This commit improves the tests of pg_walinspect on a few things:
- Remove aggregates for queries that should fail. If the code is
reworked in such a way that the behavior of these queries is changed,
we would get more input from them, written this way.
- Expect at least one record reported in the valid queries doing scans
across ranges, rather than zero records.
- Adjust a few comments, for consistency.
Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACVaoXW3nJD9zq8E66BEf-phgJfFcKRVJq9GXkuX0b3ULQ@mail.gmail.com
This commit reworks a bit the set-returning functions of pg_walinspect,
making them more flexible regarding their end LSN:
- pg_get_wal_records_info()
- pg_get_wal_stats()
- pg_get_wal_block_info()
The end LSNs given to these functions is now handled so as a value
higher than the current LSN of the cluster (insert LSN for a primary, or
replay LSN for a standby) does not raise an error, giving more
flexibility to monitoring queries. Instead, the functions return
results up to the current LSN, as found at the beginning of each
function call.
As an effect of that, pg_get_wal_records_info_till_end_of_wal() and
pg_get_wal_stats_till_end_of_wal() are now removed from 1.1, as the
existing, equivalent functions are able to offer the same
possibilities.
Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACU0_q-o4DSweyaW9NO1KBx-QkN6G_OzYQvpjf3CZVASkg@mail.gmail.com
The regression tests of pg_walinspect are reworked on a few aspects:
- Reorganization on the validation checks done for the start and end
LSNs on the six SQL functions currently available in 1.1.
- Addition of a few patterns doing bound checks for invalid start LSN,
invalid end LSN, and failures in reading LSN positions, for anything
that's been missing.
- Use of a consistent style across the whole, limiting blank lines
across the queries.
- Addition of a new test script for upgrades. For the time being, this
is straight-forward with a check that the upgrade from 1.0 works
correctly. This will be made more complicated once the interface of
this extension is reworked in 1.1 with a follow-up patch.
Most of the contents of this commit are extracted from a larger patch by
the same author, largely reorganized by me to minimize the differences
with the upcoming work aimed to lift the bound checks on the input LSNs
used by the functions of this extension.
Author: Bharath Rupireddy, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACU0_q-o4DSweyaW9NO1KBx-QkN6G_OzYQvpjf3CZVASkg@mail.gmail.com
This commit reworks pg_get_wal_fpi_info() to become aware of all the
block information that can be attached to a record rather than just its
full-page writes:
- Addition of the block id as assigned by XLogRegisterBuffer(),
XLogRegisterBlock() or XLogRegisterBufData().
- Addition of the block data, as bytea, or NULL if none. The length of
the block data can be guessed with length(), so there is no need to
store its length in a separate field.
- Addition of the full-page image length, as counted without a hole or
even compressed.
- Modification of the handling of the full-page image data. This is
still a bytea, but it could become NULL if none is assigned to a block.
- Addition of the full-page image flags, tracking if a page is stored
with a hole, if it needs to be applied and the type of compression
applied to it, as of all the BKPIMAGE_* values in xlogrecord.h.
The information of each block is returned as one single record, with the
record's ReadRecPtr included to be able to join the block information
with the existing pg_get_wal_records_info(). Note that it is perfectly
possible for a block to hold both data and full-page image.
Thanks also to Kyotaro Horiguchi and Matthias van de Meent for the
discussion.
This commit uses some of the work proposed by Melanie, though it has
been largely redesigned and rewritten by me. Bharath has helped in
refining a bit the whole.
Reported-by: Melanie Plageman
Author: Michael Paquier, Melanie Plageman, Bharath Rupireddy
Discussion: https://postgr.es/m/CAAKRu_bORebdZmcV8V4cZBzU8M_C6tDDdbiPhCZ6i-iuSXW9TA@mail.gmail.com
This function is able to extract the full page images from a range of
records, specified as of input arguments start_lsn and end_lsn. Like
the other functions of this module, an error is returned if using LSNs
that do not reflect real system values. All the FPIs stored in a single
record are extracted.
The module's version is bumped to 1.1.
Author: Bharath Rupireddy
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/CALj2ACVCcvzd7WiWvD=6_7NBvVB_r6G0EGSxL4F8vosAi6Se4g@mail.gmail.com
There are still some alignment-related failures in the buildfarm,
which might or might not be able to be fixed quickly, but I've also
just realized that it increased the size of many WAL records by 4 bytes
because a block reference contains a RelFileLocator. The effect of that
hasn't been studied or discussed, so revert for now.
RelFileNumbers are now assigned using a separate counter, instead of
being assigned from the OID counter. This counter never wraps around:
if all 2^56 possible RelFileNumbers are used, an internal error
occurs. As the cluster is limited to 2^64 total bytes of WAL, this
limitation should not cause a problem in practice.
If the counter were 64 bits wide rather than 56 bits wide, we would
need to increase the width of the BufferTag, which might adversely
impact buffer lookup performance. Also, this lets us use bigint for
pg_class.relfilenode and other places where these values are exposed
at the SQL level without worrying about overflow.
This should remove the need to keep "tombstone" files around until
the next checkpoint when relations are removed. We do that to keep
RelFileNumbers from being recycled, but now that won't happen
anyway. However, this patch doesn't actually change anything in
this area; it just makes it possible for a future patch to do so.
Dilip Kumar, based on an idea from Andres Freund, who also reviewed
some earlier versions of the patch. Further review and some
wordsmithing by me. Also reviewed at various points by Ashutosh
Sharma, Vignesh C, Amul Sul, Álvaro Herrera, and Tom Lane.
Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com
Michael Paquier
Robert Haas
Jeff Davis