Auto_explain {#pg16-3-5-1-auto-explain} The following features have been added to the auto_explain: [[d4bfe41](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=d4bfe41281705c1bcb7093b3d07ce5ff1114341b), [9d2d972](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=9d2d9728b8d546434aade4f9667a59666588edd6)] ##### Parameter log_parameter_max_length {#pg16-p89-parameter-log-parameter-max-length} Add the log_parameter_max_length parameter. This parameter limits the maximum log output width. The default value is -1, which imposes no limit. Specifying 0 for this parameter disables logging. ##### Output of the query ID {#pg16-p89-output-of-the-query-id} The query ID is output if the parameter auto_explain.log_verbose is set to 'on' and compute_query_id is set to 'on'. **Example 103.** Output of the query ID ```sql $ tail -5 data/log/ postgresql-2023-09-16_135719.log LOG: duration: 0.005 ms plan: Query Text: SELECT 1; Result (cost=0.00..0.01 rows=1 width=4) Output: 1 Query Identifier: -1801652217649936326 ``` #### 3.5.2 Fuzzystrmatch {#pg16-3-5-2-fuzzystrmatch} The daitch_mokotoff function has been added to the fuzzystrmatch module. This function is superior to the SOUNDEX function for non-English languages. [[a290378](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=a290378a3752f787cdc2252889ba513f6fb393db)] **Example 104.** Execute the daitch\_mokotoff function ```text postgres=> SELECT daitch_mokotoff('Müller') ; daitch_mokotoff ----------------- {479000} (1 row) ```

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#### 3.5.3 Ltree {#pg16-3-5-3-ltree} Hyphens (-) are now allowed in labels. Previously, only letters, numbers, and underlines (_) were permitted. The maximum label size has been increased from 255 to 1,000 characters. [[b1665bf](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=b1665bf01e5f4200d37addfc2ddc406ff7df14a5)] #### 3.5.4 Pageinspect {#pg16-3-5-4-pageinspect} The following features have been added to the pageinspect: [[1fd3dd2](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1fd3dd2048991a164c287dc29fdb78b1f7e6e14e), [3581cbd](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=3581cbdcd6), [428c0ca](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=428c0cae929b7d2b26a830fbba55619c57ceba55)] ##### Bt_multi_page_stats function {#pg16-p90-bt-multi-page-stats-function} Add function bt_multi_page_stats to print B-Tree index page summaries. This function is the multipage version of the bt_page_stats function. Specify the first block number and number of pages. **Example 105.** Execute the bt\_multi\_page\_stats function ```text postgres=# SELECT * FROM bt_multi_page_stats('idx1_data1', 2, 1) ; -[ RECORD 1 ]-+----- blkno | 2 type | l live_items | 367 dead_items | 0 avg_item_size | 16 page_size | 8192 free_size | 808 btpo_prev | 1 btpo_next | 4 btpo_level | 0 btpo_flags | 1 ``` ##### Brin_page_items function {#pg16-p90-brin-page-items-function} The "empty" column has been added to the output of the brin_page_items function to indicate free blocks. #### 3.5.5 Pg_buffercache {#pg16-3-5-5-pg-buffercache} The following functions have been added to the pg_buffercache module. [[f3fa313](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=f3fa31327ecba75ee0e946abaa56dbf471ba704b), [f3fa313](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=f3fa31327ecba75ee0e946abaa56dbf471ba704b)]

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##### Pg_buffercache_summary function {#pg16-p91-pg-buffercache-summary-function} Add the pg_buffercache_summary function that can check buffer cache summary by SQL statement. **Example 106.** Execute the pg\_buffercache\_summary function ```text postgres=# SELECT * FROM pg_buffercache_summary() ; -[ RECORD 1 ]--+------------------- buffers_used | 251 buffers_unused | 16133 buffers_dirty | 62 ``` ```text https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=2589434ae0fbfe08e46b6a4ffba4001 ``` ```text buffers_pinned | 0 ``` ```text 40b636074 ``` ```text usagecount_avg | 3.3346613545816735 ``` **Table 35.** Results of the pg\_buffercache\_summary function | Column name | Description | Note | | --- | --- | --- | | buffers_usedbuffers_unusedbuffers_dirtybuffers_pinnedusagecount_avg | Total number of buffers used Number of free buffers Number of dirty buffers Number of pinned buffers Average amount of dirty buffers used | | ##### Pg_buffercache_usage_counts function {#pg16-p91-pg-buffercache-usage-counts-function} Returns a summary of the state of all shared buffers. It is easier to check the information than by aggregating the pg_buffercache view. **Example 107.** Execute the pg\_buffercache\_usage\_counts function ```text postgres=# SELECT * FROM pg_buffercache_usage_counts() ; usage_count | buffers | dirty | pinned -------------+---------+-------+-------- 0 | 16035 | 0 | 0 1 | 76 | 6 | 0 2 | 31 | 1 | 0 3 | 13 | 6 | 0 4 | 8 | 3 | 0 5 | 221 | 48 | 0 (6 rows) ```

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#### 3.5.6 Pg_stat_statements {#pg16-3-5-6-pg-stat-statements} Updated how SQL statements are generalized. SET statements, CHECKPOINT statements, CREATE statements, etc. are collected as the same query ID regardless of case. [[9ba37b2](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=9ba37b2cb6a174b37fc51d0649ef73e56eae27fc), [daa8365](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=daa8365a900729fe2a8d427fbeff19e763e35723)] **Example 108.** Select the pg\_stat\_statements view ```text postgres=> SET enable_seqscan = off ; SET postgres=> set enable_seqscan = off ; SET postgres=> CHECKPOINT ; CHECKPOINT postgres=> checkpoint ; CHECKPOINT postgres=> SELECT queryid, query FROM pg_stat_statements WHERE userid=16384 ; queryid | query ----------------------+-------------------------- -4537744274534392533 | SET enable_seqscan = off -7184411855217750948 | CHECKPOINT (2 rows) ``` #### 3.5.7 Pg_walinspect {#pg16-3-5-7-pg-walinspect} Add the pg_get_wal_block_info function. This function extracts a full-page image between specified LSNs. [[c31cf1c](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=c31cf1c03d01ce86f20bef8c980fe56a257b3b4b), [9ecb134](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=9ecb134a93f0a82540b0e0bed67b30d0c9eb836a), [122376f](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=122376f028a0e31b91d6c6bad2a9a6e994708547)] #### Syntax 17 - Pg_get_wal_block_info function {#pg16-syntax-17} ```sql record pg_get_wal_block_info(start_lsn pg_lsn, end_lsn pg_lsn, show_data boolean) ```

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**Example 109.** Execute the pg\_get\_wal\_block\_info function ```text postgres=# SELECT start_lsn, relfilenode, relblocknumber, record_type FROM pg_get_wal_block_info('1/7E25EA98', '1/7E25EB98', false) ; start_lsn | relfilenode | relblocknumber | record_type ------------+-------------+----------------+------------- 1/7E25EAA0 | 33253 | 5405 | INSERT 1/7E25EAE8 | 33254 | 2744 | INSERT_LEAF 1/7E25EB28 | 33255 | 788 | INSERT_LEAF (3 rows) ``` ```text Executing this function will return the following information: ``` **Table 36.** Return value of the pg\_get\_wal\_block\_info function | Column name | Data type | Description | Note | | --- | --- | --- | --- | | start_lsn | pg_lsn | Start LSN | | | end_lsn | pg_lsn | End LSN | | | prev_lsn | pg_lsn | Previous LSN | | | block_id | smallint | Block ID | | | reltablespacereldatabase | oid | OID of the tablespace | | | | oid | OID of the database | | | relfilenoderelforknumber | oid | OID of the relation file node | | | | smallint | Relation fork number | | | relblocknumberxid | bigint | Block number of the table | | | | xid | Transaction ID | | | resource_managerrecord_type | text | Resource manager name | | | | text | WAL record type | | | record_lengthmain_data_length | integer | WAL record length | | | | integer | Main data length | | | block_data_lengthblock_fpi_length | integer | Block data length | | | | integer | Block FPI data length | | | block_fpi_infodescription | text[] | Block FPI information | | | | text | Description | | | block_datablock_fpi_data | bytea | Block data | | | | bytea | FPI data | |

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#### 3.5.8 Postgres_fdw {#pg16-3-5-8-postgres-fdw} The following enhancements have been implemented in the postgres_fdw module. [[97da482](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=97da48246d34807196b404626f019c767b7af0df), [8ad51b5](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=8ad51b5f446b5c19ba2c0033a0f7b3180b3b6d95), [983ec23](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=983ec23007bd83a649af9bc823f13feb0da27e0e)] ##### COPY FROM statement {#pg16-p94-copy-from-statement} The COPY FROM statement now uses the foreign table's batch_size option. Below is the log using the log_statement parameter for the instance that owns the table. It can be confirmed that multiple records are inserted in batch. **Example 110.** Execution log on the external table side ```sql LOG: statement: START TRANSACTION ISOLATION LEVEL REPEATABLE READ LOG: statement: TRUNCATE public.data1 CONTINUE IDENTITY RESTRICT LOG: statement: COMMIT TRANSACTION LOG: statement: START TRANSACTION ISOLATION LEVEL REPEATABLE READ LOG: execute pgsql_fdw_prep_7: INSERT INTO public.data1(c1, c2) VALUES ($1, $2), ($3, $4), ($5, $6), ($7, $8) DETAIL: parameters: $1 = '1', $2 = 'data1', $3 = '2', $4 = 'data2', $5 = '3', $6 = 'data3', $7 = '4', $8 = 'data4' LOG: statement: DEALLOCATE pgsql_fdw_prep_7 LOG: statement: COMMIT TRANSACTION ``` ##### Analyze_sampling option {#pg16-p94-analyze-sampling-option} The analyze_sampling option has been added to FOREIGN SERVER and FOREIGN TABLE. Previous versions fetched the entire foreign table record for statistics. The load on the remote database can be reduced by using the TABLESAMPLE clause when retrieving information from external tables. The default value is auto, which is assumed to be random for PostgreSQL < 9.5 and bernoulli for PostgreSQL 9.5 and higher. The values that can be set are as follows. **Table 37.** Possible values for the analyze\_sampling option | auto | version (default value) | | --- | --- | | random | Sampling is done using the random function. | | system | Sampling is done using the TABLESAMPLE SYSTEM clause. | | bernoulli | Sampling is done using the TABLESAMPLE BERNOULLI clause. | Value Description Off Do not sample.

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**Example 111.** Execute the ANALYZE statement ```text postgres=> CREATE FOREIGN TABLE foreign1(c1 INT, c2 VARCHAR(10)) SERVER remsvr1 OPTIONS (analyze_sampling 'bernoulli', table_name 'data1') ; CREATE FOREIGN TABLE postgres=> ANALYZE VERBOSE foreign1 ; INFO: analyzing "public.foreign1" INFO: "foreign1": table contains 1000000 rows, 30000 rows in sample ANALYZE ``` ```text No sampling is performed if no ANALYZE statement is executed on the source table of the external table. ``` ##### Parallel_abort option {#pg16-p95-parallel-abort-option} Postgres_fdw aborts remote transactions one at a time if it aborts the local transaction. Setting the option parallel_abort to 'true' aborts remote transactions in parallel, improving performance. The default value for this option is 'false'.